Sample Preparation and X-Ray Fluorescence Analysis of Sulfide Ores

Sulfide ores with varied concentrations, including four ore reference materials (zinc, copper, and iron sulfides) and two copper-nickel and iron sulfide samples, were used to develop an improved method for their analysis by X-ray fluorescence. The optimum conditions were established for the fusion of homogeneous stable glass disks. Different weights of silica were added to the samples, which were then fused with a lithium borate flux. The amount of silica varied from 1:20 for samples with low sulfur concentrations to 1:5 for those with high concentrations. The weight ratio of sample (including silica) to lithium tetraborate was 1:14. Lithium nitrate was used as a pre-oxidizing reagent to prevent degradation of platinum–gold crucibles. After pre-oxidation at 580°C for 13 minutes, the temperature was increased to 1100°C for 12 minutes. The relative standard deviations for major and trace elements were generally better than 5% and 10%, respectively.