METHOD FOR RECOVERING COPPER OXIDE AND ALKALI METAL CHROMATE FROM COPPER CHROMITE

摘要

1,223,734. Treating copper chromite. SUMITOMO CHEMICAL CO. Ltd. 4 Oct., 1968, No. 47221/68. Heading C1A. Alkali-metal chromate and cupric oxide are obtained by reacting copper chromite, CuO. CuCr 2 O 4 , with a compound M n B m , where M= Na or K, B is O=, OH-, HCO 3 - or CO 3 = and m and n= 1 or 2, and mixing the reaction mixture with water to recover CuO as an insoluble solid and alkali-metal chromate as a solution. The chromate may be recovered from solution by concentration and crystallization. Preferably the chromite, which may be a waste catalyst material, and the alkali-metal compound are mixed in the appropriate stoichiometric amounts and reacted at 300-1200‹ C. in the presence of oxygen or molecular oxygencontaining gas, the product being cooled, and then boiled with water. The M n B m compounds which may be used are NaHCO 3 , KHCO 3 , Na 2 CO 3 , K 2 CO 3 , NaOH, KOH, Na 2 O, K 2 O, Na 2 O 2 and K 2 O 2 . The copper chromite may also be formed from a reduced copper chromite (Cu 2 Cr 2 O 4 ) catalyst by oxidation. The reaction mixture may be poured into 1 to 5 times by weight of water and boiled for 0À5-3 hours.