{"id":14474,"date":"2022-11-17T15:22:07","date_gmt":"2022-11-17T14:22:07","guid":{"rendered":"https:\/\/www.rct-online.de\/magazin\/koenigswasser-verwendung-und-eigenschaften\/"},"modified":"2025-07-11T16:07:15","modified_gmt":"2025-07-11T14:07:15","slug":"aqua-regia-applications-and-properties","status":"publish","type":"post","link":"https:\/\/www.rct-online.de\/magazin\/en\/aqua-regia-applications-and-properties\/","title":{"rendered":"Aqua Regia: Applications and Properties"},"content":{"rendered":"<div id=\"ez-toc-container\" class=\"ez-toc-v2_0_73 ez-toc-wrap-center counter-hierarchy ez-toc-counter ez-toc-white ez-toc-container-direction\">\n<div class=\"ez-toc-title-container\">\n<p class=\"ez-toc-title\" style=\"cursor:inherit\">Table of contents<\/p>\n<span class=\"ez-toc-title-toggle\"><a href=\"#\" class=\"ez-toc-pull-right ez-toc-btn ez-toc-btn-xs ez-toc-btn-default ez-toc-toggle\" aria-label=\"Toggle Table of Content\"><span class=\"ez-toc-js-icon-con\"><span class=\"\"><span class=\"eztoc-hide\" style=\"display:none;\">Toggle<\/span><span class=\"ez-toc-icon-toggle-span\"><svg style=\"fill: #999;color:#999\" xmlns=\"http:\/\/www.w3.org\/2000\/svg\" class=\"list-377408\" width=\"20px\" height=\"20px\" viewBox=\"0 0 24 24\" fill=\"none\"><path d=\"M6 6H4v2h2V6zm14 0H8v2h12V6zM4 11h2v2H4v-2zm16 0H8v2h12v-2zM4 16h2v2H4v-2zm16 0H8v2h12v-2z\" fill=\"currentColor\"><\/path><\/svg><svg style=\"fill: #999;color:#999\" class=\"arrow-unsorted-368013\" xmlns=\"http:\/\/www.w3.org\/2000\/svg\" width=\"10px\" height=\"10px\" viewBox=\"0 0 24 24\" version=\"1.2\" baseProfile=\"tiny\"><path d=\"M18.2 9.3l-6.2-6.3-6.2 6.3c-.2.2-.3.4-.3.7s.1.5.3.7c.2.2.4.3.7.3h11c.3 0 .5-.1.7-.3.2-.2.3-.5.3-.7s-.1-.5-.3-.7zM5.8 14.7l6.2 6.3 6.2-6.3c.2-.2.3-.5.3-.7s-.1-.5-.3-.7c-.2-.2-.4-.3-.7-.3h-11c-.3 0-.5.1-.7.3-.2.2-.3.5-.3.7s.1.5.3.7z\"\/><\/svg><\/span><\/span><\/span><\/a><\/span><\/div>\n<nav><ul class='ez-toc-list ez-toc-list-level-1 ' ><li class='ez-toc-page-1 ez-toc-heading-level-2'><a class=\"ez-toc-link ez-toc-heading-1\" href=\"https:\/\/www.rct-online.de\/magazin\/en\/aqua-regia-applications-and-properties\/#Industrial_Applications_and_Compatible_Hose_Technology\" title=\"Industrial Applications and Compatible Hose Technology\">Industrial Applications and Compatible Hose Technology<\/a><\/li><li class='ez-toc-page-1 ez-toc-heading-level-2'><a class=\"ez-toc-link ez-toc-heading-2\" href=\"https:\/\/www.rct-online.de\/magazin\/en\/aqua-regia-applications-and-properties\/#Applications_of_Aqua_Regia\" title=\"Applications of Aqua Regia\">Applications of Aqua Regia<\/a><\/li><li class='ez-toc-page-1 ez-toc-heading-level-2'><a class=\"ez-toc-link ez-toc-heading-3\" href=\"https:\/\/www.rct-online.de\/magazin\/en\/aqua-regia-applications-and-properties\/#Materials_for_Working_with_Aqua_Regia\" title=\"Materials for Working with Aqua Regia\">Materials for Working with Aqua Regia<\/a><\/li><li class='ez-toc-page-1 ez-toc-heading-level-2'><a class=\"ez-toc-link ez-toc-heading-4\" href=\"https:\/\/www.rct-online.de\/magazin\/en\/aqua-regia-applications-and-properties\/#Fluorinated_Homopolymers_PCTFE_and_PTFE\" title=\"Fluorinated Homopolymers: PCTFE and PTFE\">Fluorinated Homopolymers: PCTFE and PTFE<\/a><\/li><li class='ez-toc-page-1 ez-toc-heading-level-2'><a class=\"ez-toc-link ez-toc-heading-5\" href=\"https:\/\/www.rct-online.de\/magazin\/en\/aqua-regia-applications-and-properties\/#Fluorinated_Copolymers_ETFE_ECTFE_FEP_PFA_and_MFA\" title=\"Fluorinated