How to melt a beer can at home. How to pour molten aluminum into a mold, does it need to be heated so that the metal is homogeneous? Benefits from recycling and environmental benefits

Today we will look at a way to melt aluminum cans using a simple small melting furnace at home. This time we're using our high-tech backyard and a bucket of soda or beer cans. To make crafts from aluminum, or rather from cans, let's start by getting ours, which was already made earlier, and a large bag of coal briquettes. They are commonly used for barbecues. When several coals are distributed at the bottom of the smelter, a crucible made from a steel fire extinguisher can be added.

Just look what they sell in this Chinese store.

If you place the crucible on a layer of coal, they will melt faster. Now we connect the steel tube through the air supply hole. This will provide enough temperature for melting, but we still need to find a way to get air inside. A household hair dryer, which can be bought at any store, is perfect for this.

Let's connect the hair dryer to a piece of PVC pipe, using two three-centimeter couplings to attach the steel tube on one side and make it easier to disconnect the hair dryer on the other. The entire structure is very easy to disassemble and place in a 20 liter bucket.

The blower is at the right angle, it doesn't hurt to prop it up so it doesn't move away. This way you will keep the walls intact and significantly increase the service life of the smelter. Now that the smelter is ready, let's fill it to the top with coal. You can use a propane torch because it heats everything up very quickly. The coals are burning, so let's turn the hairdryer on low and blast the oxygen into the coals to really heat everything up. As you can see, the lid we made retains the heat and the temperature rises. The crucible and the holes in the center of the lid are precisely adjusted.

Now let's take aluminum cans prepared for melting and steel tongs. After 10 minutes the smelter is extremely hot. You can see that the steel crucible glows orange, which means everything is ready. The crucible is 8 centimeters in diameter and is therefore perfect for melting drink cans and at temperatures over 500 degrees Celsius they melt in just a couple of seconds. Let's bring the smelter's power to full to melt everything as quickly as possible. The productivity of the device is on average 10-12 cans per minute.

The nice thing is that the cans can be dirty and painted, with the remains of soda. No matter, as we will soon see, the mini-smelter absorbs everything and produces pure liquid aluminum. According to experience, 35-45 cans are enough to produce 450 grams of aluminum. If you crush the jars first, you don’t even have to remove the lid, which means that even less metal will oxidize during melting. After melting 50 cans, the crucible is full, but there is a lot of waste inside that we don’t need.

A good way to insulate aluminum is to use a steel form. To begin, carefully remove the crucible, making sure that you grip it very securely with steel tongs. Then very slowly pour the melt into a steel mold. As you can see, the slag remains in the shade or and acts almost like a filter, preventing solid particles from leaving it. Having separated what we need, we can tap the crucible on a piece of cement and remove the slag. Once the crucible is cleaned, we can use it again immediately.

For fun, a few more cans were melted down to fill a new muffin tin. The goal is to give the bars a beautiful, unusual appearance. The form is made of steel, but sometimes fire breaks out. This burns the non-stick coating. But this will happen only the first time. After a few minutes, the ingots begin to harden, but they are still terribly hot, so much so that the paper instantly catches fire from them. It's a good idea to have a bucket of water to cool them down. The ingots thrown into cold water are still hot enough to instantly boil it, but after about 10 seconds they cool down and can already be reached with your hands.

Use a mini muffin tin to make smaller ingots. The results were very cute little cupcakes. The purpose of ingots is to have pure metal ready when you want to do something. Now, if necessary, you just need to throw a couple of ingots into a clean crucible. With this configuration, the ingots will melt in 5-10 minutes. When using ingots, we do not need to get rid of slag, except perhaps a thin film of aluminum oxide, which means the crucible is full of liquid aluminum ready for casting.

Let's pour aluminum into sand, in which a special mold is made, which burns, absorbing 900 grams of liquid metal. After 10 minutes, the metal is hard enough to grip with pliers. We can break the mold and pull out our castings. At the link at the beginning of the article you can see how the sword was cast in more detail.

When the work is completed, all the equipment can be conveniently placed in a 20 liter bucket, and when the melting pot has cooled down, you can easily shake out the ashes by holding the handle. Cleanup is quick and when you place a plant pot inside, the melting furnace turns into decor.

Well, now you know how to turn empty soda cans into shiny metal muffins at home. You can simply be proud of them and admire them, or you can use them to cast anything that comes to mind.

Aluminum is a metal that is widely used in industry and everyday life.

It is used to produce not only aircraft and ship parts, but also dishes and other utensils. Therefore, there is often a need to independently manufacture aluminum parts that have failed.

The ability of aluminum to melt at relatively low temperatures makes it possible to produce cast products from it in artisanal conditions. In order to independently produce cast aluminum products, you need to know the behavior of this metal at high temperatures and its physical and chemical properties.

Characteristics of aluminum

The melting point of aluminum depends on the purity of the metal and is approximately 660 °C. Its boiling point is 2500 °C.

Aluminum is distinguished by its lightness and ductility, so it bends well and can be processed by stamping.

This metal is an excellent conductor of heat and actively enters into a chemical reaction at high temperatures with atmospheric oxygen, forming an oxide film on the surface. It protects aluminum from further oxidation, but when scrap melts, it significantly affects the composition of the alloy. During the metal smelting process, the structure of aluminum changes.

When it cools sharply, internal stresses and shrinkage of the resulting alloy may occur. This must be taken into account when working with aluminum at home.

Technologies for home aluminum casting and necessary equipment

The principle of casting aluminum at home should be based on the technology for its production in production, adjusted for conditions that can be used at home.

Aluminum products are produced by casting in several ways. In domestic conditions, the most common and convenient method is the technology of casting molten aluminum into specially made molds.

Therefore, to carry out the process, two things must be ensured:

• build a furnace for melting aluminum scrap;
• create the desired shape to produce a cast alloy or a separate part.

The casting process must include several stages:

Preparation of aluminum scrap, including cleaning from dirt, impurities and various fillers, as well as grinding it to a small size.

Carrying out the smelting process in the planned way. When the metal is completely melted, slag formations must be removed from its surface.

Filling the prepared mold with liquid aluminum melt. After solidification, the ingot is freed from the molding mass.

Homemade furnaces and methods for melting aluminum

In order to melt aluminum, you need to heat it to a temperature close to 660 °C. It is impossible to reach such a temperature on an open flame of a fire. Therefore, a closed space is needed, which a homemade stove can provide. It can be heated by burning coal and wood or using natural gas.

You can also use an electric muffle furnace if you have one on the farm.

With a self-made stove, forced ventilation must be provided to maintain the combustion process.

1. The simplest version of a homemade fireplace can be made from old pots.

Its design is as follows:

• As a frame, use a steel container, for example, an old pan, on the side of which you need to make a hole to supply air through a connected metal pipe.
• Air can be forced through the hose using a vacuum cleaner.
• Coal is placed inside the device.
• Then the coal is set on fire and air is supplied to keep the fire from going out.
• A container for melting aluminum is first placed inside an improvised furnace structure and lined with coal on its sides. When it burns, uniform heat distribution is ensured.
• To prevent heat from being lost to the surrounding air, the top of the “pan” stove should be loosely covered with a lid, leaving a small gap for the smoke to escape.

An ideal design would be a firebox with an oval arch made from a masonry mixture used for heat-resistant bricks. You can use it as a frame to create an oval arch. flower pot the right size.

After the mixture dries, a good firebox is obtained that can withstand several heats.

2. The second version of the furnace involves using the flame of a household gas burner to heat aluminum.

It can only be used for piece products made of aluminum weighing no more than 150 grams. An imitation oven is created by using two containers inserted into each other with a small gap. These can be ordinary cans from canned food.

• low hardness but high ductility;
• excellent electrical conductivity and deformability;
• high chemical activity and corrosive properties (quickly oxidizes to form a protective surface film with high density, hardness and melting point).

The purity, resistance in oxidizing environments and non-toxicity of the material predetermined its widespread use in the food and medical industries. They even make vessels from it for transporting and producing nitric acid, etc.

Due to its low strength, pure aluminum is rarely used as a structural material in the production of frames, pipes, etc. As a rule, it is required in its pure form in the electrical, chemical and food industries in the production of tires, wires and other electrically conductive materials and elements. In alloys with magnesium, copper, zinc, silicon, etc., this light metal becomes durable and obtains good technological properties. Corners, frames, profiles, etc. are produced from alloys.

The growth in consumption of products made of aluminum and its alloys is stable. Aluminum production has been established:

• wires;
• foil;
• ingots;
• ribbons;
• sheets;
• slabs;
• rods;
• profile, etc.;
• roofs;
• welded structures for various purposes.

Pure aluminum is usually used in electrical engineering (there is a high demand for aluminum electrical busbars, wire, etc.), food and medical industries. In mechanical engineering, products made from light aluminum alloys are used. Aluminum frames are popular in vehicle construction.

This is a promising structural material in all respects. Semi-finished products are used in structures - sheets, profiles, frames, pipes, etc. from deformable alloys. When manufacturing more complex solutions or when restoring damaged cast products (frames, etc.), aluminum welding is required, which is carried out in different ways. The priority one is selected depending on the goals, objectives and type of rafting. The main goal of welding is to achieve high quality and strength of the joint.

Features of melting and welding aluminum

Aluminum is easily processed under pressure in cold and hot states. Welding aluminum and its alloys is fundamentally different from welding steel. Aluminum has high thermal conductivity. It is five times higher than that of steels, and therefore heat is actively removed from the area being welded. In this regard, high heat inputs are required.

