Method for measuring niobium content in tungsten carbide added with niobium or simultaneously added with tantalum and niobium

Abstract

The invention relates to a method for measuring a niobium content in tungsten carbide added with niobium or simultaneously added with tantalum and niobium, which comprises the following analytical steps that: after a sample is ground and sieved, the obtained product is melted by sodium peroxide, and the product is leached by hot water; after twice precipitations are carried out on the leached solution by using a coprecipitator to precipitate and using a gallotannic acid to precipitate, niobium or niobium and tantalum are separated from the main tungsten and other impurities, and then tartaric acid solution is prepared; when the prepared tartaric acid solution is in the sulphuric acid medium, the niobium and 5-Br-PADAP form a red chelate, the color depth is in positive proportion to the niobium content, hereby, the niobium content can be measured by photometry according to the working curve of the niobium; and if the sample comprises the niobium and tantalum simultaneously, the interference of tantalum to the measurement of the niobium content is eliminated by a method of adding excessive solution of high-concentration tartaric acid to carry out complexing and screening. The method of the invention has high precipitate recovery rate, simple and convenient operation, small interference, and good accuracy and repeatability.

Description

technical field [0001] The invention relates to a method for determining niobium content in tungsten carbide added with niobium or simultaneously added with niobium and tantalum. [0002] In this specification, the term "secondary precipitation" refers to the separation of niobium or niobium and tantalum from the main tungsten and other impurities after the sample is subjected to the secondary precipitation of co-precipitant and tannic acid. The first precipitation refers to adding co-precipitating agents lanthanum salt and iron salt to the alkaline solution to form co-precipitation of niobium or niobium and tantalum. The first precipitation completes the enrichment of niobium or tantalum and niobium and separates from the bulk tungsten. The second precipitation refers to the addition of tannic acid to precipitate niobium or niobium and tantalum in an acidic solution. The second precipitation separates the niobium or both niobium and tantalum from impurities other than tungs...

AI Technical Summary

Problems solved by technology

The accuracy and reproducibility of the analysis are not ideal when it is applied to the determination of the content of niobium in tungsten carbide with niobium added alone or added with niobium and tantalum at the same time.

Due to the unsatisfactory enrichment effect of silicic acid on the high content of niobium and tantalum, the recovery rate is low and unstable, resulting in low measurement results and poor reproducibility

After enriching niobium or niobium and tantalum in silicic acid, it is time-consuming and inefficient to filter, and it is difficult to clean the main tungsten, and there are more residual tungsten, which is easy to interfere with the determination of niobium

Chlorosulfonol S, the chromogenic agent used in the analysis, is prone to turbidity and sticks to the inner wall of the container, and the absorbance is unstable during colorimetric determination, resulting in poor reproducibility of results

The organic compound acetone and a large amount of hydrofluoric acid are used in the analysis process, which has a certain impact on the environment and the health of analysts

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