1、 Characteristics of titanium
Titanium is a transition metal element with the chemical symbol Ti and an atomic number of 22. It is located in the fourth period and group IVB of the periodic table of chemical elements. There are 13 known isotopes of titanium, including Titanium-41 to Titanium-53. Among them, there are five stable isotopes of titanium: Titanium-46, Titanium-47, Titanium-48, Titanium-49, and Titanium-50. The rest of the isotopes are radioactive.

Chemical characteristics:
Titanium is a metal with relatively active chemical properties. When heated, it can interact with non-metallic substances such as oxygen, nitrogen, hydrogen, sulfur, and halogens. But at room temperature, the surface of titanium is prone to forming an extremely thin, dense, inert oxide film that can repair cracks on its own. It has excellent corrosion resistance and is not corroded by nitric acid, humid chlorine gas, dilute sulfuric acid, dilute hydrochloric acid, and dilute alkali. Even aqua regia (a mixture of concentrated hydrochloric acid and concentrated nitric acid in a volume ratio of 3:1) cannot dissolve it in acid. The protective oxide film of titanium is often formed when the metal comes into contact with water, even in small amounts of water or water vapor. If titanium is exposed to a highly oxidizing environment without any water, it will undergo rapid oxidation and violent reactions, and even spontaneous combustion is common. This phenomenon has occurred in the reaction between titanium and fuming nitric acid containing excessive nitrogen oxides, as well as between titanium and dry chlorine gas. So to prevent such reactions, a certain amount of water is necessary. Titanium cannot be used in dry chlorine gas. Even dry chlorine gas with a temperature below 0 ℃ will undergo violent chemical reactions, producing titanium tetrachloride, which will then decompose into titanium dichloride and even burn. Titanium can only maintain reliable stability when the moisture content in chlorine gas is above 0.5%.
For safety reasons, wet and passivate with no less than 25% water during storage. Store in a cool and ventilated warehouse. Stay away from sources of fire and heat. The storage temperature should not exceed 35 ℃, the container should be kept sealed, and contact with air is strictly prohibited. It should be stored separately from oxidants, acids, halogens, etc., and avoid mixing storage. Equip with corresponding types and quantities of fire-fighting equipment. The storage area should be equipped with suitable materials to contain leaked materials.
Physical characteristics:
Elemental titanium appears silver white with a metallic luster. Powdered titanium appears gray in color. Titanium has a high melting point (1660 ℃) and a boiling point of 3287 ℃. It has a low density (4.5g/cm ³, which is 43% lighter than steel) and good ductility. In terms of hardness, heat resistance, and electrical and thermal conductivity, it is similar to other transition metals such as iron and nickel, but much lighter than other metals with similar mechanical and heat resistance properties; The propagation speed of sound in it is 5090 m/s. Titanium is soluble in dilute acid and insoluble in cold and hot water. Liquid titanium can dissolve almost all metals, so it can form alloys with various metals. Titanium steel made by adding titanium to steel is tough and elastic. Titanium forms interstitial compounds or intermetallic compounds with metals such as Al, Sb, Be, Cr, Fe, etc. Titanium metal can maintain its metallic properties even after long-term use at high temperatures of 500 ℃/-253 ℃. Typically, aluminum loses its original properties at 150 ℃ and stainless steel at 310 ℃, while titanium alloys maintain good mechanical properties at around 500-600 ℃. Moreover, titanium metal can still maintain good ductility and toughness at low temperatures of -253 ℃. Titanium is non-magnetic. Titanium has a low thermal conductivity, only 1/5 of steel, 1/13 of aluminum, and 1/25 of copper. The anti damping performance is low. When using titanium and other metal materials (copper, steel) to make clocks of the same shape and size, striking each clock with the same force will reveal that clocks made of titanium oscillate for a long time, meaning that the energy given to the clock by striking is not easily dissipated. Therefore, we say that titanium has low damping performance.
2、 Discovery of Titanium

