# First Catalyst recovery



## Duxthe1 (Sep 22, 2011)

I've had my first successful drop of Pt and Pd, from a catalyst recovery this evening. I started with 8 converters from various Mercedes models. I broke out the honeycombs and gave them a coarse crushing using some water to keep the dust down. Using a cement mixing tub I spread them out level in the bottom and added about 1/3 gallon HCL. Next I poured on some Nitric acid, approx 1/2 liter of 10%. I stirred the mixture occasionally and gave it a day until it quit reacting. Now, being out of Nitric I added bleach for the oxidizer in small increments. Soon a deep red / orange color appeared. I gave it another day of mixing and settling. This evening I filtered off about 1 qt, less than half the liquid total. I first tried using copper to cement out the values and learned first hand what Lasersteve meant by copper "plating" the values. Undaunted, a google search reminded me that every day dry cell batteries use zinc for the case. A quick search around the house turned up a few spent "aa" batteries that soon shed their case for the cause. With the case peeled apart I torched them for a minute to burn off the plastic coating, and then gave them a quick brushing with the wire wheel to remove any oxides. In they went and the reaction kicked into high gear. The zinc bubbled away and cemented nice large flakes of Pt and Pd. An assumption of coarse but I'm feeling really good about the sheer volume of precipitated flakes. Its still bubbling as I type and I'm excited to see the solution clear and show me my values. 

I owe this success to this forum, thank you all for sharing your wealth of knowledge. Soon I shall try my hand at refining these recovered flakes but for now, just recovering them feels like a huge success to a newbie. I'm assuming that there will be a small bit of copper dropped out by the zinc, I have some rather strong HCL and some weak Sulphuric, would one be better than the other to rinse the flakes with to dissolve out the copper?


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## nickvc (Sep 22, 2011)

A word of caution, by introducing copper to try and cement the values in your solution and then precipitating with zinc you will have copper amongst the values.


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## Lino1406 (Sep 23, 2011)

Before adding zinc, it is recommended to
reduce acidity 2 degrees by using pH paper and caustic


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## Duxthe1 (Oct 4, 2011)

Well after my first recovery I washed once with sulphuric and twice with hydrochloric. I dried the powders and weighed them...13.2 grams. Not bad for a first try. I've let the substrates sit in a weakened solution for a couple of weeks and will soon see how much I get from a second pass.


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## Lino1406 (Oct 5, 2011)

13.2 g for 8 cats looks fine. Did you keep
the cats in original structure (what I recommend)
or ground it?


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## Duxthe1 (Oct 5, 2011)

I ground them up in an effort to use less chemicals to cover them. Filtering the resulting ceramic powder has proven to be a real pain. I'm in no way ashamed of a 13.2g recovery, but I do feel that there is a fair bit more left yet to recover. These catalysts were all from various Mercedes models (day job) and my reading has led me to believe that the high end European cars have more PGM than average. The question now is what to do with the Pt, Pd mixed powder. I'm tempted to try to sell as is. It doesn't seem enough to pursue chemical seperation to end up with less than 10 grams of either Pt or Pd and not have the ability to melt it. Mercedes now charges cores for the catalysts so I'm not likely to get a line on any more anytime soon. Suggestions?


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## Lino1406 (Oct 5, 2011)

You mean Europeans are not mean...


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