Determination of Cu, Ni, Fe and MgO in Rich Fe-Mg Peridotite Rocks by Inductively Coupled Plasma-Atomic Emission Spectrometry

Samples were digested with mixed acids of HF-HCl-HNO₃-HClO₄, in 5% HCl solution. Peridotite enriched Cu, Ni, Fe, MgO were directly determined by inductively coupled plasma-atomic emission spectrometry (ICP-AES). The method overcomes the shortfalls of traditional methods such as: long-term, complicated chemical procedure and the chemical procedure being difficult to control. The detection limits of the method are 2.0 μg/g for Cu, 3.0 μg/g for Ni, 10 μg/g for Fe and 20 μg/g for MgO. The reliability of the method has been tested by determination of those elements in national standard references and the results are in good agreement with certified values with precisions of 0.8%-4.1% RSD (n=12). Satisfactory results were obtained for the ores present in Fe-Mg enriched rocks with higher sulfides composition by using the technique of cold soaking in mixed acids to remove sulphur and then digestion with heating. The sample solution was diluted before measurement to decrease matrix effect for the sample with high concentrations of Fe and MgO. This method exhibits simplicity, rapidity, good reproducibility and wide linearity. It is suitable for a multi-elemental determination of dissolved minerals.