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本文叙述用铋酸钠定量地氧化铬的条件,使测定钢中之铬的方法简便而迅速。在硫酸或硝酸溶液中,铋酸钠氧化三价铬为六价铬: 2Cr_2(SO_4)_3+6NaBiO_3+6H_2SO_4→2H_2Cr_2O_7+3Na_2SO_4+3Bi_2(SO_4)_3+4H_2O 我们在硫酸溶液中用铋酸钠氧化铬;溶液中过量的铋酸钠直接用氯化钾(或钠)还原。已经得出结论,定量地氧化铬,主要依据溶液的酸度、温度及铋酸盐的数量和铬离子的浓度。在100毫升溶液中含有1～25毫升浓硫酸时,用铋酸钠可完全氧化铬。最适当的酸度是100毫升溶液中含硫酸10～15毫升。与锰恰恰相反,用铋酸钠定量地氧化铬,须在溶液煮沸时进行。氧化铬时所需最适当的铋酸钠量如下:含铬在3%
This paper describes the use of sodium bismuth oxide quantitative chromium conditions, so that the determination of chromium in steel is simple and rapid method. In sulfuric acid or nitric acid solution, sodium bismuthate oxidation of hexavalent chromium trivalent chromium: 2Cr_2 (SO_4) _3 + 6NaBiO_3 + 6H_2SO_4 → 2H_2Cr_2O_7 +3Na_2SO_4 + 3Bi_2 (SO_4) _3 + 4H_2O We are in the sulfuric acid solution with sodium bismuthate oxidation Chromium; excess sodium bismuth in solution is directly reduced with potassium chloride (or sodium). It has been concluded that the quantitative chromium oxide is mainly based on the acidity of the solution, the temperature and the amount of bismuthate and the concentration of chromium ions. In 100 ml of solution containing 1 ~ 25 ml of concentrated sulfuric acid, with sodium bismuth can completely chromium oxide. The most appropriate acidity is 100 ml of solution containing 10 to 15 ml of sulfuric acid. In contrast to manganese, quantitative determination of chromium oxide with sodium bismuth must take place when the solution is boiled. The most appropriate amount of sodium bismuthate required for chromium oxide is as follows: chromium in 3%