Research On Crushing Mechanism Of High Voltage Pulse Metal Ore And Development Of Equipment

At present,the process of metal ore processing mainly relies on mechanical stress crushing,through the impact,scraping,shearing and grinding of the ore,in order to realize the metal ore dissociation.However,the mechanical crushing process is generally characterized by large dust,serious noise pollution,high energy consumption and poor wear resistance of mechanical drilling tools.Therefore,a new ore crushing method is urgently needed to make up for the shortcomings of mechanical crushing method,namely high voltage pulse pretreatment crushing method.Firstly,the target minerals are pretreated by high voltage pulse,and then the mechanical stress crushing method is used.Its principle is that high-voltage pulse is applied to the surface of ore,due to the obvious differences in electrical properties and chemical structures between useful minerals and gangue minerals in ores,the plasma channel with dendrite structure is formed at the interface of mineral crystals,and complex physical and chemical reactions such as plasma explosion and thermal stress expansion are generated around the channel,so as to achieve the separation of useful minerals and gangue minerals.Firstly,this paper introduces the traditional crushing methods and high voltage pulse pretreatment method,briefly summarizes the crushing principle,and compares and analyzes their advantages and disadvantages.Then,the theoretical basis of high voltage pulse pretreatment crushing method,namely pulse power technology,is introduced in detail.Subsequently,in the research on the mechanism of high voltage pulse breaking solid dielectric,the discharge development simulation of solid-liquid mixed dielectric three-dimensional model is carried out by using the computer simulation pulse discharge development software HV-LAB.The simulation results show the whole process of the generation and development of the plasma channel in the solid-liquid mixed dielectric and the relationship between the parameters such as energy,power,voltage and current with time,which can provide a theoretical reference for the subsequent high-voltage pulse crushing experiment of metal ores.After that,the design and development of high-voltage pulse crushing equipment for metal ore are introduced,including high-voltage pulse charging power supply,improved Marx generator,double spark switch,discharge electrode and discharge chamber.Main performance indexes of the equipment: theoretical output pulse voltage is 0?160k V,measured output pulse voltage is 0?360k V,single pulse energy is 0?1.944 k J,rising time of output pulse is about 250 ns,output pulse frequency is about 0.2?5Hz,single crushing ore weight should be 200?500g.Finally,the high voltage pulse discharge equipment is used to carry out metal ore crushing experiment.The experimental results show that: compared with mechanical crushing without high voltage pulse pretreatment,high voltage pulse pretreatment technology can effectively improve the monomer dissociation degree of useful minerals,promote the mutual dissociation of useful minerals and gangue minerals,improve the productivity of each particle size of crushing products,and help to improve the grinding efficiency.From the perspective of economic,social and environmental benefits,the high voltage pulse pretreatment method is undoubtedly a better choice at present.It can not only avoid the waste of useful mineral resources,but also can control the energy and save the cost,and the whole crushing process has no pollution.Therefore,a series of work carried out in this paper has certain practical industrial application value and scientific significance.