Harmless treatment of used foundry sands and dewatered municipal sludge by microwave

A new method to treat four solid wastes of sodium silicate used sands, dewatered municipal sludge, clay sands sludge and waste polyethylene, was discussed. About wt/ 50 % sodium silicate used sands and wt/ 50 % dewatered sludge were mixed, and then cured by microwave with a certain thickness film of clay sands sludge and waste plastic of polyethylene in the surface. The results showed that the compression strength of granulation sample with the size of Ф 50 × 50 mm was over 0,45 MPa. The waste plastic was the key factor for the durability, and curing temperature must be over melting temperature, so the thicker film could be coated in the surface of used sands and sludge