Comprehensive Utilization Of Manganese-containing Waste Slag In Hydrometallurgical Process And Extraction And Elimination Of Sodium Dithionate Dehydrate In Electrolytic Manganese Solution

According to the principles of environmental protection and sustainable development,this paper proposes corresponding solutions for several problems that need to be solved in the development process of manganese industry,and conducts specific experimental process research according to the proposed solution.The content of the paper is mainly divided into the following four parts:1.The introduction part mainly expounds the properties and application of manganese and its compound,the current status of domestic manganese ore resources,the production method and existing problems in the electrolysis of manganese,and propose the basis and significance of this topic.2.Based on the feature that the manganese slag produced in the iron oxide removal process of lead and zinc ore contains a lot of manganese while the low content of impurities such as calcium and magnesium,reduced by sodium hydrogen sulfite under acidic conditions,manganese sulfate product was prepared that meets the national battery-level technical standards and solved the problem of resource waste and dangerous solid waste polluting the environment.The results show that the optimum conditions for the reduction of the manganese slag by sodium bisulfite are as follows,Liquid-to-solid ratio of H₂SO₄:MnO₂ 1:2.4?mL/g?,temperature is 55 C,sodium bisulfite dosage is 1.20 times than the theoretical dosage and the leaching time is 3 hours.The average leaching rate of manganese is 95.21%.3.In the electrolysis process of manganese,the deposition of manganese and magnesium complex salt precipitated from the catholyte causes blockage of pipes and diaphragm,ammonium bicarbonate was used to distribute the complex salt to achieve effective separation of manganese and magnesium.The manganese sulphate product,which is finally prepared to meet the national standard of HG/T 2962-2010,can be incorporated into the manganese sulphate production line,which solves the problem of solid waste dumping and environmental pollution.It is found that the optimum conditions for separating manganese and magnesium with ammonium bicarbonate are as follows,initial concentration of ammonium Bicarbonate is 0.8 mol/L,ammonium bicarbonate dosage is 1.15 times than the theoretical dosage,solution the pH of solution is about 7.5,the temperature of reaction is 45?,the time is 4h.4.Na₂S₂O₆·2H₂O crystals were extracted from the manganese sulfate electrolyte by the method of crystallization.Meanwhile using ICP,XRD,SEM,TG,IR,single crystal structure,theoretical calculation and UV-visible spectrophotometry to research the properties of sodium dithionate dehydrate and the disproportionation reaction.In addition,according to the research on the properties of sodium dithionate dehydrate,discussing the influencing of hydrazine sulfate on the reduction reaction of sodium dithionate dehydrate and the influence of reaction conditions on the digestion efficiency of dithionate.That provides a basis for eliminating the dithionite ion from the manganese sulfate electrolyte and guaranteed the process of electrolysis proceed normally.