Copolymers: ETFE, ECTFE, FEP, PFA and MFA\">Fluorinated Copolymers: ETFE, ECTFE, FEP, PFA and MFA<\/a><\/li><li class='ez-toc-page-1 ez-toc-heading-level-2'><a class=\"ez-toc-link ez-toc-heading-6\" href=\"https:\/\/www.rct-online.de\/magazin\/en\/aqua-regia-applications-and-properties\/#Perfluoroelastomer_FFKM\" title=\"Perfluoroelastomer FFKM\">Perfluoroelastomer FFKM<\/a><\/li><\/ul><\/nav><\/div>\n<h2><span class=\"ez-toc-section\" id=\"Industrial_Applications_and_Compatible_Hose_Technology\"><\/span>Industrial Applications and Compatible Hose Technology<span class=\"ez-toc-section-end\"><\/span><\/h2>\n<p style=\"text-align: justify;\"><strong>Many people have heard the term aqua regia, but what exactly is this special &#8216;water&#8217; and what is it made of? The name \u201caqua regia\u201d (literally \u201croyal water\u201d) refers to its ability to dissolve the \u201croyal\u201d metals gold and platinum. Another, less common name is royal acid.<\/strong><\/p>\n<div class=\"box info  \"><div class=\"box-inner-block\"><i class=\"fa tie-shortcode-boxicon\"><\/i>\n\t\t\tAqua regia is a mixture of two acids. It consists of three parts concentrated hydrochloric acid and one part concentrated nitric acid.\n\t\t\t<\/div><\/div>\n<p style=\"text-align: justify;\">When mixed, these acids produce nitrosyl chloride (NOCl) and chlorine radicals, which are responsible for dissolving the metal. Pure concentrated nitric acid cannot dissolve gold alone; only when chloride ions from the hydrochloric acid are present can the oxidised gold ions form complexes, resulting in tetrachloroauric acid (HAuCl\u2084).<\/p>\n<p style=\"text-align: justify;\">In addition to gold and platinum, metals such as rhenium, osmium, rhodium, iridium, palladium and mercury can also be dissolved by aqua regia. Metals like zirconium, hafnium, niobium, tantalum, titanium and tungsten form a passivation layer on their surfaces and therefore do not dissolve in this solution at room temperature. Silver does not dissolve either, as it forms an insoluble layer of silver chloride.<\/p>\n<figure id=\"attachment_8019\" aria-describedby=\"caption-attachment-8019\" style=\"width: 450px\" class=\"wp-caption aligncenter\"><img loading=\"lazy\" decoding=\"async\" class=\"wp-image-8019 size-full\" src=\"https:\/\/www.rct-online.de\/magazin\/wp-content\/uploads\/2023\/11\/gold-wird-in-koenigswasser-aufgeloest-klein.jpg\" alt=\"\" width=\"450\" height=\"179\" srcset=\"https:\/\/www.rct-online.de\/magazin\/wp-content\/uploads\/2023\/11\/gold-wird-in-koenigswasser-aufgeloest-klein.jpg 450w, https:\/\/www.rct-online.de\/magazin\/wp-content\/uploads\/2023\/11\/gold-wird-in-koenigswasser-aufgeloest-klein-300x119.jpg 300w\" sizes=\"(max-width: 450px) 100vw, 450px\" \/><figcaption id=\"caption-attachment-8019\" class=\"wp-caption-text\"><center>Aqua regia dissolving gold (start left, final state right)<\/center><\/figcaption><\/figure>\n<p>Aqua regia can only be used for a short time since nitrosyl chloride, chlorine and nitrous gases (a mix of various nitrogen oxides) decompose or escape over time. Therefore, it must be freshly prepared before each use.<\/p>\n<h2><span class=\"ez-toc-section\" id=\"Applications_of_Aqua_Regia\"><\/span>Applications of Aqua Regia<span class=\"ez-toc-section-end\"><\/span><\/h2>\n<p style=\"text-align: justify;\">Aqua regia is mainly used to produce tetrachloroauric acid, which serves as an electrolyte in the so-called Wohlwill process, an electrochemical refining method for non-ferrous and precious metals that achieves gold purities of over 99.99\u202fpercent.