不锈钢中镍的测定方法——丁二酮肟光度法的改进

Improvement of the Determination of Nickel in Stainless Steel by Dimethylglyoxime Spectrophotometric Method

针对国标GB 223.25丁二酮肟重量法测定镍含量操作步骤繁琐和国标GB 223.23丁二酮肟分光光度法测定镍量含量范围窄的现状,提出了利用氨水和溴酸钾–溴化钾替代氢氧化钠和过硫酸铵的改进方法。研究了氨水用量、溶液pH值及溴酸钾–溴化钾作氧化剂对测试结果的影响。在1∶1的氨水用量约20 mL及pH≥10.2时,该方法的重复性小于1.16%、再现性小于0.86%,测量结果的相对标准偏差小于1%(n=6)。与国标相比,该方法具有快速、易掌握、测量结果准确等优点。

According to the fussy operation steps of nickel determination by dimethylglyoxime gravimetric method within GB 223.25,and the narrow measurement range of dimethylglyoxime photometry method in GB 223.23,an improved method was proposed. In this method ammonia and potassium bromate-potassium bromide were used instead of sodium hydroxide and ammonium persulfate. This research was mainly focused on the effect of ammonia dosage,solution pH and oxidizing agent to Ni test. The results showed that on the condition of 20 mL ammonia（1∶1） and pH≥10.2,the repeatability and the reproducibility of the method was less than 1.16%and 0.86%,respectively. The relative standard deviation was lower than 1%（n=6）. Compared with the national standard,this method is rapid,easy,and accurate,which is not affected by chromium and manganese.