Method for measuring tungsten trioxide contentofhigh-impurity tungstate

Abstract

The invention discloses a method for measuring tungsten trioxide contentof high-impurity tungstate. The method comprises the following steps: S1, co-decomposing a test sample with a small amount ofNaOH solution and hydrogen peroxide; S2, adding a precipitant for precipitating tungsten; S3, performing firing and weighing after filtering and washing; transferring residue obtained in the S1 and filtering paper into an iron crucible, placing the iron crucible on an electric burner for drying and ashing, cooling,adding sodium peroxide into a high-temperature burner for smelting to red and transparent, taking the mixture out, cooling slightly, pouring filtrate prepared in the step S3 into an original beaker in order to leach molten objects with the filtrate, leaching the molten objects out of the crucible with water, cooling, transferring into a volumetric flask, fixing the volume with water, mixing uniformly, standing for clarifying or dry filtering; transferring supernatant or filtrate, measuring tungsten trioxide content according to a thiocyanate method, and calculating the result. By adopting the method, the defect of remarkably high and unstable measuring result for the tungsten due to high impurity in the conventional tungstate analysis method is overcome.The method is simple, feasible, accurate and stable.

Description

technical field [0001] The invention relates to the field of analysis and detection methods for tungsten elements, in particular to a method for measuring the amount of tungsten trioxide in high-impurity tungstic acid. Background technique [0002] At present, the determination of tungsten trioxide in tungstic acid is generally first dissolved with alkali, and then decomposed with acid, according to the national standard (GB / T6150.1-2008) ammonium tungstate burning gravimetric method. But high impurity tungstic acid is different from general tungstic acid, it is processed with various catalysts and cemented carbide waste. The general ammonium tungstate insoluble matter is less than 0.5%, and the high impurity ammonium tungstate insoluble matter exceeds 50%. It is difficult to completely decompose the sample by alkali decomposition alone. Although acid decomposition is added later, the sample still cannot be completely decomposed, resulting in The residue also contains high ...

AI Technical Summary

Problems solved by technology

The general ammonium tungstate insoluble matter is less than 0.5%, while the high-impurity ammonium tungstate insoluble matter exceeds 50%. It is difficult to decompose the sample completely by alkali decomposition alone. Although acid decomposition is added later, the sample still cannot be completely decomposed, resulting in The residue also contains high tungsten, which makes the determination result inaccurate

At the same time, due to the high impurity elements such as Co, Ni, Cr, V, Ti in high-impurity tungstic acid, it seriously interferes with the determination of tungsten trioxide

Especially in low-grade tungstic acid, the interference of impurity elements is more serious, which brings great difficulties to the determination of tungsten trioxide

If the analysis is carried out according to the existing method, the result of the measured tungsten trioxide is obviously high and extremely unstable. Although each sample is analyzed several times, the accurate result cannot be reported, which greatly increases the detection cost and reduces the work efficiency. , for this reason, we design a method for the determination of the amount of tungsten trioxide in high-impurity tungstic acid

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