Aluminum has a low melting point and the heating process significantly reduces its strength. This makes fast welding difficult due to the shallow penetration depth and requires the use of maximum current at the beginning with a gradual decrease towards the end of welding.

The fluidity of the molten metal makes it difficult to control the weld pool. When welding, it is necessary to use heat-dissipating pads. Very little time is needed for the weld pool to harden, which leads to incomplete gas release, the formation of pores in the seam, and poor connection.

An additional difficulty is that this lightweight metal will not change color when heated, i.e. the welder does not receive visual information about the temperature reached. This specificity increases the risk of damage and burning of tires, tape, frame, and other elements during the welding process.

Another feature of aluminum in comparison with steels is that when melted, its casting shrinkage is twice as high. As the weld pool material solidifies, internal stress develops. The consequence of stress is the appearance of defects, including hot cracks. The tendency to form them leads to weakening of the seam.

Hydrogen dissolved in aluminum is responsible for the pores, tending to escape from the metal to the outside. Cracks are more typical for aluminum alloys; they occur when the metal cools due to the increased silicon content. To avoid complications, use:

• higher welding current compared to steel welding;
• preheating of a workpiece, semi-finished product, frame, tire, rod, wire, etc.;
• shielding gas or gas mixture.

Features of the choice of materials and welding wire

Welding materials are selected according to the type of welding. If you want to weld technical aluminum using manual arc welding, use OZA-1 and OZANA-1 electrodes. In the event that uneven castings or cracks in silumin are welded, use OZA-2 and OZANA-2 electrodes, the coating of which contains chloride and fluoride salts. These components not only provide a stable arc, but also allow the elimination of the oxide film.

In semi-automatic welding of aluminum and its alloys, shielding gas or gas mixtures are used, and in argon-arc welding, tungsten electrodes are used. Welding of aluminum pipes and other aluminum products is usually carried out end-to-end due to the characteristics of the metal. To create butt joints where full penetration is achieved, removable grooved spacers will be required. Molten metal and slag will flow down them.

As a filler material, as a rule, welding wire is used, which can consist of pure technical aluminum or an aluminum alloy with:

• manganese;
• magnesium
• silicon;
• copper.

When welding wire metal, it is necessary to select according to the chemical composition of the part, with the exception of aluminum alloys. In this situation, the wire should contain more magnesium than the part.

Aluminum wire is considered a rather complex material. This applies to both its use and storage. If the sealed package is opened, it is recommended to use the wire in a timely manner, since after opening, rapid oxidation of the material begins with the formation of a layer of Al 2 O 3. Its melting point is many times higher, which makes welding difficult.

Storage in opened packaging is a guarantee of reduction in the quality of the wire. Deterioration progresses if the wire is exposed to a damp environment. The aluminum oxide layer formed on the surface of the product must be removed. The cleaning effect is achieved at the moment of welding with positive polarization. The place of the future weld on all parts and elements, wire, pipes, frames, etc., immediately before welding, is carefully freed from any contamination - grease, dust, etc. are removed.

Aluminum welding methods

Welding of aluminum alloys and aluminum is carried out in several ways. It is carried out using specialized equipment and welding materials. The welding area is protected by inert gases or fluxes. Among the methods are:

• using inert gases (these are special electrodes for welding aluminum - larger in diameter than for welding steel);
• welding with stick electrodes without the use of shielding gas (manual);
• more productive semi-automatic welding of aluminum in an inert gas environment (the wire is fed automatically during such welding).

Aluminum cannot be welded with direct current of straight polarity. Welding requires alternating or direct current of reverse polarity: in the presence of cathode sputtering, the resulting oxide film will be destroyed, which is necessary for its alloys. With straight polarity, cathode sputtering does not occur, and therefore the film remains on the wire and other elements - frames, corners, sheets, and so on.

Preparing metal for welding

Regardless of the method used, pipes and other structural elements are carried out only after thorough cleaning - preparation of the edges to be welded, which is the key to high welding results. To do this, immediately before starting the process, you must:

• cleaning of dirt and degreasing of all welded parts and filler material using any suitable solvent (acetone, aviation gasoline, white spirit, etc.);
• if necessary - cutting of edges (not required when welding parts up to 4 mm thick; when welding with coated electrodes - cutting only when the material thickness is more than 20 mm);
• if necessary - flanging (for elements made of thin sheets);
• removal of Al 2 O 3 by mechanical (edges are cleaned with a file, metal brush, sandpaper) or chemical method;
• removing moisture with light preheating;
• preheating of massive parts to reduce the likelihood of hot cracks.

Due to the fact that the melting point of aluminum is low, welding should be carried out quickly, with a high speed of movement of the torch. This avoids burns. Even with proper preheating when starting welding, any product (wire, frames, etc.) remains relatively cold, and therefore at maximum current.

Next, the current strength is reduced, since part of the heat will go in front of the arc, warming up the welding site. Moreover, if the current is not reduced, the process will become more difficult due to the fact that the heat front will approach the end of the parts, and then there will be nowhere for it to go.

When welding aluminum or metal alloys, a crater appears at the end of the weld. This is due to the fact that the metal quickly hardens at a high coefficient of thermal expansion. The concave surface of the crater is compressed. It may rupture, leading to the destruction of the finished product along the welded seam. In this regard, it is necessary to carry out melting of the crater. A bulge should form in its place. This effect can be achieved by changing the arc movement to the opposite direction at the very end of welding while continuing to feed the wire.

Aluminum is an element from the periodic table known to everyone from school chemistry courses. In most compounds it exhibits trivalency, but at high temperatures it achieves some degree of oxidation. One of its most important compounds is aluminum oxide.

Main characteristics of aluminum

Aluminum is a silvery metal with a specific gravity of 2.7 * 10 3 kg/m 3 and a density of 2.7 g/cm 3 . Lightweight and plastic, it is good as a conductor of electricity, due to the fact that the thermal conductivity of aluminum is quite high - 180 kcal/m*hour*deg (the thermal conductivity coefficient is indicated). Thermal conductivity of aluminum exceeds the same indicator cast iron five times and iron three times.

Due to its composition, this metal can be easily rolled into a thin sheet or drawn into wire. Upon contact with air, an oxide film (aluminum oxide) is formed on its surface, which is protection against oxidation and provides its high anti-corrosion properties. Thin aluminum, such as foil or powder of this metal, burns instantly when heated to high temperatures and becomes aluminum oxide.

The metal is not particularly resistant to aggressive acids. For example, it can be dissolved in sulfuric or hydrochloric acids even if they are dilute, especially if they are heated. However, it does not dissolve in either dilute or concentrated and cold nitric acid, due to the oxide film. Aqueous solutions of alkalis have a certain effect on the metal - the oxide layer dissolves and salts are formed containing this metal as part of the anion - aluminates.

It is known that aluminum is the most common metal in nature, but for the first time I was able to obtain it in its pure form physicist from Denmark H. Ørsted back in 1925 of the 19th century. This metal is the third most abundant element in nature and is the leader among metals. The earth's crust contains 8.8% aluminum. It was found in the composition of micas, feldspars, clays and minerals.

The production process is very energy-intensive and therefore the first large plant in our country was built and launched in the 20th century. The main raw material for the production of this metal is aluminum oxide. To obtain it, it is necessary to remove impurities from minerals containing aluminum or bauxite. Next, natural or artificially produced cryolite is melted using an electrolytic method at a temperature just below 1000 ºC. Then they begin to gradually add aluminum oxide and related substances necessary to improve the quality of the metal. In the process, the oxide begins to decompose and aluminum is released. The purity of the resulting metal is 99.7% or higher.

This element has found its application in food production as foil and cutlery; in construction, its alloys with other metals are used, in aviation, electrical engineering as a copper substitute for cables, as an alloying additive in metallurgy, aluminothermy and other industries.

What is the melting temperature of metals?

The melting temperature of metals is the value of the heating temperature of the metal at which the process of transition from the initial state to another begins, that is, the process opposite to crystallization (solidification), but inextricably linked with it.

So, to melt, the metal is heated from the outside to the melting temperature and continues to be heated to overcome the phase transition boundary. The bottom line is that the melting temperature indicator means the temperature at which the metal is in phase equilibrium, that is, between a liquid and a solid. In other words, it exists simultaneously in both states. And for melting you need to heat it above the boundary temperature so that the process goes in the right direction.

It is worth saying that only for pure compositions the melting temperature is constant. If the metal contains impurities, this will shift the phase transition boundary, and, accordingly, the melting temperature will be different. This is explained by the fact that the composition with impurities has a different crystal structure, in which the atoms interact with each other differently. Based on this principle, metals can be divided into:

• easy melting, such as mercury and gallium, for example (melting temperature up to 600°C)
• medium-melting ones are aluminum and copper (600-1600°C)
• refractory - molybdenum, tungsten (more than 1600°C).

Knowledge of the melting temperature indicator is necessary both in the production of alloys for the correct calculation of their parameters, and in the operation of products made from them, since this indicator determines the limitations of their use. For a long time now, for convenience physicists compiled this data into one table. There are tables of melting temperatures for both metals and their alloys.

Melting point of aluminum

Melting is the process of processing metals, usually in special furnaces, to obtain an alloy of the desired quality in a liquid state. As mentioned above, aluminum is a medium-melting metal and melts when heated to 660ºC. In the manufacture of metal products melting temperature influences the choice melting furnace or unit and, accordingly, used for casting refractory molds.

