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href="/wiki/Contact_process_(mathematics)" title="Contact process (mathematics)">Contact process (mathematics)</a>.</div><style data-mw-deduplicate="TemplateStyles:r1251242444">.mw-parser-output .ambox{border:1px solid #a2a9b1;border-left:10px solid #36c;background-color:#fbfbfb;box-sizing:border-box}.mw-parser-output .ambox+link+.ambox,.mw-parser-output .ambox+link+style+.ambox,.mw-parser-output .ambox+link+link+.ambox,.mw-parser-output .ambox+.mw-empty-elt+link+.ambox,.mw-parser-output .ambox+.mw-empty-elt+link+style+.ambox,.mw-parser-output .ambox+.mw-empty-elt+link+link+.ambox{margin-top:-1px}html body.mediawiki .mw-parser-output .ambox.mbox-small-left{margin:4px 1em 4px 0;overflow:hidden;width:238px;border-collapse:collapse;font-size:88%;line-height:1.25em}.mw-parser-output .ambox-speedy{border-left:10px solid #b32424;background-color:#fee7e6}.mw-parser-output .ambox-delete{border-left:10px solid #b32424}.mw-parser-output .ambox-content{border-left:10px solid #f28500}.mw-parser-output .ambox-style{border-left:10px solid #fc3}.mw-parser-output .ambox-move{border-left:10px solid #9932cc}.mw-parser-output .ambox-protection{border-left:10px solid #a2a9b1}.mw-parser-output .ambox .mbox-text{border:none;padding:0.25em 0.5em;width:100%}.mw-parser-output .ambox .mbox-image{border:none;padding:2px 0 2px 0.5em;text-align:center}.mw-parser-output .ambox .mbox-imageright{border:none;padding:2px 0.5em 2px 0;text-align:center}.mw-parser-output .ambox .mbox-empty-cell{border:none;padding:0;width:1px}.mw-parser-output .ambox .mbox-image-div{width:52px}@media(min-width:720px){.mw-parser-output .ambox{margin:0 10%}}@media print{body.ns-0 .mw-parser-output .ambox{display:none!important}}</style><table class="box-More_footnotes_needed plainlinks metadata ambox ambox-style ambox-More_footnotes_needed" role="presentation"><tbody><tr><td class="mbox-text"><div class="mbox-text-span">This article includes a list of <a href="/wiki/Wikipedia:Citing_sources#General_references" title="Wikipedia:Citing sources">general references</a>, but <b>it lacks sufficient corresponding <a href="/wiki/Wikipedia:Citing_sources#Inline_citations" title="Wikipedia:Citing sources">inline citations</a></b>.<span class="hide-when-compact"> Please help to <a href="/wiki/Wikipedia:WikiProject_Reliability" title="Wikipedia:WikiProject Reliability">improve</a> this article by <a href="/wiki/Wikipedia:When_to_cite" title="Wikipedia:When to cite">introducing</a> more precise citations.</span> <span class="date-container"><i>(<span class="date">May 2020</span>)</i></span><span class="hide-when-compact"><i> (<small><a href="/wiki/Help:Maintenance_template_removal" title="Help:Maintenance template removal">Learn how and when to remove this message</a></small>)</i></span></div></td></tr></tbody></table> <p>The <b>contact process</b> is a method of producing <a href="/wiki/Sulfuric_acid" title="Sulfuric acid">sulfuric acid</a> in the high concentrations needed for industrial processes. <a href="/wiki/Platinum" title="Platinum">Platinum</a> was originally used as the <a href="/wiki/Catalyst" class="mw-redirect" title="Catalyst">catalyst</a> for this reaction; however, because it is susceptible to reacting with <a href="/wiki/Arsenic" title="Arsenic">arsenic</a> impurities in the sulfur feedstock, <a href="/wiki/Vanadium(V)_oxide" title="Vanadium(V) oxide">vanadium(V) oxide</a> (V<sub>2</sub>O<sub>5</sub>) has since been preferred.<sup id="cite_ref-1" class="reference"><a href="#cite_note-1"><span class="cite-bracket">[</span>1<span class="cite-bracket">]</span></a></sup> </p> <div id="toc" class="toc" role="navigation" aria-labelledby="mw-toc-heading"><input type="checkbox" role="button" id="toctogglecheckbox" class="toctogglecheckbox" style="display:none"><div class="toctitle" lang="en" dir="ltr"><h2 id="mw-toc-heading">Contents</h2><span class="toctogglespan"><label class="toctogglelabel" for="toctogglecheckbox"></label></span></div> <ul> <li class="toclevel-1 tocsection-1"><a href="#History"><span class="tocnumber">1</span> <span class="toctext">History</span></a></li> <li class="toclevel-1 tocsection-2"><a href="#Process"><span class="tocnumber">2</span> <span class="toctext">Process</span></a></li> <li class="toclevel-1 tocsection-3"><a href="#Purification_unit"><span class="tocnumber">3</span> <span class="toctext">Purification unit</span></a></li> <li class="toclevel-1 tocsection-4"><a href="#Double_contact_double_absorption"><span class="tocnumber">4</span> <span class="toctext">Double contact double absorption</span></a></li> <li class="toclevel-1 tocsection-5"><a href="#Notes"><span class="tocnumber">5</span> <span class="toctext">Notes</span></a></li> <li class="toclevel-1 tocsection-6"><a href="#References"><span class="tocnumber">6</span> <span class="toctext">References</span></a></li> <li class="toclevel-1 tocsection-7"><a href="#External_links"><span class="tocnumber">7</span> <span class="toctext">External links</span></a></li> </ul> </div> </section><div class="mw-heading mw-heading2 section-heading" onclick="mfTempOpenSection(1)"><span class="indicator mf-icon mf-icon-expand mf-icon--small"></span><h2 id="History">History</h2><span class="mw-editsection"> <a role="button" href="/w/index.php?title=Contact_process&action=edit&section=1" title="Edit section: History" class="cdx-button cdx-button--size-large cdx-button--fake-button cdx-button--fake-button--enabled cdx-button--icon-only cdx-button--weight-quiet "> <span class="minerva-icon minerva-icon--edit"></span> <span>edit</span> </a> </span> </div><section class="mf-section-1 collapsible-block" id="mf-section-1"> <p>This process was patented in 1831 by British vinegar merchant Peregrine Phillips.