Method for preparing cell-grade high-purity manganese sulfate by low-grade manganese ore high-pressure crystallization

Abstract

The invention discloses a method for preparing cell-grade high-purity manganese sulfate by low-grade manganese ore high-pressure crystallization. The method comprises the following steps of grinding low-grade pyrolusite and pyrite into powder particles, preparing a manganese sulfate solution, mixing the manganese sulfate solution and the pyrolusite powder particles to obtain preliminary pulp, mixing the preliminary pulp, concentrated sulfuric acid and the pyrite powder particles according to a certain ratio, carrying out heating, stirring and manganese impregnation on the mixture, adding a neutralizer into the mixture to adjust a pH value, adding barium sulphide and sodium dimethyldithiocarbamate into the mixture to remove impurities so that a pure manganese sulfate solution is obtained, carrying out heating pressurization stirring on the pure manganese sulfate solution, discharging a supernatant to obtain a manganese sulfate crystal-containing solution, carrying out standing precipitation of the manganese sulfate crystal-containing solution at a normal temperature, carrying out filtration to obtain a high-concentration manganese sulfate solution, adding the high-concentration manganese sulfate solution into a high-pressure autoclave, carrying out crystallization at a high temperature under high pressure, discharging a supernatant after crystallization to obtain manganese sulfate crystal-containing magma, separating the manganese sulfate crystal-containing magma to obtain high-purity manganese sulfate crystals, and drying and crushing the high-purity manganese sulfate crystals to obtain the cell-grade high-purity manganese sulfate.

Description

technical field [0001] The invention relates to a method for preparing battery-grade manganese sulfate, in particular to using low-grade manganese ore to prepare battery-grade high-purity manganese sulfate by a high-pressure crystallization method. Background technique [0002] Compared with ordinary manganese sulfate, high-purity manganese sulfate is a high-value-added manganese deep-processing product with higher technical content and very strict production process control. Its uses are mainly in three fields: industrial field, food and medicine industry and energy field. High-purity manganese sulfate is mainly used as a raw material for nickel-cobalt lithium manganate and lithium manganese oxide in large quantities, except for the general industrial field, food and medicine industry, and nickel-cobalt lithium manganese oxide and manganese as the positive electrode material of power battery. Lithium oxide has been widely used in the production of power batteries for automo...

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Problems solved by technology

At present, the methods for producing manganese sulfate crystals are as follows: 1. Atmospheric pressure evaporation method, the solvent is continuously evaporated by heating the solution to achieve concentrated crystalline manganese sulfate, but this method is carried out under normal pressure, and a large amount of water needs to be evaporated, consuming a large amount of energy ; 2, concentrated sulfuric acid salting out method, in the presence of sulfuric acid, the solubility of manganese sulfate significantly decreased, mainly due to SO 4 2- The same ion effect will lead to the precipitation of manganese sulfate crystals in the solid phase, but the disadvantage of this method is that it consumes a large amount of sulfuric acid, and the corrosion of the equipment is great.

These methods generally need to use high-grade manganese ore as raw material, but as the high-grade manganese ore is exhausted, these methods for preparing manganese sulfate in the face of low-grade manganese ore are not effective, have many disadvantages, and greatly increase the cost.

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