Enhancing the separation of iron and manganese from high-iron rhodochrosite through medium-low temperature calcination and leaching

Abstract

How to realize the separation of iron and manganese in complex high-iron rhodochrosite and reduce the concentration of iron ion in leaching liquid is the core to realize the resource utilization of complex high-iron rhodochrosite. In this study, enhancing iron and manganese separation from high-iron rhodochrosite during the leaching process by medium low temperature calcination was investigated. The results showed that when the calcination temperature was 400 ℃, the calcination time was 4 h, the leaching time was 2.5 h, the ore acid ratio was 1:0.22, and the leaching temperature was 50 ℃, the leaching efficiency of manganese reached 88.62 %, and the concentration of iron in the leachate decreased from 6.88 g/L to 1.95 g/L. When the calcination temperature is raised from 300 ℃ to 400 ℃, the concentration of iron in the leachate decreases, the MnO produced by the continuous decomposition of MnCO₃ in rhodochrosite and the Fe₂O₃ produced by the oxidation of FeS₂ combine to form structurally stable MnFe₂O₄, which plays a dominant role in inhibiting iron leaching. As the calcination temperature continues to rise from 400 ℃ to 500 ℃, the concentration of iron in the leachate increases, attributed to the transformation of MnO into Mn₂O₃ and a small amount of Fe₂O₃ into Fe_1-xS, resulting in a decrease in the source of MnFe₂O₄ formation. This study provides theoretical and technical support for the resource utilization of high-iron rhodochrosite.