<sup id="cite_ref-2" class="reference"><a href="#cite_note-2"><span class="cite-bracket">[</span>2<span class="cite-bracket">]</span></a></sup><sup id="cite_ref-3" class="reference"><a href="#cite_note-3"><span class="cite-bracket">[</span>3<span class="cite-bracket">]</span></a></sup><sup id="cite_ref-4" class="reference"><a href="#cite_note-4"><span class="cite-bracket">[</span>4<span class="cite-bracket">]</span></a></sup> In addition to being a far more economical process for producing concentrated <a href="/wiki/Sulfuric_acid" title="Sulfuric acid">sulfuric acid</a> than the previous <a href="/wiki/Lead_chamber_process" title="Lead chamber process">lead chamber process</a>, the contact process also produces <a href="/wiki/Sulfur_trioxide" title="Sulfur trioxide">sulfur trioxide</a> and <a href="/wiki/Oleum" title="Oleum">oleum</a>. </p><p>In 1901 <a href="/wiki/Eugen_de_Ha%C3%ABn" title="Eugen de Haën">Eugen de Haën</a> patented the basic process involving combining <a href="/wiki/Sulfur_dioxide" title="Sulfur dioxide">sulfur dioxide</a> and <a href="/wiki/Oxygen" title="Oxygen">oxygen</a> in the presence of <a href="/wiki/Vanadium_oxide" title="Vanadium oxide">vanadium oxides</a>, producing <a href="/wiki/Sulfur_trioxide" title="Sulfur trioxide">sulfur trioxide</a> which was easily absorbed into water, producing <a href="/wiki/Sulfuric_acid" title="Sulfuric acid">sulfuric acid</a>.<sup id="cite_ref-5" class="reference"><a href="#cite_note-5"><span class="cite-bracket">[</span>5<span class="cite-bracket">]</span></a></sup> This process was improved remarkably by shrinking the particle size of the catalyst (e.g. ≤ 5000 microns), a process discovered by two chemists of <a href="/wiki/BASF" title="BASF">BASF</a> in 1914.<sup id="cite_ref-6" class="reference"><a href="#cite_note-6"><span class="cite-bracket">[</span>6<span class="cite-bracket">]</span></a></sup><sup id="cite_ref-7" class="reference"><a href="#cite_note-7"><span class="cite-bracket">[</span>7<span class="cite-bracket">]</span></a></sup><sup id="cite_ref-8" class="reference"><a href="#cite_note-8"><span class="cite-bracket">[</span>8<span class="cite-bracket">]</span></a></sup> </p> </section><div class="mw-heading mw-heading2 section-heading" onclick="mfTempOpenSection(2)"><span class="indicator mf-icon mf-icon-expand mf-icon--small"></span><h2 id="Process">Process</h2><span class="mw-editsection"> <a role="button" href="/w/index.php?title=Contact_process&action=edit&section=2" title="Edit section: Process" class="cdx-button cdx-button--size-large cdx-button--fake-button cdx-button--fake-button--enabled cdx-button--icon-only cdx-button--weight-quiet "> <span class="minerva-icon minerva-icon--edit"></span> <span>edit</span> </a> </span> </div><section class="mf-section-2 collapsible-block" id="mf-section-2"> <p>The process can be divided into four stages: </p> <ol><li>Combining of <a href="/wiki/Sulfur" title="Sulfur">sulfur</a> and <a href="/wiki/Oxygen" title="Oxygen">oxygen</a> (O<sub>2</sub>) to form <a href="/wiki/Sulfur_dioxide" title="Sulfur dioxide">sulfur dioxide</a>, then purify the sulfur dioxide in a purification unit</li> <li>Adding an excess of oxygen to <a href="/wiki/Sulfur_dioxide" title="Sulfur dioxide">sulfur dioxide</a> in the presence of the catalyst <a href="/wiki/Vanadium(V)_oxide" title="Vanadium(V) oxide">vanadium pentoxide</a> at 450 °C and 1-2 atm</li> <li>The <a href="/wiki/Sulfur_trioxide" title="Sulfur trioxide">sulfur trioxide</a> formed is added to <a href="/wiki/Sulfuric_acid" title="Sulfuric acid">sulfuric acid</a> which gives rise to <a href="/wiki/Oleum" title="Oleum">oleum</a> (disulfuric acid)</li> <li>The oleum is then added to water to form sulfuric acid which is very concentrated. Since this process is an exothermic reaction, the reaction temperature should be as low as possible.