合成白钨中杂质元素对APT性能的影响及机制

For a long time, the national standards of synthetic scheelite restricted strictly the contents of impurity elements, resulting in the waste and loss of a great quantity of tungsten resources. The new national standard of synthetic scheelite in 2012 greatly relaxed the limitation of contents of impurity elements in synthetic scheelite. The implementation of the new national standard is conducive to the reduction of tungsten resources loss in metallurgical process. However, the increase of impurity contents in synthetic scheelite, greatly influenced the microstructure and properties of the deep processing products. Until to now, the related studies at home and abroad are still limited. Therefore, this project aims to study the effects and mechanisms of the impurity elements in synthetic scheelite on properties of APT, the state and the migration of impurity elements during the preparation of Ammonium Paratungstate (APT) from synthetic scheelite, and build the correlation model of the performance of APT and different grade APT. Through the implementation of this project, we will provide a theoretical basis for the control of structure and properties of deep processing tungsten products and the optimization of the preparation process, and greatly promotes the efficient application of synthetic scheelite in deep processing tungsten products.

长期以来我国的合成白钨国家标准对杂质元素的限制较严，造成了大量钨资源的浪费和流失。2012年实施的合成白钨新标准大幅放宽了合成白钨的杂质限制，该新标准有利于降低选冶工艺除杂造成的钨资源损失。然而，合成白钨中杂质含量的大幅提高，对其后续深加工产品的组织和性能产生了极为不利的影响。目前国内外的相关研究还极为有限。为此，本项目拟深入研究合成白钨中的杂质元素对仲钨酸铵(APT)性能的影响及机制，研究杂质元素在合成白钨制备APT流程中的存在状态及迁移方式，研究不同含量的杂质元素对APT性能的影响，建立不同等级合成白钨与APT性能的关联模型。通过本项目的实施，为钨深加工产品的组织性能的控制及制备工艺的优化提供理论依据，极大推动合成白钨在钨深加工产品中的高效应用。

本项目采用低品位合成白钨为研究对象，系统研究了合成白钨中高含量的杂质元素对后续APT产品性能的影响。研究结果表明S、Si等杂质元素为无害杂质元素，无需在制备过程中增加除杂步骤予以去除，Cu、Mn等杂质元素为有害杂质元素，需要在制备过程中添加除杂剂予以去除。针对稀土元素对APT性能影响的研究表明，稀土元素的添加可以起到显著的除杂效果，制备的APT产品纯净度很高，综合性能大幅提升。本项目揭示了杂质元素对APT性能的影响及机制，确定了杂质元素在APT制备过程中的存在形态、分布位置及迁移方式，为钨深加工产品的组织性能及制备工艺的优化提供了理论依据。确定了杂质元素对APT性能影响的临界值，为采用白钨原料制备APT产品的质量控制提供技术依据。上述成果已在SCI期刊发表论文6篇，申请发明专利3项，其中授权发明专利1项，主编英文专著1部（美国学术出版社出版）。