Sand is an essential material to make molds in any casting factory. It is used in used in both ferrous and non-ferrous metal casting foundries. Sand is probably the oldest method used since ancient times to make molds for casting different metals. Sand is used as a molding material to form the external shape of the component as well as a material to form the core, the internal spaces in many parts like engine blocks.
More than 100 million tons of foundry sand is used in the casting industry every year. As this sand is of high quality, it can prove very beneficial both financially and environmentally to recycle this sand and use in for other purposes.
Two methods are commonly used to bind sand grains together to form a mold: clay bonding systems known as green sand and chemically bonded systems known as resin sands. Although they have different properties, both types of the sand can be recycled.
Aluminum and ferrous foundries produce around 90% of the total foundry sand. Thus, they provide a constant and sizable supply of foundry sand to be recycled. However, the transportation cost of the sand is the biggest expense and a major challenge. Thus, it is the best to recycle and use the sand near the location of foundries. Finding ways to use it near the foundries will be beneficial for all parties.
Recycled foundry sand can be used in many industries. These industries include construction, flowable fill, cement kiln feedstock, and manufactured soils. Some more applications of the recycled sand include hot mix asphalt, precast concrete products, ready mix concrete, landfill construction material, bricks and paving material, daily landfill covers, and grouts and mortars.
If recycled with proper methods, foundry sand recycling can have environmental as well and financial benefits for the foundries and othe industries.