Dissolution behavior of ferrous sulfate in the hematite process

Among the currently available processes, iron precipitation as hematite from hydrometallurgical process solutions is the most suitable from an environmental point of view. The crystallization and dissolution of ferrous sulfate play an essential role in the hematite process. In this work, the effects of the Zn2+ concentration, temperature and oxygen partial pressure on the ferrous ion concentration, solution pH, and the composition of filter residues and crystallization sediments were studied. The influence of the dissolution behavior of ferrous sulfate on the hematite process was explained based on crystallization theory. The results indicated that the ferrous ion concentration in the solution showed a “wave-like” change in the presence of Zn2+ due to the common ion effect and the isomorphism effect. The sulfur content in filter residues increased as the concentration of SO42− was increased by the addition of zinc sulfate and due to the increasing concentration of ferrous ions. Additionally, the maximum variation was obtained for the Fe content decreased from 11.52% to 7.3% and Zn content increased from 20.86% to 24.54% in the sediments.