Metals can be recycled repeatedly without changing their properties. According to the American Iron and Steel Institute (AISI), steel is the most recyclable material on the planet. Other highly recycled metals include aluminum, copper, silver, brass and gold.
Why We Recycle Metals?
Metals are valuable materials that can be recycled repeatedly without disturbing their properties. The economic value of scrap metal makes recycling processes attractive. In addition to this financial advantage, environmental necessity should not be forgotten.
Recycling of metals requires less energy than the manufacture of new products using raw materials, while preserving natural resources.
By recycling, less carbon dioxide and lower amounts of other harmful gases are released into the atmosphere. In addition, it saves money and allows businesses to reduce production costs. Recycling also creates employment.
Metals Recycling Report
Almost any type of metal can be recycled repeatedly without deterioration in its properties. However, only 30 percent of the metals are currently being recycled. Here are some additional information:
• Approximately 40 percent of the world’s steel production is made from recycled steel.
• About 42 percent of crude steel in the United States is made of recycled materials.
• In the US alone, approximately 100 million steel and canisters are used every day.
• Steel and iron are the most recycled materials in the world due to the ease of reprocessing and the opportunity to recover large structures. The use of magnets in the sorting process allows recyclers to easily separate them from the mixed waste stream.
• Approximately 400 million tons of metal are recycled every year worldwide.
• Currently, the most recycled consumer product in the US is the aluminum case.
• Wasting a single aluminum can means wasting that can’s size of gasoline.
Recycled Metal Types
Metals can be classified as ferrous or non-ferrous. Ferrous metals consist of a combination of iron and carbon. Some common ferrous metals include carbon steel, alloy steel, wrought iron and cast iron.
On the other hand, non-ferrous metals include aluminum, copper, lead, zinc and tin. Precious metals are non-ferrous, the most common precious metals are gold, platinum, silver, iridium and palladium.
Metal Recycling Process
The main stages of metal recycling are as follows:
1. Collection
Collecting for metals differs from other materials due to its high scrap value. Therefore, they are likely to be sold to scrap sites more than those sent to the landfill. The largest source of scrap metal in the US comes from scrap vehicles.
Other sources include large steel structures, railway tracks, ships, agricultural equipment, and of course consumer scrap. Rapid scrap created during the production of new products accounts for half of the iron scrap supply.
2. Sorting
The sequencing step involves the separation of metals from the mixed scrap metal stream or from the mixed multi-material waste stream. In automatic recycling processes, magnets and sensors are used to assist in the separation of material.
Scrapers can use a magnet as well as observe the color or weight of the material to help identify the metal species.
For example, aluminum will be silver and light. Other important colors to look for are copper, yellow (for rice) and red (for red rice). Scrapers improve the value of their materials by separating clean metal from contaminated material.
3. Processing
The metals break down to allow further processing. The shredding is carried out to support the melting process, since the small shredded metals have a large surface / volume ratio. As a result, they can be melted using relatively less energy. Normally, aluminum is turned into small sheets and steel is converted into steel blocks.
4. Melting
Scrap metal is melted in a large furnace. Each metal is taken to a specific furnace specially designed for it. This step uses a significant amount of energy. However, as noted above, the energy required to melt and recycle metals is much less than the energy required to produce metals using raw materials.
Depending on the size of the furnace, the temperature of the furnace and the volume of the metal, melting may take from a few minutes to several hours.
5. Treatment
Treatment is carried out to ensure that the final product is of high quality and free of contaminants. Electrolysis is one of the most common methods used for purification.
6. Solidification
After purification, the molten metals are conveyed by the conveyor belt to cool and solidify the metals. At this stage, scrap metals are formed in specific shapes, such as rods, which can be easily used in the production of various metal products.
7. Transport of Metal Bars
When the metals are cooled and solidified, they are ready for use. They are then moved to various factories where they will be used as raw materials for the production of new products. When the products made from these metal rods are at the end of their life, the metal recycling process takes place again.
Kaynakça / References
• https://www.thebalancesmb.com
• “Recycling metals — aluminium and steel”. Archived from the original on 16 October 2007. Retrieved 1 November 2007.
• https://earth911.com/eco-tech/basics-recycling-scrap-metal-money/
