Preparation of ferrous sulfate from acid leaching solution of iron-bearing residue by reduction and purification with pyrite
Serpentine neutralization residue contains a lot of Fe and a small amount of Ni,Co,Cr and Al. In order to recover Fe,it is necessary to remove Ni,Co,Cr and Al. In this paper,the acid leaching solution was obtained by leaching serpentine neutralization residue with sulfuric acid. The resulting solution was reduced by pyrite from Hongtoushan,and the pure ferrous sulfate solution was obtained after removing Ni,Co,Cr and Al in one step by natural pyrrhotite. High-purity ferrous sulfate was prepared by evaporation and crystallization. The impurity removal mechanism with pyrrhotite was analyzed. The results show that 99.99％ Fe3+is reduced by pyrite at 85 ℃ and 260 min. Under the conditions of 90 ℃,liquid-solid ratio of 1.25,reaction time of 8 h,the removal percentages of Ni,Co,Cr and Al in reducing solution reach 99.99％,99.99％,99.56％,91.24％,respectively. The purified solution of ferrous sulfate is evaporated and crystallized to obtain iron(Ⅱ) sulfate heptahydrate,all indexes reach GB/T 664—2011 chemical-reagent standard. that Ni and Co are removed by ion exchange,Cr is removed by sulfide precipitation,and Al is removed by hydrolysis adsorption.
iron-bearing residuereduction and purificationpyriteferrous sulfate
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