Exploratory studies on total reflection X-ray fluorescence spectrometry combined with slurry sampling for the multi-element analysis of copper-nickel sulfide ore

Abstract

Major and trace elements in polymetallic minerals are crucial subjects of study in ore geology. However, efficient and convenient methods have yet to be developed for processing high-density and hydrophobic sulfide ores, like copper–nickel sulfide ore, which is a strategic metal resource. In this paper, a novel method for the multielement analysis of copper-nickel sulfide ore using total reflection X-ray fluorescence spectrometry (TXRF) combined with slurry sampling was developed. This approach is based on the preparation of a suspension in a liquid at a certain viscosity without sample digestion. The effects of the sample amount and particle size on the analysis results were evaluated. The method validation was achieved through these processes: comparison with inductively coupled plasma atomic emission spectrometry (ICP-AES) results; analysis of certified reference materials, including copper-nickel cobalt ore and cobalt-rich nodule. The dispersants of ethylene glycol and 1% Triton X-100 applied in sulfide ore were also evaluated. For most elements, the relative error and relative standard deviation were under 10% in ethylene glycol. By contrast, suspensions with 1% Triton X-100 showed poorer reproducibility, particluarly in samples with sulfide-rich content, requiring further enhancement. For high-specific gravity sulfide ores, a dispersant of ethylene glycol is recommended to enhance the result of accuracy and reproducibility.