Removal of molybdenum from MnSO 4 solution with freshly precipitated “nascent” Mn 3O 4

Abstract

The scavenging of molybdenum from MnSO 4 solution with freshly precipitated “nascent” Mn 3O 4 is reported. Firstly, nascent Mn 3O 4 was prepared from MnSO 4 solution by adding NaOH and aerating. The aeration time had a significant influence on the preparation of nascent Mn 3O 4, 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 Mn 3O 4. A study was then carried out on the effects of time, concentration of Mn, initial pH, temperature and dosage of nascent Mn 3O 4 on the adsorption of Mo from MnSO 4 solution. The results showed that the concentration of Mo in 70–200 g L − 1 MnSO 4 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 Mn 3O 4 in suspension. Accordingly, the removal capacity of nascent Mn 3O 4 can reach 4.42 mg Mo/g Mn 3O 4. This Mo removal exceeds the requirement for special electrolytic MnO 2 used in the production of alkaline zinc–manganese batteries.