Method for recovering raw and auxiliary materials in the production of lithium bis(fluorosulfonyl)imide

A method for recovering raw and auxiliary materials in production of lithium bis(fluorosulfonyl)imide, the production of lithium bis(fluorosulfonyl)imide comprising reaction 1 of subjecting sulfuryl fluoride, triethylamine and ammonia gas to reaction and subsequent reaction 2 of alkalinizing a reaction product,

• and
• wherein the method comprises:
• a recovery section A:
• separating a product mixture produced by reaction 1 into an oil phase comprising (SO2F—NH—SO2F)·Et3N and an aqueous phase comprising a triethylamine hydrogen fluoride salt and impurity ions;
• subjecting the oil phase comprising (SO2F—NH—SO2F)·Et3N to an alkalinization process according to reaction 2, and introducing the aqueous phase comprising the triethylamine hydrogen fluoride salt and the impurity ions into an alkalinization kettle to mix and react with an alkali metal hydroxide under stirring, and then introducing a solution obtained after reaction in the alkalinization kettle into a layered tank for phase separation, with an upper layer oil phase being an organic phase comprising water and triethylamine, which is separated out and stored in an oil phase secondary layered tank;
• and
• a recovery section B:
• passing a product mixture obtained by the alkalinization process according to reaction 2 through an evaporator to remove the triethylamine and part of the water, and introducing the evaporated triethylamine and water into a condenser for condensation and standing for liquid separation;
• transferring an upper layer triethylamine solution obtained after the liquid separation to a triethylamine transfer tank, to be separated into an aqueous phase and an oil phase through a centrifuge, the oil phase being an organic phase comprising water and triethylamine;
• introducing the organic phase and the organic phase comprising the water and the triethylamine obtained in the recovery section A together into a single-effect evaporation system to obtain a water-containing triethylamine phase;
• then removing remaining water by dehydration in a dehydration tower and rectification in a rectification tower respectively to obtain high-purity triethylamine.