PROCESS FOR TREATING PLASTIC WASTE

• Main Authors: HINO KOICHI, UEMURA FUMIHIKO, MORIYA NOBUO, SAKASHITA KOJI, KOSHIRO MASAZUMI
• Format: Patent
• Language: English
• Published: 26.01.1999
• Edition: 6
• Subjects: AFTER-TREATMENT NOT COVERED BY SUBCLASSES C08B, C08C, C08F,C08G; CHEMISTRY; COMPOSITIONS BASED THEREON; DISPOSAL OF SOLID WASTE; GENERAL PROCESSES OF COMPOUNDING; INDEXING SCHEME ASSOCIATED WITH SUBCLASSES B29B, B29C OR B29D, RELATING TO MOULDING MATERIALS; MAKING GRANULES OR PREFORMS; METALLURGY; ORGANIC MACROMOLECULAR COMPOUNDS; PERFORMING OPERATIONS; PREPARATION OR PRETREATMENT OF THE MATERIAL TO BESHAPED; RECLAMATION OF CONTAMINED SOIL SOIL; RECOVERY OF PLASTICS OR OTHER CONSTITUENTS OF WASTE MATERIALCONTAINING PLASTICS; THEIR PREPARATION OR CHEMICAL WORKING-UP; TRANSPORTING; WORKING OF PLASTICS; WORKING OF SUBSTANCES IN A PLASTIC STATE, IN GENERAL; WORKING-UP

PROBLEM TO BE SOLVED: To provide an industrially advantageous process containing a step of separating plastic wastes into soluble plastics and insoluble plastics by treatment with a separating solvent. SOLUTION: This process includes (i) a dissolution step comprising contacting plastic wastes with a separating solvent to form a separating solvent solution containing plastics and a solid matter comprising undissolved plastics, (ii) a solid/liquid separation step comprising separating the separating solvent solution from the solid, (iii) a decomposition step comprising concentrating the separating solvent solution and heat-decomposing it, (iv) separating solvent evaporation step comprising contacting the solid with a noncondensible gas heated to 50-200 deg.C to evaporate the separating solvent from the solid to form a solid having reduced content of the separating solvent and a gaseous mixture containing a vapor of the separating solvent and the noncondensible gas, (v) a condensation step comprising forming a liquid separating solvent and the noncondensible gas, (vi) a heating step comprising heating the noncondensible gas to 50-200 deg.C and (vii) a recirculation step comprising recirculating the heated noncondensible gas into the evaporation step.