熔融还原法镍渣炼铁的热力学与动力学

Thermodynamic and kinetic in recovery of iron from nickel residue

  • 摘要: 利用熔融还原法进行了闪速炉水淬镍渣提铁的实验研究,探讨了熔渣二元碱度、反应温度和反应时间对提铁效果的影响.XRD测试结果表明水淬镍渣由正硅酸铁FeO·SiO2和玻璃态物质组成.镍渣中的氧化铁主要以FeO·SiO2的形式存在,通过常规的选矿方法很难实现铁氧化物的富集,故采用熔融还原方法进行镍渣提铁实验.实验结果表明增加配合料中CaO的加入量、提高反应温度以及延长熔制时间都能不同程度地提高镍渣中铁的还原率.通过比较1450~1600℃范围内各反应温度下不同类型还原反应的Gibbs自由能,镍渣熔融还原过程的主要反应形式为(FeO)+C(S)→Fe+CO↑.本实验确定的最佳配方组成为:镍渣100g、CaO34.7g、CaF24.04g和焦炭8.5g;最佳反应条件为1500℃熔制180min.以上条件下的渣铁分离效果较好,铁还原率达到96.32%.

     

    Abstract: A study of extracting iron from nickel residue was done by smelting reduction method. The experiments were conducted to investigate the effect of slag basicity, melting time and temperature on the iron recovery ratio. XRD analysis indicates that the nickel residue is composed of FeSiO3 and glassy silicates, so it is impossible to reach the target of FeO content by regular ore-dressing method except by smelting reduction method. Experimental results show that the recovery ratio of iron increases with increasing the content of CaO added, melting temperature and time. The key reduction reaction is firmed as (FeO) + C(s) →Fe + CO↑ by comparing Gibbs free energies at different temperatures from 1450 to 1600℃. The batch of nickel residue 100 g, CaO 34.7 g, CaF2 4.04 g and coke 8.5 g was the best formula in this study, and it was indicated that after melting at 1500℃ for 180 min, the slag and iron were well separated and the recovery ratio was up to 96.32% for this batch.

     

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