The steel industry is an important branch of the economy. Part of it is based on the remelting of ferrous and non-ferrous metals, which reduces the cost of melting metal from ore raw materials. Accepting and recycling junk cars in etobicoke is a profitable enterprise that many businessmen in major Russian cities are engaged in.
Where to use recycled metal
Ferrous and non-ferrous metals in proper purification and remelting acquire the properties of primary raw materials, so they are successfully used in industry. The result is a quality rolled metal, it is used to build cars, ships, trains, houses, precision instruments and machines.
The most profitable enterprise is the recycling of ferrous metal. It is mixed with pig iron in furnaces, and the result is quality steel. The more scrap used in smelting, the better steel is produced.
The advantages of recycling scrap:
Conservation of natural ore;
saving energy resources;
reduction of environmental pollution;
accelerating the production of rolled steel.
Unlike plastic and other recyclables, metal can be recycled countless times, and it will not lose its properties.
The greatest demand for recycled metal billets in the production of steel containers and wire. Next, in descending order, are the steel construction, construction and machine building industries.
Recycling nonferrous scrap is a more complex process. This type of raw material includes batteries with high lead content, precious metals, and products with mercury. The difficulty is that the company needs to separate the metal from household appliances and let it go into further recycling.
Stages of scrap metal recycling
The stages of recycling scrap have been formed historically, they include 4 stages: reception and sorting, cutting of raw materials, cleaning from impurities, melting the metal. They can be carried out both within a single enterprise, and be divided between several firms.
Primary shops accept only ferrous and non-ferrous metals and do not sort or cut them. The form in which the raw material arrived at the point, it is resold to other companies that perform the remelting.
Another scheme of operation: receiving and sorting. This is the most common type of company in today’s market. Metal is sorted by profile and type, and then sold to factories. The disadvantage of such companies is low-quality sorting, often there are non-metallic elements in the raw material.
The most modern type of operation is the full cycle of scrap metal processing. In large shops, non-ferrous and ferrous metal is sorted, and impurities are separated. All kinds of raw materials are remelted in furnaces. The implementation of such activities is possible in metallurgical plants and steelworks.
A prerequisite for working with scrap is radiation control. The firm is obliged to check the raw material for radiation hazards several times:
at the time of receipt;
at the time of preparation for sale;
The results of the checks are recorded in a log, on the basis of which a protocol of radiation control for each batch is prepared. If the radiation background radiation is exceeded, additional dosimetric control must be carried out.
The first thing to do at the sorting stage is to separate non-ferrous metal from ferrous metal. Most collection points limit themselves to this process.
Quality sorting also involves:
separating scrap by size;
separation of metals by chemical composition;
removal of impurities and debris.
These processes are automated at large facilities, which greatly speeds up recycling. Special loading equipment is used to move large oversized structures.
The sorting of scrap metal according to its chemical composition takes into account the quality of the metal and its type. Scrap is sorted by its carbon content, as well as by 28 qualitative indicators. At some facilities, this is done manually. Scrap metal is separated into large and small pieces, and heavy and light pieces are separated. In the next stage, large structures have to be cut for remelting.
Cutting and cutting metal
Large pieces of scrap metal are cut immediately upon receipt at the collection point. Scissors and plasma cutting machines are used for this purpose. Recycling plants have specific requirements for the size of the raw material.
Small pieces are pressed into briquettes using presses. They are similar to waste paper presses, but have a high pressure force. Sheets of metal are cut into fragments in shredders.
For the raw material to get the desired shape, it is cut with special scissors and pressed into bars. They also use special machines to bundle the sheet metal. After that, it is sent for cleaning and remelting.
Scrap metal cleaning
Metal bars are sent to a special chamber where they are crushed. This is necessary to determine the type of impurities. The raw material must be cleaned of dust, dirt and non-metallic elements.
For this purpose, separation is used. All foreign impurities are blown from the surface of the bar with a large air jet. Dirt and dust are removed from the crushing chamber.
To sift out non-metallic impurities, a magnetic separator is used. It consists of a conveyor, on which the metal parts travel. They are attracted by a magnet, and non-metallic particles remain at the bottom. Separators can be drum type or conveyor type. The machine can have different magnet capacities.
The cleaned and sliced metal is sent for remelting. The briquettes are pressed by hydraulic or mechanical presses. This is a convenient way to store and ship the material to smelters.
Smelting is done in melting furnaces. They can be electric or plasma. The first are more productive and safe for workers. The latter have a low cost, but their efficiency is lower than that of electric units.
Melting consists of several stages. Scrap metal is poured into a steel ladle with a special coating. Molten pig iron is poured on top and blown with oxygen.
At this stage it is important to get rid of the sulfur, silicon and phosphorus in the steel. They impair its properties and increase brittleness. Special additives are used to burn them out.
To make the steel stronger and more wear-resistant, they add:
Such steel is valued on the market and is used to produce parts that are subject to high wear and tear.
Modern melting units are fully automated. Workers control every step of the smelting process. Furnaces of different capacities are used for different metals.
Large metallurgical companies do not only smelting, but also rolling of the metal. Finished ingots are easier to transport and sell, so such companies are more profitable.