Where does palladium occur naturally and how is it commercially produced?

Native palladium is rare, though it occurs naturally in alloyed forms with platinum, iridium, and other metals. Significant deposits are found in Colombia (Chocó department), Brazil (Itabira, Minas Gerais), the Ural Mountains, and South Africa (Transvaal). Additionally, palladium is associated with various gold, silver, copper, and nickel ores.1

Commercially, palladium is primarily produced as a by-product during the refining of copper and nickel ores. The extraction process typically begins with a mineral concentrate, which is leached with aqua regia to dissolve the palladium and platinum. After the platinum is precipitated from the solution, the remaining palladium is precipitated by adding ammonia. The resulting palladium salts are recovered, redissolved, and reprecipitated to ensure purity before being converted into metallic form, often through chemical reduction with formic acid.12

Palladium is also recovered from recycled materials, particularly from automotive catalytic converters, by melting the scrap with iron or copper and subsequently refining the resulting concentrate.3