Certified Reference Materials Preparation of Ilmenite Chemical Composition

At present, there are no ilmenite chemical composition certified reference materials, the closest being of vanadium-titanium magnetite ore composition. Internationally, ilmenite standards consist mainly of ilmenite concentrate, which is unsuitable for effective quality control. Therefore, there is an urgent need to develop ilmenite chemical composition reference materials. Five certified chemical composition reference materials of ilmenite were prepared by first collecting samples from Ju County and Yishui Changzhuang ilmenite mines in Shandong Province, and Chengde Montenegro ilmenite mine in Hebei Province. The samples were ground to a particle size of less than 50 μm by using an advanced jet mill, and then loaded in a coulter-mixing machine for thorough mixing. Inductively Coupled Plasma-Mass Spectrometry (ICP-MS) and Inductively Coupled Plasma-Atomic Emission Spectrometry (ICP-AES) were conducted for homogeneity and stability testing. For the homogeneity test, the variance test F value was less than the threshold, indicating a good homogeneity. After 18 months, six analysis results showed that no significant statistical changes were found in the elements and components. The results demonstrate that the samples have high uniformity and stability which meets the requirements for standard reference materials. Drying temperature (20-60℃) has no effect on the stability of FeO based on a ferrous experiment. According to JJF 1343—2012 and standard material specifications, 11 qualified laboratories were selected to give certified values and uncertainties of 46 elements, including major, trace and rare earth elements, by using the combination of classical methods and modern instrumental technologies. More than two kinds of methods with different principles were applied to yield accurate values. The content range of TiO₂ was 2.97%-19.76%, and the content range of TFe was 18.88%-51.30%, which covered many variations of ilmenite ores in China. These reference materials meet the requirements of ilmenite exploration, evaluation and development demand.