As a typical oxide of non-ferrous metal tungsten, needle-shaped purple tungsten oxide particles are also finely divided purple tungsten oxide powder crystals. Because of their excellent physical and chemical properties, they are popular in many fields. In addition to being an important raw material for tungsten products such as metal tungsten powder and tungsten carbide powder, purple tungsten oxide is also an important additive for products such as energy storage electrodes, photocatalysts, shielding materials, resistance components, dimming glass and energy-saving films.
In terms of energy saving film, the purple tungsten oxide particles have strong near-infrared absorption characteristics and ultraviolet blocking ability, which can make the prepared film products have better heat insulation effects and anti-ultraviolet capabilities. As a result, not only can effectively improve the indoor or car comfort, but also effectively prevent the aging of the decorations. In general, the thin film containing needle-shaped purple tungsten is more in line with the future development than the ordinary thin film.
The steps of a method for preparing high-purity homogeneous acicular purple tungsten oxide powder are as follows: raw materials are prepared to obtain uniform high-purity single crystal ammonium paratungstate crystals, the raw materials are pretreated, and then ammonia gas is introduced. The total amount of impurity elements in APT should be controlled below 60ppm, so that purple tungsten powder with better physical and chemical properties in various aspects can be obtained, such as single phase, large specific surface area, good fluidity, and impurity elements K and Na content lower than 1ppm etc. By controlling the particle size composition of the high-purity single-crystal ammonium paratungstate raw material, it is more beneficial to control the morphology and uniformity of the subsequent purple tungsten, ultra-fine tungsten powder and ultra-fine tungsten carbide powder.
In addition, the process of preparing purple tungsten powder by high-temperature micro-reduction of high-purity single crystal ammonium paratungstate in a rotary furnace has the characteristics of simple operation. During the reaction, ammonia replaces hydrogen reduction, which is beneficial to control the micro-reduction atmosphere and eliminate the safety hazards caused by hydrogen.