The indicated temperatures refer to the melting process of pure aluminum. Since in its pure form it is used less often, and the introduction of impurities into its composition changes the melting point. Aluminum alloys are manufactured in order to change any of its properties, increase strength, for example, or heat resistance. The following are used as additives:

• magnesium
• silicon
• manganese.

The addition of impurities entails a decrease in electrical conductivity, deterioration or improvement of corrosion properties, and an increase in relative density.

Typically, adding other elements to a metal causes the melting point of the alloy to decrease, but not always. For example, adding copper in a volume of 5.7% leads to a decrease in the melting point to 548ºC. The resulting alloy is called duralumin; it is subjected to further thermal hardening. And aluminum-magnesium compositions melt at a temperature of 700 - 750ºС.

During the melting process Strict control of melt temperature is required, as well as the presence of gases in the composition, which are detected through technological tests or by vacuum extraction. At the final stage of production of aluminum alloys, they are modified.

ALUMINUM
Al
(from Latin aluminum), a chemical element of subgroup IIIA of the periodic table of elements (B, Al, Ga, In, Tl), the most common metal in the earth's crust, found in a large number of minerals, such as clay and granite. The main raw material for aluminum production is bauxite, an ore that is mainly hydrated aluminum oxide Al2O3Х2H2O. The world leader in aluminum production is the USA, followed by Russia, Canada and Australia. Aluminum is best known as a raw material for the production of alloys used for the manufacture of food containers (cans, cylinders, jars, etc.), light kitchen utensils and other household utensils. Crude aluminum was first isolated by H. Oersted in 1825, although back in 1807 H. Davy discovered an unknown metal when treating clay with sulfuric acid. Davy was unable to isolate the metal from the compounds, but called it aluminum (from the Latin alumen - alum), and its oxide - alumina (alimina); Soon this name of the metal, by analogy with the names of other metals, was changed to “aluminum”, which became generally accepted.
Properties. A remarkable property of aluminum is its lightness; The density of aluminum is approximately three times less than that of steel, copper or zinc. Pure aluminum is a soft metal, but forms alloys with other elements to provide a wide range of useful properties. In terms of thermal conductivity and electrical conductivity, aluminum ranks after silver and copper. Aluminum is highly reactive, so it does not occur in nature in a free state. Metallic aluminum dissolves quickly in hydrochloric acid to form AlCl3 chloride, and more slowly in sulfuric acid to form Al2(SO4)3 sulfate, but it reacts with nitric acid only in the presence of mercury salts. In reaction with alkalis it forms aluminates, for example, with NaOH it forms NaAlO2. Aluminum exhibits amphoteric properties, as it reacts with both acids and alkalis. In air, aluminum is quickly covered with a durable protective film of Al2O3 oxide, protecting it from further oxidation. Therefore, aluminum is stable in air and in the presence of moisture, even with moderate heating. If the protective film of the oxide is broken, then when heated in air or oxygen it burns with a bright white flame. When heated, aluminum reacts actively with halogens, sulfur, carbon and nitrogen. Molten aluminum reacts explosively with water. PROPERTIES OF ALUMINUM
Atomic number 13 Atomic mass 26.9815 Isotopes

stable 27

unstable 24, 25, 26, 28, 29

Melting point, ° C 660 Boiling point, ° C 2467 Density, g/cm3 2.7 Hardness (Mohs) 2.0-2.9 Content in the earth's crust, % (wt.) 8.13 Oxidation state +3
Application. Since ancient times, alum has been used in medicine as an astringent, in dyeing for mordant, and for tanning leather. Alum is often called mixed sulfates of mono- and trivalent metals, such as aluminum and potassium (the mineral solvaterite). The Roman scientist Pliny the Elder (1st century AD) in his Natural History mentions alum as a salt whose properties were studied by alchemists. The Egyptians were the first to use alum for tanning leather and for medicinal purposes; they, as well as the Lydians, Phoenicians and Jews, knew that some dyes, such as indigo and cochineal, were better preserved if they were mixed or soaked in alum. Crystalline aluminum oxide, found naturally as corundum, is used as an abrasive due to its high hardness. Ruby and sapphire are varieties of corundum colored by impurities and are gemstones.
Application of aluminum metal. Aluminum is one of the lightest structural metals (see table). Alloys obtained from aluminum after heat treatment, along with low density, are distinguished by high strength and other important mechanical properties, which makes aluminum indispensable for the manufacture of vehicle parts (pistons and crankcases, blocks and cylinder heads of aircraft and automobile engines, bearings, power trains and casing fuselages, etc.). Aluminum is easily drawn and drawn, which is used in the production of food containers. The electrical conductivity of aluminum is approx. 61% of the electrical conductivity of copper, but aluminum is three times less dense. The combination of good conductivity with high corrosion resistance in air expands the use of aluminum cables, often reinforced with steel, for high-voltage power transmission. Aluminum is also distinguished by its high thermal conductivity, which is used in engines, cooling systems and other devices. The metal is easily polished mechanically and electrolytically, so it is also used for telescope reflectors and similar purposes. Aluminum is widely used as a packaging material and has the highest recycling recovery rate among other packaging materials. Recovering aluminum recyclables allows you to save energy, since its consumption in this case is less than when producing aluminum from ore. In 1981, the share of recovered aluminum in the production of food containers was 53.2%, and by 1991 it reached 62.4% and continues to grow. Aluminum is highly resistant to corrosion due to the formation of an oxide film on its surface and is therefore used as roofing material, sheathing, and in daylight and infrared light reflectors. Its corrosion resistance can be further enhanced by electrolytic anodic oxidation, known as anodizing, which increases the thickness and adhesion of the oxide film. The anodized surface is easy to paint; this method is often used for architectural panels
(see also CORROSION OF METALS).
The corrosion resistance of aluminum, combined with its beautiful appearance, ensures its widespread use in refrigeration technology. Aluminum is a strong reducing agent and is used to isolate less active metals and as an antioxidant in the production of steel and explosives. Aluminum powder is used in finishing works. Aluminum paint is resistant to industrial emissions and exhaust gases, therefore it is widely used as a protective coating on the facades of metal structures, oil tanks, railway equipment and other structures. Aluminum foil is a shiny insulating material used for packaging food products and for wrapping them in culinary processing, as a decorative covering for books, letter signs, and also in the production of electrical capacitors. Aluminum powder is used in powder metallurgy for the manufacture of precision parts, and also serves as an additive in solid fuels for rocket engines. Thermite mixture is widely used as a welding material for repairing thick-walled structures, for example for welding steel rails
(see also POWDER METALLURGY).
Alloys. Pure aluminum, soft and ductile, is unsuitable for direct technical use. The Hall-Heroult process is used to produce a wide range of light aluminum alloys (see also ALUMINUM INDUSTRY). The needs of aeronautics during the First World War contributed to the intensive development of aluminum alloy technology. Today, the field of special alloys is developing using various technologies. Some aluminum alloys are used to produce rolled sheets and profiles; others are used to draw rods, pipes, and produce beams with a given angle, complex sections, and workpieces for pressure processing. Many alloys can be pressed, drawn, drawn and stamped using room temperature, others are processed only at elevated temperatures (see also ALLOYS).
Heat treatment. Most important in the technology of aluminum alloys was the discovery by A. Wilm in 1911 that some alloys improve their mechanical properties as a result of a special heat treatment known as aging. This was first established for alloys with copper and magnesium, and then for all alloys. Aging is carried out in two stages; In the first, the alloy is heated to a temperature slightly below the melting point of aluminum, while components such as copper form a solid solution. During rapid quenching, the alloy components remain in solid solution. In the second stage, at relatively low heat, the dissolved components of the alloy are released as extremely fine particles in the aluminum matrix, improving the mechanical properties of the alloy. But not all strength-increasing effects are a consequence of heat treatment; some of them are explained by the fact that the alloy components form solid solutions or intermetallic compounds.
See also HEAT TREATMENT OF METALS.
Casting and pressure processing. Casting in the ground (more precisely, in clay-sand molds) is used for the production of massive parts such as engine cylinder blocks, and for the mass production of small parts, casting in standard molds, including injection molding, is used. Casting molds made of ceramic, steel or cast iron (permanent mold casting, or die casting) are widely used. A typical cast alloy can contain up to 8% Cu or up to 13% Si. The most common aluminum casting alloys contain Mg, Ni, Fe, Mn or Zn additives. The low melting point of aluminum and its good casting properties contribute to the widespread use of aluminum casting.
See also METAL CASTING. In addition, aluminum billets are used, which acquire excellent qualities after heat treatment and pressure treatment. Previously, duralumin was widely used - an alloy of aluminum with 4% copper, previously subjected to heat and mechanical treatment. Now duralumin is a wide range of high-strength aluminum alloys, containing, in addition to copper, also manganese, magnesium, silicon, etc. These alloys have a tensile strength of up to 414 MPa (42.2 kg/mm2), close to the strength of low-carbon steel. A more modern alloy containing zinc has a tensile strength of up to 690 MPa (70.3 kg/mm2) at room temperature. These alloys are used in the production of aircraft parts and can replace some older copper-containing alloys.
Hot and cold worked alloys. Aluminum and its alloys can be cold and hot worked. During hot processing, the structure of the ingot is destroyed and transformed into a homogeneous fine-grained structure with improved properties. Hot forming and stamping make it possible to produce thin blanks that cannot be produced by cold working. In this way, rods, wires, wire rods, sheets and other special profiles are obtained. Cold working is done in the final stage to produce mainly sheet, rod, wire and pipes. Cold working increases the strength and hardness of the product. In general, hot working is used for the initial processing of the ingot, while cold working has an advantage in the final stage of processing.
See also CHEMICAL ELEMENTS.
LITERATURE
Belyaev A.I. Metallurgy of light metals. M., 1970 Industrial aluminum alloys. M., 1984

Collier's Encyclopedia. - Open Society. 2000 .

