Magnetite ore from Dagushan was pretreated by magnetic pulse .The cracks and fissures within the ore were generated at the interface of different minerals ,which improved the grinding efficiency and separation index of the magnetite .The testing results showed that the content of -0 .074 mm in the ground product increased 0 .25% ~2 .4% after preprocessing by magnetic pulse with the magnetic intensity of 39 .81kA/m .The grade of iron concentrate increased 0 .41% ~2 .43% and the recovery increased 0 .55%~1 .81% after pretreatment under appropriate condition of grinding‐magnetic separation .Furthermore ,the microstructure of raw materials and the liberation degree of the grinding products before or after pretreatment were investigated by means of biological microscope and the scanning electron microscope , respectively .The function mechanism of magnetic pulse pretreatment improving the grinding efficiency and separation index of iron ore was explained .%对大孤山磁铁矿石进行了磁脉冲预处理，使矿石内部沿不同矿物界面生成扩展裂纹和裂缝，进而提高磁铁矿的磨矿效率和分选指标。结果表明，在磁脉冲预处理磁场强度为39．81kA／m时，预处理后磨矿产品中－0．074mm含量提高0．25％～2．4％。在适宜的磨矿‐磁选条件下，预处理后精矿的 T Fe品位提高0．41％～2．43％，铁回收率提高0．55％～1．81％。借助扫描电子显微镜和生物显微镜等检测手段，对预处理前后矿样的微观结构及磨矿产品的单体解离度进行分析，探讨了磁脉冲预处理提高铁矿石磨矿效率和分选指标的机理。
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