</li></ol> <p>Purification of the air and sulfur dioxide (SO<sub>2</sub>) is necessary to avoid catalyst <i>poisoning</i> (i.e. removing catalytic activities). The gas is then washed with <a href="/wiki/Water_(molecule)" class="mw-redirect" title="Water (molecule)">water</a> and dried with sulfuric acid. </p><p>To conserve energy, the mixture is heated by exhaust gases from the <a href="/wiki/Catalytic_heater" title="Catalytic heater">catalytic converter</a> by heat exchangers. </p><p>Sulfur dioxide and dioxygen then react as follows: </p> <dl><dd>2 SO<sub>2(g)</sub> + O<sub>2(g)</sub> ⇌ 2 SO<sub>3(g)</sub> : Δ<i>H</i> = -197 kJ·mol<sup>−1</sup></dd></dl> <p>According to the <a href="/wiki/Le_Chatelier%27s_principle" title="Le Chatelier's principle">Le Chatelier's principle</a>, a lower temperature should be used to shift the chemical equilibrium towards the right, hence increasing the percentage yield. However too low of a temperature will lower the formation rate to an uneconomical level. Hence to increase the reaction rate, high temperatures (450 °C), medium pressures (1-2 <a href="/wiki/Atmosphere_(unit)" class="mw-redirect" title="Atmosphere (unit)">atm</a>), and <a href="/wiki/Vanadium(V)_oxide" title="Vanadium(V) oxide">vanadium(V) oxide</a> (V<sub>2</sub>O<sub>5</sub>) are used to ensure an adequate (>95%) conversion. The catalyst only serves to increase the rate of reaction as it does not change the position of the <a href="/wiki/Thermodynamic_equilibrium" title="Thermodynamic equilibrium">thermodynamic equilibrium</a>. The mechanism for the action of the catalyst comprises two steps: </p> <ol><li>Oxidation of SO<sub>2</sub> into SO<sub>3</sub> by V<sup>5+</sup>: <dl><dd>2SO<sub>2</sub> + 4V<sup>5+</sup> + 2O<sup>2−</sup> → 2SO<sub>3</sub> + 4V<sup>4+</sup></dd></dl></li> <li>Oxidation of V<sup>4+</sup> back into V<sup>5+</sup> by dioxygen (catalyst regeneration): <dl><dd>4V<sup>4+</sup> + O<sub>2</sub> → 4V<sup>5+</sup> + 2O<sup>2−</sup></dd></dl></li></ol> <p>Hot sulfur trioxide passes through the heat exchanger and is dissolved in concentrated H<sub>2</sub>SO<sub>4</sub> in the absorption tower to form oleum </p> <dl><dd>H<sub>2</sub>SO<sub>4</sub> + SO<sub>3</sub> → H<sub>2</sub>S<sub>2</sub>O<sub>7</sub></dd></dl> <p>Note that directly dissolving SO<sub>3</sub> in water is impractical due to the highly exothermic nature of the reaction. Acidic vapor or mists are formed instead of a liquid. </p><p>Oleum is reacted with water to form concentrated H<sub>2</sub>SO<sub>4</sub>. </p> <dl><dd>H<sub>2</sub>S<sub>2</sub>O<sub>7</sub> + H<sub>2</sub>O → 2 H<sub>2</sub>SO<sub>4</sub></dd></dl> </section><div class="mw-heading mw-heading2 section-heading" onclick="mfTempOpenSection(3)"><span class="indicator mf-icon mf-icon-expand mf-icon--small"></span><h2 id="Purification_unit">Purification unit</h2><span class="mw-editsection"> <a role="button" href="/w/index.php?title=Contact_process&action=edit&section=3" title="Edit section: Purification unit" class="cdx-button cdx-button--size-large cdx-button--fake-button cdx-button--fake-button--enabled cdx-button--icon-only cdx-button--weight-quiet "> <span class="minerva-icon minerva-icon--edit"></span> <span>edit</span> </a> </span> </div><section class="mf-section-3 collapsible-block" id="mf-section-3"> <p>This includes the dusting tower, cooling pipes, scrubbers, drying tower, arsenic purifier and testing box. Sulfur dioxide has many impurities such as vapours, dust particles and <a href="/wiki/Arsenous_oxide" class="mw-redirect" title="Arsenous oxide">arsenous oxide</a>. Therefore, it must be purified to avoid catalyst poisoning (i.e.: destroying catalytic activity and loss of efficiency). In this process, the gas is washed with water, and dried by sulfuric acid. In the dusting tower, the sulfur dioxide is exposed to a steam which removes the dust particles. After the gas is cooled, the sulfur dioxide enters the washing tower where it is sprayed by water to remove any soluble impurities. In the drying tower, sulfuric acid is sprayed on the gas to remove the moisture from it. Finally, the <a href="/wiki/Arsenic_oxide" title="Arsenic oxide">arsenic oxide</a> is removed when the gas is exposed to <a href="/wiki/Ferric_hydroxide" class="mw-redirect" title="Ferric hydroxide">ferric hydroxide</a>. </p> </section><div class="mw-heading mw-heading2 section-heading" onclick="mfTempOpenSection(4)"><span class="indicator mf-icon mf-icon-expand mf-icon--small"></span><h2 id="Double_contact_double_absorption">Double contact double absorption</h2><span class="mw-editsection"> <a role="button" href="/w/index.php?title=Contact_process&action=edit&section=4" title="Edit section: Double contact double absorption" class="cdx-button cdx-button--size-large cdx-button--fake-button cdx-button--fake-button--enabled cdx-button--icon-only cdx-button--weight-quiet "> <span class="minerva-icon minerva-icon--edit"></span> <span>edit</span> </a> </span> </div><section class="mf-section-4 collapsible-block" id="mf-section-4"> <p>The next step to the contact process is <i>double contact double absorption</i> (DCDA). In this process the product gases (SO<sub>2</sub>) and (SO<sub>3</sub>) are passed through absorption towers twice to achieve further absorption and conversion of SO<sub>2</sub> to SO<sub>3</sub> and production of higher grade sulfuric acid. </p><p>SO<sub>2</sub>-rich gases enter the catalytic converter, usually a tower with multiple catalyst beds, and are converted to SO<sub>3</sub>, achieving the first stage of conversion. The exit gases from this stage contain both SO<sub>2</sub> and SO<sub>3</sub> which are passed through intermediate absorption towers where sulfuric acid is trickled down packed columns and SO<sub>3</sub> reacts with water increasing the sulfuric acid concentration. Though SO<sub>2</sub> too