Synonyms:

See what "ALUMINUM" is in other dictionaries:

Or clay (chemical designation Al, atomic weight 27.04) a metal that has not yet been found in nature in a free state; but in the form of compounds, namely silicates, this element is ubiquitous and widespread; It is part of the mass of rocks... Encyclopedia of Brockhaus and Efron

- (clay) chemical zn. AL; at. V. = 27.12; beat V. = 2.6; m.p. about 700°. Silvery white, soft, sonorous metal; in combination with silicic acid, it is the main component of clays, feldspar, and mica; found in all soils. Goes to... ... Dictionary of foreign words of the Russian language

- (symbol Al), a silvery-white metal, an element of the third group of the periodic table. It was first obtained in its pure form in 1827. The most common metal in the earth's crust; Its main source is bauxite ore. Process… … Scientific and technical encyclopedic dictionary

ALUMINUM- ALUMINUM, Aluminum (chemical symbol A1, at. weight 27.1), the most common metal on the earth’s surface and, after O and silicon, the most important component of the earth’s crust. A. occurs in nature, mainly in the form of silicic acid salts (silicates);... ... Great Medical Encyclopedia

Aluminum- is a bluish-white metal that is particularly light. It is very ductile and can be easily rolled, drawn, forged, stamped, and casted, etc. Like other soft metals, aluminum also lends itself very well... ... Official terminology

Aluminum- (Aluminium), Al, chemical element of group III of the periodic table, atomic number 13, atomic mass 26.98154; light metal, melting point 660 °C. Content in the earth's crust is 8.8% by weight. Aluminum and its alloys are used as structural materials in... ... Illustrated Encyclopedic Dictionary

ALUMINUM, aluminum male, chemical alkali metal clay, alumina base, clay; as well as the basis of rust, iron; and burn copper. Aluminite male a fossil similar to alum, hydrous sulphate of alumina. Alunit husband. a fossil very close to... ... Dictionary Dahl

Crucible is a vessel for melting metal. As a rule, conversion metal is melted in crucibles, i.e. already brought to the required degree of quality for casting into a mold or refining (deep purification from impurities). The general line of development of large-scale metallurgy is to reduce the number of processing steps, up to the release of conditioned metal directly from the melting furnace, but in industry crucible melting still retains significant importance, and in handicrafts and jewelry it dominates.

The crucible is not just a fairly heat-resistant vessel. Its chemical composition and design must correspond to the type of metal being melted and the melting mode. This article describes how to make a crucible with your own hands and what conditions it must satisfy for use at home or in a small workshop. For beginner metallurgists, you will first have to touch on the metal smelting process itself, because... The requirements for the crucible are determined mainly by its conditions.

A little about melting

In a deep vacuum, the high-purity metal being melted can be heated exactly to the melting temperature or slightly higher, and kept at it for some time so that tiny, literally a few atoms, remains of crystallites melt. Then the metal can be allowed to cool slightly below its melting point - it will remain liquid, like a supersaturated solution without a seed crystal. If we now pour the metal, also in a vacuum, into a mold made of a chemically absolutely inert material, in which a seed crystal of the same metal is placed, then, observing all the subtleties of this technology, we will obtain a single-crystal casting with unique properties.

In amateur conditions, vacuum melting, alas, is not feasible. In order to properly make a crucible for melting metal yourself, you need to take into account a number of features of melting in a non-inert chemical gas environment. The melted metal, firstly, interacts with air, causing part of it to be lost to the formation of oxide, which is especially important when melting scrap precious metals: at its melting temperature (1060 degrees Celsius), even gold noticeably oxidizes. To compensate to some extent for oxidation, the crucible must provide a reducing environment for the melt or be chemically inert if the metal is melted with a clean open flame, see below.

Secondly, so that the metal in the crucible does not freeze until it is brought to the casting mold, so that the remnants of the original crystallites do not spoil the casting, and the melt acquires sufficient fluidity, the metal in the crucible is overheated. For example, the melting point of zinc is 440 degrees, and its foundry temperature is 600. Aluminum, respectively, 660 and 800. Since overheating of the metal after melting takes some time, degassing of the melt also occurs at the same time, this is the third thing.

Recovery

In metallurgy, atomic carbon C, carbon monoxide CO (carbon monoxide) and hydrogen H are used as reducing agents. The latter is most often an accidental guest, because for this purpose it is too active and is absorbed by metals without forming with them chemical compounds, in large quantities, which spoils the casting material. For example, solid platinum at room temperature can absorb up to 800 volumes of hydrogen. A platinum blank in a hydrogen atmosphere literally swells before our eyes, cracks and falls into pieces. If you take them out of the hydrogen chamber and heat them, hydrogen will be released back.

Note: in a similar way, but in smaller quantities, metals absorb/emit other gases, e.g. nitrogen. This is why degassing of the melt is required, see also below.

A noticeable proportion of hydrogen reduction occurs when heated by an open flame of a gas burner, upon its contact with a less heated surface. The metal does not deteriorate - the absorbed hydrogen is released and burned later in the smelting process. But, if the crucible material is also prone to gas absorption, it may crack and burst during melting; this must be kept in mind.

CO reduction is noticeable if the metal in the crucible is melted by the open flame of a liquid (gasoline, kerosene, diesel) burner, for the same reasons. Liquid fuel burns much slower than gas, and its afterburning zone extends several cm from the burner nozzle. Reduction with carbon monoxide is the cleanest from the point of view of the metal: it does not spoil the metal and does not produce by-products with a strong excess of the reducing agent. Therefore, CO reduction is widely used in metallurgy when smelting metal from ore, but no one has yet figured out how to make a crucible furnace (see below), in which oxidation compensation would be completely provided by CO.

Atomic carbon is a reducing agent energetic enough to compensate for oxidation. It is also not difficult to create a reducing environment in a crucible using C: it is enough to introduce free carbon in one or another allotropic modification into the composition of its material or make the entire crucible from a heat-resistant and mechanically sufficiently strong allotrope C; graphite is one of them. When reducing C, there is a danger of carburization of the melt, but graphite releases very little atomic carbon when heated. If you heat the metal in a graphite crucible with a gas flame, then the excess C will immediately find a more “tasty” H for it and the danger of carburization will be reduced to zero. And for other heating methods (see below), you can select the dimensions, configuration of the crucible and the addition of graphite to its material so that there is simply no excess C under any conceivable melting mode. This is a very valuable property of graphite, keep it in mind too.

Note: the coefficient of thermal expansion of graphite TKR is negative, which significantly compensates for the thermal expansion of the crucible, increases its durability and increases its service life. Also valuable quality.

Excerpt

So, it’s clear why the melt in the crucible needs to be overheated and held. Although metal casting is a completely different topic, it still needs to be mentioned here that the melt holding time should be observed quite accurately. Chemically pure metals are almost never used in practice, for example. gold 9999 wears out very quickly; The exception is electrical copper and zinc for galvanizing, the cleaner they are, the better. Most often they use the so-called. eutectic alloys; eg steel is a eutectic of iron and carbon, and duralumin is a complex eutectic of several components. If the melt is allowed to sit, the structure of the eutectic in the casting will change and the finished product will be spoiled. The holding time is especially critical for bronze and brass: they need to be cast immediately, as soon as the play of the melt in the crucible apparently changes and becomes calmer. Remember how the engineer Telegin in A. N. Tolstoy’s “Walking Through Torment” was worried that the bronze would not wear out?

In relation to the manufacture of a homemade crucible, degassing of the melt during exposure is significant in that at this time it (the crucible) experiences significant dynamic loads from bubbles of released gases and/or the play of the melt itself. That is, make the crucible withstand a large amount of thermal deformation and, if recovery is required, a small amount. Its material must also be viscous enough to withstand shock waves from bursting bubbles and shocks from melt jets. It is this circumstance that explains the low durability and reliability of homemade graphite crucibles (see below).

What to make from

Melting crucibles are made (see figure below):

1. ceramic chemically neutral;
2. ceramic graphite;
3. graphite;
4. cast iron;
5. steel.

Their comparative characteristics are as follows:

• Ceramic neutral - used for melting scrap jewelry while preserving the sample, because with indirect heating (see below), the properties of the metal do not change. You can do it yourself, but it’s a little complicated (see below) and is it worth it? A 50 g gold crucible costs up to 100 rubles in a jewelry store. Without any problems, they are suitable for melting in an induction furnace (see below), because almost do not absorb the energy of the electromagnetic field (EMF). Resource – 10-30 melts.
• Ceramic graphite – suitable for melting any metal; at home up to 1.5-2 kg at a time. To use an induction furnace, its power for the same amount of metal will have to be increased by 1.5-2 times due to the absorption of EMF by conductive graphite. You can do it yourself, see below. Resource – up to 50 or more melts.
• Graphite - suitable for melting old, oxidized scrap non-ferrous and precious metals, because create a strong restorative environment. Melting silver with an open gas flame in a graphite crucible makes it possible to almost completely restore the original weight of the oxidized metal. You can’t do it yourself, see below. Resource – more than 100 melts.
• Cast iron - used mainly for melting red copper into oxygen-free copper, because actively absorb oxygen. The resource is up to 30 melts, and then the amorphous carbon leaves the cast iron and the crucible degrades.
• Steel - a homemade cheap option for melting small quantities of aluminum and magnesium alloys and other chemically inert metals in the melt. Can be used for melting small amounts of lead into fishing weights, etc.

