Editing Chloralkali process (section)

==Electrodes==
{{See also|Mixed metal oxide electrode}}
Due to the corrosive nature of chlorine production, the anode (where the chlorine is formed) must be non-reactive and has been made from materials such as [[platinum]] metal,<ref name="Faraday1849">{{cite book |last=Faraday |first=Michael |year=1849 |title=Experimental Researches In Electricity |volume=1 |url=http://www.gutenberg.org/files/14986/14986-h/14986-h.htm |location=London |publisher=The University of London |author-link=Michael Faraday}}</ref> [[graphite]] (called plumbago in Faraday's time),<ref name="Faraday1849" /> or platinized [[titanium]].<ref name="Land1972">{{cite journal |title=Anodic chlorate formation on platinized titanium |author=Landolt, D. |author2=Ibl, N. |journal=Journal of Applied Electrochemistry |volume=2 |issue=3 |year=1972 |pages=201–210 |publisher=Chapman and Hall Ltd. |doi=10.1007/BF02354977|s2cid=95515683 }}</ref> A [[Mixed metal oxide electrode|mixed metal oxide clad titanium anode]] (also called a dimensionally stable anode) is the industrial standard today. Historically, platinum, [[magnetite]], [[lead dioxide]],<ref name="Muni1988">{{cite journal |title=Insoluble anode of α-lead dioxide coated on titanium for electrosynthesis of sodium perchlorate |author=Munichandraiah, N. |author2=Sathyanarayana, S. |journal=Journal of Applied Electrochemistry |volume=18 |issue=2 |year=1988 |pages=314–316 |publisher=Chapman and Hall Ltd. |doi=10.1007/BF01009281|s2cid=96759724 }}</ref> [[manganese dioxide]], and [[ferrosilicon]] (13–15% silicon<ref name="Dina1927">{{cite thesis |last=Dinan |first=Charles |date=1927-10-15 |title=The Corrosion of Durion Anodes |page=4 |type=BSc |publisher=Massachusetts Institute of Technology |hdl=1721.1/87815 |url=https://dspace.mit.edu/handle/1721.1/87815 |access-date=2019-09-25}}</ref>) have also been used as anodes.<ref name="Hale1918">{{cite book |last=Hale |first=Arthur |title=The Applications of Electrolysis in Chemical Industry |url=https://archive.org/details/applicationsofel00haleuoft |access-date=2019-09-15 |year=1918 |publisher=Longmans, Green, and Co. |page=[https://archive.org/details/applicationsofel00haleuoft/page/13 13]}}</ref> Platinum alloyed with [[iridium]] is more resistant to corrosion from chlorine than pure platinum.<ref name="Hale1918" /><ref name="Danneel1902">{{cite journal |author=Denso, P. |journal=Zeitschrift für Elektrochemie |volume=8 |issue=10 |year=1902 |pages=149–150 |title=Untersuchungen über die Widerstandsfähigkeit von Platiniridium-Anoden bei der Alkalichlorid-Elektrolyse |doi=10.1002/bbpc.19020081004|url=https://zenodo.org/record/2494519 }}</ref> Unclad titanium cannot be used as an anode because it [[Anodizing#Titanium|anodizes]], forming a non-conductive oxide and [[Passivation (chemistry)|passivates]]. Graphite will slowly disintegrate due to internal electrolytic gas production from the porous nature of the material and carbon dioxide forming due to carbon oxidation, causing fine particles of graphite to be suspended in the electrolyte that can be removed by filtration. The cathode (where hydroxide forms) can be made from unalloyed titanium, graphite, or a more easily oxidized metal such as [[stainless steel]] or [[nickel]].