Gregor
In 1791, Reverend William Gregor (1762-1817), an amateur mineralogist from England, found some black sand by the Manacan Creek in Cornwall. Later, he discovered that the sand was attracted by magnets and realized that this mineral (ilmenite) contained a new element. After analysis, it was found that there are two types of metal oxides in the sand: iron oxide (the reason why sand is attracted by magnets) and a white metal oxide that he cannot identify. He soon realized that this unidentified oxide contained an undiscovered metal, which was the precursor to titanium. Gregor published this discovery in the Royal Geological Society of Cornwall and the German Journal of Chemistry. Around the same time, Franz Joseph M ü ller von Reichenstein also produced a similar substance, but could not identify it.
In 1795, German chemist Martin Heinrich Klaproth (1743-1817) also discovered this oxide while studying Hungarian produced hematite. He advocated naming uranium (discovered by Klaproth in 1789) and named the new element "Titanium" after the Greek mythological Titan, which is transliterated as "titanium" in Chinese. After learning about Gregor's previous discoveries, he also obtained some samples of Manakan minerals and confirmed that they contained titanium. Chemistry expert Craprott did not compete with Gregor for the title of discoverer of titanium, so the scientific community generally agrees that Gregor discovered titanium.
In 1910, the titanium discovered by Gregor and Craprott was powdered titanium dioxide, not metallic titanium. Because the oxide of titanium is extremely stable, and metallic titanium can directly and strongly combine with oxygen, nitrogen, hydrogen, carbon, etc., it is difficult to produce elemental titanium. Until 1910, American chemist Matthew A. Hunter reduced TiCl4 with sodium to produce metallic titanium with a purity of 99.9%.
3、 The Development of Titanium

