Patent ID: 8211997

Claim:
A process for producing polyarylene sulfide, comprising the steps of: reacting an alkali sulfide source and an aromatic dihalide compound in a polar organic solvent to obtain a polymerizate slurry containing polyarylene sulfide particles, by-produced alkali metal salt fine particles, by-produced polyarylene sulfide oligomer and the polar organic solvent, feeding the polymerizate slurry into a horizontal vibrating screen through a slurry feed port at one end, said vibrating screen further having a sub-screen liquid withdrawal port and a solid discharge port, withdrawing a slurry containing the alkali metal salt fine particles, the polyarylene sulfide oligomer and the polar organic solvent through the sub-screen liquid withdrawal port of the vibrating screen and, withdrawing the polyarylene sulfide particles through the solid discharge port of the vibrating screen, re-slurrying the withdrawn polyarylene sulfide particles with a re-slurrying liquid in a re-slurrying vessel equipped with a stirrer, introducing the re-slurried polyarylene sulfide particles into a countercurrent washing apparatus enclosing a movable part and subjecting the polyarylene sulfide particles to continuous countercurrent contact with a washing liquid to wash the polyarylene sulfide particles, and recovering the washed polyarylene sulfide particles, wherein the re-slurrying liquid and the washing liquid are each a liquid which is miscible with the polar organic solvent and has a lower boiling point than water, and wherein the solid discharge port is not directly connected to the countercurrent washing apparatus.