Abstract:
Manganese ores are significant raw materials in the iron and steel industry. Accurately determining their major components is critical for the analysis of manganese ore composition. Based on three acid dissolution systems, i.e., aqua regia (HNO3+HC), tetracid (HNO
3+HF+HClO
4+HCl), and pentaacid (HNO
3+HF+H
2SO
4+HClO
4+HCl) solutions, and three extraction conditions, i.e., hydrochloric acid, nitric acid, and aqua regia, this study determined five oxides in manganese ores using inductively coupled plasma-optical emission spectroscopy (ICP-OES). The results indicate that the pentaacid or pentaacid solution and the extraction with hydrochloric acid achieved encouraging determination results. Spectral lines with wavelengths of 766.490 nm (K), 184.006 nm (Ca), 589.592 nm (Na), 279.553 nm (Mg), and 396.152 nm (Al) were analyzed. The possible interference in the determination process was eliminated based on the standard solution matrix matching principle. The detection limits of Na, Mg, K, Ca, and Al were 0.000 27%, 0.000 21%, 0.000 15%, 0.000 17%, and 0.000 23%, respectively. The determination results of all five oxides in two national primary reference materials for manganese ores showed relative standard deviations (RSD) not exceeding 5.0%, suggesting fair precision. The verification results of all five oxides in five reference materials showed relative errors (RE) below 10%, demonstrating high accuracy, with the measured values roughly consistent with the recommended values. The spiked determination of five oxides in five manganese ores with unknown content yielded recovery rates ranging from 90% to 110%, suggesting that the accuracy met the analytical requirements. Therefore, the ICP-OES method simplifies sample pretreatment, improves efficiency, and reduces costs, thereby applying to batch sample analysis. The verification using reference materials demonstrates that its accuracy and precision meet industrial standards, establishing the ICP-OES method as an effective approach for determining the five oxides in manganese ore samples.