Electrostatic Separation Of Semiconductors,Insulators And Conductors

Waste semiconductor storage medium is a special type of electronic waste with a large number.For the information is stored in a semiconductor chip.On the one hand,the information need to be destroyed safely,on the other hand,storage medium is rich in conductor,semiconductor and insulator.After crushing,the semiconductor silicon can be crushed,in that the storage information can be destroyed safely,and the high voltage electrostatic separation can also be applied to separate the semiconductor,conductor and insulator.Wind separation can improve the separation efficiency of high voltage electrostatic separator and reduce its working load.In this paper,the process is studied about the high voltage electrostatic separation for three kinds of particles,including semiconductors,conductors and insulators.Semiconductor storage medium is broken up to a certain size to achieve information security destruction.Then the high-voltage electrostatic separation can separate the semiconductor,conductor,insulator.In this paper,the motion law of semiconductor and conductor in high voltage electrostatic field is analyzed,and the experiment of optimization parameters are designed.Then the best parameters of semiconductor,conductor and insulator are obtained.Finally,it is proposed that the destruction of semiconductor storage medium and the separation of semiconductor,conductor and insulator materials can be realized by crushing-wind separation-high voltage electrostatic separation.The separation of semiconductors,conductors and insulators can beachieved by two-stage high voltage electrostatic separation.The first-stage separation can separate the insulator.And the second-stage separation in the appropriate parameters can separate the semiconductor and conductor.Two-stage electrostatic separation is carried out in terms of center composite design based on the separation effect influenced by the two factors of the voltage(U),the rotary speed(n)on.A mathematical model is set up to make the contour map and the response surface figure.For the optimal parameters for 0.15-0.3mm particle size,the optimum parameters for the separation of metal(semiconductor,conductor)and non metal(insulator)are n=74rpm,U=27kV.The optimum parameters for the separation of semiconductor silicon and copper conductor are U=2.5kV,n=61rpm.For the recovery of semiconductor storage medium,it is processed by the crushing-cyclone-electrostatic separation system.The information storage material is broken up to 0.15 mm,so that the information can not be recovered.After the separation of cyclone-electrostatic separation,different particles,which include the semiconductor,conductor and insulator,can be collected respectively and further used.In order to determine the best parameters of the separation system,the nonlinear mathematical model is established after the study on the relationship between semiconductor quality(M)and butterfly angle(?),fan frequency(f),electric voltage(U),the speed of rotation(n).Thus the optimal parameters of the process are obtained: ?=30°,f=45 Hz,U=30 kV,n=40rpm.Under these parameters,the collection rate of the metal conductor is above 90%,and the collection rate of semiconductor silicon is 61%.The safe destruction and resource recovery of the semiconductor storage medium is realized.