Abstract: The present invention provides methods for preparing trimanganese tetroxide with low BET specific surface area and methods for controlling particle size of trimanganese tetroxide and trimanganese tetroxide product.

Abstract: Provided is a method for preparing barium titanate, which comprises: dissolving BaCl2.2H2O into TiCl4 solution to prepare Ba—Ti mixed solution with a Ba/Ti mol ratio of 1:1; adding ammonia and ammonium bicarbonate into deionized water to prepare synthetic agent with a NH4OH/NH4HCO3 mol ratio of 5:1; adding Ba—Ti mixed solution and synthesis agent into a reactor for synthesis to obtain a slurry; pressure filtering, thermal washing and then pressure filtering, to obtain a filter cake; calcining the filter cake for 1 hour at 590-610° C., followed by further calcining for 2 hours at 700-950° C.; crushing the obtained solid produced by a crusher, and thereby obtaining barium titanate. The obtained barium titanate is spherical, and has a narrower particle size distribution. The method reduces costs.

Abstract: The present invention provides methods for preparing trimanganese tetroxide with low BET specific surface area and methods for controlling particle size of trimanganese tetroxide and trimanganese tetroxide product.

Abstract: A method for preparing manganese sulfate monohydrate by desulfurizing fume with middle-low grade manganese dioxide ore, which includes: preparing a slurry by using middle-low grade manganese dioxide ore powder, putting sulfur-containing fume in an absorbing device and controlling gas velocity and gas-liquid ratio, and then adding manganese dioxide slurry and controlling the slurry to backwards flow relative to the sulfur-containing fume, discharging the desulfurized fume from the absorbing device, pressure-filtering and separating the slurry discharged from the absorbing device, recycling the mother liquor to the absorbing device, and continuing the recycling operation until the manganese sulfate in the mother liquor is >=200 g/l, the obtained filter cake at 60-70° C., adjusting pH value of the clear solution obtained to 2-4, adding manganese sulfide under agitation at 25-95° C.

Abstract: Provided is a method for preparing manganese sulfate monohydrate, which comprises the following steps: (1) reacting MnO with (NH4)2SO4 solution under heat, and separating solid from liquid after reaction 2) determining the concentration of MnSO4 in the resulting solution of step 1), adding equimolar ammonium sulfide solution thereto to carry out reaction under agitation, separating solid from liquid after reaction, and then washing solid phase: 3) dissolving the solid phase with concentrated sulfuric acid, adding hydrogen peroxide to the obtained solution, heating to boiling, adjusting the pH value of the solution to 5-6, removing the solid phase through precise filtration, evaporating and oven drying the filtrate to obtain MnSO4.H2O product. The impurities are separated away and the amount of byproducts is reduced by this method, and the yield of manganese sulfate monohydrate is improved.

Abstract: Provided is a method for preparing manganese sulfate monohydrate, which comprises the following steps: (1) adding equimolar BaS or SrS solution into manganese sulfate solution to carry out reaction fully, and separating and washing the obtained solid; (2) mixing the solid with deionized water to prepare a slurry, dissolving the slurry with concentrated sulfuric acid, and separating solid from liquid to obtain MnSO4 solution; (3) adding proper amount of hydrogen peroxide to the MnSO4 solution, heating to boiling, adjusting the pH value of the solution within 5-6, evaporation the filtrate after a precise filtration, and crystallizing and drying to obtain MnSO4 H2O product. Manganese sulfate monohydrate can be produced at high yield in a cost-efficient manner by this method.

Abstract: A method for preparing manganese sulfate monohydrate by desulfurizing fume with middle-low grade manganese dioxide ore, which includes: preparing a slurry by using middle-low grade manganese dioxide ore powder, putting sulfur-containing fume in an absorbing device and controlling gas velocity and gas-liquid ratio, and then adding manganese dioxide slurry and controlling the slurry to backwards flow relative to the sulfur-containing fume, discharging the desulfurized fume from the absorbing device, pressure-filtering and separating the slurry discharged from the absorbing device, recycling the mother liquor to the absorbing device, and continuing the recycling operation until the manganese sulfate in the mother liquor is >=200 g/l, the obtained filter cake at 60-70° C., adjusting pH value of the clear solution obtained to 2-4, adding manganese sulfide under agitation at 25-95° C.

Abstract: Provided is a method for preparing manganese sulfate monohydrate, which comprises the following steps: (1) adding equimolar BaS or SrS solution into manganese sulfate solution to carry out reaction fully, and separating and washing the obtained solid; (2) mixing the solid with deionized water to prepare a slurry, dissolving the slurry with concentrated sulfuric acid, and separating solid from liquid to obtain MnSO4 solution; (3) adding proper amount of hydrogen peroxide to the MnSO4 solution, heating to boiling, adjusting the pH value of the solution within 5-6, evaporation the filtrate after a precise filtration, and crystallizing and drying to obtain MnSO4 H2O product. Manganese sulfate monohydrate can be produced at high yield in a cost-efficient manner by this method.

Abstract: Provided is a method for preparing manganese sulfate monohydrate, which comprises the following steps: (1) reacting MnO with (NH4)2SO4 solution under heat, and separating solid from liquid after reaction; 2) determining the concentration of MnSO4 in the resulting solution of step 1), adding equimolar ammonium sulfide solution thereto to carry out reaction under agitation, separating solid from liquid after reaction, and then washing solid phase; 3) dissolving the solid phase with concentrated sulfuric acid, adding hydrogen peroxide to the obtained solution, heating to boiling, adjusting the pH value of the solution to 5-6, removing the solid phase through precise filtration, evaporating and oven drying the filtrate to obtain MnSO4.H2O product. The impurities are separated away and the amount of byproducts is reduced by this method, and the yield of manganese sulfate monohydrate is improved.

Abstract: Provided is a method for preparing barium titanate, which comprises: dissolving BaCl2.2H2O into TiCl4 solution to prepare Ba—Ti mixed solution with a Ba/Ti mol ratio of 1:1; adding ammonia and ammonium bicarbonate into deionized water to prepare synthetic agent with a NH4OH/NH4HCO3 mol ratio of 5:1; adding Ba—Ti mixed solution and synthesis agent into a reactor for synthesis to obtain a slurry; pressure filtering, thermal washing and then pressure filtering, to obtain a filter cake; calcining the filter cake for 1 hour at 590-610° C., followed by further calcining for 2 hours at 700-950° C.; crushing the obtained solid produced by a crusher, and thereby obtaining barium titanate. The obtained barium titanate is spherical, and has a narrower particle size distribution. The method reduces costs.