Leachability of Foundry Process Solid Wastes

A laboratory procedure was developed for testing the leachability of foundry process solid wastes. This procedure uses a shake-flask technique to provide distilled water-foundry waste contact, plus filtration or centrifugation, or both, to separate the resulting liquid for analysis. The procedure was used to examine the leaching characteristics of eight different foundry process wastes, each of which had been previously subjected to temperatures ranging from room temperature to temperatures of molten metal. This was done to simulate the burn-out which would actually be experienced with some wastes. The eight wastes exhibited widely different leaching characteristics, but in all cases the amount of matter leached per unit weight of water decreased markedly as the temperature to which the waste was subjected increased. Additional experiments utilizing the shake-flask procedure indicated that progressively larger particles of waste, such as core butts, release less matter to leachate per unit weight of waste than the unagglomerated sand.