Sustainable Mining and Metallurgy

In this paper, nickel sulfate, a by-product of copper electrolysis, was refined and purified by the process of “roasting deamination-dissolution liquid-oxidation iron removal-P204 extraction impurity removal-evaporation crystallization”. The experimental results show that after 40min calcination and deamination, there is almost no ammonium ion in the crude nickel sulfate; using H2O2 as oxidant and Ni(OH)2 as neutralizer, under the conditions of reaction time 60min, reaction temperature 60-70℃ and no adjustment of acidity, the removal rates of iron and arsenic were 98.8% and 94.3%, respectively. Using P204 as extractant, the extraction rate of nickel is only 0.72%, the extraction rates of calcium, copper, iron, manganese and zinc impurities are all greater than 99%, and the concentrations of calcium, copper, iron, manganese and zinc in the raffinate are all less than 10mg/L; finally, the main grade of nickel sulfate obtained by evaporation crystallization is more than 22%, which meets the requirements of refined nickel sulfate products of HG/T 2824—2022.