Nickel production has seen increasing demand in recent times, as nickel is a key component in lithium-ion batteries, used in electric vehicles. Hence a fast, accurate, and precise method is needed for quantification of these ores both in the mining and refining processes.
Nickel is produced from two very different ores: lateritic and sulfidic. Lateritic ore is found primarily in tropical countries such as Indonesia and is mined from various depths beneath the surface, while sulfidic ore is usually found in combination with copper ore and is mined underground.
According to the USGS Minerals Report, “In 2022, the underground Eagle Mine in Michigan produced approximately 18,000 tons of nickel in concentrate, which was exported to smelters in Canada and overseas. Nickel in crystalline sulfate was produced as a byproduct of smelting and refining platinum-group-metal ores mined in Montana…. Estimated global nickel mine production increased by about 20%, with almost all of the increased production attributed to Indonesia. The largest share of the increase was facilitated by the ongoing commissioning of integrated nickel pig iron and stainless-steel projects. In addition, several companies continued to develop projects to produce intermediate matte or mixed nickel-cobalt hydroxide that were intended to be used as feedstock to produce battery-grade nickel sulfate.”
X-ray fluorescence spectrometry (XRF) is a well-established analytical method to determine chemical composition in materials with high accuracy and minimum sample preparation; therefore, it is a preferred technique in both exploration and process and quality control across many industries – including mining and smelting.
At the exploration stage, a quick, non-destructive analysis is often required for outcrop and soil analysis, advanced exploration and drilling, core sample analysis, mine mapping, grade control, and cuttings analysis for mud logging and reservoir characterization. Handheld XRF analyzers enable miners and geologists to perform fast, accurate geochemical analysis – virtually anywhere on site. With substantial capital investments at stake, it is crucial for mining operations to quickly identify and recover the most economically viable resources. Portable XRF analyzers help identify drill targets, increase discovery rates, enable on-site decisions, and pinpoint where to focus on the grid – ultimately guiding geochemical decisions and optimizing mining operations.
Lab-based analysis, however, Wavelength Dispersive X-ray Fluorescence (WDXRF) is preferable for high resolution applications (~15-150 eV) and analysis of lower atomic mass elements and rare earths. Rather than process a complete spectrum, WDXRF separates fluorescent signals into individual wavelengths using crystals and a series of optical components (collimator, optical encoders, detectors, etc.).
The WDXRF Spectrometer uses crystals to disperse the fluorescence spectrum into individual wavelengths of each element, providing high resolution and low background spectra for accurate determination of elemental concentrations. XRF Mapping is a great tool to measure the homogeneity of a sample in a sub-millimeter size range. This can help validate sample preparation or indicate problems in a process. Geologists use XRF elemental mapping to select or screen samples for more in-depth analysis with a scanning electron microscope (SEM), which requires highly controlled sample preparation and provides information in the sub-micrometer size range.
We analyzed nickel ore to discover if the chemical composition could be determined with high accuracy and minimum sample preparation and if a WDXRF Spectrometer was suitable for the analysis of nickel ore samples. You can read about the instrumentation used, the analytical conditions, sample preparation, calibration, and validations in the application note Analysis of nickel ore with the ARL OPTIM’X WDXRF Spectrometer.
In addition, we analyzed nickel ore as a pressed powder in an air environment with an EDXRF Spectrometer, which is a convenient front-end analysis tool that helps enable quick and easy analysis of even irregular samples with little-to-no sample preparation. In EDXRF, sensitivity and precision are achieved by targeted excitation of the sample to fluoresce only the elements of interest. EDXRF technology is engineered to simultaneously process whole groups of elements for qualitative or quantitative analysis and can be used in portable and laboratory-based formats. As a result, EDXRF can accommodate samples of almost any shape and size. This is a significant advantage for nickel ore mines which often operate in remote areas. You can read about the details in the application note EDXRF Analysis of Nickel Ore as Pressed Powders in an Air Environment.
Resources:
- Application Note: Analysis of nickel ore with the ARL OPTIM’X WDXRF Spectrometer
- EDXRF Analysis of Nickel Ore as Pressed Powders in an Air Environment.
- Image above: istock photo of nickel spheres
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