Girdler sulfide process 679919 220785638 2008-06-21T15:53:25Z DOI bot 6652755 Citation maintenance. You can [[WP:DOI|use this bot]] yourself! Please [[User:DOI_bot/bugs|report any bugs]]. The '''Girdler sulfide (GS) process''', also known as the '''Geib-Spevack (GS) process''',<ref>{{US patent|4620909}}, ''Method for isotope replenishment in an exchange liquid used in a laser induced isotope enrichment process''</ref> is an industrial production method for making [[heavy water]] ([[deuterium|deuterium]] oxide), an important component of many [[nuclear reactor]]s because it acts as a [[neutron moderator]]. It takes its name from [[Karl-Hermann Geib]] and [[Jerome S. Spevack]], who independently invented it in the early 1940s, or the Girdler company, which built the first American plant using the process. The method is an [[isotope|isotopic]] exchange process between [[Hydrogen sulfide|H<sub>2</sub>S]] and [[Water (molecule)|H<sub>2</sub>O]] ("light" water), that produces heavy water over several steps. It is a highly energy intensive process.<ref>[[Federation of American Scientists]], [http://www.fas.org/nuke/intro/nuke/heavy.htm Heavy Water Production], accessed 1 Feb 2007.</ref> Normal water contains 155 [[parts per million]] of deuterium, relative to hydrogen<ref>[[Vienna Standard Mean Ocean Water]]</ref>. Until its closure in 1997, the Bruce Heavy Water Plant in [[Ontario]] (located close to the [[Bruce Nuclear Generating Station]]) was the world's largest heavy water production plant, with a capacity of 700 tonnes per year. It used the Girdler sulfide process to produce heavy water, and required 340,000 tonnes of feed water to produce one tonne of heavy water. Presently, India has seven heavy water production plants. The first of these to use the Girdler process is located at Rawatbhata near Kota, Rajasthan. <ref>[http://www.heavywaterboard.org/htmldocs/general/HistoryBG.asp :: Heavy Water Board - A unit under Department of Atomic Energy, Govt. of India<!-- Bot generated title -->]</ref>. == The process == Each of a number of steps consists of two sieve tray columns. One column is maintained at 30°C and is called the ''cold tower'' and the other at 130°C and is called the ''hot tower''. [[Deuterium]] extraction is done based on the difference in separation between 30°C and 130°C. [[Hydrogen sulfide]] gas is circulated in a closed loop between the cold tower and the hot tower. [[Water purification|Demineralised]] and [[deaeration|deaerated]] water is fed to the cold tower where deuterium migration preferentially takes place from the hydrogen sulfide gas to the liquid water. This "enriched" water from the cold tower is fed to the hot tower where deuterium transfer takes place from the liquid water to the hydrogen sulfide gas. An appropriate "cascade" setup accomplishes enrichment. Normally in this process, water is enriched to 15% to 20% deuterium. Further enrichment to "reactor-grade" heavy water (>99% deuterium) is done in a [[vacuum distillation]] unit. <ref>{{cite journal | title = Separating of Hydrogen Isotopes in H<sub>2</sub>O-H<sub>2</sub>S System | author = Boris M. Andreev | journal = Separation Science and Technology | year = 2001 | volume = 36 | issue = 8-9 | pages = 1949–1989 | doi = 10.1081/SS-100104764 }}</ref> ==References== <references/> {{reaction-stub}} [[Category:Industrial processes]] [[Category:Isotope separation]] [[nl:Girdlersulfideproces]]