Simultaneous Quantification Measurement of Si, Fe, Ti, Ca, Mg, Zr in Corundum by Inductively Coupled Plasma-Atomic Emission Spectrometry with Secondary-Melting Method

Due to the refractory feature of corundum, secondary melting was adopted to decompose samples. The solution was then lixiviated by HCl and subsequently measured by Inductively Coupled Plasma-Atomic Emission Spectrometry (ICP-AES) to determine the contents of silicon, iron, titanium, calcium, magnesium and zirconium. Boracic acid-sodium carbonate (mass ratio=2∶1) was added as the fluxing agent. The large amount of boracic acid in the flux can completely decompose corundum without grinding. However, it is difficult to dissolve the smelts. Therefore, the solution was to increase the proportion of sodium carbonate in the flux so that the smelts dissolve quickly and simply. The experimental conditions of proportion of boracic acid-sodium carbonate flux, melting temperature and time, sample content, sample grain size and so on were optimized. The results indicate that the detection limit of the method is 0.0003%-0.0051% and the precision (RSD, n=11) is 0.88%-4.78%. The consistent results were verified by standard materials and the national standard method. For this method, the samples were decomposed sufficiently. The grain size accommodation limit of the samples easily meets the requirement for quick inspection.