passes through the tower it is unreactive and comes out of the absorption tower. </p><p>This stream of gas containing SO<sub>2</sub>, after necessary cooling is passed through the catalytic converter bed column again achieving up to 99.8% conversion of SO<sub>2</sub> to SO<sub>3</sub> and the gases are again passed through the final absorption column thus achieving not only high conversion efficiency for SO<sub>2,</sub> but also enabling production of a higher concentration of sulfuric acid. </p><p>The industrial production of sulfuric acid involves proper control of temperatures and flow rates of the gases as both the conversion efficiency and absorption are dependent on these. </p> </section><div class="mw-heading mw-heading2 section-heading" onclick="mfTempOpenSection(5)"><span class="indicator mf-icon mf-icon-expand mf-icon--small"></span><h2 id="Notes">Notes</h2><span class="mw-editsection"> <a role="button" href="/w/index.php?title=Contact_process&action=edit&section=5" title="Edit section: Notes" class="cdx-button cdx-button--size-large cdx-button--fake-button cdx-button--fake-button--enabled cdx-button--icon-only cdx-button--weight-quiet "> <span class="minerva-icon minerva-icon--edit"></span> <span>edit</span> </a> </span> </div><section class="mf-section-5 collapsible-block" id="mf-section-5"> <style data-mw-deduplicate="TemplateStyles:r1239543626">.mw-parser-output .reflist{margin-bottom:0.5em;list-style-type:decimal}@media screen{.mw-parser-output .reflist{font-size:90%}}.mw-parser-output .reflist .references{font-size:100%;margin-bottom:0;list-style-type:inherit}.mw-parser-output .reflist-columns-2{column-width:30em}.mw-parser-output .reflist-columns-3{column-width:25em}.mw-parser-output .reflist-columns{margin-top:0.3em}.mw-parser-output .reflist-columns ol{margin-top:0}.mw-parser-output .reflist-columns li{page-break-inside:avoid;break-inside:avoid-column}.mw-parser-output .reflist-upper-alpha{list-style-type:upper-alpha}.mw-parser-output .reflist-upper-roman{list-style-type:upper-roman}.mw-parser-output .reflist-lower-alpha{list-style-type:lower-alpha}.mw-parser-output .reflist-lower-greek{list-style-type:lower-greek}.mw-parser-output .reflist-lower-roman{list-style-type:lower-roman}</style><div class="reflist"> <div class="mw-references-wrap"><ol class="references"> <li id="cite_note-1"><span class="mw-cite-backlink"><b><a href="#cite_ref-1">^</a></b></span> <span class="reference-text"><style data-mw-deduplicate="TemplateStyles:r1238218222">.mw-parser-output cite.citation{font-style:inherit;word-wrap:break-word}.mw-parser-output .citation q{quotes:"\"""\"""'""'"}.mw-parser-output .citation:target{background-color:rgba(0,127,255,0.133)}.mw-parser-output .id-lock-free.id-lock-free a{background:url("//upload.wikimedia.org/wikipedia/commons/6/65/Lock-green.svg")right 0.1em center/9px no-repeat}.mw-parser-output .id-lock-limited.id-lock-limited a,.mw-parser-output .id-lock-registration.id-lock-registration a{background:url("//upload.wikimedia.org/wikipedia/commons/d/d6/Lock-gray-alt-2.svg")right 0.1em center/9px no-repeat}.mw-parser-output .id-lock-subscription.id-lock-subscription a{background:url("//upload.wikimedia.org/wikipedia/commons/a/aa/Lock-red-alt-2.svg")right 0.1em center/9px no-repeat}.mw-parser-output .cs1-ws-icon a{background:url("//upload.wikimedia.org/wikipedia/commons/4/4c/Wikisource-logo.svg")right 0.1em center/12px no-repeat}body:not(.skin-timeless):not(.skin-minerva) .mw-parser-output .id-lock-free a,body:not(.skin-timeless):not(.skin-minerva) .mw-parser-output .id-lock-limited a,body:not(.skin-timeless):not(.skin-minerva) .mw-parser-output .id-lock-registration a,body:not(.skin-timeless):not(.skin-minerva) .mw-parser-output .id-lock-subscription a,body:not(.skin-timeless):not(.skin-minerva) .mw-parser-output .cs1-ws-icon a{background-size:contain;padding:0 1em 0 0}.mw-parser-output .cs1-code{color:inherit;background:inherit;border:none;padding:inherit}.mw-parser-output .cs1-hidden-error{display:none;color:var(--color-error,#d33)}.mw-parser-output .cs1-visible-error{color:var(--color-error,#d33)}.mw-parser-output .cs1-maint{display:none;color:#085;margin-left:0.3em}.mw-parser-output .cs1-kern-left{padding-left:0.2em}.mw-parser-output .cs1-kern-right{padding-right:0.2em}.mw-parser-output .citation .mw-selflink{font-weight:inherit}@media screen{.mw-parser-output .cs1-format{font-size:95%}html.skin-theme-clientpref-night .mw-parser-output .cs1-maint{color:#18911f}}@media screen and (prefers-color-scheme:dark){html.skin-theme-clientpref-os .mw-parser-output .cs1-maint{color:#18911f}}</style><cite class="citation web cs1"><a rel="nofollow" class="external text" href="https://web.archive.org/web/20100523153700/http://www.ravensdown.co.nz/Resources/Education/History.htm">"History"</a>. Ravensdown. Archived from <a rel="nofollow" class="external text" href="http://www.ravensdown.co.nz/Resources/Education/History.htm">the original</a> on May 23, 2010<span class="reference-accessdate">. Retrieved <span class="nowrap">March 1,</span> 2010</span>.