<\/p>\n<div class=\"box warning  \"><div class=\"box-inner-block\"><i class=\"fa tie-shortcode-boxicon\"><\/i>\n\t\t\tIn analytical chemistry, aqua regia is used for the digestion of difficult-to-dissolve samples \u2014 known as aqua regia digestion.\n\t\t\t<\/div><\/div>\n<p style=\"text-align: justify;\">In Germany, aqua regia digestion is standardised according to DIN EN 13346, which specifies the determination of elements such as cadmium, chromium, copper, mercury, nickel, lead and zinc in sewage sludge and soils. The related standard DIN EN 13657 covers the determination of heavy metals in biowaste, landfills and waste wood. These procedures may differ in other countries according to local regulations. During the digestion process, samples are first dried and ground, then treated with aqua regia and heated to boiling temperature for two hours. The dissolved metals can then be measured.<\/p>\n<figure id=\"attachment_8020\" aria-describedby=\"caption-attachment-8020\" style=\"width: 450px\" class=\"wp-caption aligncenter\"><img loading=\"lazy\" decoding=\"async\" class=\"wp-image-8020 size-full\" src=\"https:\/\/www.rct-online.de\/magazin\/wp-content\/uploads\/2023\/11\/platin-wird-in-koenigswasser-aufgeloest-klein.jpg\" alt=\"\" width=\"450\" height=\"139\" srcset=\"https:\/\/www.rct-online.de\/magazin\/wp-content\/uploads\/2023\/11\/platin-wird-in-koenigswasser-aufgeloest-klein.jpg 450w, https:\/\/www.rct-online.de\/magazin\/wp-content\/uploads\/2023\/11\/platin-wird-in-koenigswasser-aufgeloest-klein-300x93.jpg 300w\" sizes=\"(max-width: 450px) 100vw, 450px\" \/><figcaption id=\"caption-attachment-8020\" class=\"wp-caption-text\"><center>Platinum dissolving in aqua regia (start left, final state right)<\/center><\/figcaption><\/figure>\n<p style=\"text-align: justify;\">Another use for aqua regia is to estimate the fine gold content in jewellery. For this, several scratch samples are taken from the gold surface and exposed to solutions of varying concentrations.<\/p>\n<div class=\"box info  \"><div class=\"box-inner-block\"><i class=\"fa tie-shortcode-boxicon\"><\/i>\n\t\t\tLow gold content samples dissolve in all acid concentrations, while high gold content samples (greater than 96.5 percent by weight) dissolve only in the strongest aqua regia solution.\n\t\t\t<\/div><\/div>\n<p style=\"text-align: justify;\">This makes it relatively easy to detect so-called &#8216;fake gold&#8217;. Aqua regia is also used in metallography to etch the surface of metals or alloys to make the crystalline structure visible.<\/p>\n<h2><span class=\"ez-toc-section\" id=\"Materials_for_Working_with_Aqua_Regia\"><\/span>Materials for Working with Aqua Regia<span class=\"ez-toc-section-end\"><\/span><\/h2>\n<p style=\"text-align: justify;\">Aqua regia is a strongly corrosive acid and also an oxidiser. Therefore, special care is required when handling it. This corrosive mixture attacks most materials \u2014 only fluoropolymer-based plastics are resistant. <a href=\"https:\/\/www.rct-online.de\/en\/laboratory-equipment\/laboratory-containers\">Laboratory containers<\/a> for preparing aqua regia and <a href=\"https:\/\/www.rct-online.de\/en\/tubes-hoses\/tubings-and-pipes-made-of-rigid-plastics\">plastic tubes<\/a> for transport are made from these materials.