There are two methods for cleaning and drying waste plastics: mechanical cleaning and manual cleaning. Some products can only be cleaned manually after recycling. Some products can be cleaned and dried by mechanical cleaning. The following are the specific operations of mechanical cleaning and drying. Mechanical cleaning and drying are divided into batch and continuous types.
1. Intermittent cleaning First, the waste plastic is washed in a water tank, and a mechanical agitator is used to remove loose dirt adhering to the plastic surface, such as sand, mud, etc., to sink into the bottom of the tank; if there are many wood chips and paper sheets, It can be further purified in a sedimentation tank equipped with a special pump; for the adhesion of solid dirt, such as printing ink, adhesive-coated paper label, the larger one can be manually sorted first, and the hot alkaline aqueous solution is put into the pulverized Soak for a while in the tank, then rub them against each other by mechanical agitation to remove dirt. Finally, the washed pulverized waste plastic is sent to a centrifuge for drying, and dried by two steps of hot air to a residual moisture of ≤0.5%.
2. Continuous cleaning Waste plastic is sent to the chopper by conveyor belt, coarsely pulverized, and then sent to the large separation section. The sand and gravel are sunk into the bottom and are sent away at regular intervals. The floating material is conveyed into the wet mill through the conveying roller, and then enters the sedimentation tank. All the things heavier than the water are separated, and even the smallest particles are no exception. The material first enters the cyclone for mechanical drying and then passes through a tunnel dryer for hot air drying. The dried material is recovered by a collector and prepared for granulation by a plastic granulator.