Method for extracting lithium and battery-grade lithium hydroxide monohydrate

• Main Authors: CAO WENYU, LIU ZURONG, LI YANG, XU YUNLING, YANG MINGSHENG
• Format: Patent
• Language: Chinese; English
• Published: 12.01.2021
• Subjects: CHEMISTRY; COMPOUNDS OF ALKALI METALS, i.e. LITHIUM, SODIUM, POTASSIUM,RUBIDIUM, CAESIUM, OR FRANCIUM; INORGANIC CHEMISTRY; METALLURGY

The invention relates to a lithium extraction method and battery-grade lithium hydroxide monohydrate, and the method comprises the following steps: carrying out the impurity removal and concentrationof lithium-containing brine, and obtaining a lithium-rich concentrated solution; carrying out bipolar membrane alkali making treatment on the lithium-rich concentrated solution to obtain a mixed alkali solution and a hydrochloric acid solution; carrying out evaporative crystallization treatment on the mixed alkali solution to obtain an evaporative crystallization precipitate and evaporative crystallization endpoint mother liquor; carrying out first dissolution recrystallization treatment on the evaporative crystallization precipitate to obtain a first recrystallization precipitate and first recrystallization mother liquor; and carrying out second dissolution recrystallization treatment on the first recrystallization precipitate to obtain the lithium hydroxide monohydrate and second recrystallization mother liquor;