<\/p>\n<h2><span class=\"ez-toc-section\" id=\"Fluorinated_Homopolymers_PCTFE_and_PTFE\"><\/span>Fluorinated Homopolymers: PCTFE and PTFE<span class=\"ez-toc-section-end\"><\/span><\/h2>\n<p style=\"text-align: justify;\">Various groups of fluoropolymers offer resistance to aqua regia. One such group is homopolymers, meaning these polymers consist of only one type of monomer. This group includes <a href=\"https:\/\/www.rct-online.de\/en\/tubes-hoses\/tubings-and-pipes-made-of-rigid-plastics\/ptfe-tubing\">polytetrafluoroethylene (PTFE)<\/a> and polychlorotrifluoroethylene (PCTFE). The monomer for PTFE is tetrafluoroethylene; PCTFE is produced by polymerising 1-chloro-1,2,2-trifluoroethylene. The difference lies in one of the four fluorine atoms being substituted by a chlorine atom.<\/p>\n<p style=\"text-align: justify;\">PCTFE, developed in 1934, was the earliest fluoropolymer. It is a semi-crystalline thermoplastic with the highest hardness, strength and rigidity among fluoropolymers. It can be used in a temperature range from \u2013240\u202f\u00b0C to +205\u202f\u00b0C and is mainly processed into <a href=\"https:\/\/www.rct-online.de\/en\/semi-finished-products\">semi-finished products<\/a> and <a href=\"https:\/\/www.rct-online.de\/en\/semi-finished-products\/foils\">foils<\/a>. Due to its stiffness, it is unsuitable for plastic hoses.<\/p>\n<p><a href=\"https:\/\/www.rct-online.de\/en\/tubes-hoses\/tubings-and-pipes-made-of-rigid-plastics\/ptfe-tubing\/28770\/ptfe-chemical-tubing-standard\"><img loading=\"lazy\" decoding=\"async\" class=\"alignnone wp-image-8021\" title=\"PTFE Chemical Tubing - standard\" src=\"https:\/\/www.rct-online.de\/magazin\/wp-content\/uploads\/2023\/11\/ptfe-chemieschlauch-standard.jpg\" alt=\"PTFE Chemical Tubing - standard\" width=\"300\" height=\"300\" srcset=\"https:\/\/www.rct-online.de\/magazin\/wp-content\/uploads\/2023\/11\/ptfe-chemieschlauch-standard.jpg 450w, https:\/\/www.rct-online.de\/magazin\/wp-content\/uploads\/2023\/11\/ptfe-chemieschlauch-standard-300x300.jpg 300w, https:\/\/www.rct-online.de\/magazin\/wp-content\/uploads\/2023\/11\/ptfe-chemieschlauch-standard-150x150.jpg 150w\" sizes=\"(max-width: 300px) 100vw, 300px\" \/><\/a> <a href=\"https:\/\/www.rct-online.de\/en\/semi-finished-products\/rods\/rods-made-of-elastomers-plastics-or-glas-ceramic\/30273\/solid-rod-made-of-pctfe\"><img loading=\"lazy\" decoding=\"async\" class=\"alignnone wp-image-8022\" title=\"Solid Rod made of PCTFE\" src=\"https:\/\/www.rct-online.de\/magazin\/wp-content\/uploads\/2023\/11\/rundstab-aus-pctfe.jpg\" alt=\"Solid Rod made of PCTFE\" width=\"300\" height=\"300\" srcset=\"https:\/\/www.rct-online.de\/magazin\/wp-content\/uploads\/2023\/11\/rundstab-aus-pctfe.jpg 450w, https:\/\/www.rct-online.de\/magazin\/wp-content\/uploads\/2023\/11\/rundstab-aus-pctfe-300x300.jpg 300w, https:\/\/www.rct-online.de\/magazin\/wp-content\/uploads\/2023\/11\/rundstab-aus-pctfe-150x150.jpg 150w\" sizes=\"(max-width: 300px) 100vw, 300px\" \/><\/a><\/p>\n<p style=\"text-align: justify;\">PTFE, better known by its trade name Teflon<strong>\u00ae<\/strong>, was discovered in 1938. Initially, high production costs and limited applications restricted its use. In 1943, during the Manhattan Project, PTFE-coated equipment was used to handle large quantities of highly corrosive uranium hexafluoride for uranium enrichment. This led to broader civilian use afterwards.