Zirconium (Zirconium) is a chemical element, its chemical symbol Zr, its atomic number is 40, a high melting point metal, light gray. Density 6.49g/cc.

I. Preparation method

1. Roasting oblique zircon into zirconium tetrachloride. Zircon is co-heated with carbon, converted to zirconium carbide, and chlorinated to zirconium tetrachloride, which is then reduced with magnesium to produce zirconium metal. The better method in industry is the production of molten salt electrolysis with ZrCl4 or K2ZrF6 as raw materials.

2. Zircon is heated with carbon in an electric furnace to obtain zirconium carbide, and then chlorinated zirconium carbide at 500ºC to obtain crude zirconium tetrachloride. In order to separate the hafnium from it, the crude zirconium tetrachloride is first dissolved in water and the hafnium is separated from the aqueous solution. At present, the representative solvent extraction and separation method is isohexanone as solvent. By using this method, hafnium oxide can be obtained. The hafnium oxide is heated to 900ºC in the presence of carbon, and then chlorinated to form zirconium tetrachloride. Zirconium tetrachloride is purified by sublimation purification method. Magnesium reduction is used at about 850ºC. By-product magnesium chloride can be removed by vacuum distillation at about 900ºC, resulting in spongy zirconium.

2. Content distribution

Zirconium is the 19th most abundant in the Earth's crust, nearly equal to chromium. There are industrial zirconium-bearing minerals in nature, mainly zircon and plagiozircon. The zirconium resources in the world mainly occur in coastal placer deposits, and only a small part of them occur in deposit sand and primary ore. Of the world's estimated 40 million tonnes of zircon sand reserves, 85% are located in Australia, South Africa, the United States, India and the former Soviet Union. China's reserves of zirconium ore are the ninth in the world, with total reserves of more than 2 million tons, mainly concentrated in Guangdong, Hainan, Guangxi and Sichuan, while Yunnan is mainly rock ore, other such as Hunan, Hubei, Anhui, Fujian, Jiangxi, Liaoning, etc., also have some zirconium resources.

Three. Use

1. Industrial use

getter

Zirconium, like lithium and titanium, strongly absorbs nitrogen, hydrogen and oxygen. Zirconium violently absorbs nitrogen at temperatures above 90 ºC; At 200 degrees Celsius, 100 grams of zirconium metal can absorb 817 liters of hydrogen, more than 800,000 times as much as iron. This property of zirconium has been widely utilized. For example, in the electric vacuum industry, zirconium powder is widely applied on the surface of the anode and other heated parts of the electric vacuum components and instruments to absorb the residual gas in the vacuum tubes and make high-vacuum vacuum tubes and other electric vacuum instruments, so as to improve their quality and prolong their service time.

metallurgy

Zirconium can also be used as a "vitamin" in the metallurgical industry, playing its powerful role of deoxidation, nitrogen, sulfur. Adding only one thousandth of zirconium to steel increases its hardness and strength surprisingly; Armored steel, stainless steel and heat-resistant steel containing zirconium are important materials for the manufacture of armored vehicles, tanks, cannons, bulletproof plates and other defense weapons. When zirconium is added to copper, the copper wire is not weakened, but its melting point is greatly increased, making it suitable for high-voltage wires. Zinc-magnesium alloys containing zirconium, which are light and high temperature resistant, are twice as strong as ordinary magnesium alloys and can be used in the manufacture of jet engine components.

In addition, zirconium powder is characterized by a low ignition point and a fast combustion rate, which can be used as primer for detonators, advanced detonators that can explode even under water. Zirconium powder plus oxidizer. It's like adding fuel to a fire, burning it up in blinding light, good material for tracer bullets and flares.

Zirconium alloy

Zirconium alloy A non-ferrous alloy consisting of zirconium as a matrix with other elements added. The main alloy elements are tin, niobium, iron and so on. Zirconium alloy in 300 ~ 400ºC high temperature and pressure water and steam has good corrosion resistance, moderate mechanical properties, low atomic thermal neutron absorption cross section, has good compatibility to nuclear fuel, and is often used as the core structure material of water cooled nuclear reactor. In addition, zirconium has excellent corrosion resistance to a variety of acids, bases and salts, and has a strong affinity with gases such as oxygen and nitrogen. Therefore, zirconium alloy is also used in the manufacture of corrosion resistant components and pharmaceutical machinery components, and is widely used as a non-evapotranspiration type sterilizer in the electric vacuum and light bulb industries.

