RECUPERATION PROCESS OF ALUMINIUM OXIDE AND SILICON DIOXIDE

摘要

PCT No. PCT/IL96/00179 Sec. 371 Date Dec. 15, 1998 Sec. 102(e) Date Dec. 15, 1998 PCT Filed Dec. 12, 1996 PCT Pub. No. WO97/22554 PCT Pub. Date Jun. 26, 1997A process for the simultaneous recovery of substantially pure alumina and silica from an aluminosilicate. The process comprises the following steps: (i) heating the aluminosilicate with hydrated CaCl2 to obtain calcium-alumino-silicate and calcium-aluminate products, wherein the CaCl2 is substantially free of MgCl2; (ii) leaching the products with HCl to form a solution comprising AlCl3 and CaCl2, and insoluble silica; (iii) separating the insoluble silica from the solution; and (iv) crystallizing AlCl3 from the solution and recovering the alumina from the crystallized AlCl3. The process may further comprise the following steps: (v) substantially removing MgCl2 from the CaCl2 solution of step (iv); and (vi) recycling the CaCl2 solution for use in step (i).