Development of an Electrostatic Separator for Recycling Plastic Materials

为了回收和再利用塑料材料，有必要按塑料材料的种类进行分类和收集。本研究旨在研制一种可用于静电分离和塑料回收的分离器。塑料颗粒所获得的电荷的极性和数量取决于塑料的种类。将待分离的塑料材料提供到固定在振动freeder上的塑料板上，并通过摩擦充电来充电。样品塑料颗粒为PMMA、PC、HDPE、LDDE和PP，用PC和PMMA振动板作荷电试验，其荷电特性与摩擦荷电系列一致。然而，充电量小至<plus-minus>3 μ C/kg。采用塑料薄膜振动板提高荷电量，降低板表面电荷，使PMMA荷电量达到+10 μ C/kg，PC荷电量达到-15 μ C/kg。因此，构建了两级分离器。分别采用PC膜振动板和PMMA膜振动板作为第一级和第二级进料器。对三种塑料混合样品进行了分离试验。第一阶段收集了90%的PMMA颗粒，第二阶段分离了PC和HDPE。实验表明，通过选择在振动给料机上沉积的塑料薄膜的种类，可以实现塑料物料的分离

To recycle and reuse plastic material, it is necessary to separate and collect by the kind of plastic materials. The purpose of this research is to develop an separator for separation electrostatically and collecting plastics. It is required the condition that the polarity and the amount of charge acquired by plastic particles are depending on the kind of plastic. The plastic materials to be separated are provided onto a plastic plate fixed on a vibrating freeder and are charged by friction charging. The sample plastic particles are PMMA,PC,HDPE,LDDE,and PP.AS a result of charging test using PC or PMMA vibrating plate, the charging characterisitcs were consistent with friction charging series. However, the charge quantity is as small as <plus-minus>3muC/kg. The vibrating plate with plastic film was used to increase the charge quantity to reduce the surface charge of the plate and the charge quantity reached +10muC/kg for PMMA and -15muC/kg for PC.From the experimental results, the kind of plastic materials to be separated and the kind of vibrating plate were decided. Thus, two-stage separator was constructed. The vibrating plate with PC and PMMA film were used as the first and the second stage feeder, respectively. The tests to separate micxed sample of three kind of plastic materials were carried out. Ninty percent of PMMA particles was collected at the first stage and the PC and HDPE were separated at the second atage. It was shown experimentally that by choosing the kind of plastic film deposited on the vibrating feeder, and kind of plastic materials could be separate