| 摘要 |
<p>PURPOSE: To easily and simply obtain high purity plastic by bringing powdery plastic to a molten state in hot water and washing the molten plastic with hot water while separating impurities by specific gravity separation when the molten plastic is sedimented or floated in hot water. CONSTITUTION: Plastic 40 is ground by a jet of water to be thrown in a washing tank 12 in a slurry form along with water used in a jet of water and a stirrer 20 is operated to wash the powdery plastic 41 to mainly remove water-soluble impurities. Subsequently, the stirrer is stopped and the plastic slurry is allowed to stand to float insoluble impurities lighter than water to the vicinity of surface of water. Next, the powdery plastic 41 from which light impurities are removed and water are sent to a pressure-resistant melting tank 13 preliminarily filled with hot water and the steam sent from a boiler 31 and held to a high temp. and high pressure state under pressure by a pump 25. The dripped powdery plastic 41 is heated and melted to become molten plastic which is, in turn, washed while sedimented in hot water to be separated into a heavy impurity layer 44, a molten plastic layer 42 and a hot water layer 43 in the pressure- resistant melting tank 13.</p> |
