Palladium belongs to the Platinum group metals (Platinum, Palladium, Rhodium, Ruthenium, Osmium, and Iridium). According to the USGS, “naturally occurring platinum and platinum-rich alloys have been known for a long time. The Spaniards named the metal “platina,” or little silver, when they first encountered it in Colombia. They regarded platinum as an unwanted impurity in the silver they were mining.”
Far from unwanted, palladium has been used as an oxidation catalyst in catalytic converters to treat automobile exhaust emissions (as well as in dental restorative materials, and used as an investment metal in the form of bars and coins). The USGS Mineral Commodity Summary from January 2017 reported that “Less-expensive palladium has been substituted for platinum in most gasoline-engine catalytic converters. About 25% palladium can routinely be substituted for platinum in diesel catalytic converters; the proportion can be as much as 50% in some applications. For some industrial end uses, one PGM can substitute for another, but with losses in efficiency.”
The Minerals Education Coalition explains on its website that the lustrous silvery-white metal is named after the asteroid Pallas (which was discovered about the same time) and there are good reasons it is used for catalytic converters:
It is malleable, ductile and unreactive in the presence of air and water, but does react with acids and alkalis. Palladium is unusual in that hydrogen gas can filter through hot palladium. This quality allows palladium to purify hydrogen gas. At room temperature, palladium can absorb up to 900 times its own volume of hydrogen. It serves as a catalyst, and catalytic converters in automobile exhaust systems account for much of its use.
According to the USGS report, world resources of PGMs are estimated to total more than 100 million kilograms. The Minerals Education Coalition reports that palladium is generally found only in pure form, and along with platinum is found in sulfide concentrations in mafic igneous rocks It is mined in Russia, the USA(Montana), Zimbabwe, Australia, Canada and Finland.
Mining geologists perform ore grade control to figure out where the most profitable ore bodies are, in terms of location and mineral concentration variability. Ore deposits are inconsistent in nature, having high concentrations of metals in one area but much lower concentrations in others. Handheld XRF analyzers provide fast acquisition of geochemical data for ore deposit modeling, easily determining elemental constituents for most natural low concentration samples, as well as high grade ore concentrates. Ore-grade assessment helps manage blasting, excavation, and hauling activities, optimizing the site blend provided to the concentrator while preventing grade dilution or the erroneous transport of ore to the waste dump.
The data collected during the grade control processes helps mining geologists conduct quantitative geochemical analysis of metal concentrations necessary for geochemical mapping. Geochemical maps can be used to see an anomaly or trend, make the most efficient and economical drilling and excavation decisions, and ensure that your mining plan will yield a sufficient return on investment.
Handheld XRF analyzers are used by mining operations for measuring palladium in ore concentrates because the instruments provide on-site assay data within seconds, allowing for real-time grade control. Using handheld XRF analyzers helps mining companies to make faster decisions, while increasing operational efficiencies and financial returns.
For additional details, including analytical performance and fields of use of handheld XRF analyzers for mining, read the application note Exploring New Frontiers of In Situ Analysis.