</cite><span title="ctx_ver=Z39.88-2004&rft_val_fmt=info%3Aofi%2Ffmt%3Akev%3Amtx%3Abook&rft.genre=unknown&rft.btitle=History&rft.pub=Ravensdown&rft_id=http%3A%2F%2Fwww.ravensdown.co.nz%2FResources%2FEducation%2FHistory.htm&rfr_id=info%3Asid%2Fen.wikipedia.org%3AContact+process" class="Z3988"></span></span> </li> <li id="cite_note-2"><span class="mw-cite-backlink"><b><a href="#cite_ref-2">^</a></b></span> <span class="reference-text"><link rel="mw-deduplicated-inline-style" href="mw-data:TemplateStyles:r1238218222"><cite id="CITEREFMcDonaldHunt1982" class="citation book cs1">McDonald, Donald; Hunt, Leslie B. (January 1982). <a rel="nofollow" class="external text" href="https://books.google.com/books?id=xriMAgAAQBAJ&pg=PA229"><i>A History of Platinum and its Allied Metals</i></a>. Johnson Matthey Plc. <a href="/wiki/ISBN_(identifier)" class="mw-redirect" title="ISBN (identifier)">ISBN</a> <a href="/wiki/Special:BookSources/9780905118833" title="Special:BookSources/9780905118833"><bdi>9780905118833</bdi></a>.</cite><span title="ctx_ver=Z39.88-2004&rft_val_fmt=info%3Aofi%2Ffmt%3Akev%3Amtx%3Abook&rft.genre=book&rft.btitle=A+History+of+Platinum+and+its+Allied+Metals&rft.pub=Johnson+Matthey+Plc&rft.date=1982-01&rft.isbn=9780905118833&rft.aulast=McDonald&rft.aufirst=Donald&rft.au=Hunt%2C+Leslie+B.&rft_id=https%3A%2F%2Fbooks.google.com%2Fbooks%3Fid%3DxriMAgAAQBAJ%26pg%3DPA229&rfr_id=info%3Asid%2Fen.wikipedia.org%3AContact+process" class="Z3988"></span></span> </li> <li id="cite_note-3"><span class="mw-cite-backlink"><b><a href="#cite_ref-3">^</a></b></span> <span class="reference-text"><style data-mw-deduplicate="TemplateStyles:r1041539562">.mw-parser-output .citation{word-wrap:break-word}.mw-parser-output .citation:target{background-color:rgba(0,127,255,0.133)}</style><span class="citation patent" id="CITEREFPeregrine_Phillips_Junior1831"><a rel="nofollow" class="external text" href="https://worldwide.espacenet.com/textdoc?DB=EPODOC&IDX=UK6093">UK 6093</a>, Peregrine Phillips Junior, "Manufacturing of Sulphuric Acid", issued 1831</span><span class="Z3988" title="ctx_ver=Z39.88-2004&rft_val_fmt=info%3Aofi%2Ffmt%3Akev%3Amtx%3Apatent&rft.number=6093&rft.cc=UK&rft.title=Manufacturing+of+Sulphuric+Acid&rft.inventor=Peregrine+Phillips+Junior&rft.date=1831"><span style="display: none;"> </span></span></span> </li> <li id="cite_note-4"><span class="mw-cite-backlink"><b><a href="#cite_ref-4">^</a></b></span> <span class="reference-text"><link rel="mw-deduplicated-inline-style" href="mw-data:TemplateStyles:r1238218222"><cite id="CITEREFAndersonBoudart2012" class="citation book cs1">Anderson, John R.; Boudart, Michel (2012-12-06). <a rel="nofollow" class="external text" href="https://books.google.com/books?id=6pvzCAAAQBAJ&pg=PA16"><i>Catalysis: Science and Technology</i></a>. Springer. <a href="/wiki/ISBN_(identifier)" class="mw-redirect" title="ISBN (identifier)">ISBN</a> <a href="/wiki/Special:BookSources/9783642932786" title="Special:BookSources/9783642932786"><bdi>9783642932786</bdi></a>.</cite><span title="ctx_ver=Z39.88-2004&rft_val_fmt=info%3Aofi%2Ffmt%3Akev%3Amtx%3Abook&rft.genre=book&rft.btitle=Catalysis%3A+Science+and+Technology&rft.pub=Springer&rft.date=2012-12-06&rft.isbn=9783642932786&rft.aulast=Anderson&rft.aufirst=John+R.&rft.au=Boudart%2C+Michel&rft_id=https%3A%2F%2Fbooks.google.com%2Fbooks%3Fid%3D6pvzCAAAQBAJ%26pg%3DPA16&rfr_id=info%3Asid%2Fen.wikipedia.org%3AContact+process" class="Z3988"></span></span> </li> <li id="cite_note-5"><span class="mw-cite-backlink"><b><a href="#cite_ref-5">^</a></b></span> <span class="reference-text"><link rel="mw-deduplicated-inline-style" href="mw-data:TemplateStyles:r1041539562"><span class="citation patent" id="CITEREFCarl_Johann_Eugen_de_Haën1901"><a rel="nofollow" class="external text" href="https://worldwide.espacenet.com/patent/search/family/025346274/publication/US1371004A">US 687834A</a>, Carl Johann Eugen de Haën, "Method of Making Sulfuric Anhydrid", issued 1901-12-03</span><span class="Z3988" title="ctx_ver=Z39.88-2004&rft_val_fmt=info%3Aofi%2Ffmt%3Akev%3Amtx%3Apatent&rft.number=687834A&rft.cc=US&rft.title=Method+of+Making+Sulfuric+Anhydrid&rft.inventor=Carl+Johann+Eugen+de+Ha%C3%ABn&rft.date=1901-12-03&rft.appldate=1914-10-9"><span style="display: none;"> </span></span></span> </li> <li id="cite_note-6"><span class="mw-cite-backlink"><b><a href="#cite_ref-6">^</a></b></span> <span class="reference-text"><link rel="mw-deduplicated-inline-style" href="mw-data:TemplateStyles:r1041539562"><span class="citation patent" id="CITEREFFranz_SlamaHans_Wolf1921"><a rel="nofollow" class="external text" href="https://worldwide.espacenet.com/patent/search/family/025346274/publication/US1371004A">US 1371004</a>, Franz Slama & Hans Wolf, "Oxidation of sulfur dioxid and catalyst therefor", issued 1921-05-8, assigned to General Chemical Company</span><span class="Z3988" title="ctx_ver=Z39.88-2004&rft_val_fmt=info%3Aofi%2Ffmt%3Akev%3Amtx%3Apatent&rft.number=1371004&rft.cc=US&rft.title=Oxidation+of+sulfur+dioxid+and+catalyst+therefor&rft.inventor=Franz+Slama&rft.assignee=General+Chemical+Company&rft.date=1921-05-8&rft.appldate=1914-10-9"><span style="display: none;"> </span></span></span> </li> <li id="cite_note-7"><span class="mw-cite-backlink"><b><a href="#cite_ref-7">^</a></b></span> <span class="reference-text"><link rel="mw-deduplicated-inline-style" href="mw-data:TemplateStyles:r1238218222"><cite id="CITEREFAndersonBoudart2012" class="citation book cs1">Anderson, John R.; Boudart, Michel (2012-12-06). <a rel="nofollow" class="external text" href="https://books.google.com/books?id=6pvzCAAAQBAJ&pg=PA16"><i>Catalysis: Science and Technology</i></a>. Springer. <a href="/wiki/ISBN_(identifier)" class="mw-redirect" title="ISBN (identifier)">ISBN</a> <a href="/wiki/Special:BookSources/9783642932786" title="Special:BookSources/9783642932786"><bdi>9783642932786</bdi></a>.