Recovering sol. plastics from waste contg. plastics materials - by extracting into solvent and injecting soln. into non-solvent medium at temp. above solvent b.pt.

摘要

Soluble plastics (I) are recovered from the waste by (1) selectively dissolving (I) chemically-physically from waste using solvent (II), (2) injecting soln. into container filled with medium which is a non-solvent for (I) and at temp. above b.pt. of (II), such that (II) evaporates and (I) is released in pure state. Evaporated (II) is then recovered by means of a rectification unit. (I) is pref. polystyrene or modified polystyrene, partic. ABS or styrene-maleic anhydride copolymer. (II) is acetone, formaldehyde dimethyl acetal (III), tetrahydrofuran, Et acetate, or Me acetate. Non-solvent is water. ADVANTAGE - System can be closed, formation of azeotrope between (II) and non-solvent (which may cause difficulties in their sepn.) can be avoided; very large excess of non-solvent is achieved through (II) boiling off, avoiding sepn. of large vols. of (II)/non-solvent mixts. (0/0)