METHOD FOR COMPREHENSIVE RECYCLING OF BY-PRODUCT SLURRY DURING POLYPHENYLENE SULFIDE PRODUCTION

摘要

#$%^&*AU2018101954A420190117.pdf#####ABSTRACT The present invention discloses a method for comprehensive recycling of by-product slurry during polyphenylene sulfide (PPS) production. The method includes the following steps: adding Na2 CO 3 into slurry, distilling and drying to recover a solvent NMP, dissolving and leaching the obtained dried waste salt with an acid solution, regulating a pH value of leaching liquor, filtering to remove insoluble components, performing adsorption purification and evaporation concentration on a liquid phase to separate out NaCl, adding a Na2 CO 3 precipitate into a solution in which the NaCl is separated to obtain Li2 CO 3 , regulating a pH value of lithium-precipitated mother liquor, and mixing the mother liquor and the solution subjected to adsorption purification, thereby realizing a closed cycle of the process. The method may be applied to comprehensive recycling of by-product slurry during the PPS production, the recovered NaCl may be directly used for caustic soda preparation by virtue of ionic membrane electrolysis, and the Li 2CO 3 may directly serve as an industrial product or be further converted into LiCl to serve as a PPS production auxiliary for recycling.Destruct lithium-NMP Na2CO3 solution PPS by-product slurry Distilling/drying --------- - NMP Dissolving&leaching HCI solution - - - Dry waste salt Regulate pH NaOH solution -- cLaching liquor containing dissolved organic matters + insoluble oligomers and impurities I Filtering ------------ Insoluble oligomers and impurities Leaching liquor contains dissolved organic matters Adsorption and Dissolved organic matters purification --- Solution containing LiCl and NaCl Evaporation ---- y NaC1 Precipitate concentration Na2CO 3 solution lithium 3 Concentrated solution Filtering --- ~-- --- 2CO3 Regulate pH Precipitate lithium HCl solution mother liquor FIG. 1 02-Thetar FIG. 2 1/2