Scrap metal and iron that can be collected for recycling include metal from old automobiles, steel, cast iron kitchen pipes, aluminum, tin cans and scrap metals taken from demolition sites and old household appliances. Most of the scrap metal that is collected has a corroded surface. Fortunately, the brittle rust can be removed with a hammer or sledge hammer to "shatter" the outer plate of the metal. The interior can still be considered iron and can still be used.
Once the scraps are stripped, they needed to be sorted according to their components. These include painted iron, tin cans, aluminum, cast iron, copper or steel. Sorting is done by using a magnet to separate the steel from aluminum, while copper are inspected and graded. Copper is graded into six different types, the purer the copper is the higher its price is in the market. Meanwhile, tin cans are washed using a caustic chemical to remove the outer layer of the can, which contains majority of the tin component. Most recycling centers use machines to reduce large scraps into small pieces. All sorted scrap metal or iron needs to be crushed or broken into small pieces, called shredding, so it is easier to work with and more manageable. This also makes it easier for the shredded metal to bale and be melted.
The baling process comes next, once the sorting is done. Baling is done for easy transport to smelting facilities. Once there, the bales are fed into a smelting furnace where they are melted and then poured into casters, in which they are molded into ingots. The ingots, which are formed after melting the scrap iron and metal, are then sold to manufacturers for a price that usually depends on the market demand and supply.
Manufacturers flatten these ingots and use them to form the basis for new metal or iron materials. These include car chassis, metal piping, tin cans and furniture. The processed iron and metal are also used in the construction of roads, building, bridges and electronic appliances. Some of these metals also are used in aviation and shipping because of the more economical price of used iron. There are also companies that use iron scrap to purify water. Ferrous metals are also being used to detox industrial waste water to make it safer for consumption, especially in cities notorious for the lack of potable water.