US 12,247,267 B2
Method of producing lithium hydroxide from lithium concentrate through sodium sulfate addition and roasting
Min-Woo Lee, Chungcheongbuk-do (KR); Suk-Joon Park, Chungcheongbuk-do (KR); Myung Gyu Lee, Gyeonggi-do (KR); Kwang Seok Lee, Chungcheongbuk-do (KR); Jong Sun Park, Chungcheongbuk-do (KR); and Da-Mo-A Kim, Chungcheongnam-do (KR)
Assigned to ECOPRO INNOVATION CO., LTD., Chungcheongbuk-do (KR)
Appl. No. 17/299,632
Filed by ECOPRO INNOVATION CO., LTD., Chungcheongbuk-do (KR)
PCT Filed Nov. 4, 2019, PCT No. PCT/KR2019/014863
§ 371(c)(1), (2) Date Jun. 3, 2021,
PCT Pub. No. WO2020/116795, PCT Pub. Date Jun. 11, 2020.
Claims priority of application No. 10-2018-0156174 (KR), filed on Dec. 6, 2018.
Prior Publication US 2022/0017991 A1, Jan. 20, 2022
Int. Cl. C22B 26/12 (2006.01); C01D 15/02 (2006.01); C22B 1/06 (2006.01); C22B 3/04 (2006.01)
CPC C22B 26/12 (2013.01) [C01D 15/02 (2013.01); C22B 1/06 (2013.01); C22B 3/04 (2013.01)] 9 Claims
OG exemplary drawing
 
1. A method of producing lithium hydroxide from a lithium concentrate through sodium sulfate addition and roasting, the method comprising:
preparing a lithium-containing concentrate;
mixing sodium sulfate to the lithium-containing concentrate and roasting the lithium-containing concentrate mixed with the sodium sulfate to form a roasted lithium-containing concentrate mixture;
leaching the roasted lithium-containing concentrate mixture with water under stirring; wherein an acid is not added during the leaching step, and the water is added during the leaching step in an amount that is one to ten times the mass of the roasted lithium-containing concentrate mixture,
performing solid-liquid separation to separate a resultant of the leaching into a leachate in which lithium is dissolved and residues;
concentrating the leachate in which lithium is dissolved in a process of evaporating the leachate at a temperature in a range of 60° C. to 120° C., at a vacuum pressure, for 30 minutes to 10 hours such that the concentration of lithium in the leachate becomes 16 g/L to 30 g/L;
mixing sodium hydroxide (NaOH) with the concentrated solution under stirring to give a sodium hydroxide mixture;
performing cooling crystallization to precipitate sodium sulfate using a change in solubility by cooling the sodium hydroxide mixture;
recovering a lithium hydroxide solution by separating a resultant of the cooling crystallization into a precipitate and the lithium hydroxide solution;
performing concentration crystallization to recover lithium hydroxide monohydrate crystals by concentrating the lithium hydroxide solution; and
washing and drying the lithium hydroxide monohydrate crystals to recover dried lithium hydroxide monohydrate crystals.