titanium
Global Development History
1940: Luxembourg scientist W J. Kroll reduced TiCl4 with magnesium to produce pure titanium. From then on, the magnesium reduction method (also known as the Crowell method) and the sodium reduction method (also known as the Hunter method) became industrial methods for producing sponge titanium.
In 1948, the United States began industrial production of titanium by using magnesium reduction method to produce 2 tons of sponge titanium.
In 1955, production surged to 20000 tons.
In 1972, the annual production reached 200000 tons.
According to statistics, the amount of titanium used for space travel in the world each year has exceeded one thousand tons. Extremely fine titanium powder is still a good fuel for rockets, so titanium is known as the cosmic metal and space metal.
The Development History of Titanium in China
In 1954, the Beijing Nonferrous Metals Research Institute began research on the preparation process of sponge titanium.
In 1956, China included titanium as a strategic metal in its 12 year development plan.
In 1958, the sponge titanium industry experiment was achieved at Fushun Aluminum Plant, and * sponge titanium production workshops in China were established. At the same time, * titanium plate and strip processing material production experiment workshops in China were established at Shenyang Nonferrous Metal Processing Plant. Baoji's titanium processing equipment, technological level, and production capacity all rank first in the country, accounting for about 60% of China's total production capacity. Its market share accounts for 85% of China's domestic titanium processing market and 22% of the world's production. It undertakes the production tasks of more than 90% of China's high-end titanium products and is known as the Titanium Valley of China.
In the 1960s and 1970s, under China's unified planning, more than 10 sponge titanium production units, represented by Zunyi Titanium Plant, were successively built.
In 1967, China established * titanium tube and rod processing material production test workshops and the second titanium plate and strip production test workshop at Luoyang Copper Processing Plant, and mainly undertook the trial production and development tasks of * nuclear submarines, * missile destroyers, and aviation titanium materials in China at that time.
In 1972, after the completion and operation of Baoji Nonferrous Metal Processing Plant, Luoyang Copper Processing transferred the process data to Beijing Nonferrous Research Institute. According to the professional division of the Ministry of Metallurgy, it no longer undertook the development and trial production of titanium materials; Beijing Nonferrous Research Institute, Shenyang Aluminum and Magnesium Institute, Fushun Aluminum Plant, Shenyang Nonferrous Metal Processing Plant, Northeast Light Alloy Processing Plant, Luoyang Copper Processing Plant and other units were the main ones to assist in the construction of Baoji Nonferrous Metal Processing Plant and Baoji Precious Metal Institute. From then on, according to industry division, Baoji Colored Metal Processing Plant and Baoji Precious Metal Institute were the main ones to undertake the production, development and trial production of most titanium processing materials in China. At the same time, China has become the fourth country after the United States, the former Soviet Union, and Japan to have a complete titanium industry system.
Around 1980, China's sponge titanium production reached 2800 tons. However, due to the insufficient understanding of titanium metal by most people at that time and the high price of titanium materials, the application of titanium was also limited. The production of titanium processed materials was only about 200 tons, and China's titanium industry was in a difficult situation.
In 1982, at the initiative of Vice Premier Fang Yi of the State Council and with the support of Comrades Zhu Rongji and Yuan Baohua, a cross ministerial national titanium application promotion leadership group was established in July to specifically coordinate the development of the titanium industry. This led to a prosperous production and sales of sponge titanium and titanium processing materials in China from the 1980s to the early 1990s, and the rapid and stable development of the titanium industry.
2011 was the year of China's 12th Five Year Plan, during which the production of sponge titanium and titanium processed materials continued to grow steadily. According to the statistics of the Titanium Zirconium Hafnium Branch of the China Nonferrous Metals Industry Association, the total output of 14 domestic sponge titanium production enterprises in 2011 was 64952 tons, an increase of 12.4% year-on-year. According to statistics from 30 companies, China produced a total of 50962t of titanium processing materials in 2011, a year-on-year increase of 33.0%.
In September 2014, China's "Electronic Grade Low Oxygen Ultra High Purity Titanium" furnace was successfully developed and put into operation in Yuyao City, Zhejiang Province, breaking the monopoly of foreign countries in China. Low oxygen ultra-high purity titanium is mainly used in core industrial fields such as semiconductor sputtering targets, aerospace, and offshore oil, with significant strategic significance. As a high-end strategic metal material, the US and Japanese governments strictly restrict exports to China. China often has to look at the "face" of the United States and Japan in the field of ultra-high purity titanium. The production of the "250 ton electronic grade low oxygen ultra-high purity titanium project" by Ningbo Chuangrun New Materials Co., Ltd. has filled the technological gap in China's high-end titanium materials, indicating that China has the independent production capacity of low oxygen ultra-high purity titanium and achieved the independent self-sufficiency of this strategic metal, completely eliminating dependence on foreign countries. After the monopoly is broken, the aerospace industry will directly benefit.
There are two important indicators for measuring the scale of a country's titanium industry: sponge titanium production and titanium material production. Sponge titanium production reflects raw material production capacity, while titanium material production reflects deep processing capacity. The titanium industry has formed five major producers and consumers in China, the United States, the Commonwealth of Independent States, Japan, and Europe.
In summary, China's titanium industry has roughly gone through three development periods: the pioneering period in the 1950s, the construction period in the 1960s and 1970s, and the initial development period in the 1980s and 1990s. In the new century, thanks to the sustained and rapid development of the national economy, China's titanium industry has also entered a period of rapid growth.
4、 The source of titanium

Titanium ore
Titanium is a rare metal, but in fact, it is not rare. In the ten kilometer thick strata on the Earth's surface, titanium contains up to 0.6%, 61 times more than copper, and ranks tenth in terms of content in the Earth's crust (ranking of elements in the crust: oxygen, silicon, aluminum, iron, calcium, sodium, potassium, magnesium, hydrogen, titanium). Widely distributed in the crust and lithosphere. Titanium also exists simultaneously in almost all organisms, rocks, water bodies, and soils. However, due to the lively nature of titanium and the high requirements for smelting processes, it has been difficult to produce large quantities of titanium for a long time, thus being classified as a "rare" metal.

