大西沟难选菱铁矿石综合利用新工艺

采用强磁预选—磁化焙烧—磁选联合工艺对大西沟难选菱铁矿石进行试验研究.结果表明:在磨矿细度-74μm占55%、强磁粗选磁场强度318kA/m、强磁扫选磁场强度717kA/m的条件下，可得到TFe品位为28.47%、回收率为96.78%的强磁精矿；强磁精矿在中性气氛中于焙烧温度700℃、焙烧时间40min、磨矿细度-43μm占95%、弱磁选磁场强度104kA/m的综合条件下，获得TFe品位为59.29%、回收率87.50%的精矿产品.XRD、光学显微镜和VSM等分析结果表明:难选菱铁矿和褐铁矿经焙烧后转变为易选磁铁矿，新生成的磁铁矿表面疏松多孔，多呈胶状，与脉石矿物紧密共生，其磁化强度和比磁化系数均显著提高.

New Process of Comprehensive Utilization for Daxigou Refractory Siderite Ore

Daxigou refractory siderite ore was investigated through high intensity magnetic preconcentration-magnetization roasting-magnetic separation. The results showed that high intensity magnetic concentrate with iron grade of 28.47% and recovery of 96.78% was obtained under the test conditions that the grinding fineness of 55% ores is less than 74μm， high intensity magnetic field for roughing is 318kA/m and magnetic field for scavenging is 717kA/m. Iron concentrate with iron grade of 59.29% and recovery of 87.50% was obtained under roasting temperature of 700℃， roasting time of 40min with neutral atmosphere， 95% grinding fineness less than 43μm and low intensity magnetic field intensity of 104kA/m. The analysis results of XRD， optical microscope and VSM showed that refractory siderite and limonite are transformed into easily separated magnetite by roasted， meanwhile， the surface of the newly generated magnetite showed loose and porous， symbiosis between magnetite and gangue minerals is close， and the magnetization intensity and specific susceptibility increase greatly.