HYDROMETALLURGICAL EXTRACTION AND PRODUCTION OF MANGANESE DIOXIDE FROM KAOJE MANGANESE ORE DEPOSITS, NIGERIA

Battery-grade Manganese Dioxide (MD) was synthesised from manganese ore obtained from Kaoje ore deposits in Kebbi State, Nigeria, using hydrometallurgicalextraction and thermal decomposition methods. Manganese from pre-reduced ore samples was leached out using dilute nitric acid as leachant. Effects of the acid concentration and temperature on leaching efficiency were investigated after which the eluate was purified using aqueous NaOH as the precipitation agent. The purified and crystallized manganese nitrate was thermally decomposed at 130 °C to synthesize the MD. The result showed that synthetic manganese dioxide with purity of 87.9 % was achieved. The MD was utilized in building Alkaline cell (Zn/NaOH/MnO2) to establish its activeness. The constructed electrochemical battery had the produced MD as the cathode active material. The battery actively discharged upon loading (1 K and 2 K resistors) for 120s after which the current stabilized. The voltage discharge was from 1.9 V to 0.21 V in 720 s. The battery practically re-energized itself back to initial state when unloaded. The results showed that the produced MD is a suitable active material in production of MnO2 based batteries.