Method and apparatus for reclaiming foundry sand

Claim 1

A method for reclaiming foundry sand from foundry sand contaminated with a binder which comprises: separating ferromagnetic contaminants from the contaminated sand in a magnetic separating zone, thermally treating the remaining contaminated sand in a fluidized bed at a temperature of at least 870° C. for up to 45 minutes to cause burning off of carbon and embrittlement of binder constituents among the remaining contaminants, cooling the sand after such thermal treatment, cleaning the thus treated sand in a counterflow impact jet mill operating at air velocities of from 30 to 50 m/sec to strip solid binder crusts from the surfaces of the sand grains essentially by collisions of said particles with each other, and sifting the thus cleaned sand to separate relatively coarse, non-comminuuted sand grains from finer grained particles of fractured binder crusts.