Note: graphite, cast iron and steel crucibles for use in induction furnaces (see below) are completely unsuitable, because completely absorb EMF energy.

About graphite crucibles

Graphite crucibles are made either turned from massive natural graphite (expensive), or sintered at high temperatures from graphite powder (cheaper, but still not very cheap). Hobbyists often try to make “graphite” crucibles from ground graphite with a kaolin binder, etc., but what they end up with is not graphite, but overly graphitized ceramic crucibles - fragile, withstanding no more than 10 melts and spoiling the metal due to excessive release of atomic carbon by finely dispersed graphite . A more or less rational way to use ground graphite in amateur crucible melting is to make a tabletop mini crucible furnace from it for ceramic neutral crucibles, see fig.

Cold welding for assembling this furnace should be used at a temperature of at least 800 degrees - the cheeks, which conduct electricity well, do not heat up above 400 during one melt. Graphite powder will not heat up much more without a crucible, but when the crucible is pressed into it, it will be hot spot over 1000 degrees due to compaction of the powder under the crucible.

If gold is melting, then after the melting is completed and the furnace has cooled, the graphite powder is poured out and shaken, because it gets baked. To melt silver and cupronickel, the powder is removed and shaken after 3-5 melts, so the furnace heats up faster. In any case, to maintain a reducing environment, the furnace is covered with a mica lid during melting.

Heating Methods

If you need to melt more than 150-200 g of metal at a time, then you will need to build a crucible furnace next to the crucible, otherwise it will be very difficult to achieve homogeneity of the melt and high quality casting. The exception is low-melting and easily recoverable lead: up to 20-30 kg of it can be melted at a time at home. A relative exception is zinc for hot galvanizing; its melt in a crucible without a furnace can be up to 2-2.5 kg, but borax must be sprinkled on top of it so that the surface of the melt is completely covered with its fluidized layer. Steel fasteners are thrown into the melt through a layer of borax.

The optimal method in all respects for heating the crucible in a furnace is with gas, pos. 1 in Fig., but a gas crucible furnace is a rather complex structure, although it can easily be made independently. The most suitable crucible for a gas furnace is a graphite ceramic crucible, because its material has a fairly high thermal conductivity. If there are particularly high requirements for metal purity, it is better to use a neutral ceramic crucible. When lower for fusible metals - cast iron, as it conducts heat better and thereby saves fuel. Graphite crucibles are placed in a gas furnace only if strong reduction of old oxidized metal is required, and the danger of carburization is insignificant, for example, when melting silver extracted from the earth for refining

For low-melting metals, the electric crucible furnace, pos. 2; it may be the so-called ohmic (with heating by a nichrome spiral) or induction, with heating from an electromagnetic oscillation generator, see below. Only ceramic neutral or, to a limited extent, graphite crucibles are suitable for induction furnaces.

If the crucible contains more than 2-2.5 kg of metal, then according to safety rules the crucible furnace must be made tiltable (item 3), because and 1 kg of melt spilled on the floor is already a big disaster. On the contrary, it is preferable to heat metal in small jewelry crucibles without a furnace, directly with the flame of a burner, pos. 4. In this case, the crucible is held throughout the melting process with a special spring grip, pos. 5 and 6.

Note: silver and its alloys, as well as lead for sinkers, can be melted at home in quantities of up to 15-20 g, using instead of a crucible... a food grade stainless steel spoon, see fig. on right. For safety, then you need to make gaskets for the jaws of the vice with longitudinal cuts under the handle of the spoon. The flame is exclusively gas; gasoline can burn a spoon.

Electric heating

Ohmic crucible furnaces are mainly used for smelting lead or tin. For more refractory metals, they turn out to be uneconomical, but up to 20 kg of lead can be melted at a time in a home crucible electric furnace; how to make your own electric crucible for melting lead, see for example. video:

Video: electric crucible for melting lead

Melting aluminum in a crucible turns out to be more profitable by induction due to its high electrical conductivity, but this trick no longer works with copper - its temperature and latent heat of fusion are much higher. With the induction melting method, the metal is heated by Foucault eddy currents, for which the crucible with it is placed in an EMF coil of thick copper wire, powered by an electromagnetic oscillation generator. How to make a generator with your own hands for inductively heating small amounts of metal, for example, for trinkets, is described in other materials, or, for example, see next. video guide.

Video: DIY induction heating

With an increase in the amount of melted metal, not only does the required power of the generator increase, but its optimal frequency also decreases, this affects the so-called. surface effect (skin effect) in metal. If 100-200 g of aluminum can be melted into EMF from any homemade generator, then installing 1.5-2 kg of duralumin or magnesium alloy is already a solid structure, see fig. on right. If you intend to work with aluminum, then think carefully - is it worth building something like this? Wouldn't it be easier to use a mini gas furnace for melting small quantities of aluminum alloys, see for example. video clip

Video: mini furnace for melting aluminum

Making crucibles

Now it's time to make your own melting crucible. From the above it is clear that it makes sense to make crucibles with your own hands:

1. Steel;
2. Ceramic neutral;
3. Ceramic graphite.

There is nothing special to say about steel crucibles - they are just a steel vessel with a welded handle. Steel crucibles are used for melting low-melting metals; sometimes - zinc for hot galvanizing with quality up to 3+. Steel crucibles for lead, tin and zinc are only suitable for melting one specific metal, because... after 1-2 melts they themselves are covered with it from the inside.

Ceramic neutral

The composition of the mixture for forming a neutral ceramic crucible is 7 parts of fireclay clay, 1 part of finely ground fireclay (up to the fraction

Fireclay mill

Finely ground chamotte is part of the raw material for molding both neutral and graphite crucibles, and the quality and durability of the crucible largely depend on it, and crushing chamotte using artisanal methods is very labor-intensive and does not produce a completely good-quality material. The structure of a chain mill for mineral raw materials is shown in Fig. on right. Material – steel. Chains – 4; they are hung crosswise so that they sag horizontally by approx. by 1/3 of the tank diameter. An option instead of chains for 1 broken fireclay brick is 2-3 handfuls of balls from the bearing. New store-bought chains will cost more than chains, but old ones from broken bearings are quite suitable. Any drive: manual, electric. Both chain and ball mills are capable of grinding fireclay into dust like cement; To obtain certain fractions, the mill is stopped earlier. To prevent dust from forming, the mouth of the tank is covered with something during grinding. To grind a brick, simply drop it from a height onto a hard floor and load the resulting pieces into the mill.

Preparing the molding material

Mix dry clay with ground fireclay until completely homogeneous (uniform). The ideal option is to scroll 15-20 times in the same mill; if it is spherical, then you don’t have to throw balls into the tank. Unload the mixed mass and add a little water (1.5-2.5 parts), mixing by hand until it reaches the consistency: clenched in a fist, sticks together into a lump, but does not stick to the skin and is not pressed between the fingers. Add liquid glass, also stirring until completely homogeneous, this is the most labor-intensive step.

Deaeration

Just one remaining air bubble in the ceramic crucible mixture can cause the crucible to burst due to heating. Therefore, you need to knock the air out of the mass. To do this, lay a clean film on the hard floor; newspaper, as some manuals advise, is not necessary - the mass will accumulate from paper fibers.

To knock out the air, the entire lump of mass is thrown forcefully onto the floor many times. Practically - after the bubbles have stopped jumping out of the flopping mass, at least 10 more times.

Storage

For storage, the beaten mass is placed in a glass container with a hermetically sealed lid. In plastic, and especially when wrapped in several layers of film, the mass dries out in a few weeks and cannot be restored, but in glass in a cool place it is stored for more than six months.

Usage

Crucibles from the resulting mass are simply sculpted by hand or molded in a destructible plaster mold or in a collapsible one, as described below. The molded crucible is dried, and, which is absolutely necessary for this mass, after drying it is annealed in a muffle furnace for an hour or two at a temperature of 800 degrees. It is at this temperature that the liquid glass will melt and firmly bind the other components. Below - the crucible will collapse during the first melting; higher – during annealing. This is a very significant drawback of this technology, because Muffle furnace equipment is not cheap and not simple, though. The maximum operating temperature of the resulting crucibles is up to 1600 degrees; resource, with high-quality grinding of chamotte - up to 30 melts.

Graphite

Manufacturing technology of graphite crucibles for melting any metals, incl. black scrap, using any heating method, is well described in an article by the author A. Ramir from 2006 (see dendrite-steel.narod.ru/stat-ramir-3.htm). A. Ramir, apparently, is self-taught, but even more credit to him - his products fully correspond to good industrial designs. However, firstly, his article was rewritten many times by rewriters who clearly did not cast metal in their lives. Secondly, you can’t always get to it in a search, and for some reason the drawings are not downloaded, although they seem to be freely distributed. Thirdly, there is something to add to A. Ramir’s materials, no offense to him. One of the rules of technology is that in a good design there is always something to improve. Therefore, we will repeat and supplement the main points of this publication.

