METHOD OF PRODUCTION OF HIGH-PURITY PRIMARY BASE ALUMINUM Russian patent published in 2003 - IPC

FIELD: production of primary base aluminum by electrolysis. SUBSTANCE: proposed method includes leaching of alumina-containing ore, such as bauxites, calcinating agent thus obtained at high temperature, cleaning sulfuric and/or hydrofluoric acid for reduction of content of silicon in surface layer and placing alumina in Hall-Herult electrolyzer as main starting material. Used as additional starting material in Hall-Herult electrolyzer is anode made from decalcified coke and/or decalcified pitch. According to second version, anode for electrolysis is made with the use of carbon material; anode is placed in Hall-Herult electrolyzer as additional starting material. Decalcified coke is obtained due to treatment of starting coal tar by organic solvent, repeated distillation and calcination. Decalcified pitch is obtained by treatment of starting coal pitch by organic solvent followed by repeated distillation. EFFECT: reduced content of silicon and iron in primary aluminum; purity close to purity of refined aluminum. 4 cl, 2 dwg, 6 tbl, 4 ex