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高频感应热等离子体在粉体球化领域中具有独特优势。介绍了高频感应热等离子体及其在微细球形粉体材料制备中的应用。以一台30kW装置为例,简略介绍了高频热等离子体的球化过程,展示了部分自制的关键设备,其中送粉器可以实现原料粒径在0.05～50μm范围内、加料质量流量在1.00～100g/min范围内的均匀稳定供给。结合钨粉、氧化硅、氧化铝、镍粉等几种典型产品的球化,分析了热等离子体运行参数、载气量、加料质量流量等关键因素对球化过程和产品质量的影响,提出了热等离子体在球化μm级和nm级粉体时对原料的基本要求。球化μm级粉体时,密实原料的球化率>98%,球化后二氧化硅粉体的密度达到理论值的98.2%;球化后钨粉松装密度增加了19.56%,流动性提高至球化前的2倍以上。球化nm级粉体时可以采用μm级原料,疏松的原料粉体更便于球化,在20～100nm范围内的产品粒径可以通过改变冷却气体积流量进行调控。此外,针对运行成本较高的问题,提出了开发高附加值产品和有效降低热等离子体运行成本是未来发展的主要方向。
High-frequency induction thermal plasma in the field of powder ball has a unique advantage. The high frequency induction thermal plasma and its application in the preparation of fine spherical powder materials are introduced. Taking a 30kW unit as an example, the ball milling process of high-frequency thermal plasma is introduced briefly. Some key equipment made by ourselves is shown. The powder feeder can realize the particle size of material in the range of 0.05 ~ 50μm, the mass flow rate of feedstock is 1.00 ~ 100g / min range of uniform and stable supply. Combining with the spheroidization of several typical products, such as tungsten powder, silicon oxide, aluminum oxide and nickel powder, the influence of the key factors such as operating parameters of thermal plasma, carrier gas and feed mass flow on the process of spheroidization and product quality was analyzed Thermal plasma in the nodular μm and nm powder-based materials on the basic requirements. In spheroidized μm-sized powder, the nodularity of the dense raw material is more than 98%, and the density of nodular silica powder reaches 98.2% of the theoretical value. The nodulizing density of tungsten powder increases 19.56% Increase to more than 2 times before the ball. Spherical nm powder can be used when the level of raw materials, loose raw material powder is more easy to spheroidization, in the range of 20 ~ 100nm product particle size can be controlled by changing the volume flow of cooling gas. In addition, in view of the high operation cost, it is proposed that developing high value-added products and effectively reducing the operating cost of thermal plasma are the main directions for future development.