印染污泥与铁尾矿磁化焙烧回收铁资源

Recovery of iron from iron tailings and textile dyeing sludge with co-magnetization roasting

我国铁尾矿累计堆存量超1×10^(10)t,主要为难选的赤铁矿、褐铁矿、菱铁矿等,由于脉石矿物组成复杂,重金属等有害杂质含量高,难以直接资源化利用。利用铁尾矿与印染污泥共同磁化焙烧,回收铁尾矿和印染污泥中铁资源,研究了焙烧温度、焙烧时间和印染污泥掺烧量对铁品位和铁回收率的影响及作用机制。最佳焙烧条件为,800℃、30 min、印染污泥掺烧量15%,对焙烧产物进行120 mT的湿法磁选,得到铁品位63.78%,回收率92.58%的铁精矿。铁尾矿中的针铁矿失水留下孔隙转化为赤铁矿,进而被还原为磁铁矿,其还原路径为FeO(OH)→Fe_(2)O_(3)→Fe_(3)O_(4)。SEM+MAPPING分析结果表明,磁化焙烧后赤铁矿和铝化合物的连生体被破坏,通过磁选可提升铁精矿品位及回收率。本研究可为印染污泥和铁尾矿的协同处理及资源化利用提供参考。

The accumulated stockpile of iron tailings in China exceeds 1×10^(10)t,mainly difficult to select hematite,limonite,and rhodochrosite,etc.,which are difficult to resource directly due to the complex composition of vein minerals and high content of heavy metals and other harmful impurities.In this study,iron tailings and textile dyeing sludge were co-magnetized and roasted to recover iron resources from iron tailings and textile dyeing sludge,and the effects of roasting temperature,roasting time and the amount of textile dyeing sludge blending on iron grade and iron recovery and the mechanism of action were investigated.The optimum roasting conditions were:800℃,30 min,15%textile dyeing sludge blending,120 mT wet magnetic separation of the roasted product,and the iron concentrate with 63.78%Fe grade and 92.58%recovery was obtained.The goethite in the iron tailings lost water leaving pores transformed into hematite,which was then reduced to magnetite with the reduction path of FeO(OH)→Fe_(2)O_(3)→Fe_(3)O_(4).SEM+MAPPING analysis showed that the congeners of hematite and aluminum compounds were destroyed after magnetization roasting,and the iron concentrate grade and recovery could be enhanced by magnetic separation.This study provides a scientific basis for the synergistic treatment and resource utilization of textile dyeing sludge and iron tailings.