<\/p>\n<div class=\"box success  \"><div class=\"box-inner-block\"><i class=\"fa tie-shortcode-boxicon\"><\/i>\n\t\t\tAmong all plastics, PTFE offers the highest chemical resistance and solvent resistance. It is also physiologically safe and has been approved by the FDA for food applications since 1960.\n\t\t\t<\/div><\/div>\n<p style=\"text-align: justify;\">PTFE can be used in a temperature range from \u2013200\u202f\u00b0C to +260\u202f\u00b0C. In sealing technology, it is used as <a href=\"https:\/\/www.rct-online.de\/en\/semi-finished-products\/adhesive-tapes-and-tapes\/adhesive-tapes-and-tapes-made-of-elastomers-or-plastics\/30100\/ptfe-sealing-tape\">PTFE tape<\/a>, <a href=\"https:\/\/www.rct-online.de\/en\/seals-and-gaskets\">sealing rings<\/a> and bellows.<\/p>\n<p style=\"text-align: justify;\">Thanks to its corrosion resistance and non-stick properties, it is also a popular coating material for tanks and pipelines. Another important field is <a href=\"https:\/\/www.rct-online.de\/en\/tubes-hoses\">hose technology<\/a>: fluoropolymer hoses are widely used in the chemical, pharmaceutical and medical sectors, as well as the food industry, due to their chemical and thermal resistance, negligible gas permeability, mechanical flexibility and sterilisation capability.<\/p>\n<h2><span class=\"ez-toc-section\" id=\"Fluorinated_Copolymers_ETFE_ECTFE_FEP_PFA_and_MFA\"><\/span>Fluorinated Copolymers: ETFE, ECTFE, FEP, PFA and MFA<span class=\"ez-toc-section-end\"><\/span><\/h2>\n<p style=\"text-align: justify;\">The second group consists of copolymers, made from two different monomers. Examples include ethylene-tetrafluoroethylene (ETFE), ethylene-chlorotrifluoroethylene (ECTFE), perfluoroethylene-propylene (FEP), poly[tetrafluoroethylene-perfluoro(alkoxy vinyl ether)] (PFA) and modified PFA (MFA).<\/p>\n<p><a href=\"https:\/\/www.rct-online.de\/en\/tubes-hoses\/tubings-and-pipes-made-of-rigid-plastics\/pfa-tubing\/28757\/pfa-chemical-tubing\"><img loading=\"lazy\" decoding=\"async\" class=\"alignnone wp-image-8024\" title=\"PFA Chemical Tubing\" src=\"https:\/\/www.rct-online.de\/magazin\/wp-content\/uploads\/2023\/11\/pfa-chemieschlauch1.jpg\" alt=\"PFA Chemical Tubing\" width=\"300\" height=\"300\" srcset=\"https:\/\/www.rct-online.de\/magazin\/wp-content\/uploads\/2023\/11\/pfa-chemieschlauch1.jpg 350w, https:\/\/www.rct-online.de\/magazin\/wp-content\/uploads\/2023\/11\/pfa-chemieschlauch1-300x300.jpg 300w, https:\/\/www.rct-online.de\/magazin\/wp-content\/uploads\/2023\/11\/pfa-chemieschlauch1-150x150.jpg 150w\" sizes=\"(max-width: 300px) 100vw, 300px\" \/><\/a> <a href=\"https:\/\/www.rct-online.de\/en\/semi-finished-products\/foils\/ptfe-foils\/31270\/ptfe-film-virgin\"><img loading=\"lazy\" decoding=\"async\" class=\"alignnone wp-image-8025 size-full\" title=\"PTFE Film (virgin)\" src=\"https:\/\/www.rct-online.de\/magazin\/wp-content\/uploads\/2023\/11\/ptfe-folie-virginal1.jpg\" alt=\"PTFE Film (virgin)\" width=\"300\" height=\"300\" srcset=\"https:\/\/www.rct-online.de\/magazin\/wp-content\/uploads\/2023\/11\/ptfe-folie-virginal1.jpg 300w, https:\/\/www.rct-online.de\/magazin\/wp-content\/uploads\/2023\/11\/ptfe-folie-virginal1-150x150.jpg 150w\" sizes=\"(max-width: 300px) 100vw, 300px\" \/><\/a><\/p>\n<p style=\"text-align: justify;\">ETFE and ECTFE differ, like PTFE and PCTFE, by substitution of a fluorine atom with chlorine. Both are polymerised from tetrafluoroethylene and ethylene or chlorotrifluoroethylene and ethylene, respectively. They are partially fluorinated, have lower density than PTFE, and offer high transparency and light transmission while showing similar chemical resistance. ETFE is mainly used in architecture for roofs, walls and fa\u00e7ades \u2014 for example, the roof of the Allianz Arena in Munich is made of ETFE film. ECTFE is used as a coating for pipes and tanks and as a glass replacement for laboratory items in chemical applications.