CaO-SiO2-FeO-La2O3-Nb2O5五元渣系相图的研究

Bayan Obo ore in Inner Mongolia of China is a super large RE-Nb-Fe complex ore. However, the beneficiation of the valuable elements from Bayan Obo ore is difficult because of the multiple-element symbiotic specificity. Thus a large amount of niobium and rare earth resources are wasted with tailings in the process of ore dressing. In the pyrometallurgy extraction process of niobium and rare earth resources from Bayan Obo tailings, a complex slag is formed. However, the phase diagram of correlative slag system has not been drawn up to now. So the uncertainty of thermodynamic property of correlative slag system restricts the research and development of recovery and utilization technology of niobium and rare earth resources from Bayan Obo tailings. Therefore, a research project about drawing the phase diagram of slag system of CaO-SiO2-FeO-La2O3-Nb2O5 under the specified condition of composition and temperature is proposed. In this project, the slag systerm of CaO-SiO2-FeO-La2O3-Nb2O5 will be researched by thermodynamic equilibrium experiment and several determination methods of XRD, SEM, CSLM. And the phase diagram will be drawing with the thermodynamic calculation software of FactSage. Previously, the sufficient preparatory work has shown that the research method of this project is scientific, feasible and rational. The expected results of this project can enrich the data and information of phase diagram of metallurgy slag system and provide adequate theoretical basis and references for the research and development of comprehensive utilization technology of niobium and rare earth resources in Bayan Obo tailings.

我国内蒙古地区的白云鄂博矿是超大型的稀土铌铁复合矿，然而多元素共生的特殊性造成其难选难冶，大量的铌和稀土资源进入尾矿，造成了巨大的资源浪费。尾矿中铌和稀土资源火法提取过程所形成的渣系成分十分复杂，与其相关的相图信息和数据的缺失导致渣系热力学性质的不确定性，严重制约了铌和稀土资源回收利用工艺的研究开发。为此申请人通过热力学平衡实验（静态法），结合高温X射线衍射分析仪、扫描电镜和高温共焦激光扫描显微镜等检测设备，运用FactSage相图计算软件，并借鉴相关相图的数据信息，研究和绘制特定成分区间和温度条件下的CaO-SiO2-FeO-La2O3-Nb2O5五元渣系相图。前期充分的预备性研究工作已经验证了该方法的科学性、可行性和合理性。该项目不仅可丰富冶金渣系的相图数据和信息，还可为白云鄂博尾矿中铌和稀土资源综合利用工艺的研究开发提供充足的理论依据和丰富的参考资料。

我国内蒙古地区的白云鄂博矿是超大型的稀土铌铁复合矿，然而多元素共生的特殊性造成其难选难冶，大量的铌和稀土资源进入尾矿，造成了巨大的资源浪费。尾矿中铌和稀土资源火法提取过程所形成的渣系成分十分复杂，与其相关的相图信息和数据的缺失导致渣系热力学性质的不确定性，严重制约了铌和稀土资源回收利用工艺的研究开发。为此，本项目通过热力学平衡实验（静态法），结合X射线衍射分析仪、扫描电子显微镜、能谱分析仪和热丝法结晶性能测定仪等检测设备，运用分子离子共存理论，并借鉴相关相图的数据信息，研究了特定成分区间和温度条件下的CaO-SiO2-FeO-La2O3-Nb2O5五元渣系中各组元的活度变化与相变规律，以及1000℃和1200℃时该渣系在特定成分范围内平衡相的共存关系、液相线温度的分布状况以及固相面的等温截面图等相图信息。项目的研究成果不仅可以弥补含铌含稀土渣系相图的空白，同时还提出了一种热力学平衡实验与相关热力学计算相结合的高效、合理的相图绘制方法。研究成果已在国内外相应期刊公开发表，并得到了国内外专家学者的肯定。本渣系的相图信息和数据可以对铌和稀土资源回收利用工艺的研究开发提供有效科学的指导。