The mystery of several magical metals
Tungsten Tungsten (W) is the metal with the highest melting point, and its vapor pressure is still very low at a high temperature of 2000℃-2500℃. Tungsten has high hardness, high density and good high temperature strength. Tungsten was first used to make incandescent filaments, and most of tungsten was used to produce cemented carbide. Tungsten, chromium, molybdenum, and cobalt form a heat-resistant alloy used to make cutting tools, metal surface hardening materials, gas turbine blades and combustion tubes. Tungsten is a refractory alloy with tantalum, niobium, molybdenum, etc. Tungsten copper and tungsten silver alloys are used as electrolytic contact materials. The high-density tungsten-nickel alloy is used as a radiation shield. Metal tungsten wires, rods, sheets, etc. are used to make parts of light bulbs, electronic tubes, and electrodes for arc welding. Tungsten powder should be sintered into filters with various porosities. Some compounds of tungsten can be used as fluorescent agents, pigments, dyes, and used in tanning and making fireproof fabrics. Tungsten is more expensive, and increasing the recovery rate in the production process is also an important issue. Silver (Ag) white metal is one of the metals used earlier. Silver is widely distributed in nature, and it is less in elemental state, and is mostly associated with other non-ferrous metal ores in the state of sulfide. The main method of extracting silver is to enrich the silver in heavy metal sulfide concentrates through beneficiation, and extract them in the process of smelting these heavy metals. The silver coexisting with gold is recovered in the process of gold conversion. Another way to extract silver is to recover silver from waste.
Among all metals, silver has the best electrical conductivity, thermal conductivity and reflectivity to visible light, as well as good ductility. Among the precious metals, silver has the most active chemical properties. The silver compound with the most industrial value is silver halide.
Silver has a wide range of uses. In ancient times, silver and its combined amount were used to make money and decorations. In modern times, it was mainly used to make photosensitive materials and electrical equipment, electroplating, medical equipment, and dental implants. Bismuth Bismuth (Bi) gray-red metal, people used bismuth in the Greek and Roman times, but they did not regard them as an element, and for a long time they mistakenly considered lead, tin, silver, antimony and so on. Bismuth is brittle and rich in luster. The volume of bismuth increases during solidification, and the expansion rate is 3.3%. Bismuth is the most diamagnetic metal. Under the action of a magnetic field, the resistivity increases while the thermal conductivity decreases. In addition, bismuth is the metal with the lowest thermal conductivity. Bismuth and its alloys have a thermoelectric effect. Bismuth is mainly used for the preparation of fusible alloys in metal mining. The melting point ranges from 47°C to 262°C. The most commonly used alloys are bismuth with metals such as lead, tin, antimony, and indium. Bismuth alloys have the characteristics of condensation and non-shrinkage.
Bismuth is also a major member of superconducting materials, and the demand for bismuth-based high-temperature superconducting materials is increasing.
Bismuth can be used in medicine in the form of a compound. Cobalt (Co) is a silver-white ferromagnetic metal with a light blue luster after polishing.
In 1735, the Swedish chemist Brandt produced metallic cobalt. In 1780, the Swedish chemist Bergman identified cobalt as an element. Cobalt minerals or cobalt compounds have been used as glazes for ceramics, glass, and enamel for a long time. By the 20th century, cobalt and its alloys have been widely used in the electrical machinery, machinery, chemical, aviation and aerospace industries, and have become an important strategic metal, with consumption increasing year by year. China began to extract cobalt from cobalt earth ore, nickel ore and cobalt-containing pyrite in the 1950s. It exists in nature as compounds of arsenic, oxygen and sulfur, such as cobaltine (CoAsS) and linneite (Co3S4).
It is used in cemented carbide, magnets, ceramics and special glass. It is also used in the manufacture of permanent magnets and razors. Cobalt-60 is used for cancer radiotherapy.
State: Hard silver-white transition metal.
