Particulate refractory compositions for use in the manufacture of foundry moulds and cores, methods of preparing same and corresponding uses

摘要

The invention relates to a method of preparing a particulate refractory composition for use in the manufacture of foundry moulds and cores from spent foundry moulds or cores formed of refractory material and an alkaline binder containing alkali metal ions, the method comprising the following steps: providing broken material from spent foundry moulds or cores or preparing broken material from spent foundry moulds or cores, mixing the broken material with an additive comprising or consisting of one or more particulate constituents selected from the group consisting of aluminum hydroxide, synthetic zeolites and natural zeolites and subjecting the mixture to a heat treatment at a temperature in the range of from 400 to 750 °C. Furthermore the invention relates to particulate refractory composition for use in the manufacture of foundry moulds and cores.