含铅锌难选赤褐铁矿还原焙烧及铅锌杂质同步脱除效果研究

    Reduction roasting of lead-zinc-containing refractory hematite and limonite and evolution process of lead and zinc impurities synchronously

    • 摘要: 磁化还原焙烧-弱磁选是处理难选赤褐铁矿的有效方法,而铅锌在高炉炼铁中是有害杂质,严重影响高炉生产。针对含铅0.39%、含锌0.30%、全铁(TFe) 47.04%的含铅锌难选赤褐铁矿,采用化学分析、岩矿鉴定、还原焙烧等方法,通过查明铅锌杂质的矿物特征和赤褐铁矿的产出特性,探讨了磁化还原焙烧过程中在还原弱磁性铁矿物的同时达到铅锌杂质的脱除效果。结果表明:试样中赤褐铁矿为42.97%、磁性铁仅为1.89%;含铅杂质的90.3%为氧化铅和铅铁矾中的铅存在,含锌杂质的90.6%以氧化锌中的锌存在。显微特征表明:试样中赤褐铁矿的还原过程存在磁化焙烧、富氏体和深度还原3个过程;在铁矿物的磁化焙烧和富氏体温区,均可见铅锌杂质矿物,而深度还原阶段未见铅锌杂质矿物存在。当还原焙烧温度1 200 ℃、还原剂C∶O=2.25、焙烧时间为60 min时,弱磁选精矿铁品位89.63%,回收率达86.09%,且有害元素Pb、Zn的脱除率达98.97%、91.19%,为该类铁矿物的分选加工及同步脱铅锌杂质提供了新途径。

       

      Abstract: Magnetization reduction and roasting-weak magnetic separation is an effective method to treat refractory hematite and limonite, while lead and zinc are harmful impurities in blast furnace ironmaking, which can seriously affect the production of blast furnace.Aiming at the refractory hematite and limonite containing 0.39% lead, 0.30% zinc and 47.04% total iron(TFe), the mineral characteristics of lead-zinc impurities and the production characteristics of hematite and limonite are investigated by chemical analysis, rock-mineral determination and reduction roasting.Reduction roasting of lead-zinc-containing refractory hematite and limonite and evolution process of lead and zinc impurities synchronously is also discussed.The results show that hematite is 42.97% and magnetic iron is only 1.89%, lead oxide and plumbojarosite are 90.3% of lead impurities, and zinc oxide is 90.6% of zinc impurities.Microscopic characteristics show that there are three processes in the reduction process of hematite and limonite:magnetization roasting, fused body and deep reduction.Lead and zinc impurity minerals can be found in the magnetization roasting and fused body temperature range of iron ore, but lead and zinc impurity minerals cannot be found in the deep reduction stage.When reduction roasting temperature is 1 200 ℃, reducing agent C∶O=2.25 and roasting time is 60 min, the iron grade of weak magnetic separation concentrate is 89.63%, the recovery rate is 86.09%, and the removal rates of harmful elements Pb and Zn are 98.97% and 91.19%, which provides a new way for the separation and processing of this kind of iron ore and the removal of impurities of lead and zinc synchronously.

       

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