The invention discloses a method for producing battery-grade
lithium hydroxide monohydrate by a suspension
roasting method, which comprises the following steps: S1, preheating a
raw material, transforming and
roasting, cooling and discharging; s2, mixing the roasted material with
sulfuric acid, acidifying and
roasting; s3, water is added for size mixing,
calcium carbonate powder is added for
neutralization and leaching, and leaching
clear liquid is obtained; s4, adding caustic soda liquid and
sodium carbonate, and filtering to obtain purified
clear liquid; s5, evaporating and concentrating the purified
clear liquid, adding caustic soda liquid for reaction, and filtering to obtain conversion liquid; s6, freezing
crystallization and
centrifugal separation are performed to obtain frozen liquid and
sodium sulfate decahydrate; s7,
sodium sulfate decahydrate is subjected to redissolution, MVR sodium thermal
precipitation,
drying, cooling and packaging, and
anhydrous sodium sulphate is obtained; s8, evaporating, concentrating and centrifugally separating the frozen solution to obtain a crude product mother solution and a crude product
lithium hydroxide; s9, re-dissolving the crude product
lithium hydroxide; s10, evaporating and concentrating the heavy solution, and separating to obtain a
lithium hydroxide refined product; s11,
drying, screening, crushing, batch mixing and demagnetizing are conducted, and a finished product is obtained. The production efficiency and the product quality are effectively improved through the method.