Determination of oxygen and nitrogen impurities in magnesium metal by vacuum distillation and ICP-OES techniques

Due to the various promising properties of magnesium as a structural material and certain other applications such as a reducing agent for refractory metals, magnesium metal has great commercial importance in many technical industries but the presence of oxygen and nitrogen impurities adversely affects its physico-chemical and mechanical properties. Therefore, the exact measurement of oxygen and nitrogen impurities is essential. The accuracy of analytical values of micro amounts of nitrogen and oxygen ($\mu g.g^{-1}$ level) in magnesium metal has been measured indirectly. The conditions for the vacuum distillation (VD) method were optimized. Analysis of residue for magnesium content was studied by inductively coupled plasma optical-emission spectroscopy (ICP-OES). The VD method is capable of measuring oxygen and nitrogen impurities in the microgram range. The reliability and sensitivity of the method is limited only when the specimen contains > 2 impurities. Results obtained by the VD and ICP techniques were compared with those obtained by other techniques. The data was statistically analysed. Student's t-test and variance ratio test methods (F-test) were performed for the significance of results by utilizing the analysis of variance (ANOVA).