氰化渣磁化焙烧过程中铁化合物反应行为的热力学分析

来源期刊:中南大学学报(自然科学版)2011年第12期

论文作者:张亚莉 于先进 李小斌 张丽鹏 李德刚

文章页码:3623 - 3629

关键词:氰化渣;焙烧;Fe2O3;Fe3O4;热力学分析

Key words:cyanide tailings; roasting; Fe2O3; Fe3O4; thermodynamics analysis

摘    要:通过对磁化焙烧过程中氧化铁还原的热力学平衡分析,以及Fe2O3与硅酸钙、铁橄榄石与氧化钙、Fe3O4与二氧化硅反应的热力学分析,研究氰化渣中含铁化合物在磁化焙烧过程中的热力学反应规律。对氰化渣进行焙砂?磁选实验研究,采用全谱直读等离子体(ICP)、X线衍射(XRD)、X线荧光(XRF)等方法对氰化渣和焙烧渣进行分析和表征。研究结果表明:Fe2O3在较低温度范围内易被还原为Fe3O4,且CaO与SiO2的物质的量比n(CaO)/n(SiO2)为1:1时,Fe2O3不与硅钙化合物反应,不会造成铁的损失;产物Fe3O4在焙烧炉料中与SiO2不能发生反应,有CO存在时,加入适量的添加剂,亦能够稳定存在;在焙烧过程中加入氧化钙,铁橄榄石中的铁能被取代出来,可以提高磁化焙烧效率,且氧化钙的配入量是影响磁化焙烧效率的重要因素;当n(CaO)/n(SiO2)=1:1,时间为90 min,N2和CO的物质的量比n(N2)/n(Co)为4:1,添加1% Na2SO4,温度为880 K时,铁的回收率达到84%,铁精粉中铁品位达到60%,符合工业炼铁的原料要求。实验结果与热力学理论计算结果相吻合。

Abstract: Based on the thermodynamic analyse of ferric oxide reductive and ferric oxide with calcium silicates, fayalite with calcium oxide and Fe3O4 with silicon dioxide during roasting-preparing process, respectively, the thermodynamic of those reactions was determined. The magnetic roasting followed by magnetic separation experiments was done, cyanide tailing and calcine were characterized by ICP, XRD and XRF. The results show that ferric oxide can be reduced to Fe3O4 at low temperature and low concentrations of CO, and when molar ratio of CaO and SiO2 i.e., n(CaO)/n(SiO2) is 1:1, ferric oxide does not react with composition of calcium and suicides, which will not result in the loss of iron. Even when CO is added, Fe3O4 can be in steady existence with the proper amount of additives. If calcium oxide is added, the iron in fayalite can be replaced, thus the roasting effect can be promoted. The adding capacity of calcium oxide is an important factor of influencing roasting effect. When n(CaO)/n(SiO2)=1:1, time is 90 min, n(N2):n(CO)=4:1, and temperature is 880 K, a iron ore concentrate with total iron content of 60% and Fe recovery rate of 84% can be received. The experiment results well accord with the calculation results.

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