<\/p>\n<p style=\"text-align: justify;\">FEP, obtained by copolymerising tetrafluoroethylene and hexafluoropropylene, is a fully fluorinated polymer, meaning all hydrogen atoms are replaced by fluorine. Of all fluoropolymers, it offers the widest thermal working range from \u2013250\u202f\u00b0C to +205\u202f\u00b0C. In hose technology, it is used for transparent plastic hoses with non-porous, anti-adhesive inner walls suitable for all sterilisation methods.<\/p>\n<p style=\"text-align: justify;\">PFA and MFA are fully fluorinated copolymers of tetrafluoroethylene and perfluoroalkoxyethylene. They differ in the length of the ether group. Unlike PTFE, PFA is thermoplastically processable, has better non-stick properties, higher chemical resistance, but slightly lower scratch resistance. An important area of application for vessels and <a href=\"https:\/\/www.rct-online.de\/en\/tubes-hoses\/tubings-and-pipes-made-of-rigid-plastics\/pfa-tubing\">plastic tubing made from PFA<\/a> is trace element analysis. Since PFA, unlike commonly used materials such as glass, quartz, polyethylene and polypropylene, shows less interaction with sample and reference solutions, using PFA vessels and hoses results in more reliable analytical results.<\/p>\n<p><a href=\"https:\/\/www.rct-online.de\/en\/tubes-hoses\/tubings-and-pipes-made-of-rigid-plastics\/mfa-tubing\/28722\/mfa-chemical-tubing\"><img loading=\"lazy\" decoding=\"async\" class=\"alignnone wp-image-8023\" title=\"MFA Chemical Tubing\" src=\"https:\/\/www.rct-online.de\/magazin\/wp-content\/uploads\/2023\/11\/mfa-chemieschlauch.jpg\" alt=\"MFA Chemical Tubing\" width=\"300\" height=\"300\" srcset=\"https:\/\/www.rct-online.de\/magazin\/wp-content\/uploads\/2023\/11\/mfa-chemieschlauch.jpg 450w, https:\/\/www.rct-online.de\/magazin\/wp-content\/uploads\/2023\/11\/mfa-chemieschlauch-300x300.jpg 300w, https:\/\/www.rct-online.de\/magazin\/wp-content\/uploads\/2023\/11\/mfa-chemieschlauch-150x150.jpg 150w\" sizes=\"(max-width: 300px) 100vw, 300px\" \/><\/a> <a href=\"https:\/\/www.rct-online.de\/de\/dichtungen\/o-ringe\/ffkm-o-ringe\/ffkm-o-ringe\"><img loading=\"lazy\" decoding=\"async\" class=\"alignnone wp-image-8026 size-full\" title=\"FFKM-O-Ringe\" src=\"https:\/\/www.rct-online.de\/magazin\/wp-content\/uploads\/2023\/11\/ffkm-o-ringe.jpg\" alt=\"FFKM-O-Ringe\" width=\"300\" height=\"300\" srcset=\"https:\/\/www.rct-online.de\/magazin\/wp-content\/uploads\/2023\/11\/ffkm-o-ringe.jpg 300w, https:\/\/www.rct-online.de\/magazin\/wp-content\/uploads\/2023\/11\/ffkm-o-ringe-150x150.jpg 150w\" sizes=\"(max-width: 300px) 100vw, 300px\" \/><\/a><\/p>\n<p style=\"text-align: justify;\">MFA is valued for its chemical, thermal and mechanical stability and its excellent light transmission. <a href=\"https:\/\/www.rct-online.de\/en\/tubes-hoses\/tubings-and-pipes-made-of-rigid-plastics\/mfa-tubing\">MFA tubing<\/a> is mainly used in the food, pharmaceutical and medical industries due to their FDA compliance.