Turkish Platinum Leach Formula

[Jef]

Has anyone used this formula for leaching platinum scrap or perhaps with ore concentrate?

Platinum Catalytic Converter Recovery Chemistry (Turkish)
10 HCl to 1 H2O2
15 liquid to 1 solid ratio
1000mg powder to 20 mL solution
9.44Kev and 11.1 Kev Pt peaks
300 rpm, 80C 144F, 2 hours = 95% recovery

Chemistry References
Baghalha M., Khosravian H. and Mortaheb, “Kinetics of Platinum Extraction from Spent Reforming Catalysts in Aqua-Regia Solutions”, Hydrometallurgy, (in press),doi:10.1016/j.hydromet.2008.06.003, 2008.Benson M., Bennett C.R., Harry J.E. and et al., “The Recovery Mechanism of Platinum Group Metals From Catalytic Converters in Spent Automotive Exhaust Systems”, Resources, Conservation and Recycling, 31 1–7,2000.Chen, J., and Huang, K., “A New Technique for Extraction of Platinum Group Metals by Pressure Cyanidation”, Hydrometallurgy, 82, 164–171, 2006.Dessler, A.E., The Chemistry and Physics of Stratospheric Ozone, Academic Press, San Diego, 2000.Hennion F.J. “Availability of Precious Metals from Spent Catalysts. Platinum Group Metals — An In-depth View of the Industry”, 1983 IPMI Seminar, Williamsburg, VA, 10–13, 61–81, 1983.Kuczynski R.J., Atkinson G.B. and Dolinar W.J., “Re-covery of Platinum Group Metals from Automobile Catalysts — Pilot Plant Operation”, In: Third Interna-tional Symposium on Recycling of Metals and Engineered Materials. (ed. Queneau P.B. and Preston R.D.),The Minerals, Metals & Materials Society, Warrendale, Pennsylvania, 527–541, 1995.Kennedy, I. R., Acid Soil and Acid Rain, Research Stud-ies Press , Tauton, 1992.Matjie R.H., Scurrel M.S. and Bunt J. “The Selective Dissolution of Alumina, Cobalt and Platinum from a Calcined Spent Catalyst Using Different Lixiviants”, Minerals Engineering 18, 801–810, 2005.Pinheiro A.A., Lima, T.S., Campos P. C. and Afonso J.C,. “Recovery of Platinum from Spent Catalysts ina Fluoride-Containing Medium”, Hydrometallurgy 74,77–84, 2004.

 

[butcher]

There are several discussion's of using HCl and concentrated hydrogen peroxide on the forum (both in liquid form), I have used it to dissolve gold, but I personally have not tried it with platinum.

 

[lazersteve]

If the article you cited is the one I think it is, I have a copy of it around somewhere.

I've used 10:1 HCl:H2O2 (32%:35%) for dissolving Pt and it works fine as long as you provide gentle heating (~40C), stirring, and the Pt is in the form of thin foils or finely divided. It works really great for redissolving thin foils or sponge for a second refining.

I'll see if I can locate the full article.

Steve

 

[Jef]

Thanks Steve

My Southwest Science stirrer/hotplate arrived 2 days ago, my 2500ml filter flask and beakers yesterday, and the scale should be here sometime Monday, so I am itching to run some of my Pt concentrate (1-3% by weight per XRF from Thermo). I am thinking of doing a 1 lb heated batch at several hundred rpm as the SWS stirrer/heater is capable of 4-5 liters. If it is even in the ballpark of 1-3% I will get a 5000ML filter flask for the next runs. I sent you a pm recently when I ordered your DVD.

 

[lazersteve]

Jef,

Keep us posted on your experiments.

If I haven't already responded to your PM, I most likely didn't see it ( I get lots of PMs everyday). Please resend if I have not responded.

Steve

 

[Jef]

Thanks Steve

I received your Pt DVD (WELL DONE!) however my LW Instruments MCT series scale arrived DOA new out of the box so there will be a couple of days delay so I can have an accurate lab log. After viewing the DVD a couple of times I need to decide on a leach method from one of the 3 listed below. No matter which one is chosen I will use the 2500ml filterflask with the top sealed and the vacuum tube vented out the window for noxious fume safety and gas expansion. The Southwest Science magnetic stirrer hotplate will be used to maintain heat (low in the case of bleach being used) and also to maintain the stir rate RPMs as both greatly accelerate the leach process which will help down the road when I do a few batches a week.

Making the concentrate is a multiple hour process. I have included a pic of the concentrate and the makeshift lab I threw together. It is an old 8 foot bench in my storage building that I hit with a course sander and put some new linoleum on and placed several 1ft squares of stone on to help with the heat from the microkiln which will be next to the recovery setup. The microkiln cylinder may get over 2000F for some parts of the concentrate manufacturing so I will use the stone as a base and add K23 brick or ceramic fiber board for the nest material.

The 3 choices I hope you will give me your opinion on are
1. HCl 31.5% and Nitric acid 70% in a concentrated mix so all of the Pt is leached.
2. HCl 31.5% and H2O2 35%.
3. HCl 31.5% and bleach at a lower temp.

You can see from the pic the concentrate is ground reasonably well and I may use a mortar and pestle to really get it fine as this will only speed up the leach time.

