Detection Arsenic on Tungsten Trioxide

N Carbide and alloy performance is largely determined by the quality of tungsten trioxide. Common methods of preparing tungsten trioxide including the following major steps: first of all, removing Arsenic, silicon, fluorine, arsenic, phosphorus, and molybdenum by solution purification, secondly, the precipitation of artificial scheelite based on calcium chloride solution. Thirdly, using hydrochloric acid to decompose artificial scheelite; finally, the tungsten trioxide is prepared by washed, filtered, dried and calcined in tungstate. This article focuses on the methods for determination of Arsenic in high-purity tungsten trioxide.

The definition of Colorimetry is based on the color reaction of the colored compound by measuring or comparing the depth of the colored substance solution. As a method of quantitative analysis, the basic requirements of the Colorimetry are: high sensitivity and selectivity, stable colored compound and different color. The color reaction and control of the reaction conditions is the key for colorimetric analysis.

Determination of Arsenic in High-Purity Tungsten Trioxide Method
Burning the fat high-purity tungsten trioxide at 1400 ℃, and the resultant of Arsenic sulfide reacts with oxygen form Arsenic dioxide. This compound is condensed with formaldehyde, and the purple compound can generate in 560nm colorimetric determination. The experiment of the color, the time and the sample of absorption time can reduce combustion conditions such as blank test. Finally, we can obtain the amount of available mercuric chloride, sodium, chromogenic agent, the influence of magenta and fading. Detection limit of this method is 0.5ppm; the relative standard deviation is ± 4.8%.

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