A new multi-stage process is in use for regenerating used foundry sand. Preheated air and natural gas burn the carbon, followed by a second reaction chamber to ensure the gases are completely burned.
Heat is recovered to the foundry by counter-current water flow through the regenerated sand.
The sand is further cleaned of impurities in a counter-current impact mill consisting of two gas jets, which clean the particles with application of friction. This process is effective, lower costs, and produces regenerated sand of similar quality to fresh sand.