METHOD FOR OBTAINING LITHIUM HYDROXIDE MONOHYDRATE FROM ALCOHOLS AND THE PLANT FOR ITS IMPLEMENTATION Russian patent published in 2018 - IPC C01D15/02 C25B1/16 

FIELD: chemistry.

SUBSTANCE: invention can be used in chemical industry. Method for obtaining high purity hydroxide monohydrate from natural lithium-containing brines involves the preparation of the primary lithium concentrate, the solution of lithium chloride, by means of sorption lithium enrichment of the brines. Primary lithium concentrate is concentrated and purified from calcium and magnesium impurities. Concentration is carried out first by reverse osmosis, then by electrodialysis, followed by thermal pre-vaporization in order to salt out the NaCl and KCl impurities. Evaporated solution of lithium chloride is diluted until the productive makeup solution with the LiCl concentration of 350–380 g/l is supplied to the anode circuit of the electrolysis cell. Electrolysis of the solution of lithium chloride is carried out at the current density of 1–4 kA/m² and at the constant concentration of LiCl in the anolyte of 115–125 g/l. LiOH solution, which is obtained as a result of the LiCl conversion, is evaporated with the obtainment of LiOH⋅H₂O. Mother liquor, while simultaneously passing carbon dioxide, is used for reagent purification of the reverse osmosis concentrate from calcium and magnesium. Deep purification from calcium and magnesium is carried out by means of ion exchanging using the Lewatit-208-TP ionite in the Li form with the two-stage regeneration of spent ionite. Anodic chlorine is trapped using the urea solution in order to produce hydrochloric acid for acid regeneration of ionite. Transferring of ionite from the H⁺ form into the Li⁺ form is carried out using the mother liquor LiOH after separation of LiOH⋅H₂O crystals. Excess chlorine is trapped using the NaOH solution in order to obtain the commercial sodium hypochlorite.

EFFECT: invention allows to increase the productivity of the process for the production of lithium hydroxide monohydrate with the simultaneous increase in the purity of the product obtained, and to avoid the waste formation.

2 cl, 2 dwg, 2 tbl, 3 ex