In the mineral classification, the platinum group element mineral belongs to the natural platinum group, including the natural element minerals of ruthenium, rhodium, palladium and platinum. They have a wide range of isomorphism and substitution phenomena with each other, thus forming a series of isomorphous crystals. The metals smelted from the platinum group minerals include palladium, rhodium, iridium, platinum, and the like.
Palladium jewellery - the new favorite of white precious metals, international fashion jewelry Platinum, palladium is the two kinds of minerals with the lowest reserves in the platinum group. The two kinds of metallurgical properties are quite similar, because of their similar rarities, similar uses, so often in each Application of alternatives to each other.
The platinum group metal includes six metals of platinum (Pt), palladium (Pd), osmium (Os), iridium (Ir), ruthenium (Ru), and rhodium (Rh).
Platinum group metals are known for their precious properties and precious resources; they are also called precious metals with gold and silver. But its discovery and use are much later than gold and silver. Gold and silver jewelry were discovered in the tombs before the Human Era, and humans have learned and used PGMs for more than two hundred years. Platinum was first discovered in 1735 by A.De.Ulloa, and other elements were known as late as the 19th century. For example, Palladium was discovered by WH Wollaston in 1804. The trick was discovered by K. Claus in 1845. Although found relatively late, they soon learned that they have some valuable features and are therefore widely used in modern industry and cutting-edge technologies. It is therefore called "modern precious metal." According to reports, from the year 4,000 BC to the end of the 19th century, the world accumulated a total of 29,000 tons of gold, and in the 19th century, the average annual output of gold was 123 tons. By 1973 to 1980, the average annual gold output was 1,375 tons. The world production of platinum group metals began to exceed 100 tons in 1969 and doubled in the late 1980s to reach 200 tons (Zhang Wenpu, 1997). In the early 1990s, it produced nearly 300 tons annually. From these data, it is not difficult to appreciate the deep meaning of “precious metals†and “modern precious metalsâ€: ​​both are rare and precious, and although the absolute number of platinum group elements is not comparable to gold and silver, the speed of its development indicates that it is “ Meaning of modernity.
Platinum group metals have similar physical and chemical properties as well as their own characteristics. Their common characteristic is: In addition to the steel gray, the rest are silver white; high melting point, high strength, stable electrical properties, high resistance to spark erosion, excellent corrosion resistance, high temperature oxidation resistance, The catalytic activity is good. The respective characteristics determine the different uses. For example, platinum has good plasticity and stable temperature coefficient of resistance and resistance. It can be forged into platinum wire, platinum foil, etc.; it is not directly combined with oxygen, is not attacked by acid and alkali, and is only soluble in hot aqua water; palladium can be Soluble in concentrated nitric acid, can absorb 350-850 times the volume of hydrogen at room temperature. Indole and indole are insoluble in aqua regia and can react with molten sodium hydroxide and sodium peroxide to form a compound that dissolves in acid. Indole and indole are insoluble in aqua regia but are easily oxidized to tetraoxide.
More than 200 PGE minerals have been discovered so far. Can be divided into 4 categories: 1 Natural metals: natural platinum, natural palladium, natural germanium, natural germanium, etc.; 2 intermetallic compounds: palladium, platinum, ore, antimony ore, and platinum group metals and iron, nickel Metal intermetallic compounds such as copper, gold, silver, lead, tin, etc.; 3 intermetallic compounds: platinum, palladium, rhodium, iridium, etc. with metallic bonds, niobium, selenium, tellurium, etc. Bond component of the covalent bond; 4 sulfide and arsenide. The main minerals of the platinum group elements and their composition are shown in Table 3.17.2. Industrial minerals mainly include arsenic or platinum minerals, natural platinum, isoprene palladium ore, ruthenium-palladium ore, arsenoplatin-niobium, ruthenium-palladium-barium ore, and ruthenium-palladium-nickel. Arsenic and platinum mines and equiaxed palladium minerals are more common in primary platinum deposits, and natural platinum is more prolific in sand platinum minerals. &Nbsp; noble metal is a general term for precious metals and rare metals. Since gold and silver are franchised by the People's Bank of China, the precious metals operated by the materials department are mainly platinum group elements, while selenium, tellurium and arsenic are rare elements and are often called semimetals.
Platinum: Platinum is a silver-white metal with a melting point of 1769 degrees and a density of 21.45 g/cm3. It is mainly used in electrical meters, chemical industry, and precision alloys.
Palladium: Palladium is a silver-gray metal with a melting point of 1552, a density of 12.16g/cm3, good plasticity, poor corrosion resistance in precious metals, power supply gas, instrumentation, chemical industry, and precision alloys.
é“‘: é“‘ is a smoke-gray metal with a melting point of 1960 degrees and a density of 12.44 g/cm3. It is a brittle metal. For electrical, instrumentation, high-temperature alloys and precision alloys.
铱: 铱 is a silver-gray metal with a melting point of 2443, which is the highest melting point in precious metals. The density is 22.4g/cm3, which is brittle metal, chemically stable, resistant to acid and alkali corrosion, and high in hardness. For electrical, chemical, instrumentation, light industry and other aspects, the preparation of precision alloys.
é•“: Liquid helium is silver-white metal, solid cerium is blue crystalline metal, soft texture, melting point is 29.8 degrees, density is 5.9g/cm3, chemical stability in the air, helium is mainly used in the semiconductor industry, making thermometers, preparation Fusible metals and so on.
Indium: Indium is a silvery white metal with a melting point of 156.6 degrees and a density of 7.31g/cm3. It is softer than lead, has good ductility, and is stable in chemical properties. It is mainly used for the preparation of precious metal alloys, low-melting-point alloys, bearing alloys, and electroplating industries. aspect.
Selenium: Selenium is a black or dark gray glass amorphous ingot (red selenium and gray selenium are selenium crystal modifications, with the principal component unchanged), which are rare elements, also called semimetals. Selenium has a melting point of 220 degrees, a boiling point of 685 degrees, a density of 40,808 g/cm3, and is brittle. It is mainly used in the manufacture of rectifiers, selenium photographic plates, copying cartridges, alloys, enamels, and glass industries.
碲: 碲 is a silver-gray semimetal, a rare element with a melting point of 450 degrees and a density of 6.24g/cm3. It is brittle, has a high resistivity, and is a counter-magnetic metal, so it is a good semiconductor material. Mainly used to make semiconductor devices, alloys, chemical raw materials and additives for cast iron, rubber, glass and other products.
Arsenic: Arsenic is a silver-gray semi-metal, a rare element. Arsenic has a melting point of 814°C. It sublimes at 613°C. Arsenic is easily oxidized in air. Arsenic oxide is highly toxic (commonly known as arsenic). The density of arsenic is 5.73G/cm3. It is insoluble in water and insoluble in organic matter. Solvents used to make alloys and semiconductor devices.
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