Recycling of ferrous metals

Extracting metals from ore materials is a complicated and expensive process which confirms scrap cars mississauga. It increases the cost of products and requires companies to have special equipment and skilled workers. That is why almost all metallurgical plants accept scrap ferrous metals for recycling. After remelting steel, pig iron and iron acquire the same characteristics as the primary raw material. Ferrous metals can be recycled many times without losing their properties. At the same time, recycling technology significantly reduces the energy costs of the enterprise, reduces the negative impact of production on the environment, and saves natural ore reserves.

Recycled materials are most in demand for the production of wire and steel containers. Recycled ferrous metals are also used to produce steel structures in some construction and machine-building industries. Let us consider the technology of scrap remelting in more detail.

Equipment for ferrous metals recycling
1. Melting furnaces.
2. Batching presses for preparation of wire and sheets.
3. Press shears with sharp knife beams for fast cutting of metal waste.
4. Lever-arm type alligator shears for cutting pipes, rolled steel, reinforced cable.
5. Plasma devices for metal cutting.
6. Dispensers for introducing alloying components.
7. Crushers and sorting equipment. 8.
8. Conveyors.
9. Shredders.
10. Hoisting equipment.

Quite recently mini factories for scrap metal processing have appeared on the market. They are often installed at the reception centers. With the help of mini-factory you can recycle recyclable materials and immediately produce finished products: wire rod, rebar, channels, beams, grinding balls, etc.

Receiving and sorting
Ferrous metals are separated from non-ferrous metals at the mills, but scrap metal is also sorted at the mills based on size and chemical composition. At the same time, the metal is cleaned from debris and impurities. The process of scrap sorting is automated in modern industrial complexes. Heavy elements are separated from light elements before being put into the line.

Sorting by chemical composition is done on the basis of laboratory analysis. Ferrous metals are sorted according to their carbon content and a few other quality parameters.

Cutting scrap
Recycling plants have their own requirements for the parameters of scrap metal for recycling. Large structural pieces are cut using flame cutting equipment or hydraulic shears. Small pieces are pressed into briquettes under high pressure. Large sheets of metal are cut into pieces for easy transport.

Some modern scrap collection sites have special equipment for pressing the metal into bars. This greatly simplifies the subsequent processes of loading/unloading and transporting recyclables to the plant.

Metal cleaning
Black scrap in the form of briquettes, bars, structural elements are sent to a special crusher. The machine separates the metal into small pieces to determine the type of contaminant. After that, the scrap is cleaned from dust, traces of fuel and lubricants and non-metallic inclusions by separation method.

1. Mechanical solid impurities are blown out of the mass of metal using a pneumatic unit.
2. Non-metallic impurities are sieved with the help of magnets. For this purpose, scrap is placed on a conveyor. The metal parts are held by magnets, and the non-metal parts are poured into the hopper on the belt. The type of construction of the separators can be not only conveyor, but also drum type. The power of the magnets is adjusted to the weight and size of the metal pieces.

Remelting scrap
Sliced and cleaned ferrous metal is sent to plasma or electric melting furnaces. Plasma units are cheaper, but their efficiency is lower, so they are gradually being phased out.

Electric furnaces can be:

arc furnaces (DC and AC). Compared to plasma equipment, these units have high productivity with lower energy and capital construction costs. In the working chamber of the arc furnace it is possible to melt metal weighing from 50 tons with simultaneous blowing;
medium frequency induction crucible furnaces. Melting is performed by direct heating of the metal without accompanying heat loss, so the furnaces have a high efficiency. Induction units are economical in operation and provide a sadoic melting mode. They can produce steel and pig iron with high content of steel chips and scrap. Induction crucible furnaces of medium frequency are used for high-speed melting in small batches;
channel-type induction furnaces of industrial frequency. Large units for melting and accumulation of non-ferrous metals. Such furnaces usually operate at night, when electricity costs are lower, and during the day they perform continuous casting into large molds.

The remelting process includes the following steps.

1. Scrap metal is poured into a ladle with a refractory coating.
2. 2. Pig iron is poured on top of the recycled material and the mass is blown with oxygen. Oxidizing the metal gets rid of the sulfur, phosphorus and silicon impurities that are often found in steels. These elements reduce the strength of the alloys and make them brittle. For effective burning out of impurities, special additives are additionally used.
3. Alloying components are added to the melt, according to the technological chart. It can be nickel, chromium, cobalt, vanadium. Alloy steels are wear-resistant, so they are more in demand on the market.

Melting processes are automated. Working parameters are controlled by a computer and an operator, who can make manual adjustments if necessary. At steel mills, ferrous metals can be rolled to make ingots after melting. It is cheaper and more convenient to transport the materials in this form. Enterprises with rolling mills have a higher profit margin.

Every year, large funds from private foundations and the state budget in the USA and Europe are allocated to improve the technology of ferrous metal recycling. The research costs are recouped by the savings on the recycling processes and lower taxes at the enterprise due to the improvement of the environmental performance. We can say that the issue of ferrous metal recycling is one of the major issues in the metallurgical industry. In the coming years the technology will improve and the quality of the melted metal will improve.

 

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