Metal is a valuable and prevalent commodity, but it is often very heavy and bulky, especially scrap metals. Scrap metals can be recycled many times without changing their properties. Steel and aluminum are the most recycled material on the planet, according to the American Iron and Steel Institute (AISI). The other commonly recycled metals are copper, silver, brass, and gold. In this article, we will explain what is metal recycling? and do we need it.
Do We Need to Recycle Metals?
Metals are valuable materials that can be re-forged and reused. Scrap metal has values, which attract people to collect it for sale to recycling operations.
Other than a monetary incentive, there is also an environmental need. Metals on earth are limited. The recycling of metals enables us to save natural resources while requiring less energy to process new metals from ores. The production process emits carbon dioxide and other harmful gasses. Conversely, the more we reuse, the less harmful wastes are created. More importantly, it saves money because recycled metals are cheaper.
Metal Recycling Figures
Better than plastic recycling at 10%, 30% of metal is recycled. Below are some data:
Types of Recyclable Metals
Metals can be classified as 2 types: ferrous or non-ferrous. “Ferrous” means “containing iron” in Greek, therefore, ferrous metals are combinations of iron. Some examples are carbon steel, alloy steel, wrought iron, and cast iron.
Non-ferrous metals include aluminum, copper, lead, zinc, and tin. Precious metals are non-ferrous. The most common precious metals include cobalt, gold, platinum and silver.
How Metal Recycling Works
What is Metal Recycling? There are 6 main stages of the metal recycling process:
The collection process is for consumer products and industrial products. Consumer products range from like batteries to food cans. Industrial waste is more often bulky objects. High value(heavy) products are more likely to be sold to wreck yards than landfills. The largest source of scrap ferrous metal in the U.S. is from scrap automobiles and home appliances.
Sorting involves separating metals from the mixed scrap metal stream. In a scrap metal recycling line, it often consists of manual sorting, magnetic and sensors.
To allow further processing, metals are processed in the shredder. Shredding is done to reduce the volume then easier to enter melting pots. Here is a video of metal shredding demo.
Scrap metal is melted in a large furnace. Different types of metal are taken to melt independently. A significant amount of energy is spent on this step. This process takes up several minutes to hours.
Purification ensures the final product is of high quality and free of contaminants. One of the most common methods is electrolysis.
After purification, melted metals are carried by a long conveyor belt to cool and solidify the metals. In this stage, scrap metals are formed into specific shapes such as bars and plates that can be easily used for the production of various metal products.
In the last step, the final products are sold and transported to factories to make.
Metal Recycling Equipment
Modern recycling technologies can effectively reclaim ferrous metals, however, we need a better way of recycling non-ferrous metals. As mentioned, separating ferrous metals from non-ferrous metals is the earliest step in the sorting process. Magnetic separator easily removes ferrous metals contain iron from stream materials. This leaves non-ferrous metal alone.
Next, the use of Eddy current separation rejects different types of ferrous metals altogether. Based on different magnetic forces induced by ferrous metals, the metals are shot away at a different range of trajectories. Usually to separate 2 non-ferrous at 1 time is common. In the end, only plastics and other resides remain.
Other advanced technologies are x-ray and infra-red scanning. These two require finely crushed particles of metals. Speak of any high technologies, categorizing, and primary sorting are far more essential. Why and how to recycle metal? Wiscon wishes this topic is explained thoroughly.