Because of the high volume of scrap and waste metal produced by the metalworking industry and other industrial, commercial and consumer sources, an effective method of processing the scrap in advance of reuse is necessary.
Production of new steel and other metals can be resource intensive and expensive. Recycling ferrous metals is about 75% cheaper just in terms of energy consumption expenditures than is the mining and processing of new materials. Any method that allows for the reuse of discarded metal is a method that saves money. But in order for a discarded metal product to be remade into something usable, a few things have to happen first.
Metals like aluminum need to be melted and then formed. In order to be melted, the aluminum has to be manageable. Metal shredders take discarded metal products and shred them into sizes that can be easily reprocessed into something useful. For this reason, they are a critical component of the metal recycling process. The range of metal products that require shredding is enormous; discarded metal products can be as large as automobile frames and as small as soda cans.
Because the range of metal products that require shredding is so variable, the range of shredders must be equally variable to accommodate them. Shredders can be large enough to efficiently shred entire vehicles; the shredder a Sims plant in Wales can shred 450 cars in an hour. Metal shredders can also be mobile for the management of specialized, individual shredding projects. Most shredders involve at least two rollers layered with sharp teeth that rotate toward each other.
A chute positioned above the rollers directs individual items or a flow of items, depending on the scale of the shredding operation, into the rollers. The turning of the rollers and the interaction of the metal scrap with the sharp teeth tears the material apart. Once the torn scrap pieces are small enough, they pass between the rollers into a collection area or onto a conveyor belt. From that point, depending on the purpose and size of the operation, the material is directed or hauled to its next point of processing.