Zirconium alloys produced on an industrial scale are zirconium tin series and zirconium niobium series. The former alloy grade Zr-2, Zr-4, the typical representative of the latter is Zr-2.5Nb. In zirconium tin alloys, the alloying elements of tin, iron, chromium and nickel can improve the strength of the material, corrosion resistance and thermal conductivity of the corrosion resistant film, and reduce the sensitivity of the surface state to corrosion. Usually Zr-2 is used in boiling water reactors and Zr-4 is used in pressurized water reactors. In zirconium - niobium alloy, the corrosion resistance of the alloy is the best when the addition of niobium reaches the solution limit of zirconium crystal structure at the service temperature. Zirconium alloy has an isocrystalline transition. The crystal structure is body-centered cubic at high temperature and densely packed hexagonal at low temperature. Zirconium alloy has good plasticity, which can be made into pipe, plate, bar and wire by plastic processing. Its weldability is good, can be used for welding processing.

Because of its small thermal neutron capture cross section and outstanding nuclear performance, zirconium is an indispensable material for the development of atomic energy industry and can be used as a structural material for reactor core. Zirconium powder burns easily in air and can be used as detonator and smokeless powder. Zirconium can be used as an additive to deoxidize and desulfur high-quality steel, and is also the building block of armor steel, cannon steel, stainless steel and heat-resistant steel. Zirconium is an important alloying element of magnesium alloy, which can improve the tensile strength and workability of magnesium alloy. Zirconium is also an aluminum-magnesium alloy modifier, which can refine grain. Zirconium dioxide and zircon are the most valuable compounds in refractories. Zirconium dioxide is the main material of new ceramics, which can not be used as a heating material to resist high temperature oxidation. Zirconium dioxide can be used as an additive for acid-resistant enamel and glass. It can significantly improve the elasticity, chemical stability and heat resistance of glass. Zircon has strong light reflection and good thermal stability. It can be used as a sunblock in ceramics and glass. Zirconium can absorb a large amount of oxygen, hydrogen, ammonia and other gases when heating, is an ideal getter, such as the electron tube with zirconium powder as a degassing agent, with zirconium wire zirconium plate as grid support, anode support, etc.

Powdered iron mixed with zirconium nitrate can be used as glitter. Zirconium is used almost exclusively as a cladding for uranium fuel components in nuclear reactors. It is also used in the manufacture of flash lamps for photography, and corrosion resistant vessels and pipes, especially hydrochloric acid and sulfuric acid. Zirconium chemicals can be used as crosslinking agents for polymers.

2. Military applications

From the military point of view, steel as long as the addition of one-thousandth of zirconium, hardness and strength will be surprisingly improved. Zirconium-containing armor steel, cannon forging steel, stainless steel and heat-resistant steel are important materials in the manufacture of armored vehicles, tanks, artillery and bulletproof plates.

From the perspective of atomic energy and nuclear energy, zirconium has outstanding nuclear energy properties and is an indispensable material for the development of atomic energy industry. China's large nuclear power plants generally use zirconium materials. If nuclear power is used to generate electricity, 20 to 25 tons of zirconium metal will be consumed per one million kilowatts of power generation capacity in a year. A 30,000-horsepower nuclear submarine can use 20 to 30 tons of zirconium alloy for nuclear fuel jacket and pressure tube.

Zirconium is a rare metal, with amazing corrosion resistance, extremely high melting point, ultra-high hardness and strength and other characteristics, is widely used in aerospace, military, nuclear reaction, atomic energy fields. "God six" on the use of corrosion resistance, high resistance of titanium products, its corrosion resistance is far less than zirconium, its melting point about 1600 degrees, and zirconium melting point is above 1800 degrees, zirconium dioxide melting point is as high as 2700 degrees above, so zirconium as aerospace materials, its performance in all aspects is greatly superior to titanium.

Iv. Storage and transportation

Storage is often moistened and passivated with no less than 25% water. Store in a cool, ventilated warehouse. Keep away from fire and heat. The package is sealed. It should be stored separately from acids and avoid mixed storage. Explosion-proof lighting and ventilation facilities are adopted. Do not use mechanical equipment and tools that are prone to spark. The storage area should be equipped with suitable materials to contain leaks. In the process of transportation to prevent rain, shock. Handling should be handled with care to prevent collision and rolling and mechanical damage.