Abstract：Based on the properties of ductile iron deoxidizer, the sample was decomposed by nitric acid-hydrofluoric acid. Silicon in sample was removed with perchloric acid. The interference elements such as rare earths, manganese, iron and titanium were precipitated and separated by ammonia-ammonium chloride-hydrogen peroxide-copper reagent. Subsequently, the content of calcium, aggregate content of calcium and barium and the content of magnesium in sample was determined by EDTA and DCTA complexometry, respectively, and the content of barium was obtained by subtraction method. The sample dissolution method, the selection of indicator, the interference and elimination method of impurities were discussed to obtain the optimal experimental conditions. The proposed method was applied to parallel determination of calcium, magnesium and barium in rare earth intermediate alloy certified reference materials which have similar component with ductile iron deoxidizer. The results were consistent with the certified values. The relative standard deviation (RSD, n=5) was 1.2 %-3.6 %.
Lorimer G W,Apps P J,Karimazadeh H,et al. Improving the performance of Mg-rare earth alloys by the use of Gd or Dy additions[J].Materials Science Forum,2003:419-422.
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