Metal Recycling

Metals can be recycled repeatedly without losing 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 Do We Recycle Metals?

Metals are valuable materials that can be recycled repeatedly without degradation of their properties. The economic value of scrap metal makes recycling operations attractive. Beyond this financial advantage, the environmental imperative must not be forgotten. Metal recycling requires less energy than manufacturing new products using raw materials, while protecting natural resources. Recycling results in less carbon dioxide and lower amounts of other harmful gases being released into the atmosphere. Moreover, most importantly, it saves money and reduces production costs for businesses. Recycling also creates employment.

Metal Recycling Report Card

Nearly every type of metal can be recycled repeatedly without degradation of its properties. Nevertheless, currently only 30% of metals are being recycled. Additional information is provided below: • Approximately 40% of global steel production is made using recycled steel. • Approximately 42% of crude steel in the United States is made from recycled materials. • Approximately 100 million steel and tin cans are used daily in the US alone. • Steel and iron are the world's most recycled materials due to their ease of reprocessing and the opportunity to recover large structures. The use of magnets in sorting allows recyclers to easily separate them from mixed waste streams. • Approximately 400 million tons of metal are recycled globally each year. • Currently, the most recycled consumer product in the US is the aluminum can. • Wasting a single aluminum can is equivalent to wasting a can full of gasoline. Types of Recyclable Metals 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. Non-ferrous metals, on the other hand, 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 the metal recycling process are as follows:

1. Collection

Collection for metals differs from other materials due to their high scrap value. For this reason, it is more likely to be sold to scrap yards than sent to landfills. The largest source of scrap ferrous metal in the US comes from scrap vehicles. Other sources include large steel structures, railroad rails, ships, farm equipment and of course consumer scrap. Prompt scrap generated during new product manufacturing comprises half of the ferrous scrap supply.

2. Sorting

The sorting stage involves separating metals from mixed scrap metal streams or mixed multi-material waste streams. In automated recycling operations, magnets and sensors are used to assist in material separation. Sorters can observe the color or weight of material as well as use a magnet to help determine metal type. For example, aluminum will be silver and light. Other important colors to note include copper, yellow (for brass) and red (for red brass). Scrapers improve the value of their materials by separating clean metal from dirty material.

3. Processing

Metals are shredded to enable further processing. Shredding is performed to support the melting process because small shredded metal pieces have a large surface area to volume ratio. As a result, they can be melted using relatively less energy. Typically, aluminum is converted into small flakes and steel into steel blocks.

4. Melting

Scrap metal is melted in a large furnace. Each metal is fed into a furnace specifically designed for it. Significant amounts of energy are used in this step. Nevertheless, as mentioned above, the energy required to melt and recycle metals is far less than the energy needed to produce metal using raw materials. Depending on the furnace size, furnace temperature and metal volume, melting can take anywhere from several minutes to several hours. 5. Purification Purification is performed to ensure the final product is of high quality and free of contaminants. One of the most common methods used for purification is electrolysis. 6. Solidification After the purification process, molten metals are transported via conveyor belt for cooling and solidification. At this stage, scrap metals are formed into specific shapes, such as rods, that can be easily used in the production of various metal products. 7. Transportation of Metal Rods When metals cool and solidify, they are ready for use. They are then transported to various factories where they will be used as raw material in the production of new products. When products made from these metal rods reach the end of their service life, the metal recycling process occurs again. 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/   Prepared by: Serhat Cengiz