Experimental Study On Hydrometallurgical Leaching Of Pyrolusite With Biomass Reductant

The preparation of manganese sulfate by Pyrolusite direct reduction leaching is the focus and hot topic in the manganese industry.The other methods is difficult to push forward because of the high cost of reducing agent,low efficiency of leaching,and severe process conditions,at present,only two ore one step method have entered the production application.Therefore,to explore a low cost,high leaching rate and green environmental reducing agent for leaching pyrolusite has important realistic significance and research value.Reductive leaching of pyrolusite by biomass reducing agent has become the main research direction because a wide range of raw materials,simple operation,low energy consumption advantages.In this paper,it studied that the process of present situation of roasting reduction and direct reduction leaching of soft manganese ore at home and abroad.On this basis,the mineralogical characteristics and leaching characteristics of soft manganese ore were studied by ICP(atomic emission spectrometry),XRD(X ray diffraction),SEM(scanning electron microscopy),TGA(thermogravimetric analysis)and other advanced means.Finally,the thermodynamic and kinetic problems of the reaction system were theoretically analyzed.In this paper,the best reducing agent is selected in several kinds of biomass reducing agents by experiment.Through the single factor experiments,to explore the related factors on the impact of direct reduction efficiency and to analysis of the impact mechanism in-depth,the optimum leaching process is as follows: The soft manganese mine is 50 g,the particle size is 96μm,the reducing agent dosage of 30 g,the dosage of sulfuric acid is 45 mL,the leaching time of 5h,leaching temperature of 90℃,and in this case the leaching rate of manganese reached over 95%;Through orthogonal experiment,the factors that influence the leaching rate of manganese are determined as follows: leaching temperature > sulfuric acid dosage > reducing agent dosage > leaching time and the optimum leaching process is A2B3C3D3.At the same time,through the analysis of the reducing agent hydrolysis and reduction mechanism of biomass,the optimized process was put forward from the idea of promoting hydrolysis of the point of view,in the experimental study for leaching time,leaching temperature,leaching agent consumption in large quantity,and according to the experimental research program,the optimized condition was obtained with higher feasibility.Finally,the metal impurities elements and organic compounds in the leaching solution were removed by experiments,the leaching solution basically meets the requirements of the electrolytic process and provides a theoretical and practical basis for the next industrial experiment.