Comprehensive Utilization for the Organic Solvent and the By-products of Salt Slurry in the Process of Polyphenylene Sulfide

Abstract

Polyphenylene sulfide (PPS) is a kind of excellent special engineering plastics, and its by-product salt slurry usually contains a large number of N-methyl-pyrrolidone (NMP), oligomers, lithium chloride and sodium chloride. The green recycling of the salt slurry has important significance for the sustainable development of PPS industry. In this paper, the recovery of NMP from PPS by-products by flash evaporation and solvent extraction, and the recovery of lithium chloride by calcination, precipitation and organic solvent extraction were reviewed in details. The key problems existed in these recycling methods were analyzed, and the new tends for the comprehensive recycling of PPS by-products in the future were also pointed out.