Drawings of crucibles from the mentioned article are given in Fig.:

The maximum weight of melted steel is indicated in kg; it must be recalculated for another metal. The main difficulty in this case is the manufacture of the flask - the round shell of the mold. Its inner surface is conical, otherwise the finished crucible cannot be removed after molding, so A. Ramir used turned flasks.

Meanwhile, a flask for any of these forms can be made from a piece of plastic pipe. It is secured in 3 places, at the bottom, in the middle and at the top, with screw clamps, and heated from the inside with a hairdryer. By tightening the clamps, the surface is not completely conical, but the flask will be removed from the crucible. You only need to use worm-drive clamps (see figure on the right) or their homemade analogues. Any other clamp deforms the pipe across. The flask from it will most likely come off the crucible, but it will not last long or will crack during the first melting.

The composition of the mixture used by the author is 7 volume parts of ground fireclay, 3 parts of pottery or oven clay and 1 part of ground graphite. A. Ramir also gives a recipe with 2 parts of graphite, but in terms of reducing power this is clearly too much, and the likelihood of cracking a crucible from a 7:3:1 mixture will be reduced to zero if the fireclay is crushed into dust in a mortar or ground in a mill (see above) .

It is necessary to soak the fireclay brick, as A. Ramir advises, only before crushing it using the artisanal method he described. The dry components are mixed until completely homogeneous in the specified sequence (fireclay, clay, graphite) and mixed with water with continuous stirring until the consistency is as described above. There is no need to knock the air out of this mass, because... it is de-aired during the molding process. The mixture is not stored, so it must be prepared immediately before making the crucible.

To form the inner surface of the crucible, you need to carve a block from hard wood (filled with gray in positions 1-5 of the figure), sand it and, very preferably, walk over it with leather until the surface is completely smooth. In the center of the surface of the block that forms the bottom of the crucible, drill a blind hole and insert a toothpick or, better, a round smooth plastic stick from an ear picker into it. The match that A. Ramir used is not the best option - when pulled out, it often breaks, and as a result the product is damaged.

Note: The use of any lubricants when forming a crucible is unacceptable - they will be absorbed into its material, and the crucible will burst from heating.

The mold is filled with the mixture in layers of 15 mm, and each layer is compacted with a wooden tamper. This is the most critical stage: bubbles and uneven compaction of the mixture are unacceptable. When approx. remains to the top of the flask. 12 mm, the mixture is compacted with an already turned lid with a hole for the rod in the center, pos. 2. The mixture is added in layers of 1-2 mm until the gap between the very tightly pressed lid and the upper edge of the investment box reaches 1-1.5 mm, pos. 3. If the gap is larger, part of the mixture can be taken away. Next, the lid is removed and the rod is carefully pulled out of the block using pliers, the lid is put back and the mold is turned over. A handle is attached to the bottom of the block with self-tapping screws and, carefully turning it back and forth, it is pulled out of the casting.

Note: If the rod is not inserted into the bottom of the block, it will be impossible to remove it without destroying the casting - the vacuum under the block will not work.

The formation of a crucible with a flat bottom (which is 1.2 kg) has its own peculiarities - you can’t just pull it out. Therefore, when the compacted mass rises to the flat top of the block, a circle of toilet or filter paper is placed on it.

Now the hole from the rod and minor defects in the inner surface of the crucible are sealed with the same mass. It must be completely smooth, otherwise the probability of destruction of the crucible during melting is quite high, so after correcting the defects it must be smoothed out. The best way to do this, line it with toilet paper (pos. 4), insert a block (pos. 5), and turn it several times.

All that remains is to remove the flask. To do this, turn it and the crucible back into the working (for the crucible) position, place a round wooden block and carefully tighten the flask, pos. 5 and 6. If the flask is plastic, then its protruding upper edge is slightly bent outward in several places with your fingers; Most likely, the flask will come off like clockwork after this.

And finally, the finished casting is dried. Equipment – ​​kitchen stove with oven. The casting is placed upside down on a baking sheet and placed in the oven. They heat for half an hour on the lowest gas, then another half an hour on medium (the temperature according to the built-in thermometer is about 150 degrees) and another 2 hours on full. After this, turn off the fire and leave the casting in the oven to cool until tomorrow morning. Do not open the oven during the entire drying period!

Before use, the crucible must be checked for hidden cracks. To do this, hold it by the bottom with your fingertips and tap it with your nails in a circle from top to bottom. Every knock should ring. If somewhere it doesn’t ring, it’s a defect, you can’t melt with this. Annealing is not required for a crucible manufactured using this technology. It rings everywhere - you can immediately melt in it.

What for?

A reader interested in home metallurgy “for general development” may have a question: why all this trouble? Not everyone wanders around with a metal detector in the forest after the rain, not everyone is keen on smelting damask steel at home, and not everyone has in mind hundreds of centners of old electronics, from which tens of grams of gold, platinum, and palladium can be extracted.

Let’s ask right there on the Internet how much lead bullion costs. Then, in the nearest fishing store, how many kilograms did you load from it? Let’s halve it so that the owner will certainly be tempted, and calculate the “gain.”

Surprised? You can go even steeper if you have artistic taste and lost-wax casting skills. The material for comparison is bronze scrap and figurines made from it.

But the rise will be even greater with bronze propellers for small vessels. True, making a propeller is much more difficult - you need to accurately maintain the profile, pitch and configuration of the blades. But in general, crucible melting of metal at home is a very profitable business. There would be a desire.

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Classmates

How to open your own business so that it is profitable and does not require significant financial investments?

Choose a current idea and a niche in the market for business activity, where the competition is least severe and the clientele is extensive.

You can engage in the provision of services in various spheres of the national economy or commercial commerce.

A profitable aluminum can business is an interesting solution for starting your own business.

Different ways to start

Manufacturers use several options for packaging alcoholic and non-alcoholic drinks - glass, plastic and aluminum cans.

After consuming the contents, there is a lot of container left for disposal. You can build a profitable business on this.

Possible directions:

• Open a collection point for aluminum cans with subsequent transportation of the collected material to large industrial enterprises for recycling.
• Make a profit by melting down aluminum cans by handing over recyclable materials for further processing.
• Open a production workshop for the production of new aluminum cans for companies that produce alcoholic and non-alcoholic products.

Each option is profitable, but with different capital investments.

If the starting capital is small, the best idea is to open a collection point for aluminum containers.

This will allow you to earn money for further business development.

How to take the container

The beginning of any entrepreneurial activity is the registration of an individual entrepreneur (individual entrepreneur) and the choice of a taxation system.

To do this you need:

• Pay a mandatory state fee of 800 rubles.
• Submit documents to the tax service.
• To make future work more convenient (there may be a need to enter into agreements with other market participants), it is recommended to make a seal.
• Open a bank account.

In order to save your own time, it is better to use the services of a professional lawyer.

On average, documenting an individual entrepreneur will cost from 4,000 to 5,000 rubles (lawyer, bank account, stamp) plus state duty (800 rubles). Total costs – up to six thousand.

It is advisable to choose a simplified taxation system.

The next stage is renting the premises.

The collection of aluminum containers can be organized in any area; a small basement with good heating and lighting.

The cost of renting a suitable area starts from three thousand rubles, but if you set up a business in a large city or capital, you will have to shell out a large sum.

It is necessary to hire at least one employee who will accept aluminum cans.

His monthly salary is 8,000-12,000 rubles.

In addition, you need to pay money to the people handing over the containers - 20-30 kopecks per jar, and pay for utilities - about 1000 rubles. per month.

The total investment to open a business on aluminum cans will be at least 18,000-20,000 rubles.

If the premises are located in a walk-through area, then in a month you can collect about three tons of recyclable materials.

Its implementation will bring to a large industrial enterprise:

3 tons * 30,000 rubles = 90,000 rubles.

After deducting mandatory expenses, the net profit can be 70,000 rubles minus the rental of transport for removing the resulting scrap, which proves the excellent profitability of the business.

Recycling

Collected aluminum scrap can be melted into briquettes for further shipment to processing plants.

https://youtu.be/XfxDFiep0do

Possible processing methods:

• Cutting scrap with a shredder, cleaning from household waste, washing, drying and pressing. The cost of a Chinese-made crusher is from 380,000 rubles, and the price of a new press, depending on the series, is 75,000-45,000 rubles plus an electromagnet for cleaning.
• Multi-stage grinding of aluminum scrap with removal of impurities. The result of processing is powder or fine-grained metal flakes. To organize such production, complex expensive equipment, large areas and industrial processing lines are required.
• Pyrolysis processing of recyclable materials with preliminary crushing, cleaning and washing. The production scheme is also multi-stage, but a pyrolysis unit must be added to the equipment complex, costing about 2-3 million rubles.

Without a decent start-up capital, you should first earn free funds to purchase the necessary equipment, which will allow you to earn a lot of money from smelting.

Own production

By pouring solid investments into the aluminum can business - from seventy to eighty million rubles - you can earn money by receiving 800 million units of containers per year.

What will require major investments:

• Search and rent a spacious room.
• Heating and lighting of the production workshop.
• Registering a business as an LLC.
• Food grade aluminum in rolls.
• Press for bending material.
• Machine for forming the body.
• Washer and dryer.
• Paints and varnishes.
• Rotary apparatus.
• Installation for neck molding.
• Container inspection camera.
• Press for recycling waste.

