New technology for preparing electrolytic manganese metal solution and recycling iron by reducing pyrolusite with iron scraps

The invention discloses a new technology for preparing manganese sulfate solution which is used for electrolyzing manganese metal and recycling iron through the atmospheric pressure leaching of pyrolusite and iron scraps. The technology comprises the following steps: adding pyrolusite in a certain concentration of sulphuric acid solution, mixing evenly; adding iron scraps used as the reductant in a reaction tank, performing mechanical agitation for 1h-3h under different reaction temperatures to obtain reaction leachate; according to the changes of the reaction time and the pH value, adding heavy calcium carbonate and ammonia water in turn to adjust the pH value of the solution to 6.3-6.7; then adding sodium N,N-dimethyl dithiocarbaminate (SDD) to remove impurities such as heavy metal ions and purify; filtering, adding additive to obtain manganese sulfate solution used for electrolyzing manganese; and recycling iron from filter residue through alkali leaching and acid leaching to produce polyferric sulfate. The invention has the advantage that iron scraps are used as the reductant which have wide sources and rich raw materials and can be leached out under the atmospheric pressure; and iron scraps can be recycled to produce the water purification agent and have great economic benefit.