合金鐵分析えの燐酸溶解法の應用 : フクロム中のクロム, フバナヂウム中のバナヂウムの定量

概要

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Hot concentrated phosphoric acid is thought to be most effective to dissolve rapidly certain kind of high carbon ferroalloys not easily decomposed by ordinary acid mixture. The authors used it in rapid analysis of ferro-chromium for chromium and ferro-vanadium for vanadium, and obtained satisfactory results in short time. The outline of the method adopted is as follows : In the case of ferro-chromium, transfer 0.1 gram of finely powdered sample to a 400cc beaker, cover it with a watch-glass, dissolve the sample in about 5cc of H_3PO_4 (sp. gr. 1.7) by heating carefully and keeping the state of slight fuming. Cool slowly on the asbestos to a little viscous but not yet syrupy state, add 20cc of H_2SO_4 (1 : 4) and a little HNO_3 (sp. gr. 1.42), and boil for 1 minute to expel oxides of nitrogen. Add about 150cc of hot water and determine chromium by the ordinary silver-persulphate method. This procedure occupies about 20-23 minutes. In the case of ferro-vanadium, dissolve 0.2 gram of finely powdered sample in 5cc of H_3PO_4 in the same way as the case of ferro-chromium, dilute to about 200cc with water and determine vanadium by the Gakushin method. The time required for the whole procedure is about 14 minutes.
社団法人日本鉄鋼協会の論文
1950-06-25