In addition to the cost of purchasing equipment for a complete production line, it is necessary to pay for the work of a large number of maintenance personnel.

All expenses are recouped by the cost of products produced annually.

The downside is the large starting capital.

Business on aluminum cans is a profitable business that generates income that exceeds financial investments by 2-3 times.

Therefore, it makes sense to consider the idea as quite suitable for starting your own business.

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It's no secret that the recycling of human waste is practically a gold mine, and it is quite problematic to objectively assess the volume of this market, in particular in our country. But, in order to at least general outline To understand the existing volumes, just consider a simple example. Have you ever thought about how many people are doing this at the same time around the globe as you throw away another soft drink can in the bin? Simply put, there are millions of them, and that is why recycling aluminum cans is not only a profitable business, but also makes a significant contribution to environmental protection and the rational use of natural resources.

General view of the problem.

According to statistics, the capacity of the Russian aluminum can market is estimated at approximately 2-3 billion. Taking into account the weight of even a small can, which is about 15 grams, we get the amount of aluminum consumed, which is approximately 30-40 thousand tons of pure metal. And if we take into account the energy resources necessary for the production of metal from primary raw materials, the prospects for the development of the processing industry become obvious.

This option will also have a beneficial effect on the environmental situation. An example of the effective use of recycling technologies is the North American company Novelis, which in 2009 was able to recycle more than 39 billion aluminum cans, which made it possible to obtain more than 530 thousand tons of pure metal from melting.

Technology for recycling aluminum cans.

The current level of development of recycling of secondary raw materials allows the use of several methods for obtaining pure aluminum from cans. The most common are the following:

• The simplest, and therefore most often used, is pressing. The source material undergoes primary sorting and cleaning from household waste. Afterwards, the raw materials are crushed with simultaneous cleaning of various iron components using an electromagnet. The resulting substance is pressed, forming briquettes of a certain weight, and sent for smelting to a metallurgical plant. The disadvantages of this method include the high content of various impurities due to imperfect purification methods.
• Another, more advanced method, providing better cleaning, is based on similar principles. Its difference lies in the use of multi-stage grinding and impurity removal schemes. As a result of processing, aluminum powder, or material in the form of small metal flakes, is obtained. Despite the higher quality processing, it has a significant disadvantage. To organize such chains of this type, extensive production areas are required. Also, the use of a multi-stage cycle significantly increases the cost of the product.
• Recycling aluminum cans based on pyrolysis is the most effective method. The additional costs required for the appropriate equipment are offset by the cost of the material obtained as a result.

The initial stages of processing are similar to existing steps in other methods.

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Recycled raw materials are washed, sorted, and various impurities are removed. Small pieces of aluminum obtained by grinding are subjected to pyrolysis in special installations.

The essence of this process is to heat the elements of crushed cans to a temperature that is 100 degrees or more higher than the melting point of aluminum, up to approximately 750 degrees. During the heating process, all organic and some inorganic impurities decompose, and the resulting liquid aluminum is poured into pre-prepared forms. The product obtained in this way is distinguished by the minimal presence of various inclusions, and can be processed at metallurgical plants without additional purification, which makes it a highly competitive material.

Considering the economic feasibility of processing such raw materials, we can conclude that organizing enterprises of this type is quite a profitable undertaking. The only problematic issue due to the peculiarities of the mentality of the majority of residents of our country is the issue of waste sorting by each person. In most countries, this method of waste collection has already proven its effectiveness, and for a resident of, for example, Japan, it is considered unacceptable to throw an aluminum can into a waste container. food waste. The introduction, and most importantly the acceptance by the population of such a separate method of collecting waste, will significantly increase the economic efficiency of processing any secondary raw materials.

How to melt aluminum cans

Re: Melting Aluminum :)

at the chipmaker they melted it on a gas stove using household gas.

In general, I’m copying it here so that we can have it too.

So, the task: melt a small amount of aluminum (to begin with) to obtain a stable liquid phase and cast it. Budget: 0 rub. Only a gas stove and available materials are available. Time before wife arrives: 2 hours. Go!

1. Oven - a tin can with a diameter of 100 mm. At the bottom there is a hole for the flame to enter, the crucible stands on three pillars of bolts inside the jar, 20mm from the bottom (Fig. 1). The flame must flow around the crucible, creating a thermal air cushion - this solves problem No. 1: colossal heat loss by radiation and convection when heating an open crucible with a burner.

2. Crucible - a tin can with a diameter of 70 mm. The crucible must be closed with a lid to reduce heat loss. There is a risk of burning through the bottom, so have water and sand at hand and pour water onto the stove (at the same time protecting the stove from overheating).

Melting aluminum beer cans

The crucible heats up more from the edges, the risk of burning through the center is minimal.

3. The burner is designed on the basis of a regular burner. First of all, the flame divider is removed and a piece of pipe is installed - I used a diameter

10mm and long

40mm (Fig. 2). The larger diameter of the outlet hole compared to the standard one allows the flame not to go out with a larger volume of gas supplied (this was problem No. 2). And now the main secret of the burner - using a wire, the pipe is fixed further than the outlet! So

In this way, the gas sucks in air, and the gas-air mixture at high speed (this is important so that the mixture does not have time to burn) is thrown into the furnace and burns there, flowing around the crucible on all sides (Fig. 3). At the same time, the flame is transparent blue, without soot, etc. — burns very well (in photo 3 the burner is working at full capacity, although the flame is not visible). Just in case, the room is well ventilated.

The crucible heats up to red instantly. I add aluminum (wire), close the lid - melting begins (Fig. 4). The metal melts, slag floats and/or settles to the bottom. For safety reasons, the process is not left unattended for a minute. Metal is added in parts every 5 minutes. In total, it took about 20 minutes (it could have been faster, it took longer out of habit). Then I add salt, remove the waste, and voila! An excellent liquid metal (Fig. 5), suitable for casting small products. The metal is cast into a tin can, resulting in an ingot weighing about 100g (Fig. 6). Problem solved!

Results. According to preliminary estimates, melting up to 0.5 kg in such a furnace is easy, up to

1 kg (330 ml - jar volume) should be tried. In the future, since everything is working, it will be possible to improve the design and optimize the process: definitely replace the crucible with stainless steel, flux and degass the metal more correctly, consider casting issues, etc. Now we need to cover our tracks so that the wife can fry her cutlets there as if nothing had happened. I did it!

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» At home

How to melt aluminum at home

We melt aluminum at home

Date: 01/01/1970

It is extremely sad when small but important functional elements break down in the house: guides for roller shutters or sliding doors (burst), fittings (something fell off), etc. As a rule, such elements are made of aluminum. Finding a replacement is a difficult task, and it happens that it is necessary to fix a malfunction in the functionality of a door or window right now, at least temporarily.

Fortunately, if you know how to solder, many problems with aluminum fittings or profiles can be eliminated. However, such work requires experience and accuracy.

The main snag is to obtain the working material, that is, molten aluminum, which will be used to solder the broken parts.

At what temperature does aluminum melt?

That's right, at a temperature of 660 degrees. An ordinary gas stove won’t give us this, and we shouldn’t do such things at home - it’s better to take the work outside. Let's look at how you can prepare solder by melting aluminum at home. Let us remind you once again that if you are not handy with a soldering iron, then we would not recommend starting all this.

So, the price of aluminum ingots ranges from 55 to 150 rubles. per kg depending on the brand of alloy. If we are not aiming for a particularly high quality of work, then any will do. In principle, you can use scraps of the old profile.

To successfully complete the operation, we will need a portable gas torch or blowtorch. Depending on the model, they give a temperature of 1000 - 1300 degrees.

How to melt aluminum cans and make something unusual out of them

This is quite enough.

What are we going to melt in?

For this we need a refractory container, for example, made of stainless steel. You can use a scoop bowl if nothing else is available. We will also need a calcined steel plate or another container into which we will pour molten aluminum.

• We make a small well out of bricks, so that our container can be installed on top (by the way, it can be placed on skewers, they are also quite refractory).
• Before installing the container, light a fire in the well. It will help keep the container warm when we stop using the burner. In addition, the fire will help warm up the aluminum from below.
• When a certain amount of hot coals is formed, we put our container with aluminum and heat it for about 15 minutes. Here you can leave the second container or plate to warm up.
• After this, turn on the gas burner to maximum and heat the aluminum from above.
• The metal will begin to melt in just a few seconds, however, our goal has not yet been achieved - we need uniform heating.
• To do this, the container must be shaken periodically. This should be done extremely carefully, using pliers and thick gloves (for welders this is the best). In principle, the molten composition can be stirred with steel wire (just as carefully).
• Please note that when using recycled materials (remnants of the profile), paint may evaporate, which is not recommended to breathe.
• When melting, aluminum oxide is formed, which in turn forms scale.
• After the formation of homogeneous (adjusted for scale) liquid aluminum, the container is carefully taken with pliers. The contents are poured onto a hardened steel surface. It should be poured in such a way that only the metal pours out, and the scale remains in the original container (in principle, this is not difficult - the main thing is not to tilt it too much).
• That's it, your molten aluminum is ready for further work.

How to melt aluminum at home with a blowtorch?

