Process for reclaiming foundry sand wastes

摘要

A process for treating waste foundry core and/or molding sand in a manner which upgrades these scrap streams to new sand quality for entry at the core making point. The process consists of incrementally heating the sand as required up to temperatures in the 1800 DEG to 2500 DEG F range, followed by cooling. The degree of heating is chosen to achieve a desired lowering of acid demand value (ADV) from that which would result from heating only to conventional high temperatures, about 1500 DEG F. Lowering of ADV reduces the variability which would otherwise be introduced into a mixture of new and recycled sand for cores.