Noble Gases

Abstract

The article contains sections titled: 1. Introduction 2. Properties 2.1. Physical Properties 2.1.1. Single‐Component Systems 2.1.2. Two‐ and Multicomponent Systems 2.2. Chemical Properties 2.2.1. Chemistry of Helium, Neon, and Argon 2.2.2. Chemistry of Krypton 2.2.3. Chemistry of Xenon 2.2.4. Radon Compounds 2.2.5. Molecular Structures of Noble Gas Compounds 2.2.6. Noble Gas Clathrate Compounds 3. Occurrence and Availability 3.1. Terrestrial Occurrence 3.2. Occurrence of Radioactive Isotopes 3.3. Lunar and Solar Occurrence 4. Extraction and Isolation 4.1. Isolation From Air 4.1.1. Helium and Neon 4.1.2. Argon 4.1.3. Krypton and Xenon 4.2. Helium Extraction from Natural Gases 4.2.1. Crude Helium Extraction 4.2.1.1. Low‐Temperature Fractionation 4.2.1.2. Crude Helium Extraction by Permeation Processes 4.2.2. Purification of Helium 4.2.2.1. Purification of Helium by Pressure Swing Adsorption 4.2.2.2. Other Processes for Purification of Helium 4.2.3. Example of a Complete Process 4.3. Isolation of Argon from Ammonia Purge Gases 5. Liquefaction of Helium 5.1. Processes for Liquefaction of Helium 5.1.1. Recuperative Processes 5.1.2. Regenerative Processes 5.2. Gas Purification for Helium Liquefiers 5.3. Examples of Helium Cryo Plants 5.3.1. Liquefier Using the Claude Process 5.3.2. Liquefier Using the Stirling Process 5.3.3. Helium Cryo Plant Using the Gifford ‐ McMahon (GM) Process 5.4. Process Developments 6. Quality Specifications and Analysis 7. Uses 7.1. Welding 7.2. Illumination 7.3. Other uses 8. Storage and Transportation 9. Economic Aspects

Addressing the terawatt challenge: scalability in the supply of chemical elements for renewable energy

“…As in the case of neon, there is no public domain data available for how much krypton is annually separated during air distillation so the data in Table 4 View Article Online global argon production and the ratio of krypton to argon in the atmosphere (1.14 ppm : 9320 ppm). 24 Ho. Holmium belongs to the HREE group and production occurs almost exclusively in China.…”

“…Argon is a primary product of the distillation of air which contains 9320 ppm of argon and supply follows demand. 24 F. Fluorspar (calcium fluoride), is a major source of fluorine, but phosphate rock could also become a major source. Table 1 displays the fluoride content.…”

“…All helium is thus recovered from natural gas which can have helium concentrations up to 8 000 times higher, but not all natural gas contains economic concentrations of helium. 24 The largest producer is the USA (74%). Smaller producer countries include Algeria (17%), Russia (5%) and Poland (2%).…”

“…View Article Online output must be constrained below 18.2 ppm : 9320 ppm (concentration ratio) of argon production. 24 Au. Gold is mostly a product of primary mining (leading to elastic supply) and among the metals, it is exceeded only by steel and copper in monetary importance.…”

“…As a minor by-product of air distillation, xenon supply has nearly no elasticity. 24 Ru. Ruthenium is always a by-product of platinum.…”