Important! When melting aluminum, use protective equipment: gloves, protective shoes, overalls, a respirator, special tools to avoid contact of molten aluminum with your body. When molten metal comes into contact with water droplets, it can splash and cause very dangerous burns. Be extremely careful! Ready-made melting furnaces in this store.

The video shows how you can melt aluminum at home using a simple blowtorch. The method is quite simple; it does not require blowing, which is necessary in cases where firewood, coals, etc. are used to create the required melting temperature of aluminum. solid fuel. The video clearly shows how the preparation is carried out necessary materials aluminum and the smelting process itself.

In this video, another master will present his model of a melting furnace and explain how to make a crucible for melting aluminum and prepare it for work.

And here the actual smelting process is shown and practical advice is given. Notice how the master is protected from injury.

Here there are materials about how to make crafts from plaster, and here about the simplest oven for aluminum. There is another article on this topic here.

How to melt aluminum at home?

As you know, the melting point of aluminum is 660 degrees. This is a fairly low-melting metal that can be melted at home using a gas torch or blowtorch, which can produce temperatures in the range of 1000-1300 degrees (this is quite enough to completely melt aluminum).

This metal will need to be melted in a fairly refractory container, for example, stainless steel.

Under the container we make a small fireplace made of bricks, in which you will need to build a fire in order to warm up the aluminum from below and not allow it to cool.

The bowl with aluminum is placed not on the fireplace, but on top of it, we heat it with a blowtorch or burner.

Aluminum will begin to melt fairly quickly. In order for the molten composition to be homogeneous, it should be stirred periodically using steel wire or something else refractory.

This must be done very carefully. Be sure to wear protective clothing and boots, as well as thick gloves, as molten metal splashes on your skin can cause serious burns. Therefore, you need to take care of your protection first.

For many, the term “foundry” is closely associated with back-breaking labor and specialized professional skills. In fact, casting a part from the required metal is possible for the most ordinary person without professional training at home. The process has its own subtleties, but it can be done at home with your own hands. Outwardly it resembles the production of lead weights for fishing. Features of the aluminum casting process are related to technical characteristics material.

How to cast aaluminum

Characteristics of aluminum. Aluminum is one of the most common metals.

It is silver-white in color and lends itself quite well to casting and machining. Due to its characteristics, aluminum is equipped with high thermal and electrical conductivity, and also has corrosion resistance.

Technical aluminum has a melting point of 658 degrees, high-purity aluminum has a melting point of 660, and the boiling point of aluminum is 2500 degrees.

For aluminum casting, home heating devices are unlikely to be useful and will provide the required temperature. It is necessary to melt aluminum by heating it to a temperature of over 660 degrees.

Aluminum casting: choosing a heat source

The following can be used as a heat source for aluminum melting:

• A very effective method is achieved using a self-made crucible muffle furnace. A crucible ( necessary tool for aluminum smelting), raw materials are added to it. Using a muffle furnace you can cast aluminum very easily.
• To obtain the melting temperature of aluminum, the combustion temperature of liquefied or natural gas is sufficient; in this case, the process can be performed in a homemade furnace.
• With a small volume of melting, you can use the heat obtained by burning gas in a household gas stove.
• The required temperature will be provided by gas cutters or acetylene generators, if available in the household.

Aluminum preparation

Despite the fact that the melting process will be performed at home, it must be handled responsibly. The metal must first be cleaned of dirt and crushed into small pieces. In this case, the melting process will go faster.

The choice is made on softer aluminum, as a purer material with fewer impurities. During melting, slag is removed from the liquid surface of the metal.

Sand casting

Several technologies are used to produce casting parts. The simplest is sand casting:

• If you need to make an aluminum part of a simple shape, then open casting can be done directly into the soil - silica. A small model is made from any material: wood, foam. Install in the flask. The soil is laid around in small layers and compacted thoroughly. Once the sample is removed, the silica holds its shape well and the casting is done directly into it.

• As a forming mixture, you can use sand combined with silicate glue, or cement mixed with brake fluid. The ratio of materials should be such that if the mixture is compressed, it retains its shape.

Video “Casting aluminum into an earthen (sand) mold at home”

For parts with complex shapes, a different technology is used.

Lost wax casting

This long-known method for making aluminum products at home can be slightly modified. The casting principle is as follows:

The model is made from low-melting material. It is placed in a certain shape and filled with plaster. One sprue or several are installed. After the plaster has hardened, it is dried well. At high temperatures, the low-melting material turns into a liquid state and flows out through the sprue. An aluminum billet is poured into the resulting mold.

Details of the process can be clarified in the video.

Video "High Pressure Aluminum Casting"

Thus, even the most ordinary amateur craftsman can make the necessary part from aluminum of various shapes.

How to cast a complex-shaped part from aluminum

Industrial enterprises often use metal molds. Aluminum casting molds can be made from a variety of materials. Most often, gypsum is used. Gypsum can be purchased at any hardware store at any price acceptable to you. It is recommended to use sculptured or white plaster.

An excellent option is sculptural, which is marked G-16. Due to the high price, it can be replaced with G-7 - ordinary white plaster. It is strictly forbidden to replace with alabaster, despite the fact that they are in construction work often interchangeable.

Let's look at a simple way to cast an aluminum part with your own hands at home.

To cast an aluminum part we need:

• melting vessel;
• scrap metal;
• melting mold.

Main stages of the process:

1. Prepare a vessel for melting (you can use a vessel from part of a steel pipe).

2. We make a mold for melting. If the item has complex design, then the form can have several components.

In our version, the form will consist of two parts. First, think about how to simplify the part for convenience (we recommend strengthening the holes with tape).

The mold is very easy to make from sculpting plaster (do not use alabaster!). You can use plasticine.

3. Before pouring plaster, you should lubricate the container with oil so that the plaster cannot stick to the container.

4. Carefully pour the plaster, shaking the mold periodically to release the bubbles.

It is important to know: The hardening process of plaster is quite fast, so be careful and try to install the model in plaster in time.

5. A primary layer is required for the upcoming filling.

Take a drill and make 4 small holes, treat the shape with oil. This is necessary to ensure that the finished mold parts lie as stable as possible during the casting process.

6. Fill the second layer.

7. After hardening occurs, you need to carefully remove the mold from the container and separate the halves.

8. Before casting, we treat the mold with soot to avoid sticking of liquid aluminum. The form must be dried. The natural drying process takes place all day long. It is advisable to dry the gypsum blank in the oven. Start with temperature 11 0 0 WITH- one hour and two hours at temperature 300 0 C. It is necessary to provide holes in the plaster for pouring aluminum and removing residual air.

This is how we melt aluminum.

9. Then we place the liquid metal in the mold and wait for it to cool completely.

As a result we get the required workpiece, then we grind it and make special holes.

Burnout casting: technology features

Manufacturing a part from aluminum using burn-out casting has its own characteristics, which will be discussed below. The work is performed in the following sequence:

• Foam plastic is used as a material for the model at home. Using cutting elements and glue, make a figure that resembles the required shape in outline.

• Prepare a container for making the model. You can use an old shoe box. Mix alabaster with water. Pour the mixture into the box. Place the foam model. Level it out. Give the material time to harden well. Due to the rapid hardening process of alabaster, perform the work at an accelerated pace.

• Remove the box. Heat the mold in the oven to dry the alabaster and remove any remaining moisture. Otherwise, all the water from the alabaster will enter the aluminum and turn into steam, which will lead to pores in the metal and aluminum splashing out of the mold during work.
• Melt the aluminum. Remove molten slag from the liquid surface. Pour the metal into the mold in place of the foam. Due to the high temperature, the latter will begin to burn out and aluminum will take its place.

• After the metal has cooled, break the mold and remove the resulting cast aluminum model. You can watch the process in more detail in the video.

Safety precautions and workplace preparation

High-temperature work is characterized by harmful fumes and is accompanied by the release of smoke, so they must be performed in the open air or in a forced-ventilated area. A side-flow fan must be used.

The casting process is accompanied by splashes and flows of molten metal are possible. Workplace You will need to first cover it with a sheet of metal. It is not recommended to carry out work in a residential area - it is unsafe for others.

Basic mistakes when casting aluminum

Before casting aluminum at home, pay attention to the main errors that are observed when performing work:

• When making plaster molds, it is necessary that all moisture evaporate during the drying process. Otherwise, when filling the mold, the water begins to evaporate, turns into steam and may remain inside the aluminum in the form of pores and shells.
• If the heating is insufficient or if the aluminum has time to cool before starting work, the metal will not fill the mold well and distant areas will remain hollow.
• Do not cool metal by immersion in liquid. In this case, the internal structure of the material is disrupted.

Aluminum can bend like paper or be as hard as steel. Aluminum is everywhere, even inside us.

Every adult gets about 50 mg of aluminum every day through food, this is not some kind of diet, it just cannot be avoided.

Aluminum is the most common metal on the planet. Its content in the earth's crust is 8%, but it is not easy to extract, at least in its pure form.

Unlike gold and silver, aluminum is not found in nuggets or whole veins. Aluminum is 3 times lighter than iron or copper.

Aluminum in its original form does not look like metal at all, this is all because of aluminum’s special “love” for oxygen.

In fact, the first use of aluminum in history occurred when Eastern potters added aluminum-rich clay to their wares to make them stronger. .

Sufficient for the production of beer cans, strong for racing cars, flexible for the skin of airplanes, capable of being turned into anything, aluminum is an indispensable material for the modern world.

And these are not all the features that this useful metal stores.