Method for reconditioning green foundry sand.

摘要

Green sand having a residuum of retained clay is reconditioned by screening and predrying it to about zero moisture; calcining the sand to burn off organic matter; cooling the sand; mechanically scrubbing the cooled sand to free mechanically bonded clay and a portion of the clay magnetically adhered to the sand; mixing an acid/water solution with the sand to react with the remaining magnetically adhered clay to permit such clay to break free from the sand; drying the sand to release the freed clay; and extracting the thus-released clay from the sand.