Palladium, a member of the platinum group, has the element symbol Pd, which is similar to platinum in appearance, silvery white metallic luster and bright color. The specific gravity is 12, which is lighter than platinum and has strong ductility. Melting point 1555℃, hardness 4-4.5, slightly harder than platinum. Chemical properties are relatively stable, insoluble in organic acids, cold sulfuric acid or hydrochloric acid, soluble in nitric acid and aqua regia, and it is not easy to oxidize and lose luster under normal circumstances.

Palladium) 1803 was discovered by British chemist wollaston when he was separating platinum. Similar to platinum, it has excellent characteristics and will not be oxidized and tarnished in air under normal circumstances. It is an extremely rare precious metal resource.

In mineral classification, platinum group minerals belong to natural platinum subgroup, including natural elemental minerals such as iridium, rhodium, palladium and platinum. There is a wide range of isomorphic substitution between them, thus forming a series of isomorphic mixed crystals. Metals smelted by platinum group elements include palladium, rhodium, iridium and platinum.

Palladium is one of the rare precious metals in the world. In 2008, the global total output of palladium was similar to that of platinum, accounting for less than 8% of the total output of gold. (Source: Platinum and Palladium Yearbook 2009) Palladium, platinum, gold and silver are all international precious metal spot and futures trading varieties, and their prices were once higher than platinum in history. Palladium is a non-renewable scarce resource, and its future value will be gradually reflected with the deepening of mining and the improvement of market demand.