　Titanium is mainly distributed on Earth in countries such as Australia, China, India, South Africa, and Canada. There are about 140 known titanium minerals, but the main minerals used in industrial applications are ilmenite (FeTiO3), rutile (TiO2), and perovskite. The ore is processed to obtain volatile titanium tetrachloride, which is then reduced with magnesium to produce pure titanium.
The total amount of titanium resources in China is 965 million tons, ranking first in the world and accounting for 38.85% of the world's proven reserves. It is distributed in 108 mining areas in 21 provinces (autonomous regions, municipalities directly under the central government). The main production area is Sichuan, followed by Hebei, Hainan, Guangdong, Hubei, Guangxi, Yunnan, Shaanxi, Shanxi and other provinces (regions). Among them, Panxi (Panzhihua Xichang) is China's largest titanium resource base, with a titanium resource of 870 million tons.
5、 The use of titanium

　Titanium alloy
Titanium metal is increasingly valued by people and is known as the "modern high-tech metal". It is an indispensable strategic material for improving the level of national defense equipment. Due to its high melting point, low specific gravity, corrosion resistance, low thermal conductivity, good high and low temperature tolerance, and low stress under rapid cooling and heating conditions, titanium's commercial value began to be recognized in the 1950s and has been applied in high-tech fields such as aviation, aerospace, chemical industry, petroleum, and power.
Military applications
Titanium has a wide range of applications in the military industry. Titanium is extensively used in armor plates, propeller blades, mortar barrels, anti tank missiles, missile launchers, tank shields, automatic rifles, recoilless gun launchers, bulletproof vests, and other military vessels for nuclear powered submarines, hydrofoil boats, and military vessels. According to information, a typhoon class nuclear submarine uses up to 9000 tons of titanium, indicating a huge demand for titanium materials in the military industry.
Aerospace and aviation
Titanium alloy has good heat resistance, low-temperature toughness, and fracture toughness, so it is often used as a structural material for military supersonic aircraft, compression components for jet engines, components for aircraft frames, casings, firewalls, rivets, structural components for air transport equipment, and structural components for rockets and missiles.
The amount of titanium used in civil aircraft accounts for about 20-25% of the weight of the structure, and aircraft made of titanium alloy can carry more than 100 passengers than other aircraft made of the same weight of metal.
The strength of certain titanium alloys (such as Ti-5AI-2.5SnELI) increases with decreasing temperature, but the plasticity does not decrease much. They still have good ductility and toughness at low temperatures and are suitable for use at ultra-low temperatures. It can be used for liquid hydrogen and liquid oxygen rocket engines, spacecraft, artificial satellite antennas, ultra-low temperature containers and storage tanks on manned spacecraft, etc.

　Marine industry
Submarines made of titanium are not only resistant to seawater corrosion (according to experiments, titanium is not corroded when placed on the seabed for 20-50 years), but also resistant to deep pressure. Their diving depth is 80% higher than that of stainless steel submarines. Meanwhile, titanium is non-magnetic and will not be detected by mines, providing excellent anti monitoring capabilities.
In addition, titanium is also used in various advanced titanium deep-sea submersibles and underwater laboratory devices for marine research. Titanium equipment and devices are widely used in coastal power plants, offshore oil extraction equipment, seawater desalination, marine chemical production, and marine aquaculture.

