Research On The Method Of Pulsed High Voltage Electric Field To Assist The Fractured Hard Rock Ore

High voltage pulse discharge has many advantages,such as steeply rising edge pulse voltage,short pulse duration,discharge controllable,low energy dissipation,high efficiency,non-pollution.So it widely used in rock crushing,oil extraction,sewage treatment and other fields.However,mineral processing meeting with the problems of high energy consumption,low degree of mineral dissociation and low leaching rate.Based on the traditional mineral grinding process,the paper proposed to use high-voltage pulsed discharge to decrease the mechanical strength of the ore,increase the ore porosity,and then assist the ore breaking.Which can make high-voltage pulse discharge technology for other mineral processing The field provides a certain application reference.In order to achieve the best crushing effect of different minerals and ore sizes,this article chooses hydrogen thyristor devices as the switching devices for high-voltage pulse power supply,and PSPICE is used to simulate the main circuit of the pulse source,and the high voltage pulse power is designed,which can adjust the parameters of amplitude,repetition frequency and pulse width.In order to get the general law of crushing hard rock under the action of high pressure pulse,the numerical simulation of discharge electric field and high pressure pulse crushing test for uranium ore are also carried out in this paper.The main research work of this paper is as follows:(1)In this paper,the mechanism of high-voltage pulse-discharge crushed rock in water is first described.and then determines the water as discharge medium by comparing the four dielectric breakdown fields of water,rock,air and insulating oil.Finally,analysis the selective of rock fragmentation which provides a theoretical basis for analyzing the electric field characteristics of high voltage pulse discharge.(2)The based on a hydrogen thyratron of high-voltage pulse generator was designed,which can generate the maximum amplitude of 28 k V,the repetition rate of 1 Hz-1 k Hz,and a pulse width of 0-5 us.The parameters of each device are verified by PSPICE simulation.Finally,the equivalent circuit was theoretically analyzed and the calculation formula of the discharge voltage and current was obtained.The boundary conditions are provided for the COMSOL Multiphysics simulation of high voltage electrodes.(3)Taking hard uranium rock as an example,COMSOL Multiphysics software simulates the effect of the composition of uranium ore,the size of ore particles,and the distance between the discharge electrodes,which can affect the characteristics of high-voltage pulsed discharge electric fields.And obtained the corresponding conclusions that affect the magnitude and distribution of the electric field strength.(4)Besides,in order to find the influencing factors of uranium ore crushing degree,the high-voltage pulse crushing test for uranium ore was carried out.The experimental results show that the high-voltage pulse may not necessarily make the ore significantly broken,but it can reduce the mechanical strength of the ore.In addition,the total metal content of uranium ore greatly determine the uranium ore crushing effect.Electrode distance and grain size also affect the breakdown time and breakdown voltage.