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铸铝合金中加入锶变质剂后,可改善合金熔体的流动性,提高合金的机械性能、降低废品率,使该工艺受到人们关注。铸铝合金中锶的测定目前尚无一个简便快速的化学分析方法。原子吸收光谱法测定锶消耗大量稀土元素镧,成本较高。三溴偶氮胂(TBA)是测定稀土元素的新显色剂,而用该试剂光度法测定锶至今尚无文献报道。本文研究了该显色反应,发现三溴偶氮胂与锶在磷酸介质中可形成紫红色络合物,最大吸收峰为618nm。表观摩尔吸光系数为3.8×10~4。试剂与络合物稳定,25ml中0～8μg锶符合比耳定律。根据产品控制的锶含量范围作了标准加入回收试验,表明此法的重现性和准确度均好,此方法可简便快速地测定铸铝合金中锶。
After adding strontium modifier into the cast aluminum alloy, the fluidity of the alloy melt can be improved, the mechanical properties of the alloy can be improved, the rejection rate can be reduced, and the process has attracted people’s attention. Determination of strontium in cast aluminum alloy Currently there is no simple and quick chemical analysis methods. Determination of strontium by atomic absorption spectrometry consumes a large amount of rare earth element lanthanum, the cost is high. Tribromoarsenazo (TBA) is a new chromogenic reagent for the determination of rare earth elements. However, the spectrophotometric determination of strontium with this reagent has not been reported yet. In this paper, the color reaction was studied. It was found that the complexes of tribromoarsenazo and strontium can form purple complex in phosphoric acid medium, the maximum absorption peak is 618nm. The apparent molar absorptivity is 3.8 × 10 ~ 4. Reagents and complexes stable, 25ml 0 ~ 8μg strontium in line with Beer’s law. According to the range of strontium content controlled by the product, a standard recovery test was carried out, which shows that this method has good repeatability and accuracy. This method can measure strontium in cast aluminum alloy easily and quickly.