Recovery of Alumina from Alunite by Acid Sulfation.
Wouden-ML; Froisland-LJ; Shirts-MB
Metall Soc AIME Tech Pap A87-22 1987 :10 pages
This paper describes research in separating and recovering alumina from domestic alunite (kal3(so4)2(oh)6) deposits by an acid sulfation process. Development of this process would lessen U.S. dependency on alumina from outside bauxite sources in times of national emergency. In the process, alunite is sulfated by reaction with 200 deg to 300 deg c concentrated sulfuric acid. Acid- insoluble aluminum sulfate is water-leached at 95 deg c and recovered by crystallization upon cooling the solution. Following purification, calcination of the crystals can produce cell-grade alumina. The potassium component of alunite is extracted into the sulfuric acid for eventual recovery in a separate process. This paper describes the effects of reaction variables in the acid sulfation step. Reaction conditions are selected to yield a minimum of 95 pct aluminum and potassium extraction and separation.
Metall. Soc. AIME Tech. Pap. A87-22, 1987, 10 PP.