吸光光度法によるフェロクロム中のクロムの迅速定量方法

概要

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In order to establish a rapid method for photometric determination of chromium in ferrochromium, various investigations were carried out on a green colored solution obtainable after decomposition of the sample with a mixture of phosphoric acid and sulfuric acid. The best result was obtained by the following procedure: a 0.1 g sample was placed in a 100 ml beaker 10 ml sulfuric acid (1 : 1) and 5 ml phosphoric acid (d 1.7) were added, heated gently without boiling until white fumes were evolved, cooled, diluted to about 40 ml with water, transferred at once into a 50mlvolumetric flask, cooled immediately with the running water, made up to the mark with water and the light absorbancy of the solution was measured ; it was necessary to heat the sample solution with precaution to avoid an excessive heating after the appearance of the white fume. The relation between the amount of chromium and the light absorbancy was linear up to 70 mg of chromium and the coloration remain unchanged during the experimental period of 60 min. The presence of nickel less than 5 mg, copper less than 0. 5 mg, and 50 mg of iron gave no great error in the determination with the filter S-61 corresponding to 610 mμ, in wave length. The time required for determination of chromium in ferrochromium by this method was about 20 min.
社団法人日本分析化学会の論文