Method for preparing MnSO4.H2O by performing flue gas desulphurization on medium-and-low-grade MnO2 ore

Abstract

The invention discloses a method for preparing MnSO4.H2O by performing flue gas desulphurization on a medium-and-low-grade MnO2 ore, which comprises the steps of: preparing medium-and-low-grade MnO2 ore powder into slurry; aerating sulfur-bearing flue gas into an absorption device; controlling a gas velocity and a gas-liquid ratio; then adding the MnO2 slurry into the absorption device; controlling the Mn2O slurry to flow reversely relative to the sulfur-bearing flue gas; discharging desulfurized flue gas from the absorption device; filter-pressing and separating the slurry discharged from the absorption device; returning mother solution to the absorption device; continuing the returning operation until the [MnSO4.H2O] in the mother solution is more than or equal to 200 g / L; stirring and washing an obtained filter cake at the temperature of between 60 and 70 DEG C; regulating the pH value of settled solution obtained by filtering-pressing and separating to be between 2 and 4; adding manganous sulfide under stirring at the temperature of between 25 and 95 DEG C; filtering the mixture and removing impurities from the mixture; continuing stirring the mixture; filter-pressing and separating the mixture; evaporating the obtained settled solution; and drying by the air stream to obtain the MnSO4.H2O. The method improves desulphurization efficiency, reduces the production cost for the manganous sulfate, and improves the recovery rate of total manganese, thereby recycling valuable metals efficiently.

Description

technical field [0001] The invention relates to a method of utilizing low- and medium-grade MnO 2 Desulphurization of flue gas to produce MnSO 4 ·H 2 O's method. Background technique [0002] There have been many literatures and patent applications related to the research on the use of manganese dioxide in flue gas desulfurization. For example, CN1824372A mentions microwave catalytic flue gas desulfurization technology, which has higher desulfurization efficiency to simulated flue gas, but requires special equipment, and the gas after desulfurization still needs to be absorbed by dilute acid; It is beneficial to the smooth operation of continuous large-scale industrial production equipment. CN1883764A uses chemical manganese dioxide with high value itself, and electrolytic manganese dioxide is used for desulfurization treatment. The cost is high and the operation is complicated, which does not meet China's national conditions. At the same time, it does not involve the su...

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Problems solved by technology

For example, CN1824372A mentions microwave catalytic flue gas desulfurization technology, which has higher desulfurization efficiency to simulated flue gas, but requires special equipment, and the gas after desulfurization still needs to be absorbed by dilute acid; Conducive to the smooth operation of continuous large-scale industrial production equipment

CN1883764A uses chemical manganese dioxide with high value itself, and electrolytic manganese dioxide is used for desulfurization treatment. The cost is high and the operation is complicated, which is not in line with China's national conditions. At the same time, the subsequent treatment of manganese sulfate solution produced by desulfurization is not involved.

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