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由于硫化镍矿生产镍铁在经济和环境上不断出现的问题,采用红土镍矿生产镍铁越来越受到重视。但是红土镍矿制备镍铁的火法工艺中,在提高铁镍产品中的镍含量方面的理论研究仍存在许多不足。出于这方面的考虑,假设Fe2O3、Fe O和Fe3O4的活度为1,计算了CO2/CO、H2O/H2和CO2/H2三种气氛下选择性还原红土镍矿时,不同铁活度下铁-铁氧化物的平衡条件。从已有的热力学数据出发,利用Miedema二元合金生成热模型,计算了Ni-Fe固态二元合金中铁的活度系数。并以活度系数为纽带,最终计算出这三种还原气氛下,镍铁合金产物中的铁含量与还原气体分压、还原温度的关系。并用CO2/H2还原红土镍矿,得到的实验数据与理论值进行了对比分析与讨论,热力学计算结果很好地解释了选择性还原红土镍矿时铁金属化无法避免的原因,并较好地预测了红土镍矿还原产物中铁含量随温度和气体组分的变化趋势。
Due to the economic and environmental problems arising from the production of nickel-iron from nickel sulfide ore, nickel-iron production from laterite nickel has been paid more and more attention. However, there are still many deficiencies in theoretical research in improving the nickel content in iron-nickel products in the fire process for preparing nickel-iron from laterite nickel. For this reason, assuming that the activity of Fe2O3, FeO and Fe3O4 is 1, the selective reduction of lateritic nickel ore under three atmosphere of CO2 / CO, H2O / H2 and CO2 / H2 is calculated under different iron activity Iron - iron oxide balance conditions. Based on the existing thermodynamic data, the activity coefficient of iron in Ni-Fe solid binary alloy was calculated by using Miedema binary alloy to generate thermal model. The relationship between the iron content in the ferronickel alloy and the partial pressure of the reducing gas and the reduction temperature was finally calculated with the activity coefficient as the link. And the laterite nickel ore is reduced by CO2 / H2. The experimental data and theoretical values obtained are compared and discussed. The thermodynamic calculation results well explain the reasons that the iron metallization can not be avoided when selective reduction laterite nickel ore, and better The trend of iron content in laterite nickel ore with temperature and gas composition was predicted.