Recovering zinc and manganese from spent zinc-carbon batteries via leaching manganese dioxide

The recovery rate of manganese dioxide in the spent zinc-carbon batteries was found very low,therefore a method,in which zinc powder as reductant was added into a neutral solution to speed up the leaching process of manganese dioxide,was proposed and employed in the process.The results of experiments indicated that the liquid/solid ratio had a crucial effect on the leaching kinetics,and that a liquid/solid ratio of 2: 1 with a leaching time of 120 min yielded the best result.The leaching rate of manganese dioxide was little influenced by leaching temperature when the latter is above 50 ℃,and by agitating rate as well.The dynamic leaching mechanism of manganese dioxide with zinc reduction could be well accounted for based on a shrinking-sphere model.