The invention relates to a method for directly preparing a high-purity
manganese sulfate solution from low grade
rhodochrosite sulfuric acid extraction liquid. The rule that the PH value of a
system is changed from small to large is implemented, and an efficient
chemical coupling mechanism is played. The method includes the steps that firstly,
manganese mineral
powder is continuously dissolved into low grade
manganese ore
sulfuric acid extraction liquid, the pH value of the extraction liquid is sequentially adjusted with
barium hydroxide to reach 3 to 4, then
barium fluoride is added, and filtering is carried out; secondly, the pH value of filter liquor is adjusted with
barium hydroxide to reach 5 to 6, then
barium sulfide is added, filtering is carried out, and new filter liquor is obtained; and finally, the PH value of the new filter liquor is adjusted with
barium hydroxide to reach 8, and filtering is carried out to obtain the high-purity manganese
sulfate solution. The method is simple in operation, medicament waste caused by operation for repeatedly adjusting the PH value of the
system in an overlapped manner is avoided, the manganese content in the prepared high-purity manganese
sulfate solution is larger than or equal to 80 g / L, the main
impurity contents are all smaller than or equal to 10 ppm, the heavy
metal content is smaller than or equal to 1 ppm, and the short-process low-consumption free-
pollution high-purity manganese sulfate solution preparing method is provided.