Abstract: A new type of laboratory high-voltage pulse(HVP) pretreatment technology and a pretreatment-crushing-grinding-weak magnetic separation process were used to investigate the effect of HVP pretreatment technology on the pulverized products of Dagushan magnetite quartzite and on the grade of magnetic separation concentrate.The test results showed that the grade of pretreatment concentrate increases by 7.26%when the grinding concentration，the grinding time， the magnetic field strength and the magnetic separation time are 70%， 3min， 111.4 kA/m and 3min respectively. The analysis of liberation degree showed that the particle size distribution of the pretreated products is more uniform， and the liberation degree of the useful mineral is increased by 17.78%(-0.50mm grain size). The microstructure observed by SEM showed that the cracks inside the pretreated crushed product mainly generate and develop between the adjacent mineral interfaces. The HVP pretreatment technology can reduce the grinding time thus decreasing the energy consumption by promoting the generation and development of microcracks along different mineral grain boundaries within the ore.

Key words: high voltage pulse, ore pre-treatment, grinding, mineral liberation, microstructure