Method for producing manganese sulfate from manganese oxide ores

Abstract

The invention provides a method for producing manganese sulfate from manganese oxide ores. The method comprises the steps of mixing the manganese oxide ore powder with an appropriate amount of carbon reducing agent such as pulverized coal evenly, adding concentrated sulfuric acid without adding water and mixing evenly to obtain a mixture, controlling the initial concentration of the sulfuric acid in the mixture to be greater than or equal to 70%, curing the mixture by use of reaction heat via self-heating reduction and reducing the quadrivalent manganese in the manganese ores into bivalent manganese, mixing the cured material with water for stirring and leaching, and filtering the leached ore pulp to obtain a leachate, adding an appropriate amount of manganese oxide ores to the leachate to realize the oxidative decomposition of manganese dithionate, and performing neutralization, purification and impurity removal and crystallization on the solution obtained by filtering to produce the manganese sulfate. The method has the advantages that the low-cost easily available carbon reducing agent such as the pulverized coal is utilized to directly reduce the manganese oxide ores at a low temperature, and therefore, the energy consumption and the cost are low and the smoke pollution problem of reducing roasting is avoided; the manganese oxide ore powder is utilized to realize the oxidative decomposition of the manganese dithionate in the manganese sulfate solution and therefore, the quality of the manganese sulfate product is improved.

Description

technical field [0001] The invention belongs to the field of manganese smelting and relates to a method for producing manganese sulfate from manganese oxide ore. Background technique [0002] Manganese sulfate is a manganese salt product with a wide range of uses. The raw materials for production are rhodochrosite and manganese oxide ore. With the large consumption of rhodochrosite ore, its grade is getting lower and lower, and the cost is getting higher and higher. Manganese oxide ore has become the main source of manganese sulfate production. main ingreadient. [0003] The production of manganese sulfate from manganese oxide ore is divided into two categories: reduction roasting-acid leaching and direct reduction leaching. The common point is that the high-valent manganese oxide (MnO 2 ) is reduced to divalent manganese oxide (MnO) which is soluble in sulfuric acid solution. [0004] Reduction roasting—acid leaching method uses bituminous coal, heavy oil, natural gas, et...

AI Technical Summary

Problems solved by technology

Among them, the two-mine method using pyrite as a reducing agent is the most widely used wet method in industry, but due to the poor reductive activity of pyrite under normal pressure conditions, the leaching speed of manganese oxide ore is slow, the leaching temperature is high, and the leaching rate is low. Low, and the amount of waste residue is large, easy to cause environmental pollution

In recent years, the technology of directly reducing and leaching manganese oxide ore with sulfur dioxide to produce manganese sulfate has been applied, but because of side reactions in the process of reducing and leaching sulfur dioxide to produce manganese dithionate, which affects the quality of manganese sulfate products, and the source and transportation of sulfur dioxide are inconvenient. Failed to be widely promoted in the production of wet manganese products

[0006] In summary, the existing manganese oxide ore reduction roasting-acid leaching method has problems such as difficulty in controlling the reducing atmosphere during the roasting process, high energy consumption and environmental pollution, and is not suitable for processing low-grade ore.

However, the wet process based on direct reduction acid leaching has problems such as slow leaching speed, low manganese leaching recovery rate, side reaction manganese dithionate affecting the quality of the final manganese product, etc.

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