Removal of molybdenum from MnSO4 solution with freshly precipitated “nascent” Mn3O4

The scavenging of molybdenum from MnSO₄ solution with freshly precipitated “nascent” Mn₃O₄ is reported. Firstly, nascent Mn₃O₄ was prepared from MnSO₄ solution by adding NaOH and aerating. The aeration time had a significant influence on the preparation of nascent Mn₃O₄, but other factors such as pH and ageing time had little effect. SEM, XRD, particle size and surface area analysis were used to characterize nascent Mn₃O₄. A study was then carried out on the effects of time, concentration of Mn, initial pH, temperature and dosage of nascent Mn₃O₄ on the adsorption of Mo from MnSO₄ solution. The results showed that the concentration of Mo in 70–200 g L^− 1 MnSO₄ at pH 1–3 could be reduced from about 1 mg L^− 1 to less than 0.015 mg L^− 1 in 30 min at 80 °C by the addition of about 0.3 g L^− 1 nascent Mn₃O₄ in suspension. Accordingly, the removal capacity of nascent Mn₃O₄ can reach 4.42 mg Mo/g Mn₃O₄. This Mo removal exceeds the requirement for special electrolytic MnO₂ used in the production of alkaline zinc–manganese batteries.