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前言借草酸钙的形式使钙和其他元素分离,然后灼烧成氧化钙测定钙的重量法,或将所得之草酸钙溶解在硫酸中,用标准高锰酸钾滴定的容量法,测定范圄在0.2%以上,以上方法分隔手续复杂,不适于微量分析。用路黑T、紫脲酸铵或钙指示剂的络合滴定,可以测定微量钙。但是由于选挥性不高,对一些合金,尤其是铁基合金中微量钙的测定是不太合适的。近年来,此色法越来越多的应用于微量钙的测定。紫脲酸铵法,虽有明显的色阶,但试剂溶液很不稳定,显色时要严格控制pH在11.3,所以很难找到显色重现性所需之条件。酸性铬兰K法,也要严格控制酸度(pH12),测定范圉在30微克以下(25毫升体积内)。由于空白颜色很深,色阶间隔不大。间接此色法
Preface Calcium oxalate by the form of calcium and other elements separated, and then calcined calcium oxide Determination of calcium gravimetric method, or calcium oxalate obtained by dissolving in sulfuric acid, with standard potassium permanganate titration volumetric method, the determination of Fan 圄Above 0.2%, the above separation method is complicated and not suitable for trace analysis. With Road black T, ammonium thiocyanate or calcium indicator complex titration, can measure trace calcium. However, the determination of trace amounts of calcium in some alloys, especially in iron-based alloys, is not suitable because of its low volatility. In recent years, the color method is more and more used in the determination of trace calcium. The ammonium urea method, although the obvious level, but the reagent solution is very unstable, color control should be strictly controlled pH 11.3, it is difficult to find the conditions required for color reproducibility. Acid Chromium K method, but also to strictly control the acidity (pH12), the determination of Fan in 30 micrograms (25 ml volume). As the blank color is deep, the color level interval is not big. Indirect color method