铁酸锌钙化碳热还原的热力学行为

Thermodynamic behavior of calcified carbothermal reduction of zinc ferrite

  • 摘要: 通过热力学计算和实验相结合,分析了含锌电炉粉尘中铁酸锌钙化碳热还原过程热力学行为,讨论还原温度和碳氧摩尔比对铁酸锌钙化碳热还原行为的影响。结果表明,与传统碳热还原相比,ZnFe2O4钙化碳热还原可在较低温度生成ZnO,并可在1 100 K直接由ZnFe2O4得到部分单质Zn。当温度高于1 221 K时,ZnFe2O4钙化还原出的单质Zn以及由ZnO还原的Zn均以锌蒸气形式挥发,并随着配碳量及温度的升高还原挥发增强。钙化碳热还原不仅降低ZnFe2O4消失的温度,而且降低其还原产出金属铁和锌的温度和碳耗。CaO可重构物相从而明显降低铁酸锌反应产出ZnO、Zn和Fe的温度点,使得ZnFe2O4提前反应完全。当温度为1 270 K,碳氧摩尔比n(C)/n(O)=0.7时,ZnFe2O4中锌铁还原与分离效果较好,此时Zn以蒸气形式挥发,Fe以金属单质形式被还原出来。

     

    Abstract: By combining thermodynamic calculations and experimental study, the thermodynamic behavior of calcified carbothermal reduction of zinc ferrite in zinc-containing electric arc furnace dust was analyzed, and the effect of reduction temperature and the molar ratio of carbon to oxygen on the calcified carbothermal reduction behavior of zinc ferrite were discussed. The results showed that compared with traditional carbothermal reduction, calcified carbothermal reduction of ZnFe2O4 can produce ZnO at a lower temperature, and some elemental Zn can be directly obtained from ZnFe2O4 at 1 100 K. When the temperature was higher than 1 221 K, both elemental Zn reduced from ZnFe2O4 and Zn reduced from ZnO were volatilized in the form of zinc vapor, and the volatilization was enhanced with the increase of carbon ratio and temperature. Furthermore, calcified carbothermic reduction not only lowered the temperature at which ZnFe2O4 disappeared but also reduced the temperature and carbon consumption required for the reduction to produce metallic iron and zinc. CaO can reconstruct the phase of the material, significantly reducing the temperature points at which the reaction of zinc ferrite with iron oxide produced ZnO, Zn, and Fe, thus allowing ZnFe2O4 to react completely earlier. At a temperature of 1 270 K and a molar ratio of carbon to oxygen (n(C)/n(O)) of 0.7, optimal reduction and separation of zinc and iron in ZnFe2O4 were achieved, with Zn volatilizing in vapor form and Fe being reduced to metallic form.

     

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