</cite><span title="ctx_ver=Z39.88-2004&rft_val_fmt=info%3Aofi%2Ffmt%3Akev%3Amtx%3Abook&rft.genre=book&rft.btitle=Catalysis%3A+Science+and+Technology&rft.pub=Springer&rft.date=2012-12-06&rft.isbn=9783642932786&rft.aulast=Anderson&rft.aufirst=John+R.&rft.au=Boudart%2C+Michel&rft_id=https%3A%2F%2Fbooks.google.com%2Fbooks%3Fid%3D6pvzCAAAQBAJ%26pg%3DPA16&rfr_id=info%3Asid%2Fen.wikipedia.org%3AContact+process" class="Z3988"></span></span> </li> <li id="cite_note-8"><span class="mw-cite-backlink"><b><a href="#cite_ref-8">^</a></b></span> <span class="reference-text"><link rel="mw-deduplicated-inline-style" href="mw-data:TemplateStyles:r1238218222"><cite class="citation book cs1"><a rel="nofollow" class="external text" href="https://books.google.com/books?id=Q6XFfg8IIuAC&pg=SA10-PA816"><i>Industrial Chemistry</i></a>. Krishna Prakashan Media. 1991. <a href="/wiki/ISBN_(identifier)" class="mw-redirect" title="ISBN (identifier)">ISBN</a> <a href="/wiki/Special:BookSources/9788187224990" title="Special:BookSources/9788187224990"><bdi>9788187224990</bdi></a>.</cite><span title="ctx_ver=Z39.88-2004&rft_val_fmt=info%3Aofi%2Ffmt%3Akev%3Amtx%3Abook&rft.genre=book&rft.btitle=Industrial+Chemistry&rft.pub=Krishna+Prakashan+Media&rft.date=1991&rft.isbn=9788187224990&rft_id=https%3A%2F%2Fbooks.google.com%2Fbooks%3Fid%3DQ6XFfg8IIuAC%26pg%3DSA10-PA816&rfr_id=info%3Asid%2Fen.wikipedia.org%3AContact+process" class="Z3988"></span></span> </li> </ol></div></div> </section><div class="mw-heading mw-heading2 section-heading" onclick="mfTempOpenSection(6)"><span class="indicator mf-icon mf-icon-expand mf-icon--small"></span><h2 id="References">References</h2><span class="mw-editsection"> <a role="button" href="/w/index.php?title=Contact_process&action=edit&section=6" title="Edit section: References" class="cdx-button cdx-button--size-large cdx-button--fake-button cdx-button--fake-button--enabled cdx-button--icon-only cdx-button--weight-quiet "> <span class="minerva-icon minerva-icon--edit"></span> <span>edit</span> </a> </span> </div><section class="mf-section-6 collapsible-block" id="mf-section-6"> <style data-mw-deduplicate="TemplateStyles:r1239549316">.mw-parser-output .refbegin{margin-bottom:0.5em}.mw-parser-output .refbegin-hanging-indents>ul{margin-left:0}.mw-parser-output .refbegin-hanging-indents>ul>li{margin-left:0;padding-left:3.2em;text-indent:-3.2em}.mw-parser-output .refbegin-hanging-indents ul,.mw-parser-output .refbegin-hanging-indents ul li{list-style:none}@media(max-width:720px){.mw-parser-output .refbegin-hanging-indents>ul>li{padding-left:1.6em;text-indent:-1.6em}}.mw-parser-output .refbegin-columns{margin-top:0.3em}.mw-parser-output .refbegin-columns ul{margin-top:0}.mw-parser-output .refbegin-columns li{page-break-inside:avoid;break-inside:avoid-column}@media screen{.mw-parser-output .refbegin{font-size:90%}}</style><div class="refbegin" style=""> <ul><li><i>The Repertory of Patent Inventions</i>, no. 72 (April 1831), <a rel="nofollow" class="external text" href="https://books.google.com/books?id=EAcLAQAAIAAJ&pg=PA248">page 248</a>.</li> <li>(Anon.) (1832) "English patents: Specification of the patent granted to Peregrine Phillips, Jr. of Bristol, in the county of Somersetshire, Vinegar Maker, for an improvement in manufacturing Sulphuric Acid. Dated March 21, 1831." <i>Journal of the Franklin Institute</i>, new series, vol. 9, <a rel="nofollow" class="external text" href="https://books.google.com/books?id=RL5IAAAAMAAJ&pg=PA180">pages 180-182.</a></li> <li>Ernest Cook (March 20, 1926) "Peregrine Phillips, the inventor of the contact process for sulphuric acid," <i>Nature</i>, <b>117</b> (2942) : 419–421.</li> <li><a rel="nofollow" class="external text" href="https://books.google.com/books?id=SJIZAQAAIAAJ&pg=PA975">Lunge, <i>Theoretical and Practical Treatise on the Manufacture of Sulphuric Acid and Alkali, with the Collateral Branches</i>, 3rd ed., vol. 1, part 2 (London, England: Gurney and Jackson, 1903), page 975</a></li></ul> </div> </section><div class="mw-heading mw-heading2 section-heading" onclick="mfTempOpenSection(7)"><span class="indicator mf-icon mf-icon-expand mf-icon--small"></span><h2 id="External_links">External links</h2><span class="mw-editsection"> <a role="button" href="/w/index.php?title=Contact_process&action=edit&section=7" title="Edit section: External links" class="cdx-button cdx-button--size-large cdx-button--fake-button cdx-button--fake-button--enabled cdx-button--icon-only cdx-button--weight-quiet "> <span class="minerva-icon minerva-icon--edit"></span> <span>edit</span> </a> </span> </div><section class="mf-section-7 collapsible-block" id="mf-section-7"> <ul><li><link rel="mw-deduplicated-inline-style" href="mw-data:TemplateStyles:r1238218222"><cite id="CITEREFJim_Clark2002" class="citation web cs1">Jim Clark (2002). <a rel="nofollow" class="external text" href="http://www.chemguide.co.uk/physical/equilibria/contact.html">"The Contact Process"</a>. <i>Chemguide</i>.