Extraction of Manganese from Calcium-Roasting Vanadium Slag

As a kind of industrial waste with complex composition, converter vanadium slag contains vanadium, iron, chromium, and manganese (Mn), which made it possible to reuse this resource. In particular, the manganese content reached 6.82 wt.%, which made it a potential low-grade manganese resource. To effectively recover manganese from converter vanadium slag, acid extraction technology was adopted, and the effects of various experimental parameters, including the acid concentration, reaction time, reaction temperature, and liquid-to-solid ratio, on the extraction process were studied. The results showed that the experimental parameters all had a positive effect on the extraction process and that Mn could be easily extracted and achieved a high extraction efficiency of 66.5% in a short time. The highest extraction efficiency of 76.1% could be obtained under the optimal reaction conditions: a H2SO4 concentration of 10 vol.%, reaction temperature at 90 degrees C, reaction time of 120 min, liquid-to-solid ratio at 4:1 mL/g, and stirring rate at 500 rpm. The extraction process of Mn was controlled by the diffusion of Mn through the CaSO4 film, and the extraction kinetics behavior followed well with the shrink core model, and the Ea for Mn extracted out was calculated as 19.45 kJ mol-1.