It can be made from the ore with dry process in Industrial production; can also copper, nickel sulfide ore preparation of copper, nickel production process as a by-product as raw materials, made by wet smelting. It can also be obtained from the wet process with the byproduct of copper, nickel production from the copper sulfide ore or nickel sulfide ore.
The wet method is using the residue of extracted nickel and copper as raw materials, adding aqua for extraction, filtration, adding ammonia and hydrochloric acid to react, thus forming the precipitation of ammonium chloropalladate. After refining, filtration, reduction of ammonium chloropalladate with hydrogen 99.95% finished product of palladium can be obtained.
ChEBI: Chemical element (nickel group element atom) with atomic number 46.
In form of gold, silver, and copper alloys in dentistry; for alloy bearings, springs, balance wheels of watches; for mirrors in astronomical instruments; as catalyzer in manufacture of sulfuric acid and in other oxidizing processes; in powder form as catalyst in hydrogenation and in ignition of hydrogen or hydrocarbons with oxygen; the spongy form is used in gas analysis for separating hydrogen from mixtures of gases.
- For the production of catalysts, such as palladium asbestos, sponge and palladium;
- Making electrical instrumentation;
- For the precise alloy production, such as dental materials, watches and surgical instruments;
Among the platinum group metals, palladium is the least noble metal, exhibiting greater reactivity than other metals of the group. The metal forms mostly bivalent compounds, although a small number of tetravalent and a fewer trivalent compounds are known. Palladium exhibits a strong tendency to form complexes, most of which are four-coordinated square planar complexes of the metal in +2 oxidation state. When heated in air or oxygen above 350°C, palladium forms a black oxide, PdO coated over its surface. On further heating to over 790°C, the oxide decomposes back to the metal. Palladium dissolves more oxygen in molten state than in solid form.
Palladium reacts with fluorine and chlorine at 500°C forming its halides, the black PdF3 and the red deliquescent solid PdCl2.
Palladium is attacked by concentrated nitric acid, particularly in the presence of nitrogen oxides. The reaction is slow in dilute nitric acid. Finely divided palladium metal reacts with warm nitric acid forming palladium(II) nitrate, Pd(NO3)2. Hydrochloric acid has no affect on the metal. Reaction with boiling sulfuric acid yields palladium sulfate, PdSO4, and sulfur dioxide.
Palladium readily dissolves in aqua regia forming chloropalladic acid, H2PdCl6. Evaporation of this solution yields palladium(II) chloride, PdCl2.
Palladium absorbs hydrogen over 800 times its own volume over a range of temperature. By doing so, the metal swells, becoming brittle and cracked. Such absorption of hydrogen decreases the electrical conductivity of the metal. Also, such absorption activates molecular hydrogen, dissociating it to atomic hydrogen.
Palladium was discovered in 1803 by W.H. Wollaston during refining and purification of- platinum metal. This new metal was found in the aqua regia extract of native platinum and was detected in solution after platinum was precipitated. It was removed as ammonium chloroplatinate. Treating this solution with mercurous cyanide precipitated a yellow palladium complex salt. The precipitate was washed and ignited to form palladium metal. Wollaston named the element palladium after the newly discovered asteroid Pallas.
Palladium in nature is always associated with other platinum group metals. Its abundance in earth's crust is estimated at 0.015 mg/kg, about three times more abundant than platinum. Palladium is used mostly in alloys and the majority of its alloys are used for electronics and telecommunications. They are contacts in electrical relays and automatic switching gear. Palladium-gold alloys are applied widely in dentistry and medicine. They are in devices for replacement of damaged bones and joints and as support in porcelain-overlay bridgework. Palladium alloys are used in decoration and jewelry as a substitute for gold. They are used in gems, watch cases and brooches.
One of the most important applications of palladium is to catalyze hydrogenation, dehydrogenation, and petroleum cracking. Such reactions are widely employed in organic syntheses and petroleum refining. Palladium and platinum are installed in catalytic converters in automobiles to cut down the emission of unsaturated hydrocarbon gasses.
Palladium is a transition metal element used in catalytic reactions involving processes such as hydrogenation.
It is a silver-white metal (face-centered cubic crystal). Soluble in aqua regia, hot nitric acid, sulfuric acid, slightly soluble in hydrochloric acid, insoluble in cold water and hot water.