湿法冶金结合喷雾干燥-热解工艺纯化和控制钨颗粒

Purification and Particulate Control of Tungsten Particles by Hydrometallurgy Combined with Spray Drying-Pyrolysis Process

钨因其独特的物理化学性能而被广泛的应用于半导体和高温材料。依次采用离子交换、溶剂萃取、重结晶、喷雾干燥和煅烧还原的方法对钨酸铵进行处理,成功制备出高纯、分散性好的微米级球形钨粉。其中,利用湿法冶金去除原料中的杂质金属,喷雾干燥和煅烧还原过程控制最终钨粉形貌结构和粒径分布。研究了喷雾干燥过程中溶液浓度对雾化粉末形貌的影响规律,并揭示了雾化粉末分解还原过程中的机理。结果表明,该方法制备出的钨粉纯度高于99.995%,平均尺寸约为1.5μm。本研究中的湿法冶金和粉末技术可用于合成其它具有高性能要求的金属粉末。

high-purity well-dispersed micro-spherical W particles were synthesized by ion exchange, extraction, re-crystallization,spraying drying and pyrolysis processes with commercial ammonium paratungstate [(NH_(4))_(10)[H_(2)W_(12)O_(42)]·n H_(2)O] as raw materials. Impurities in ammonium paratungstate were eliminated by hydrometallurgy treatment. The morphology and size of as-synthesized W particles were controlled by spraying drying-pyrolysis process. The influences of solution concentration in spray drying on the morphology of(NH_(4))_(10)[H_(2)W_(12)O_(42)] particles were investigated. The pyrolysis mechanism of spraying dried(NH_(4))_(10)[H_(2)W_(12)O_(42)] particles transformed into as-synthesized W particles was revealed. Results show that the purity of as-fabricated tungsten powder is higher than99.995 wt%, and the average size is about 1.5 μm. The size and morphology of the final particles produced can be determined by the solution concentration and velocity of the droplet generated by the atomizers. Pyrolysis temperature is one of key factors for controlling the morphology and size of as-prepared W particles. It should be noted that the hydrometallurgy and powder technology in this study can be applied to synthesize other metal particles with high-performance requirements.