METHOD OF PRODUCTION OF ZINC OXIDE FROM TECHNOGENIOUS RAW MATERIAL Russian patent published in 2004 - IPC

FIELD: metallurgy; zinc hydro-metallurgy by processing zinc-containing technogenious raw materials. SUBSTANCE: proposed method includes leaching-out of raw material by sodium hydroxide solution followed by introducing calcium oxide and elementary sulfur into pulp, diluting this pulp with water, filtering and separating sediment from alkali zincate solution, decomposition of it by introducing inoculation zinc oxide, keeping this suspension at 85-95 C for 5-7 h followed by filtration and separation of mother liquor from sediment, as well as flushing, drying and calcination. Prior to decomposition of alkali zincate solution by zinc oxide, solution is treated with sodium bicarbonate at rate of 15-25 kg/cu m at 55-65 C continued for 3-5 h; sediment obtained at this is additionally separated from alkali zincate solution before decomposition. EFFECT: enhanced efficiency of cleaning; reduced amount of admixtures in finished product. 3 tbl, 3 ex