Method for preparing manganese sulfate by using manganese dioxide ore pulp to absorb sulfur dioxide in flue gases

Abstract

The invention discloses a method for preparing manganese sulfate by absorbing sulfur dioxide in flue gas with manganese dioxide ore pulp, comprising the following steps: performing wet ball milling on manganese dioxide ore and grading to obtain initial ore pulp, and the particle size of the ore material in the initial ore pulp is less than 149 μm, the initial pulp is crushed by a vertical stirring mill to obtain a reaction pulp, and 90% of the particle size of the mineral material in the reaction pulp is below 50 μm; add a manganese sulfate solution containing Fe3+ and / or Fe2+ to the obtained reaction pulp, and then make the reaction pulp Absorption reaction with high-temperature flue gas containing sulfur dioxide, the reaction temperature is controlled at 90 ° C ~ 95 ° C; after the completion of the absorption reaction, the reaction product is subjected to solid-liquid separation, iron and heavy metal removal, and then concentrated and crystallized under normal pressure to obtain monohydrate Manganese sulfate. The method of the invention has the advantages of energy saving and environmental protection, high resource utilization rate, high product added value, good flue gas desulfurization effect, continuous and thorough reaction, low cost and the like.

Description

technical field [0001] The invention belongs to the interdisciplinary technical field of hydrometallurgy, environmental protection and energy saving, and in particular relates to a method for preparing industrial-grade manganese salt by reacting high-grade natural manganese dioxide pulp with flue gas. Background technique [0002] Solid manganese sulfate monohydrate is an important chemical raw material, which can be used as fertilizer and feed additive, and is also the basic raw material of almost all manganese products. The annual demand in China alone is over one million tons, and it is also exported to other countries in large quantities. There are many domestic enterprises producing solid manganese sulfate monohydrate, which is also one of the traditional products of manganese products in China. [0003] Rhodochrosite can be used to produce manganese sulfate, but because rhodochrosite is generally symbiotic with calcium carbonate and magnesium carbonate, few domestic an...

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Problems solved by technology

These existing processes are mainly divided into two types: one is to use manganese dioxide dry powder to desulfurize at a high temperature in a reaction bed, no matter using a fixed bed reactor, a moving bed reactor or a fluidized bed reactor, this is the same as the second The process of reducing and roasting manganese oxide is similar, but its disadvantages are that the reactor has a large investment, a large floor area, and poor operating conditions, and the fixed bed reactor needs intermittent operation, which is labor intensive. After the reaction, it is necessary to ball mill the absorbent and then dissolve it , the process is long; this kind of treatment process is still in the laboratory stage or pilot test stage in China, and industrial production has not been realized; another method is wet desulfurization, using porous plate tower, turbulent ball tower, packed tower, The gas absorption tower commonly used in chemical industry such as jet bubble tower is used as a reactor for many times. The flue gas containing sulfur dioxide is blown in from the bottom of the tower, and the raw material of manganese dioxide flows countercurrently from the top of the tower. The absorption effect is very good, and the content of sulfur dioxide gas after absorption is even low. It is suitable for dry desulfurization, but the manganese dioxide slurry in this method will gradually block in the tower after running for a period of time, and the air flow channel in the tower will continue to shrink, which will affect the long-term and continuous operation of the process.

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