<\/p>\n<h2><span class=\"ez-toc-section\" id=\"Perfluoroelastomer_FFKM\"><\/span>Perfluoroelastomer FFKM<span class=\"ez-toc-section-end\"><\/span><\/h2>\n<p style=\"text-align: justify;\">The third group of fluoropolymers resistant to aqua regia is perfluoroelastomers, abbreviated as FFKM. These perfluorinated elastomers have a similar chemical composition and exhibit outstanding chemical and thermal stability, constant elasticity and low outgassing. Due to the complex manufacturing process, perfluoroelastomers are expensive, like other fluoropolymers. FFKM is primarily used as a sealing material in the form of <a href=\"https:\/\/www.rct-online.de\/en\/seals-and-gaskets\/o-rings\">O-rings<\/a>.<\/p>\n<p style=\"text-align: justify;\">All fluoropolymers offer excellent chemical resistance \u2014 they withstand even this powerful acid mixture, which is capable of dissolving gold and platinum.<\/p>\n<pre><strong>Image sources:<\/strong>\r\nCover image | \u00a9 Andres Punning, CC BY-SA 3.0 https:\/\/creativecommons.org\/licenses\/by-sa\/3.0, via Wikimedia Commons\r\nGold dissolving in aqua regia (left and right image) | \u00a9 Daniel Grohmann, CC BY-SA 3.0 https:\/\/creativecommons.org\/licenses\/by-sa\/3.0, via Wikimedia Commons\r\nPlatinum dissolving in aqua regia (left and right image) | \u00a9 Andres Punning, kuningveega solgutas Urmas Johanson, CC BY-SA 3.0 https:\/\/creativecommons.org\/licenses\/by-sa\/3.0, via Wikimedia Commons\r\n<\/pre>\n","protected":false},"excerpt":{"rendered":"<p>Industrial Applications and Compatible Hose Technology Many people have heard the term aqua regia, but what exactly is this special &#8216;water&#8217; and what is it made of? The name \u201caqua regia\u201d (literally \u201croyal water\u201d) refers to its ability to dissolve the \u201croyal\u201d metals gold and platinum. Another, less common name is royal acid. When mixed, &hellip;<\/p>\n","protected":false},"author":13,"featured_media":12833,"comment_status":"closed","ping_status":"open","sticky":false,"template":"","format":"standard","meta":{"footnotes":""},"categories":[1,2748],"tags":[3214,3201,3202,3212,3208,3209,2905,3210,3215,3216,2775,3213,3211],"class_list":["post-14474","post","type-post","status-publish","format-standard","has-post-thumbnail","","category-all-articles","category-materials-in-chemistry","tag-aqua-regia","tag-ectfe-en","tag-etfe-en","tag-fluorinated-homopolymers","tag-mfa-en","tag-pctfe-en","tag-pfa-en","tag-pfep-en","tag-plastic-hoses","tag-plastic-hoses-made-of-pfa","tag-ptfe-en","tag-semi-finished-products","tag-working-with-aqua-regia"],"yoast_head":"<!-- This site is optimized with the Yoast SEO plugin v23.1 - https:\/\/yoast.com\/wordpress\/plugins\/seo\/ -->\n<title>Aqua Regia \u00bb RCT Magazin<\/title>\n<meta name=\"description\" content=\"What is aqua regia &amp; what is it used for? \u2705 Production, properties &amp; applications \u2705 Resistant materials \u2705 Dissolving gold, platinum &amp; more\" \/>\n<meta name=\"robots\" content=\"index, follow, max-snippet:-1, max-image-preview:large, max-video-preview:-1\" \/>\n<link rel=\"canonical\" href=\"https:\/\/www.rct-online.de\/magazin\/en\/aqua-regia-applications-and-properties\/\" \/>\n<meta property=\"og:locale\" content=\"en_US\" \/>\n<meta property=\"og:type\" content=\"article\" \/>\n<meta property=\"og:title\" content=\"Aqua Regia \u00bb RCT Magazin\" \/>\n<meta property=\"og:description\" content=\"What is aqua regia &amp; what is it used for? 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