Melting point (℃): 1495 Boiling point (℃): 2870 Density (g/cc, 300K): 8.9
Specific heat/J/gK: 0.42 Heat of evaporation/KJ/mol: 376.5 Heat of fusion/KJ/mol: 16.19 Conductivity/106/cm: 0.172 Thermal conductivity/W/cmK: 1 Titanium (Ti) is widely distributed in nature , The reserves on the earth are 16 times the total amount of copper, nickel, lead, and zinc. The content of titanium in the earth’s crust is 4400 g/ton, ranking ninth. The specific gravity of titanium is only 1/2 of that of iron, but it can withstand hammering and drawing like copper. In the ultra-low temperature world, titanium will become harder and have the properties of superconductors. Compared with other metal materials, the alloy composed of titanium and other elements has higher specific strength (tensile strength/density), good mid-temperature strength, good corrosion resistance, good low-temperature performance, low elastic modulus, and low thermal conductivity. , Non-ferromagnetic characteristics, widely used in aerospace, automotive and general industrial fields. Titanium alloy artificial bone joints and shape memory alloys have become indispensable materials in the medical field. With the development of new technology, the cost of refining titanium decreases, and titanium will penetrate into all aspects of our lives and become a hot material in the 21st century. Lithium (Li) is the lightest metal in nature, silver-white. China has abundant lithium resources. Among them, the salt lake lithium resource reserves in the Qaidam Basin of Qinghai Lake alone account for about 1/3 of the world’s salt lake resources.
Lithium can be alloyed with various elements and used in nuclear energy, aviation, aerospace, welding and other industries. Civil lithium is mainly used in the fields of lithium batteries, aluminum electrolysis, glass, ceramics, absorption air conditioners and grease. The application of lithium salt in the electrolytic aluminum industry has become one of the main consumer markets for lithium products. The application of lithium in controlled nuclear fusion reactors is the largest application field of lithium. The molten carbonate battery with lithium salt as the electrolyte is expected to become the second generation fuel cell after the phosphate fuel cell. Different specifications and types of lithium batteries have significantly increased the consumption of lithium. The most worth mentioning is the application of rechargeable lithium batteries, which is expected to be in the field of electric vehicles (EV). Among electric vehicles, whether it is advanced or not lies in its power system, and lithium ion has become the first choice in the field of battery chemistry. Lead, a gray-white metal, is one of the metals extracted earlier by mankind. Lead smelting and copper smelting began roughly in the same historical period. Lead is the softest precious metal and one of the metals with high specific gravity. It has good malleability and is easily alloyed with other metals. The surface of lead oxidizes in the air to form a lead oxide film. In moist and carbon dioxide-containing air, basic lead carbonate is formed. These products can prevent the continued oxidation of lead. Lead is a metal and can form lead salts.
Lead is widely used in the manufacture of lead alloys. Lead alloys are used to make battery plates, and lead pipes and lead plates are used as anti-corrosion materials. Lead also has its unfavorable side to human life and production. In recent years, the public is mainly concerned about the lead in petroleum products. The maximum acceptable lead depth in tap water is 0.05 mg/L. Exceeding it will affect human health. Lead containers should not be used to hold food and beverages in life to avoid lead poisoning. We must improve our understanding of lead so that lead can better serve human life and production. Antimony Antimony (Sb) is a silver-white metal with rhombohedral crystals.
In 1908, Hunan Huachang Company introduced the volatilization roasting method from France and began to smelt antimony. In the following decades, China’s antimony production often accounted for more than 50% of the world’s total production, up to 80%.
Antimony is brittle and cannot be used alone. Adding an appropriate amount of antimony to lead and tin can increase its hardness and strength. The main uses of antimony alloys and antimony compounds are battery extreme plates, printing type, lead plates, lead pipes, bullets, and bearings. Tantalum Metal Tantalum (Ta) is a slightly blue, light gray metal. Due to its many strange characteristics, it has a wide range of applications. Therefore, it is known as the all-rounder of the “metal kingdom”.
At temperatures below 150°C, tantalum is one of the most chemically stable metals. Only fluorine, fluorine ion-containing acid solutions and sulfur trioxide can react with tantalum.
The texture of tantalum is very hard, and the hardness can reach 6-6.5. Its melting point is as high as 2996℃, second only to tungsten and rhenium, ranking third. Tantalum is malleable and can be drawn into filaments or made into thin foils. Its coefficient of thermal expansion is very small, and can only expand by 6.6 parts per million per degree Celsius rises. In addition, its toughness is very strong, even better than copper.
In the equipment for preparing various inorganic acids, tantalum can be used to replace stainless steel, and its life span can be increased by several tens of times compared with stainless steel. In addition, in the chemical, electronic, electrical and other industries, tantalum can replace the precious metal platinum in the past, which greatly reduces the cost. The properties of tantalum make tantalum have very broad application prospects in the fields of capacitors, high-temperature alloys, chemical and atomic energy industries, and medicine.