Editing Solvay process (section)

== Carbon sequestration and the Solvay process ==

Variations in the Solvay process have been proposed for [[carbon sequestration]]. One idea is to react carbon dioxide, produced perhaps by the combustion of coal, to form solid carbonates (such as sodium bicarbonate) that could be permanently stored, thus avoiding [[Greenhouse gas emissions|carbon dioxide emission]] into the atmosphere.<ref>Huijgen, W.J.J. and Comans, R.N.J. (February, 2003). [https://web.archive.org/web/20170809141846/http://www.ecn.nl/docs/library/report/2003/c03016.pdf "Carbon dioxide sequestration by mineral carbonation: Literature Review,"] Report ECN C-03-016,
[http://www.edn.nl/en/ Energy Research Centre of the Netherlands]. Retrieved 2006-10-14.</ref><ref>{{Cite journal | volume = 27 | issue = 1 | pages = 193–232 | last = Lackner | first = Klaus S. |author-link=Klaus Lackner | title = Carbonate Chemistry for Sequestering Fossil Carbon | journal = [[Annual Review of Energy and the Environment]] | year = 2002 | doi = 10.1146/annurev.energy.27.122001.083433|doi-access=}}</ref> The Solvay process could be modified to give the overall reaction:

: 2 NaCl + CaCO<sub>3</sub> + {{chem|CO|2}} + {{chem|H|2|O}} → 2NaHCO<sub>3</sub> + CaCl<sub>2</sub>

Variations in the Solvay process have been proposed to convert carbon dioxide emissions into sodium carbonates, but carbon sequestration by calcium or magnesium carbonates appears more promising.{{dubious|date=October 2019|reason=That would normally require calcium or magnesium oxide or hydroxide, which are produced from carbonates, so there would be no net capture of carbon dioxide!}} However, the amount of carbon dioxide which can be used for carbon sequestration with calcium or magnesium (when compared to the total amount of carbon dioxide exhausted by mankind) is very low. This is primarily due to the major feasibility difference between capturing carbon dioxide from controlled and concentrated emission sources such as from coal-fired power plants as compared to capturing carbon from non-concentrated small-scale carbon sources such as small fires, vehicle exhaust, human respiration etc. when using such methods. Moreover, variation on the Solvay process will most probably add an additional energy consuming step, which will increase carbon dioxide emissions unless [[carbon neutral]] energy sources like [[hydropower]], [[nuclear power|nuclear energy]], [[wind power|wind]] or [[solar power]] are used.