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硫氰酸盐比色法测定合金钢中钨时,釩有严重干扰。釩含量不高时虽可采取校正办法,但影响校正系数之因素颇多,难以准确。本文详细研究了采用铜铁试剂-三氯甲烷萃取分离釩、钼等干扰元素的实验条件,指出文献已有方法釩萃取不完全原因在于部分高价釩被还原。增加硫酸冒烟及高锰酸钾氧化等步骤,可使钢中釩量允许高达10％而不引起干扰。拟定了钨含量在5％以下的合金钢中钨的分析方法,对含量范围为1—5％的钨,测定误差不大于±0.06％。硫氰酸盐比色法测定合金钢中钨时,铌、钼等干扰测定。遇含釩样品,往往须事先测定釩,并按经验系数换算成钨量从结果中扣除,不仅手续繁琐,且误差较大。
When thiocyanate colorimetric determination of tungsten in alloy steel, vanadium has serious interference. Vanadium content is not high although the correction can be taken, but many factors affect the correction factor, it is difficult to accurately. In this paper, the experimental conditions for the extraction of vanadium, molybdenum and other interfering elements by copper-iron reagent-trichloromethane have been studied in detail. It is pointed out that the existing methods of vanadium extraction in the literature are not completely due to the fact that some of the high vanadium is reduced. Increase sulfuric acid smoke and potassium permanganate oxidation step, the steel can allow up to 10% of vanadium without causing interference. The method for the analysis of tungsten in alloy steels with a tungsten content below 5% has been developed. For tungsten with a content in the range of 1-5%, the measurement error is not more than ± 0.06%. Thiocyanate colorimetric determination of tungsten in alloy steel, niobium, molybdenum and other interferences. In the case of vanadium-containing samples, it is often necessary to determine the vanadium in advance, and deduct the amount of tungsten from the result according to the empirical coefficient, not only the procedure is cumbersome but also the error is large.