A New Combination Method Of Corona Electrostatic Separation And Cyclone Separation For Recovering Metal From Waste Printed Circuit Boards

The waste electrical and electronic equipment (WEEE) is a tremendous potential resource and the recycling of it has considerable economic benefit. Waste printed circuit board (PCB) is a typical part of WEEE. Non-ferrous metals and rare metals contained in waste PCBs are very considerable; metal grade of some kinds of PCBs is even higher than natural mineral deposits. On the other hand, waste PCBs also contained a lot of poisonous and harmful substances, PCB would be a serious threat to the natural environment and human health, without a properly way to recycle it. Therefore, establishing a scientific and eco-friendly recycling technology is of great significance, whether from the natural environment protection and human health, or from the recycling and utilization value perspective.The method of corona electrostatic separation (CES) was one of environmental friendly technologies for waste printed circuit boards recycle. But there were still some problems for this technology: 1) fine nonmetal particles will impact the process of separation; 2) excessive nonmetallic materials will increase the load of machine; 3) balance between metal purity and production capacity can't be satisfied at the same time by traditional CES; 4)during the materials conveying, there were a lot of dust, which was a serious health hazard to the workers.Based on the principle of improving efficiency and reducing workload of corona electrostatic separation, a new combination method of corona electrostatic separation and cyclone separation was studied in this paper. In this combination system, cyclone separator was introduced as preprocessing equipment. Cyclone separator is a typical air separation technology for waste PCBs recycling. Unfortunately, there was little published information that systematically discussed about this separation technology.The aim of this paper is to build a new combination system, which use cyclone separator to overcome the limitation of traditional CES. A series of experiments were carried out in order to study the key factors that impact the separation process and the characteristics of this new method were discussed. The effect of this combination method was discussed as well. The results indicated that: 1) fine nonmetal particles in CES feed materials sharply decreased. Particularly the particles whose size are below0.3mm, decreased from 51% to 9%; 2) the metal rate of CES feed materials reached to 88%; 3) compared to traditional CES, the productivity of combinational system increased by 436.4%, metal purity and recovery reached to 99.90% and 93.85%, increased 2.7 and 2.01 percentage points; 4) part of dust was collected by cyclone-3 and bag-type dust collector. The problems of traditional CES mentioned above have been solved in a remarkable extent by the combination system.