Patent ID: 6447738
Filing Date: 2002-09-10
Classification: C01D,C01F,C01G,C22B,Y02P

Abstract:
A process for extracting alumina and other metal values from feedstocks and ore bodies, comprising:removing a leach liquor of metal sulfates and sulfuric acid after cooking at about 200Â° C. in a pressure autoclave; reducing any ferric values in said leach liquor with SO2 to produce a ferrous sulfate which remains in said leach liquor; removing potassium by crystallizing any double salt values of aluminum alkali sulfate in said leach liquor at about 20Â° C.-60Â° C.; washing said double salt free from said leach liquor; hydrolyzing said double salt at about 180Â° C.-250Â° C. to form a basic double salt of aluminum potassium sulfate; removing, washing, drying and calcinating the basic double salt of aluminum potassium sulfate to produce an alumina and a potassium sulfate; washing said alumina and recycling said potassium sulfate; and drying said alumina washed free of potassium sulfate.