强化鲕状赤铁矿还原磁选脱磷机理研究

为研究熔剂与添加剂对国内某高磷鲕状赤铁矿高温快速还原中脱磷效果的影响, 采用内配碳球团还原-磁选工艺, 研究了二元碱度和添加剂对还原过程挥发脱磷及磁选指标的影响, 并对其脱磷行为进行了探讨。研究表明 提高碱度后, 球团在还原焙烧过程中形成大量正硅酸钙, 部分磷以磷酸根的形式存在于正硅酸钙晶格中, 通过磁选脱除, 加入添加剂可以优先磷灰石与脉石反应, 抑制了部分磷灰石的还原；在还原温度1 350 ℃、还原时间10 min、C/Fe比为0.48、碱度2.4、Na₂SO₄用量15%, 磨矿细度-0.074 mm粒级占95%以上, 磁场强度0.1 T条件下, 可获得铁品位94.06%、磷含量0.25%、全流程铁回收率91.37%、脱磷率91.79%的铁精矿。

Dephosphorization of Oolitic Hematite during the Process of Direct Reduction and Magnetic Separation

In order to study the impacts that flux and additives bring on the dephosphorization of high-phosphorus oolitic hematite during the process of high-temperature reduction, experiment was conducted with carbon-bearing pellets by using reduction-magnetic separation process to explore the effects of binary basicity and additives on dephosphorization and magnetic separation during reduction process, as well as its dephosphorization reaction. Experiment results indicated that with a higher alkalinity, a large amount of calcium silicate was generated during the process of reduction-roasting of pellets, and partial phosphorus in the form of phosphate radical was present in the calcium silicate lattice. The additives added during magnetic separation made apatite preferentially reacted with gangue and reduction of partial apatite inhabited. As a result, reduction process at 1 350 ℃ for 10 min with C/Fe ratio of 0.48, alkalinity of 2.4, dosage of Na₂SO₄ at 15%, at grinding size of -0.074 mm 95%, magnetic field strength of 0.1 T, yielded an iron concentrate assaying 94.06% Fe and 0.25% P with iron recovery of 91.37% and dephosphorization rate of 91.79%.