 

[Oz]

Jef,
Something I do often when using HCl and Cl2 gas (perhaps bleach in your case) is to use heat, but reflux the chlorine back into solution. This allows higher heat and a recycling of reagent that otherwise would be lost as a noxious fume.

 

[Jef]

Excellent idea Oz. I think I have a reflux condenser in my still kit I used years ago. BTW, I can't seem to upload pics to my post.

 

[samuel-a]

Jef,
Something I do often when using HCl and Cl2 gas (perhaps bleach in your case) is to use heat, but reflux the chlorine back into solution. This allows higher heat and a recycling of reagent that otherwise would be lost as a noxious fume.

Not trying to be petty here, Oz.
But i'm not sure i follow you here, to liquify Cl2 gas you need -151 F and lower.

Are you refluxing OR passing the effervescence through the source solution?

 

[Lou]

Chlorine is incredibly soluble in HCl when cold...


So you reflux your solution and the chlorine offgas reports to the condenser with some of the azeotropic HCl.

Works better for Br2.

 

[samuel-a]

Thanks Lou

Point being, the system does lose Cl inspite.
Questions is, how efficient it really is?

 

[Lou]

Very efficient, but yes there are losses.

 

[Jef]

Today my new replacement MCT scale from LW arrived and it functions perfectly. I bought a coffee bean grinder to
take the ore concentrate from a reasonably fine powder to a VERY fine powder and have 50 grams in a small filter
flask that I plan to test on a new leach method using DMSO. The rest of the initial grind weighed out at 1.5 pounds
which I am planning to try the HCl and hydrogen peroxide method with, unless someone can point to better extraction
with HCl and bleach. In that case, I may split the 1.5 pounds up into 2 batches or grind some more to get 2 batches of
1 pound each. I do not have any nitric so it will be out of the tests for now.

Does anyone know if I need a prewash in HCl at room temp before I do the actual leach. The lead content of the
powdered ore is 97% to 99% so I need to get the lead out so to speak and I want to do it with chem.

 

[Oz]

Did I read this last post correctly that this “ore” is 97-99% lead the balance being 1-3% platinum?

 

[Jef]

Yes, thats what the XRF from the Thedrmo rep said. It is an ore concentrate though,...not dirt. It has been processed several times.

 

[Jef]

Here are the lower samples

XL2-54336 Reading No 180 Mode Precious Metals
Time 2012-06-20 16:24 Duration 12.71 Units %
Flags Gold Not Present SAMPLE METALIC SLAG
% ± Error Pb 88.599 ± 1.308 Pt 2.424 ± 0.653 Fe 7.859 ± 0.473

XL2-54336 Reading No 185 Mode Precious Metals
Time 2012-06-20 16:40 Duration 13.45 Units %
Flags Gold Not Present SAMPLE PROC GM
% ± Error Pb 97.001 ± 0.681 Pt 1.410 ± 0.312 Fe 1.528 ± 0.105

XL2-54336 Reading No 187 Mode Precious Metals
Time 2012-06-20 16:42 Duration 18.58 Units %
Flags Gold Not Present SAMPLE CONE (GROUND)
% ± Error Pb 98.080 ± 0.640 Pt 1.067 ± 0.290 Fe 0.822 ± 0.077

XL2-54336 Reading No 188 Mode Precious Metals
Time 2012-06-20 16:43 Duration 11.45 Units %
Flags Gold Not Present SAMPLE CONE (GROUND)
% ± Error Pb 97.645 ± 1.015 Pt 1.246 ± 0.462 Fe 1.035 ± 0.136

 

[Lou]

That is the wrong instrument to be basing anything on.


Don't get me wrong, really nifty piece of equipment, use its big brother the xlt3 every day for anodes but that number doesn't mean anything.

 

[Jef]

Thanks Lou

Well, better I prepare for the bubble burst now than later. I just tried a small 1g test with DMSO and got zip, so now I
have a 4g batch on the mag stirrer hotplate with 30ml of HCl and have been adding H2O2 to see if I get a reaction at
over 120F and stirring at 300+ RPM. Yes, I really must be bored,...but curious.

 

[Jef]

Its now 20120822 at 1855 local eastern time and when I returned an hour or so ago, the sludge on the bottom of the flask
had thickened a bit so I added alot more HCl and H2O2 in about a 10:1 ratio and the reaction is moving along quite well
now after a glass rod stir. The magnetic stirer can not keep that volume of liquid and material moving even though the
manufacturer felt it could do several liters of liquid. The color (if I could post pics) is a dark yellow to orangish brown and
when glass rod stirred, it is a deep yellow. I should have pics on my site soon at http://www.jeftech.net/Miscellaneous.htm

As soon as I can get my settings fixed, they will be in my posts here. If anyone wants them before, just send me an email and I will
forward them as taken until I can post them.

 

[Jef]

I just finished the zinc adds and it would not continue to react after adding only around a teaspoon in increments and the zinc
seems to have simply clumped in the botom even with vigorous stirring with the glass rod for nearly 1/2 an hour. It looks like I
may have a dud batch. The pics are at the link http://www.jeftech.net/Miscellaneous.htm

I guess my next test will be with HCl+Bleach.

Any thoughts on the previous would be appreciated.