Separation of Platinum Group Metals
The platinum-group metals (PGMs), also known as the Platinum Group, are a set of six chemical elements possessing similar properties. PGMs include platinum, palladium, rhodium, ruthenium, iridium, and osmium – all of which are precious metals and highly valued for use in jewelry and other high-value products. Although most of the PGMs occur naturally, they are not found in concentrations that are economically viable to mine them; thus, they must be separated from other metals and minerals.
The most common method used to separate PGMs from other metals is flotation. Flotation involves passing a slurry of ore through a series of tanks containing solvents and other reagents. The solvents react with the different metal ions and form a slurry that can be collected and separated. Once the metals have been separated, they can then be further purified through processes such as smelting.
Another common method for the separation of PGMs is solvent extraction. Solvent extraction involves passing a solution of reagents through a metal-containing slurry. The metal ions are then transferred from the slurry to a metal-selective medium, such as a molecule that binds to one metal but not to another. This method is often used to separate PGMs from base metals, such as copper, nickel, and zinc. It is also used for separating PGMs from higher-valued metals, such as gold and silver.
One final method for the separation of PGMs is ion exchange. In ion exchange, metal ions are exchanged between two solutions. The metal of interest is transferred from the solution that contains it to one that does not. This method is useful for separating PGMs from some of their other common impurities, such as copper and nickel.
The separation of PGMs is an important step in the production of these metals. Without proper separation, it would be impossible to produce these metals in the quantities demanded by industry. Fortunately, these methods enable industry to produce large amounts of PGMs with a high degree of purity. This makes them more accessible to consumers, who can use them for a variety of purposes.
