钨矿中砷资源化利用和砷致钨粉细化及在WC-Co硬质合金中的应用

传统观念砷作为有害杂质元素在钨冶金过程中去除并严格控制，但通过我们前期研究发现，均匀添加一定量的砷能显著细化钨粉、大幅改善WC-Co硬质合金的力学性能，同时会形成稳定的钨砷化合物不会对人体和环境造成危害。本项目拟深入开展研究工作为将砷作为有益合金元素应用于纳米W粉及超细晶WC-Co硬质合金制备提供理论和实验依据。研究As对氧化钨形貌及结构的影响，理解As的演变情况；研究As对W颗粒形核和长大的影响，理解As在氧化钨氢还原过程中致钨粉细化的机理；研究钨粉碳化过程中As的存在状态及分布情况，建立As对WC颗粒生长影响的模型，理解纳米W-As复合粉末的碳化机理；分析As在液相烧结过程中对WC颗粒在Co相中的溶解析出的影响，得出As对硬质合金组织与性能的影响规律，调整并优化As的最佳添加量，制备出高性能WC-Co硬质合金。

Arsenic (As) is removed and controlled as a detrimental impurity element in the process of tungsten metallurgy. However, tungsten powder was significantly refined by adding a certain amount of arsenic and it improved the mechanical properties of WC-Co cemented carbide which was found by our previous experimental. The arsenic can be regard as a useful alloying element to utilize and the formation of W-As compound will not harm to human body and environment in the preparation of cemented carbide. This project will provide theoretical and practical basis for the preparation of nanometer tungsten powder and ultrafine-grained WC-Co cemented carbide by direct utilize the arsenic in tungsten ores.The evolution of arsenic is understood by its effect on the morphology and structure of tungsten oxide. The refining mechanism of As in the hydrogen reduction process of tungsten oxide is understood by studying its effect on the nucleation and growth of tungsten powder. The carbonization mechanism of W-As composite nano-powder is understood by studying the existence form and distribution of As element in WC powder and building the model of As impacts on WC grain growth. The law of As effects on the microstructure and properties of cemented carbide is concluded by analysing its effect on the dissolution and precipitation of WC particles in the process of Co liquid phase sintering. The high-performance WC-Co cemented carbide is prepared by adjusting and optimizing the best addition amount of As.