| 摘要 |
<p>PROBLEM TO BE SOLVED: To perform the simultaneous grinding and cleaning of polyethylene terephthalate bottles to upgrade their recovery efficiency by using a wet grinder for grinding the bottles and injecting water or water containing detergent into the grinder to carry out the grinding process for the bottles, when the discarded bottles are to be ground. SOLUTION: Polyethylene terephthalate(PET) bottles compressed for volume loss are charged into a grinder, then water or water containing detergent is injected into the grinder to carry out the grinding process, and thereby the PET bottles are turned to flakes. After that, a mixture of flakes and cleaning water discharged from the grinder is separated by specific gravity into the flakes and impurities such as metal and sand. Next, the flakes and the cleaning water are separated from each other and the flakes are rinsed with limpid water to be centrifiugally dehydrated. The grinds obtained as described are processed by cleaning, sorting out impurities and the like into PET flakes, which are, in turn, depolymerized using surplus ethylene glycol and preferably, in the presence of a catalyst to obtain a bis-β-hydroxyethyl terephthalate.</p> |
