Determination of Cr Content in Stainless Steel by Microwave Digestion-Potentiometric Titration Method
[Purposes]The measurement results of GB/T 223.11-2008 have relatively high accuracy,but the operation process is cumbersome and time-consuming.In order to speed up the detection rate,this study puts forward a new dissolution method.[Methods]This paper uses HCl,HNO3 and HF as digestion reagents to dissolve 0.2 g samples by microwave digestion,and measures the content of Cr in stainless steel by potentiometric titration method.[Findings]The experimental results show that the optimal diges-tion reagents are 2 mLHCl,1 mL HNO3 and 1 mLHF,the optimal digestion power of microwave digestion instrument is 200 W,the optimal power retention time is 30 min,and the optimal stirring speed of auto-matic potentiometric titration instrument is 40%.[Conclusions]The procedure control of standard sample dissolution process is realized,and the subjective error of determining the end point by the opera-tor of traditional titration analysis is overcome,and the efficiency and accuracy of detection are greatly improved.
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