METHOD FOR DECOMPOSITION AND RECOVERY OF PLASTIC

摘要

PROBLEM TO BE SOLVED: To provide a method for effective decomposition and recovery of a recoverable plastic by effective decomposition of the plastic containing a thermosetting mathacrylic resin and silica represented by the case of artificial marble, and recovery of organic components derived from the thermosetting mathacrylic resin and inorganic components derived from inorganic fillers such as silica.

SOLUTION: The method includes: a process (A) for decomposition of a plastic containing the thermosetting mathacrylic resin and silica with subcritical water under the coexistence of an alkali; a process (B) for recovery of an aqueous silica dissolved solution containing the polymethacrylate by the solid-liquid separation of the resulting plastic decomposed product; a process (C) for the solid-liquid separation of silica precipitated by supplying an acid to the aqueous silica dissolved solution containing the recovered polymethacrylate; and a process (D) for removal of water contained in the aqueous solution containing the separated polymethacrylic acid and the inorganic salt, supply of an organic solvent with large solubility of the polymethacrylic acid and little solubility of the inorganic salt thereto, and recovery of the polymethacrylic acid dissolved in the organic solvent.

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