Helium

 

V. Purity
99.2%, 99.5%, 99.8%, 99.995%, 99.999%, 99.998%, 99.9999%
Sixth, packaging specifications

 

 

Seven, helium application
The element symbol kr, atomic number 36, atomic weight 83.80, peripheral electronic arrangement 4s24p6, located in the sixth cycle of the 0 family. The elemental substance consists of monoatomic molecules, rare gases, colorless, odorless, and odorless. The density is 3.733 g / liter, the melting point is -156.6 ° C, and the boiling point is -153.3 ± 0.1 ° C. The atomic vana's radius is 198 picometers and the first ionization energy is 1351 kJ/mol. At 20 ° C, 23 ml can be dissolved per liter of water. The chemical nature is extremely inactive, and the compound cesium fluoride KRf2 which is stable at -80 ° C has been produced. Used to fill light bulbs and electronics. It can absorb X-rays and is used as a light-shielding material for X-ray operation.
Physical properties
Helium is a rare gas, colorless, odorless, non-toxic, inert, and helium is concentrated in the atmosphere. It occupies 1.1 ppm in the atmosphere. The boiling point is -153.35 ° C, and the content of cerium in the atmosphere is extremely low (trace amount, 1.14 × 10 -6 by volume). Can not burn, does not help combustion. Can absorb X-rays. The gas has a relative density of 3.736 (-152.9 ° C) and a liquid relative density of 2.155. Melting point -156.6 ° C, boiling point (-152.3 ± 1.0) ° C. The critical temperature is -63.81 ° C and the critical pressure is 55 × 105 Pa. It has high density, low thermal conductivity and high transmittance.
Chemical properties
 is chemically inert under all normal conditions. It does not combine with other elements or compounds. However, KrF2 can be produced when a mixture of cerium and fluorine is subjected to discharge at 84 K or electron beam irradiation at 123 K. KrF2 is very unstable. It decomposes rapidly at 0 °C. KrF4, which is an unstable colorless solid, has been prepared which is produced by the discharge of elements at low temperatures.
Application field
It can absorb X-rays and is used as a light-shielding material for X-rays. It forms bismuth difluoride with fluorine under low temperature and radiation, and emits a yellow-green glow when it is vacuum-discharged, which is used as a neon lamp. Also used as an inert protective gas in high efficiency bulbs. The radioactive isotope of thorium can be used to detect cracks on metal surfaces as small as two helium atoms (8 x 10-10 m).
use
Widely used in the electronics industry, electric light source industry, also used in gas lasers and plasma streams. Compared with the same-powered argon-filled bulb, the bulb filled with pure helium has the advantages of high luminous efficiency, small volume, long life, and power saving. It is widely used in the manufacture of miner's lamps, and because of its high transmittance, it can be used to manufacture illuminating lights and airstrip lights for night-time combat vehicles. Health care is used to measure cerebral blood flow. Its isotope can be used as a tracer. Radioactive cesium can be used for leak detection of closed containers and continuous measurement of material thickness, and can also be made into atomic lamps that do not require electrical energy. In addition, Kr 86 is used for international benchmarking of length and Kr 85 is used for “deuteration” of materials.
System of law
1. Air separation method: extracting mixture of krypton and xenon from air separation unit. After extracting barren, removing hydrocarbons and carbon dioxide, and separating, 99.99% of pure hydrazine was obtained.
2. Extracting argon synthesis ammonia tail gas from synthetic ammonia tail gas to produce argon and by-product mixture, and then rectifying, washing, deoxidizing, adsorbing and desorbing to obtain 99% helium gas.
3. Extracting the radioactive Kr85 from the cracked exhaust gas of the nuclear reactor from the nuclear reactor fission gas. Industrially, there is a Freon solvent absorption method.
Eight, matters needing attention
first-aid
Inhalation: Remove quickly from the scene to fresh air. Keep the airway open. If breathing stops, perform artificial respiration immediately. Seek medical attention.
Extinguishing method: Keep the container cool with water to prevent it from exploding and causing a rapid fire. Quickly cut off the air source, spray with water to protect the person who cut off the air source, and then choose appropriate fire extinguishing agent to extinguish the fire according to the cause of the fire.
On-site processing
Quickly evacuate people from the contaminated area to the upper reaches, and isolate them, strictly restricting access. Cut off the fire source. It is recommended that emergency personnel wear self-contained positive pressure breathing apparatus and wear general working clothes. Avoid contact with combustibles or flammable materials. Cut off the source of the leak as much as possible. Proper ventilation and accelerated diffusion. The leaking container should be properly disposed of, repaired, and used after inspection.
Handling and storage
Handling precautions: Closed operation. Closed operation provides good natural ventilation. Operators must be specially trained to strictly follow the operating procedures. Keep away from fire, heat, and smoking in the workplace. Keep away from flammable and combustible materials. Prevent gas from leaking into the workplace air. Avoid contact with the active metal powder. Lightly load and unload during handling to prevent damage to cylinders and accessories. Equipped with the corresponding variety and quantity of fire-fighting equipment and leakage emergency treatment equipment.
Storage Precautions: Store in a cool, ventilated warehouse. Keep away from fire and heat. The temperature of the reservoir should not exceed 30 °C. It should be stored separately from easy (combustible), active metal powder, etc., and should not be mixed. The storage area should be equipped with leakage emergency treatment equipment.
Personal protection
Engineering Control: Closed operation. Provide good natural ventilation.
Body protection: Wear general work clothes.
Hand protection: Wear general working protective gloves.
Other protection: Avoid high concentration inhalation.