　　Chemical applications
Liquid titanium can dissolve almost all metals, so it can form alloys with various metals. Titanium steel made by adding titanium to steel is tough and elastic. Titanium forms interstitial compounds or intermetallic compounds with metals such as Al, Sb, Be, Cr, Fe, etc.
Mechanical equipment: Titanium and its alloys can be used to manufacture metal wire mesh and various machine parts for various pumps, valves, filtration, and evaporation equipment.
Chemical reaction vessel: Titanium is corrosion-resistant, so it is often used in the chemical industry. In the past, the components for storing hot nitric acid in chemical reactors were made of stainless steel. Stainless steel is also afraid of the strong corrosive agent - hot nitric acid. Every six months, these components need to be replaced completely. Using titanium to manufacture these components, although more expensive than stainless steel components, can be continuously used for five years, making it much more cost-effective to calculate.
Corrosion resistant equipment: After the 1970s and 1980s, China's vacuum salt production enterprises gradually began to use titanium metal materials to manufacture equipment, resulting in a significant improvement in equipment corrosion.
Storage tank and high-pressure vessel for oxidants: Titanium alloy can also be used as a storage tank and high-pressure vessel for oxidants.
Titanium nickel shape memory alloy: It has the ability to restore its original shape under certain temperature conditions and has been widely used in instruments and meters.
Superconducting material: Nb Ti alloy. When the temperature drops to near zero degrees, the wire made of Nb Ti alloy loses resistance. Any large current passing through the wire will not generate heat or consume energy. Nb Ti is called a superconducting material.
Energy storage material: Ti-50% Fe (atomic) alloy, with the ability to absorb a large amount of hydrogen gas. By utilizing the characteristic of Ti Fe, hydrogen can be safely stored, meaning that storing hydrogen does not necessarily require the use of steel high-pressure gas cylinders. Under certain conditions, Ti Fe can also release hydrogen, and Ti Fe is called an energy storage material.
Tableware: Titanium tableware will not corrode and produce ions, and the food can still maintain its original flavor, playing a role in antibacterial preservation.
Petroleum refining
In the process of petroleum refining, sulfides, chlorides, and other corrosive agents in petroleum processing products and cooling water have serious corrosiveness to the condensing equipment at the top of the atmospheric and vacuum distillation tower, especially in the low-temperature light oil section. Equipment corrosion has become one of the prominent problems troubling the refining industry. In recent years, countries such as the United States and Japan have introduced titanium equipment into these highly corrosive processes, mainly for various containers, reactors, heat exchangers, distillation towers, pipelines, pumps, and valves, achieving good results.
Automotive industry
The lightweight and high-strength properties of titanium have long been of concern to automobile manufacturers. Titanium has been used in racing for many years, and currently almost all racing cars use titanium materials. In Japan, the use of titanium in automobiles has exceeded 600 tons, and with the development of the global automotive industry, the use of titanium in automobiles is rapidly increasing.

　　Medical applications
With the improvement of medical technology, metal implantation in the human body is a very common surgical procedure. As titanium is a "biophilic metal", it does not cause allergic reactions after implantation in the human body, has weak rejection reactions with human tissues, can resist corrosion from secretions and is non-toxic. In addition, it has a similar density to bones, so it is widely used in artificial bones, artificial joints, artificial teeth and other human implants. When new muscle fiber rings are wrapped around these "titanium bones", these titanium bones begin to maintain normal human activities.

Artificial joint
In addition, titanium is adaptable to any sterilization method and its applications in pharmaceutical machinery and medical devices have been further recognized. The future demand cannot be underestimated.
Titanium is widely distributed in the human body, with a normal content of no more than 15mg per 70kg body weight. Its function is still unclear. But it has been proven that titanium can stimulate phagocytic cells and enhance immunity.
Sports and daily necessities
The consumption of titanium in the global golf equipment manufacturing industry is enormous, with over 6000 tons of titanium material used annually for the production of titanium golf equipment. In addition, titanium is widely used in tennis rackets, badminton rackets, ski poles, snow shovels, hiking poles, hiking nails, sleds, fencing masks, fishing rods, bicycles, eyeglass frames, food utensils, watches, handicrafts, and other daily necessities.

