红土镍矿制备直接还原铁及胶凝材料的新工艺研究

发布时间：2018-05-27 19:03

  本文选题：红土镍矿 + 固态还原　； 参考：《西安建筑科技大学》2015年硕士论文

【摘要】：近年来,中国不锈钢产业的快速发展导致了金属镍的供不应求,世界上金属镍冶炼原料中硫化镍矿占60%,但其资源总量只占镍矿资源的28%左右。因此,随着硫化镍矿资源减少,红土镍矿已经成为生产镍铁产品的重要原料。由于国内红土镍矿资源储量少、品位低,促使红土镍矿的合理开发利用变得迫在眉睫。因此,从长远来看需要开发新的和更经济的处理技术,以达到红土镍矿资源的高效化利用是非常必要的。本文提出了一种以红土镍矿为原料,同时生产直接还原铁和胶凝性材料的高资源利用和环境友好的新工艺。通过合理配料与温度控制,实现金属氧化物还原和水泥中胶凝组元的生成反应的耦合,磨碎选分后可得到金属和胶凝材料。实现还原同时对脉石成分的有效利用。通过基础热力学分析(Factsage软件模拟)、物相检测与分析(X-射线衍射、扫描电镜等)、实验室还原试验(一段升温法和分段升温法),考察了还原温度、还原时间、添加剂加入量、还原剂加入量、反应气氛等因素对试验结果的影响。得到以下结论:(1)热力学研究表明:原料中金属氧化物的还原顺序由易到难依次为Fe2O3、NiO、CoO、Fe3O4、FeO和Cr2O3;2CaO·Fe2O3被C还原温度最低为910.6℃,其还原为逐级还原(2CaO·Fe2O3→CaO、Fe3O4→CaO、FeO→Fe);在温度低于1300℃时,硅酸二钙优于硅酸三钙形成,随着系统温度的进一步提高,温度在1300℃以上,先期形成的硅酸二钙开始与CaO反应形成硅酸三钙,其反应所适用的温度范围为1300℃~1800℃,并且温度在1450℃左右时,硅酸三钙的生成最快。(2)实验研究结果表明:在一段法升温实验中,在焙烧温度1450℃、焙烧时间90分钟、碱度2.9、还原剂配比10%的条件下,硅酸二钙生成量最大75.21%,由于氧化钙和还原剂加入量差距过大导致铁氧化物还原反应的动力学条件变差以及气氛原因没有出现单质Fe。在两段法升温实验中,反应产物中出现了硅酸三钙(其含量大概在30%~50%),随着配碳量的增加,硅酸三钙呈先增后减、硅酸二钙呈先减后增的趋势;还原时间对硅酸三钙的生成有很大的影响,在含碳量14%,还原温度1450℃条件下,还原时间由0.5h→1h→2h,其含量由27%→33%→52%。(3)改善还原反应的动力学条件,反应中保证反应气氛,如30%碳粉、1000℃保温15min、1450℃保温60min,可使镍铁合金和以硅酸三钙、硅酸二钙为主的胶凝性材料共存(8%Fe Ni、34%C3S、38%C2S)。通过分析金属铁、镍的还原率是72.7%和80%。
[Abstract]:In recent years, the rapid development of stainless steel industry in China has led to the shortage of nickel metal supply. In the world, nickel sulphide ores account for 60% of the raw materials for nickel smelting, but their total resources only account for about 28% of nickel ore resources. Therefore, with the decrease of nickel sulfide resources, laterite nickel ore has become an important raw material for the production of nickel iron products. Due to the low reserves and low grade of laterite nickel ore in China, the rational exploitation and utilization of laterite nickel ore becomes urgent. Therefore, in the long run, it is necessary to develop new and more economical treatment technology in order to achieve high efficiency utilization of laterite nickel resources. In this paper, a new process of producing direct reduction iron and cementitious material with laterite nickel ore as raw material and high resource utilization and environmental friendliness is proposed. The coupling of metal oxide reduction and the formation of cementitious components in cement can be realized by reasonable proportioning and temperature control. After grinding and sorting, metals and cementitious materials can be obtained. The effective utilization of gangue components can be realized simultaneously. By means of basic thermodynamic analysis and factsage software simulation, phase detection and analysis, X-ray diffraction, scanning electron microscope and laboratory reduction test (one-stage heating method and piecewise heating method), the reduction temperature, reduction time and additive content were investigated. The effect of the amount of reducing agent and reaction atmosphere on the test results. The results show that the reduction order of metal oxides in raw materials is Fe _ 2O _ 3H _ 3O _ 4 Feo _ 4 and Cr _ 2O _ 3N _ 2CaO _ 2 Fe2O3 at the lowest reduction temperature of 910.6 鈩，

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