Abstract: The magnetic conversion of limonite from Guangxi Chongzuo and its reduction mechanism were investigated. The effects of technological conditions such as roasting temperature, roasting time, the ratio of limonite and biomass on the mineral magnetization were examined. The results from contrast experiments between the reductants of biomassto lignitic coal showed that limonite was deoxidized at the optimum temperature of 650℃ for 30 min using 15%~20% biomass as reductant, which is lower than over 100℃ by using lignitic coal as reductant. The iron ore processed by using lignitic coal and biomass was chiefly deoxidized to magnetic Fe3O4 and g-Fe2O3, it easily transformed to iron silicate at high temperatures, leading to negative effect on its magnetic separation.

Key words: limonite, biomass, reduction, magnetic conversion, calcination

摘要： 研究了广西崇左褐铁矿磁性转化和还原机理. 通过生物质与褐煤焙烧还原褐铁矿的对比实验，考察了焙烧温度、焙烧时间、原料配比等工艺条件对矿物磁性的影响. 结果表明，生物质还原的最佳焙烧温度为650℃左右，焙烧时间30 min，生物质用量为15%~20%. 结合XRD分析结果，确定以褐煤及生物质还原铁矿主要得到磁性Fe3O4及g-Fe2O3，温度高时易转化成硅酸铁，影响后续磁选回收铁.

关键词: 褐铁矿, 生物质, 还原, 磁转化, 焙烧