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用过硫酸铵—银盐氧化光度法测定钢铁中的锰时,三价铬离子同时被氧化为橙红色的重铬酸根离子。因重铬酸根离子的表观摩尔吸光系数小(ε_(450)=200),其显色反应的灵敏度很低,通常是不用重铬酸根光度法测定钢铁中的铬,笔者通过增加取样量,加大吸收皿厚度及采用差示比色,可用重铬酸根光度法测定钢铁中的低铬。木法可直接联合测定合金铸铁、炭钢、中低合金钢、高速工具钢中0.05～2％的锰和0.05～7％的铬。 分析步骤 称取0.2000～0.6000g试洋于100ml两用瓶中①,加入15ml硫、磷混酸(硫酸+磷酸+水=150+150+700)②,加
Trivalent chromium ions are simultaneously oxidized to orange-red dichromate ions by the ammonium persulfate-silver oxidation photometric method for the determination of manganese in steel. Due to the small molar absorptivity (ε_ (450) = 200) of dichromate ion, the sensitivity of chromogenic reaction is very low. Chromium in steel is usually not determined by dichromate spectrophotometry. By increasing the sample volume, Increase the thickness of the absorption plate and the use of differential colorimetric, available dichromate photometric method for the determination of low chromium in steel. Wood method can be directly combined determination of alloy cast iron, carbon steel, low alloy steel, high-speed tool steel 0.05 to 2% manganese and 0.05 to 7% chromium. Analysis step Weigh 0.2000 ~ 0.6000g test ocean 100ml dual-purpose bottle ①, add 15ml of sulfur, phosphorus mixed acid (sulfuric acid + phosphoric acid + water = 150 + 150 + 700) ②, plus