Method for producing lithium compound

A method of manufacturing lithium compound comprising:

• heating a lithium-containing ore;
• preparing an acid product by roasting the heated ore with sulfuric acid;
• preparing a leachate by mixing the acid product with leaching water;
• purifying the leachate;
• obtaining a solid lithium phosphate by adding a phosphorus supply material and a basic material to the purified leachate;
• and
• obtaining a solid lithium sulfate by reacting the solid lithium phosphate with sulfuric acid,
• wherein, in the step of preparing an acid product,
• an equivalent ratio (lithium:sulfuric acid) of lithium in the heat-treated ore and the sulfuric acid is 1:1.1 to 1:1.4,
• wherein,
• the step of purifying the leachate comprises:
• separating primary impurities including Al, Si or a combination thereof by adjusting the pH of the leachate to 5 to 8;
• and
• removing secondary impurities including Mg, Ca, Mn or a combination thereof by adjusting the pH of the leachate from which the primary impurities are separated to 10 or more,
• wherein, the step of obtaining the solid lithium sulfate comprises:
• mixing the lithium phosphate with a phosphoric acid solution having a concentration of 30 to 50 wt %;
• preparing a mixture by adding sulfuric acid to lithium phosphate mixed with the phosphoric acid solution;
• and
• filtering the mixture and separating the solid lithium sulfate and filtrate.