High density yellow tungsten oxide may be used where higher density is required. In the production process, yellow tungsten oxide should be tested up to standard by relevant testing equipment including X-ray diffractometer, apparent density meter and particle size analyzer. X-ray diffractometer is used to detect the valence of tungsten, then to determine the phase composition. Apparent density meter is used for measuring apparent density and particle size analyzer for particle size measurement. X ray diffractometer includes the following main…

High-purity ultrafine yellow tungsten oxide, or high-purity ultrafine tungsten trioxide is a yellow or light green powder with purity higher than 99.99% and apparent density of 0.28~0.3g/cm3. High-purity ultrafine tungsten trioxide has good catalytic property to be used as a catalyst for petrochemicals. Also, it has good photochromic property and gas sensitivity. Vapor Phase Method to Produce Yellow Tungsten Oxide Generally in the air atmosphere, pressure of the evaporation system is controlled under 133.3~1199.9P, and the tungsten wire is heated…

High-purity high density yellow tungsten oxide is a yellow powder with excellent pressing property to prepare tungsten trioxide target with high purity and super high density. The production of high-purity high density tungsten trioxide target should be studied from the aspects of powder, forming and sintering. The optimized combination of the three aspects is necessary to prepare tungsten trioxide target with high purity and high density. The specific research contents include: 1. To produce tungsten trioxide powder with high purity,…

Medium yellow tungsten oxide or medium tungsten trioxide may be prepared by tungstic acid calcination method, in which tungstic acid is dried and calcined. The tungstic acid calcination method is commonly applied in the industry for producing tungsten trioxide. Tungstic Acid Calcination Method to Produce Yellow Tungsten Oxide It is recorded that tungstic acid is dried under 100℃, mainly by removing moisture absorbed in the product. Ammonia and combined water need to be calcinated under high temperature. Tungstic acid is…

Coarse yellow tungsten oxide or coarse tungsten trioxide may be prepared by the ammonium paratungstate – sodium complex salt method. And the coarser the particle size of prepared tungsten trioxide is, the greater the corresponding apparent density is. The Laws of Coarse Tungsten Trioxide Produced by Complex Salt Method 1. The apparent density is greater if the particle size of tungsten trioxide prepared by maintaining the original grain structure of “ammonium paratungstate – sodium complex salt” is coarser. This is…

Fine yellow tungsten oxide or fine tungsten trioxide is prepared by using double salt method. The finer the granular of yellow tungsten oxide is, the smaller the corresponding apparent density is. Fine WO3 is also produced by the reaction between artificial scheelite and hydrochloric acid (HCL). By using double salt method to produce fine tungsten trioxide, white amorphous gel tungstic acid will be formed first if the double salt and HCL react under cold conditions. And the greater the actual…