METHOD FOR REGENERATION OF LITHIUM CHLORIDE, LITHIUM ALKALI, DIMETHYLACETAMIDE AND ISOBUTYL ALCOHOL OR LITHIUM CHLORIDE, LITHIUM ALKALI AND DIMETHYLACETAMIDE FROM PROCESS SOLUTIONS AND WASTEWATER FROM PRODUCTION OF PARA-ARAMID FIBRES Russian patent published in 2023 - IPC C02F9/00 B01D61/58 C02F103/38 

FIELD: regeneration and wastewater treatment.

SUBSTANCE: methods for wastewater treatment and regeneration of organic solvents and minerals. Invention can be used in production of synthetic fibers for organizing a water circulation system and reusing dimethylacetamide (DMAA), isobutyl alcohol (IBA) and lithium chloride. The method includes neutralization of the initial solution with lithium hydroxide, precipitation of iron hydroxide, and mechanical filtration. Then micro- and ultrafiltration of the solution is carried out, followed by separation by reverse osmosis at 0.1 MPa. The permeate is returned to the process, and the concentrate is sent for rectification with the removal of pure DMAA and IBS or DMAA. A concentrated solution of lithium chloride in form of a solvate with DMAA is sent for heat treatment at 210-220°C until DMAA is completely removed and crystalline lithium chloride is obtained, it is dissolved in the permeate. The resulting solution is sent for electrodialysis at a current density of 0.5-10 A/dm² to obtain lithium hydroxide to neutralize the initial solution and 0.1-1 M hydrochloric acid to wash the filters.

EFFECT: ensures reduced consumption of reagents and environmental friendliness of production of para-aramid fibres.

1 cl, 1 dwg, 5 tbl, 2 ex