What is platinum? Platinum (Platinum), commonly known as Platinum, chemical symbol PT, belongs to the Platinum elements, is one of the precious metals; Atomic weight 195, atomic number 78, melting point 1772℃, boiling point 3827±100℃, high density, good ductility, chemical inert but has excellent thermal and electrical conductivity. Sponge platinum is a gray spongy substance with a high specific surface area and a strong ability to absorb gases (hydrogen, oxygen and carbon monoxide). Platinum is chemically inactive, stable in air and humid environment, insoluble in hydrochloric acid, sulfuric acid, nitric acid and alkali solutions, but soluble in aqua regia and molten alkali. Platinum is very rare in the earth's crust. Platinum is found in the earth's crust at only five parts per billion, far less than other scattered metals. Pt is mainly distributed in alluvial deposits and sand deposits in free state. It is easy to form alloys with other platinum elements, such as palladium and iridium. At present, the main platinum ore is arsenic platinum ore, sulfur platinum ore, antimony platinum ore, sulfur platinum palladium ore, sulfur nickel palladium ore, antimony gold platinum ore, tin lead platinum palladium ore, bismuth antimony platinum ore, platinum silver ore and so on. Platinum can be prepared in two forms: enrichment and refining. Concentration of platinum minerals is mainly carried out by gravity separation. The use of chute, jig, shaking table and wind force can effectively enrich the relatively high density platinum ore. Natural platinum can be floatated by xanthate because its surface wettability is low. Concentrate can be obtained after enrichment. The traditional refining methods include dissolution, reduction, precipitation and forging sintering. That is, platinum concentrate is dissolved with aqua Regina, platinum, palladium and gold form a solution, and gold is reduced from the solution with ferrous sulfate. Ammonium chloride is added to the solution to precipitate the platinum with ammonium chloroplatinate. Crude platinum is obtained by calcination and then refined by sodium bromate hydrolysis method. The extraction process, which began in 1970, achieved complete leaching of precious metals using Cl2/HCl mixture as the medium. Since then, the separation efficiency and product purity have been greatly improved, and also laid the foundation for modern platinum refining processes.

Platinum has diversified uses. Platinum demand is generally divided into automotive catalysts, jewelry, industrial demand and physical investment. The automotive catalyst sector has seen the highest demand for platinum over the past decade, accounting for about 39% of total demand in 2019; Jewelry consumption accounted for about 29% of the total platinum demand, second only to the automotive sector. In the industrial demand, the chemical industry, glass products, pharmaceutical field accounted for 4%, 4%, 11% respectively. The share of physical investment has historically been low but volatile, ranging from 1-10% of total demand over the past decade to about 4% in 2019. Platinum is widely used in metallurgy, instrument manufacturing, petroleum refining, chemical industry, medicine and other fields because of its high chemical stability and catalytic activity. As a catalyst, its biggest use is the catalytic converter of automobile exhaust gas; It can also be widely used in various chemical catalytic reactions (hydrogenation/dehydrogenation/isomerization/cyclamation/dehydration/cracking), such as platinum dioxide is the catalyst of hydrogenation reaction, used for the production of vegetable oil; In the defense industry, it can be used as a catalyst to make hydrogen peroxide, the fuel for missile launch. In the glass industry, platinum is more used to make corrosion resistant chemical instruments, such as reaction utensils, evaporation dishes, crucible, etc.; In the electrical and electronic industries, platinum is used to make contact points and platinum-rhodium alloy thermocouples and platinum-iridium spark plug electrodes. In other fields, platinum can be alloyed with cobalt and iron to make permanent magnets, which are used in aerospace instruments, electronic clocks, magnetrons, etc. In medicine, compounds of platinum, such as Cisplatin, are used in cancer chemotherapy. Platinum is also commonly used in jewelry manufacturing.