</cite><span title="ctx_ver=Z39.88-2004&rft_val_fmt=info%3Aofi%2Ffmt%3Akev%3Amtx%3Ajournal&rft.genre=unknown&rft.jtitle=Chemguide&rft.atitle=The+Contact+Process&rft.date=2002&rft.au=Jim+Clark&rft_id=http%3A%2F%2Fwww.chemguide.co.uk%2Fphysical%2Fequilibria%2Fcontact.html&rfr_id=info%3Asid%2Fen.wikipedia.org%3AContact+process" class="Z3988"></span></li> <li><link rel="mw-deduplicated-inline-style" href="mw-data:TemplateStyles:r1238218222"><cite class="citation web cs1"><a rel="nofollow" class="external text" href="https://web.archive.org/web/20150302044739/http://www.citycollegiate.com/sulphuric_acid1.htm">"The Contact Process"</a>. <i>City Collegiate</i>. 2009. Archived from <a rel="nofollow" class="external text" href="http://www.citycollegiate.com/sulphuric_acid1.htm">the original</a> on 2015-03-02<span class="reference-accessdate">. Retrieved <span class="nowrap">2009-05-01</span></span>.</cite><span title="ctx_ver=Z39.88-2004&rft_val_fmt=info%3Aofi%2Ffmt%3Akev%3Amtx%3Ajournal&rft.genre=unknown&rft.jtitle=City+Collegiate&rft.atitle=The+Contact+Process&rft.date=2009&rft_id=http%3A%2F%2Fwww.citycollegiate.com%2Fsulphuric_acid1.htm&rfr_id=info%3Asid%2Fen.wikipedia.org%3AContact+process" class="Z3988"></span></li> <li><link rel="mw-deduplicated-inline-style" href="mw-data:TemplateStyles:r1238218222"><cite class="citation web cs1"><a rel="nofollow" class="external text" href="http://www.mining-enc.ru/a/absorbcionnaya-kolonna">"Absorption Tower"</a>. <i>Mining Encyclopedia</i>.</cite><span title="ctx_ver=Z39.88-2004&rft_val_fmt=info%3Aofi%2Ffmt%3Akev%3Amtx%3Ajournal&rft.genre=unknown&rft.jtitle=Mining+Encyclopedia&rft.atitle=Absorption+Tower&rft_id=http%3A%2F%2Fwww.mining-enc.ru%2Fa%2Fabsorbcionnaya-kolonna&rfr_id=info%3Asid%2Fen.wikipedia.org%3AContact+process" class="Z3988"></span></li></ul>    </section></div> 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</span> <span class="minerva-icon minerva-icon-size-small minerva-icon--expand"></span> </div> </a> <div class="post-content footer-content"> <div id='mw-data-after-content'> <div class="read-more-container"></div> </div> <div id="p-lang"> <h4>Languages</h4> <section> <ul id="p-variants" class="minerva-languages"></ul> <ul class="minerva-languages"><li class="interlanguage-link interwiki-ar mw-list-item"><a href="https://ar.wikipedia.org/wiki/%D8%B9%D9%85%D9%84%D9%8A%D8%A9_%D8%A7%D9%84%D8%AA%D9%84%D8%A7%D9%85%D8%B3" title="عملية التلامس – Arabic" lang="ar" hreflang="ar" data-title="عملية التلامس" data-language-autonym="العربية" data-language-local-name="Arabic" class="interlanguage-link-target"><span>العربية</span></a></li><li class="interlanguage-link interwiki-de mw-list-item"><a href="https://de.wikipedia.org/wiki/Kontaktverfahren" title="Kontaktverfahren – German" lang="de" hreflang="de" data-title="Kontaktverfahren" data-language-autonym="Deutsch" data-language-local-name="German" class="interlanguage-link-target"><span>Deutsch</span></a></li><li class="interlanguage-link interwiki-es mw-list-item"><a href="https://es.wikipedia.org/wiki/Proceso_de_contacto" title="Proceso de contacto – Spanish" lang="es" hreflang="es" data-title="Proceso de contacto" data-language-autonym="Español" data-language-local-name="Spanish" class="interlanguage-link-target"><span>Español</span></a></li><li class="interlanguage-link interwiki-fa mw-list-item"><a href="https://fa.wikipedia.org/wiki/%D9%81%D8%B1%D8%A2%DB%8C%D9%86%D8%AF_%D8%AA%D9%85%D8%A7%D8%B3" title="فرآیند تماس – Persian" lang="fa" hreflang="fa" data-title="فرآیند تماس" data-language-autonym="فارسی" data-language-local-name="Persian" class="interlanguage-link-target"><span>فارسی</span></a></li><li class="interlanguage-link interwiki-fr mw-list-item"><a href="https://fr.wikipedia.org/wiki/Proc%C3%A9d%C3%A9_de_contact" title="Procédé de contact – French" lang="fr" hreflang="fr" data-title="Procédé de contact" data-language-autonym="Français" data-language-local-name="French" class="interlanguage-link-target"><span>Français</span></a></li><li class="interlanguage-link interwiki-hi mw-list-item"><a href="https://hi.wikipedia.org/wiki/%E0%A4%B8%E0%A4%82%E0%A4%B8%E0%A5%8D%E0%A4%AA%E0%A4%B0%E0%A5%8D%E0%A4%B6_%E0%A4%AA%E0%A5%8D%E0%A4%B0%E0%A4%95%E0%A5%8D%E0%A4%B0%E0%A4%AE" title="संस्पर्श प्रक्रम – Hindi" lang="hi" hreflang="hi" data-title="संस्पर्श प्रक्रम" data-language-autonym="हिन्दी" data-language-local-name="Hindi" class="interlanguage-link-target"><span>हिन्दी</span></a></li><li class="interlanguage-link interwiki-id mw-list-item"><a href="https://id.wikipedia.org/wiki/Proses_kontak" title="Proses kontak – Indonesian" lang="id" hreflang="id" data-title="Proses kontak" data-language-autonym="Bahasa