I am looking to separate the small quantities of platinum and palladium in a catalytic converter. However since these are very inert metals I am unsure how to proceed about doing so. Melting the converter is an option I have considered but I am unsure whether I will be able to reach high enough temperatures in order to obtain a decent amount of metal, so I am leaning more towards performing reaction.

  • $\begingroup$ As its phrased right now, it's unclear as to what you are asking. What exactly is your question? $\endgroup$
    – John Snow
    May 20, 2015 at 22:07
  • $\begingroup$ @JohnSnow I believe the question is if it is possible to chemically/physically separate the various metals present in a catalytic converter. The OP has raised the issue of chemical inertness and melting points being hard to attain. $\endgroup$ May 20, 2015 at 22:17
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    $\begingroup$ For the sake of this being a Q & A site, I would still request a rephrasing so it's clear what is being asked, rather than making assumptions. $\endgroup$
    – John Snow
    May 20, 2015 at 22:18
  • $\begingroup$ By what methods could I separate the precious metals in a catalytic converter? $\endgroup$
    – AlanZ2223
    May 22, 2015 at 0:04
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    $\begingroup$ How are you going to source a catalytic converter? The value is such that manufacturers recycle them so they are not just discarded. And it is illegal to steal them from someone else's car (though often done when scrap prices are high enough). And the recyclers will have the capacity and means unavailable to lone chemists. $\endgroup$
    – matt_black
    Nov 6, 2019 at 10:07

2 Answers 2


Let me try to talk you out of it ;-)

The precious metals in a catalytic converter sit in a honeycomb ceramic that contains a lot of synthetic Cordierite. This material isn't only heat-resistant, but also quite hard.

Industrial recycling of catalytic converters typically starts with

  1. dismantling (decanning) the ceramic monolith using guillotine shears
  2. breaking down the ceramic to smaller pieces in hammer mills connected by a closed tubing system
  3. milling the material to dust in a ball-mill blender

You might want to wear a filter mask during these steps.

Industrial recycling almost exclusively uses pyrometallurgical tretment (melting the metals) then.

Having ruled that out, there are two other options:

  • hydrometallurgical treatment
    In order to separate the metals from the ceramic, you can either try to

    • dissolve the ceramic in hot alkaline solution in a closed reactor under pressure (to reach temperatures above 100 °C). This leaves the metals intact.
    • leach the metals out by using strong oxidizing acids, such as mixtures of concentrated nitric and hydrochlorid acid. You have the metals in solution now.

    What are your plans for personal protection during these steps and for the waste water management?

  • biomobilization
    There is some ongoing research to replace the unpleasant conditions of hydrothermal treatment with microorganisms that can leach the solid metals and store them. As an example, have a look at an article by Helmut Brandl, Stefan Lehmann, Mohammad A. Faramarzi, and Daniel Martinelli, published in Hydrometallurgy, 2008, 94, 14-17. The authors examined, whether metals could be converted to cyanido complexes, such as $\ce{[Pt(CN)4]^{2-}}$, by cyanide-producing microorganisms. A PDF of their article, titled Biomobilization of silver, gold, and platinum from solid waste materials by HCN-forming microorganisms is available at no cost from ZORA (Zurich Open Repository and Archive). In the case of platinum, however, the results were rather disappointing.

  • $\begingroup$ That sounds like a great deal of opportunities for disaster! $\endgroup$
    – user15489
    May 22, 2015 at 7:33

If I understand correctly, the DIY process for Catalytiç converters, hard drive platters and gold from circuit boards and RAM are nearly identical and not very accurate at obtaining a pure product. Muriatic Acid will dissolve aluminum and many other metals, but not Platinum Group metals, Removing as much pollutant material as possible pregame is extremely important, after the material has broken down in the probably dark green acid there will be shiny flakes of metal floating around, those are undissolved platinum group(Gold, Platinum, Rhodium, Palladium, and tungsten) metals, just filter and rinse... To separate the platinum group metals, Aqua Regia is required to break them down and different chemicals specific to each metal can be added to precipitate and filter out individual compounds that can be further reacted to obtain the metal in the valuable form, for instance, adding ammonium chloride to Aqua Regia containing dissolved PG metals will precipitate Platinum Chloride, filter it out and add another chemical to precipitate a different compound containing another metal. This is all from personal experience so I don't have anything to cite for reference, but will warn that muriatic Acid alone produces painful fumes, while dissolving aluminum and cadmium and any other metals it will produce harmful respiratory vapors so I would do this outdoors unless you have a fume cabinet, adding hydrogen peroxide to muriatic Acid while dissolving will speed up oxidation and reduce total time to dissolve, also evolves more hydrogen which tends to gather in ceilings that have 4 walls around them and explode when concentrated enough at the flip of a light switch or when near a running fan.

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    $\begingroup$ I guess the term muriatic acid had to be obsolete even in early 80s when I was studying at high school. $\endgroup$
    – Poutnik
    Oct 28, 2023 at 21:38
  • $\begingroup$ I call it like I see it, that's what it says on the bottle I get at orschelns for $10.81. I know there's other names, it's the most watered down HCL available I'm sure $\endgroup$
    – Van Lawson
    Oct 29, 2023 at 13:03

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