Editing Radon (section)

=== Industrial production ===
Radon is obtained as a by-product of [[Uranium ore deposits|uraniferous ores]] processing after transferring into 1% solutions of [[hydrochloric acid|hydrochloric]] or [[hydrobromic acid]]s. The gas mixture extracted from the solutions contains {{chem|H|2}}, {{chem|O|2}}, He, Rn, {{chem|CO|2}}, {{chem|H|2|O}} and [[hydrocarbon]]s. The mixture is purified by passing it over copper at {{Convert|993|K||abbr=}} to remove the {{chem|H|2}} and the {{chem|O|2}}, and then [[potassium hydroxide|KOH]] and [[Phosphorus pentoxide|{{chem|P|2|O|5}}]] are used to remove the acids and moisture by [[sorption]]. Radon is condensed by liquid nitrogen and purified from residue gases by [[sublimation (phase transition)|sublimation]].<ref>{{cite web |url=http://rn-radon.info/production.html |archive-url=https://web.archive.org/web/20081028133937/http://rn-radon.info/production.html |archive-date=2008-10-28 |title=Radon Production |publisher=Rn-radon.info |date=2007-07-24 |access-date=2009-01-30}}</ref>

Radon commercialization is regulated,{{Citation needed|date=February 2025}} but it is available in small quantities for the calibration of <sup>222</sup>Rn measurement systems. In 2008 it was priced at almost {{US$|6000|2008}} per milliliter of radium solution (which only contains about 15 picograms of actual radon at any given moment).<ref>{{cite web |title=SRM 4972&nbsp;– Radon-222 Emanation Standard |url=https://www-s.nist.gov/srmors/view_detail.cfm?srm=4972 |url-status=dead |archive-url=https://web.archive.org/web/20200306035332/https://www-s.nist.gov/srmors/view_detail.cfm?srm=4972 |archive-date=6 March 2020 |access-date=2008-06-26 |publisher=[[National Institute of Standards and Technology]]}}</ref> Radon is produced commercially by a solution of radium-226 (half-life of 1,600 years). Radium-226 decays by alpha-particle emission, producing radon that collects over samples of radium-226 at a rate of about 1&nbsp;mm<sup>3</sup>/day per gram of radium; equilibrium is quickly achieved and radon is produced in a steady flow, with an activity equal to that of the radium (50&nbsp;Bq). Gaseous <sup>222</sup>Rn (half-life of about four days) escapes from the capsule through [[diffusion]].<ref>{{cite journal |author=Collé, R. |author2=R. Kishore |date=1997 |title=An update on the NIST radon-in-water standard generator: its performance efficacy and long-term stability |journal=[[Nucl. Instrum. Methods Phys. Res. A]] |volume=391 |pages=511–528 |bibcode=1997NIMPA.391..511C |doi=10.1016/S0168-9002(97)00572-X |issue=3 |url=https://zenodo.org/record/1259919}}</ref> Radon sources have also been produced for scientific purposes through the implantation of radium-226 into solid [[stainless steel]].<ref>{{Cite web |last=Jörg |first=Florian |last2=Blaum |first2=Klaus |last3=Schweiger |first3=Christoph |last4=Simgen |first4=Hardy |date=January 4, 2023 |title=Production of 226Ra-implanted high-quality radon sources for detector characterization |url=https://cds.cern.ch/record/2845390/files/INTC-P-647.pdf |website=European Organization for Nuclear Research}}</ref>