Indonesia" data-language-local-name="Indonesian" class="interlanguage-link-target"><span>Bahasa Indonesia</span></a></li><li class="interlanguage-link interwiki-ml mw-list-item"><a href="https://ml.wikipedia.org/wiki/%E0%B4%B8%E0%B4%AE%E0%B5%8D%E0%B4%AA%E0%B5%BC%E0%B4%95%E0%B5%8D%E0%B4%95%E0%B4%AA%E0%B5%8D%E0%B4%B0%E0%B4%95%E0%B5%8D%E0%B4%B0%E0%B4%BF%E0%B4%AF" title="സമ്പർക്കപ്രക്രിയ – Malayalam" lang="ml" hreflang="ml" data-title="സമ്പർക്കപ്രക്രിയ" data-language-autonym="മലയാളം" data-language-local-name="Malayalam" class="interlanguage-link-target"><span>മലയാളം</span></a></li><li class="interlanguage-link interwiki-ms mw-list-item"><a href="https://ms.wikipedia.org/wiki/Proses_Sentuh" title="Proses Sentuh – Malay" lang="ms" hreflang="ms" data-title="Proses Sentuh" data-language-autonym="Bahasa Melayu" data-language-local-name="Malay" class="interlanguage-link-target"><span>Bahasa Melayu</span></a></li><li class="interlanguage-link interwiki-nl mw-list-item"><a href="https://nl.wikipedia.org/wiki/Contactproces" title="Contactproces – Dutch" lang="nl" hreflang="nl" data-title="Contactproces" data-language-autonym="Nederlands" data-language-local-name="Dutch" class="interlanguage-link-target"><span>Nederlands</span></a></li><li class="interlanguage-link interwiki-ja mw-list-item"><a href="https://ja.wikipedia.org/wiki/%E6%8E%A5%E8%A7%A6%E6%B3%95" title="接触法 – Japanese" lang="ja" hreflang="ja" data-title="接触法" data-language-autonym="日本語" data-language-local-name="Japanese" class="interlanguage-link-target"><span>日本語</span></a></li><li class="interlanguage-link interwiki-pt mw-list-item"><a href="https://pt.wikipedia.org/wiki/Processo_de_contato" title="Processo de contato – Portuguese" lang="pt" hreflang="pt" data-title="Processo de contato" data-language-autonym="Português" data-language-local-name="Portuguese" class="interlanguage-link-target"><span>Português</span></a></li><li class="interlanguage-link interwiki-ru mw-list-item"><a href="https://ru.wikipedia.org/wiki/%D0%9F%D1%80%D0%BE%D0%B8%D0%B7%D0%B2%D0%BE%D0%B4%D1%81%D1%82%D0%B2%D0%BE_%D1%81%D0%B5%D1%80%D0%BD%D0%BE%D0%B9_%D0%BA%D0%B8%D1%81%D0%BB%D0%BE%D1%82%D1%8B" title="Производство серной кислоты – Russian" lang="ru" hreflang="ru" data-title="Производство серной кислоты" data-language-autonym="Русский" data-language-local-name="Russian" class="interlanguage-link-target"><span>Русский</span></a></li><li class="interlanguage-link interwiki-si mw-list-item"><a href="https://si.wikipedia.org/wiki/%E0%B7%83%E0%B7%8A%E0%B6%B4%E0%B6%BB%E0%B7%8A%E0%B7%81_%E0%B6%9A%E0%B7%8A%E2%80%8D%E0%B6%BB%E0%B6%B8%E0%B6%BA%E0%B7%99%E0%B6%B1%E0%B7%8A_%E0%B7%83%E0%B6%BD%E0%B7%8A%E0%B7%86%E0%B7%92%E0%B6%BA%E0%B7%94%E0%B6%BB%E0%B7%92%E0%B6%9A%E0%B7%8A_%E0%B6%B1%E0%B7%92%E0%B6%B4%E0%B6%AF%E0%B7%80%E0%B7%93%E0%B6%B8" title="ස්පර්ශ ක්‍රමයෙන් සල්ෆියුරික් නිපදවීම – Sinhala" lang="si" hreflang="si" data-title="ස්පර්ශ ක්‍රමයෙන් සල්ෆියුරික් නිපදවීම" data-language-autonym="සිංහල" data-language-local-name="Sinhala" class="interlanguage-link-target"><span>සිංහල</span></a></li><li class="interlanguage-link interwiki-fi mw-list-item"><a href="https://fi.wikipedia.org/wiki/Kontaktimenetelm%C3%A4" title="Kontaktimenetelmä – Finnish" lang="fi" hreflang="fi" data-title="Kontaktimenetelmä" data-language-autonym="Suomi" data-language-local-name="Finnish" class="interlanguage-link-target"><span>Suomi</span></a></li><li class="interlanguage-link interwiki-ta mw-list-item"><a href="https://ta.wikipedia.org/wiki/%E0%AE%A4%E0%AF%8A%E0%AE%9F%E0%AF%81%E0%AE%95%E0%AF%88%E0%AE%9A%E0%AF%8D_%E0%AE%9A%E0%AF%86%E0%AE%AF%E0%AE%A9%E0%AF%8D%E0%AE%AE%E0%AF%81%E0%AE%B1%E0%AF%88" title="தொடுகைச் செயன்முறை – Tamil" lang="ta" hreflang="ta" data-title="தொடுகைச் செயன்முறை" data-language-autonym="தமிழ்" data-language-local-name="Tamil" class="interlanguage-link-target"><span>தமிழ்</span></a></li><li class="interlanguage-link interwiki-tr mw-list-item"><a href="https://tr.wikipedia.org/wiki/Temas_s%C3%BCreci" title="Temas süreci – Turkish" lang="tr" hreflang="tr" data-title="Temas süreci" data-language-autonym="Türkçe" data-language-local-name="Turkish" class="interlanguage-link-target"><span>Türkçe</span></a></li><li class="interlanguage-link interwiki-zh mw-list-item"><a href="https://zh.wikipedia.org/wiki/%E6%8E%A5%E8%A7%A6%E6%B3%95" title="接触法 – Chinese" lang="zh" hreflang="zh" data-title="接触法" data-language-autonym="中文" data-language-local-name="Chinese" class="interlanguage-link-target"><span>中文</span></a></li></ul> </section> </div> <div class="minerva-footer-logo"><img src="/static/images/mobile/copyright/wikipedia-wordmark-en.svg" alt="Wikipedia" width="120" height="18" style="width: 7.5em; height: 1.125em;"/> </div> <ul id="footer-info" class="footer-info hlist hlist-separated"> <li id="footer-info-lastmod"> This page was last edited on 25 October 2024, at 16:58<span class="anonymous-show"> (UTC)</span>.</li> <li id="footer-info-copyright">Content is available under <a class="external" rel="nofollow" href="https://creativecommons.org/licenses/by-sa/4.0/deed.en">CC BY-SA 4.0</a> unless otherwise noted.</li> </ul> <ul 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