黄磷电尘灰真空碳热还原提镓过程控制机理研究

As one of the most important scattered metals, gallium (Ga) has a great impact on the development of strategic emerging industries in our country. Because there is a lack of natural independent mineral deposit for industrial mining, Ga has to be extracted as byproduct during the manufacture of other products. It is therefore highly desirable to realize robust, low cost and high volume production methods for extracting Ga from any possible resources. Recently, the yellow phosphorus (P) industry flue dust has been found to be a promising resource for extracting Ga. The beauty of this extraction approach is that, by recycling and utilizing the previously wasted industry flue dust, cleaner manufacturing of yellow phosphorus can also be achieved at the same time. However, in order to practically realize this technique, a considerable number of research efforts are still required, particularly regarding the basic control mechanism of the related chemical or physical reactions..In this project, we aim to present a novel and clean metallurgy approach to extract Ga from yellow phosphorus industry flue dust by sequentially applying pretreatment process, vacuum carbothermic reduction and graded controllable solidification. For the first time, software products such as Materials studio will be used to investigate both the physical and chemical reaction during vacuum carbothermic reduction of the yellow phosphorus industry flue dust. The mechanism of structure change in the corresponding ingredients will be explained while molecular dynamics models will be built to analyze the reduction and volatilization processes respectively. Based on comprehensive understanding of thermodynamics theory of the reaction, experiments will be carried out to obtain optimized reaction condition parameters. The effect of various factors such as temperature, vacuum degree, and mass ratio on the final outcome of the reduction process will be systematically studied. After that, the Comsol Multiphysics software product will be applied to simulate the solidification process with finite element simulation method. Finally, the obtained results will be used to support the design of a new type of graded controllable solidification system for gathering both Ga and P products during the extraction process. We believe the newly developed system will provide a prototype for further industrial application of massive producing Ga with the flue dust. More importantly, the outcome of this project will greatly improve the existing vacuum metallurgy theory system of non-ferrous metal vacuum metallurgy technology so that it can provide technical support for more and more practical industrial applications.

镓是重要的稀散金属，是我国战略性新兴产业发展的重要资源。镓几乎没有形成具有工业开采价值的独立矿床，都是从二次资源中提取。电炉法黄磷生产过程中产生的电尘灰作为一种新的提镓资源，其综合利用是黄磷产业可持续发展的重要课题，对拓展镓资源具有重要意义。项目以黄磷电尘灰为原料，提出“预处理→真空碳热还原→分级可控冷凝”提镓的清洁工艺。率先采用Materials studio软件研究黄磷电尘灰在真空碳热还原过程中的物理化学行为，阐明其物相结构变化机理，揭示还原和挥发规律，建立分子动力学模型；在热力学研究基础上，考察温度、真空度、配比等因素对还原效果的影响，优化技术参数；采用Comsol Multiphysics软件对冷凝过程仿真模拟，研发一种镓、磷分级可控冷凝系统，为未来产业化应用提供理论指导。项目将丰富和完善真空冶金理论体系，拓展真空冶金应用范围，为有色金属真空冶金技术的发展和产业化应用提供理论保障。

随着科学技术的飞速发展及人民生活、健康水平的提高，对镓的需求量越来越大，镓在国民经济中发挥的作用也越来越大。但镓在地壳中分布极其分散，几乎没有形成具有工业开采价值的独立矿床。本项目以黄磷电尘灰为原料，提出采用真空碳热还原技术处理黄磷电尘灰，合理、高效利用有限镓资源，回收其中的镓及有价成分，对我国黄磷电尘灰的资源综合利用和拓展镓的利用资源研究具有重要意义。 . 以黄磷电尘灰为研究对象，采用XRD、XRF、ICP-AES等现代分析检测手段，研究黄磷电尘灰中元素分布特征和规律。利用现有基础热力学数据库，计算了黄磷电尘灰中氧化镓真空碳热还原相关反应的吉布斯自由能，绘制了Ga-O-C的热力学平衡图，明确氧化镓真空碳热还原反应的热力学条件。通过实验，考察黄磷电尘灰真空碳热还原过程中技术参数对镓回收效率的影响，优化技术参数。研究反应温度、配碳量等关键因素对黄磷电尘灰中锌、铅、镓分离的影响规律，并得到锌、铅、镓的冷凝区域。研究碳酸钠焙烧-水浸法对黄磷电尘灰中磷预处理的影响规律，考察焙烧温度、焙烧时间、碳酸钠用量等因素对磷去除率以及镓损失率的影响，并考察了蒸发结晶方法回收磷酸根和钠离子的可能性。基于第一性原理，利用Materials studio软件模拟计算氧化镓与碳之间相互作用，得到氧化镓碳热还原反应模型。依据实验研究结果及热力学计算结果，确立碳热还原、Ga2O还原以及歧化反应过程中可能存在的气-固反应，针对气固反应体系特点，分别建立碳热还原、Ga2O还原以及歧化反应过程的反应模型，在原子尺度上解释氧化镓碳热还原提镓本质及反应机理。采用Comsol Multiphysics软件对氧化镓碳热还原过程和冷凝过程的温度变化进行了模拟计算。在项目资助下在国内外核心刊物上共发表9篇文章，其中4篇SCI收录，5篇中文核心收录。受理专利1项，1篇EI论文返修。培养硕士研究生毕业5人，培养博士研究生在读2人，硕士研究生在读1人。