Method for producing manganese(II) sulfate monohydrate from by-product of zinc refining process

A method for producing manganese(II) sulfate monohydrate, comprising:

• a pulverization and washing step of pulverizing and washing a manganese-containing by-product;
• a leaching step of leaching the pulverized manganese-containing by-product after the pulverization and washing step to produce a leachate;
• a neutralization step of neutralizing the leachate produced in the leaching step;
• an impurity removal step of removing impurities from the leachate neutralized in the neutralization step,
• wherein the impurity removal step comprises:
• a first impurity removal step of removing heavy metal impurities, and
• a second impurity removal step of removing light metal impurities;
• a solvent extraction step of recovering manganese in the form of an aqueous solution of manganese sulfate from a process liquid subjected to the impurity removal step by using a solvent extraction method, the solvent extraction step comprising:
• a loading step of extracting manganese contained in the process liquid into an organic phase,
• a scrubbing step of washing the manganese-extracted organic phase with water, and
• a stripping step of recovering manganese in the form of an aqueous solution of manganese sulfate by adding sulfuric acid to the organic phase after the scrubbing step;
• and
• a crystallization step of producing manganese(II) sulfate monohydrate by evaporating and concentrating the aqueous solution of manganese sulfate produced in the solvent extraction step.