Titanium alloy tableware
Energy materials
Titanium has a wide range of applications in battery materials, nuclear industry, building materials, geothermal development, electricity, especially exploration and development.
Titanium can also be used as electrodes, condensers for power plants, and environmental pollution control devices.
Titanium compounds

Titanium dioxide pigment
Titanium dioxide (TiO2): Pure titanium dioxide is a white powder and an excellent white pigment, marketed as "titanium dioxide". It combines the covering properties of lead white (PbCO3) and the durability properties of zinc white (ZnO). Therefore, people often add titanium dioxide to paint to make high-grade white paint. As a filler added to paper pulp in the papermaking industry; As a matting agent for artificial fibers in the textile industry; As an additive in the glass, ceramic, and enamel industries to improve their performance; Used as a catalyst in many chemical reactions. Titanium dioxide is still one of the core components of many sunscreens and moisturizers, mainly used to brighten skin tone. As a physical sunscreen, it can effectively reflect ultraviolet rays and protect the skin from UV damage.
Sunscreen cream
Titanium tetrachloride (TiCl4): Titanium tetrachloride is a colorless liquid; Melting point 250K, boiling point 409K, with a pungent odor. It is highly prone to hydrolysis in water or humid air, emitting a large amount of white smoke. Therefore, TiCl4 is used as an artificial smoke agent in military applications, especially in maritime warfare. In agriculture, people use TiCl4 to form dense fog on the ground, reducing the loss of ground heat at night and protecting vegetables and crops from the harm of severe cold and frost.
Barium Metatitanate (BaTiO3): Artificially prepared BaTiO3 has a high dielectric constant, and capacitors made from it have a large capacity. More importantly, BaTiO3 has significant "piezoelectric properties", and its crystal will generate current under pressure, which will change its shape when electrified. People place it in ultrasonic waves, and when it is compressed, it generates an electric current. By measuring the strength of the electric current, the strength of the ultrasonic waves can be determined. It is used in almost all ultrasonic instruments. With the development and utilization of titanates, they are increasingly being used to manufacture nonlinear components, dielectric amplifiers, electronic computer memory components, miniature capacitors, electroplating materials, aerospace materials, strong magnets, semiconductor materials, optical instruments, reagents, and more.
TiCl3: It is a purple crystal, and its aqueous solution can be used as a reducing agent. Ti3+has stronger reducibility than Sn3+.
Titanium carbide and titanium hydride are new types of hard alloy materials.
Titanium nitride: It has a color close to gold and is widely used in decoration.
Other applications
Deoxidizer: Powdered titanium can be used as a deoxidizer in the manufacturing process of electronic tubes.
Titanium plated jewelry: with unique color and luster, it has been loved by many designers and consumers.
The self-cleaning ability of titanium has also attracted the attention of scientists. In the future, walls coated with special titanium materials may automatically clean on rainy days, making our city more beautiful.
Titanium has a wide range of applications in various fields, including aerospace, military, industrial processes, automobiles, agricultural and food products, medicine, kitchen utensils, sports equipment, jewelry, and mobile phones, among others.
6、 The hazards of titanium
Although titanium itself is not harmful to the human body, its compounds such as titanium tetrachloride and titanium oxide powder (titanium dioxide) pose certain risks to the human body. The International Agency for Research on Cancer has classified titanium oxide as a Group 2B carcinogen for humans.
Research has found that workers engaged in titanium oxide production have a higher risk of lung cancer than other populations. After humans inhale titanium oxide powder (especially nano-sized powders), it can damage tissues and organs such as lungs, liver, and kidneys. Among them, the lungs are the main target of titanium oxide attacks. Due to its small size and large specific surface area, titanium oxide can quickly penetrate into target cells, stimulating oxidative stress to some extent and damaging cell mitochondria. However, the attack and carcinogenic mechanism of titanium oxide on lung cells are still unclear, and the classification of titanium oxide as a possible carcinogen has also received opposition from many organizations and institutions. Therefore, further research is needed on the toxic mechanism of titanium oxide.
Conclusion
From black ore on the beach to its applications in various fields today, titanium has become a symbol of human technological progress and a better life, undoubtedly bringing more convenience and joy to our lives. Although we cannot predict the future, we can be certain that titanium will continue to contribute its strength and unique charm to the future development of humanity.
Now, when you mention the name titanium again, will you think of its legendary journey like a myth, and its endless possibilities in our lives? Let's look forward to more surprises and changes it will bring us together.