Separation of Iron (III) and Nickel (II) from Acidic Sulfate Leaching Solution of Molybdenum-Nickel Black Shale

摘要

Cooling crystallization was used to separate iron (III) and nickel (II) from acidic sulfate solution produced by leaching of molybdenum-nickel black shale. The effect of K_2SO_4 concentration, crystallization temperature, solution pH and crystallization time on recovery of nickel (II) and precipitation of iron (III) was investigated, in order to obtain effective separation of nickel and iron. The optimum parameters determined were as follows: 200 g/L K_2SO_4, 10 °C crystallization temperature, solution pH of 0.5 and 24 h crystallization. Under these conditions, 97.6% nickel (II) was recovered as K_2Ni(SO_4)_2·6H_2O crystals and only 2.0% of the total iron (III) was precipitated. Recrystallization yielded K_2Ni(SO_4)_2·6H_2O crystals with a purity of 98.4%.