METHOD OF PREPARING A PARTICULATE REFRACTORY COMPOSITION FOR USE IN THE MANUFACTURE OF FOUNDRY MOULDS AND CORES, CORRESPONDING USES, AND RECLAMATION MIXTURE FOR THERMAL TREATMENT

Described is 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 a binder containing water glass, 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, wherein the broken material comprises particles and/or aggregates of particles of refractory material having hardened water glass binder on their surface, mixing the broken material with particulate amorphous oxide comprising silicon dioxide in an amount of 85 % by weight or more, based on the total amount of the particulate amorphous oxide, to give a mixture and subjecting the mixture to a heat treatment at a temperature of 400 °C or higher. Also described are a corresponding use, a reclamation mixture, and a method of making a foundry mould or core.