# PGM recovery system



## kjavanb123 (Apr 9, 2011)

All,
After sometimes, i could finally gather the right items, and put together a system that can circulate the hot AR through multiple honeycombs, although this still is a work on progress, but 90% is acid resistance, and could result in Pt in solution in few mins of starting. the propeller inside the water pump got dissolved after 2 runs, i think they are made of brass or something, which i am thinking of replacing with a nylon form.
The main advantage of using this system, less AR usage which leads to less zinc usage in later stage of process, also much better recovery of PGM from honeycombs since the showerhead pretty much expose most of the honeycomb surface to AR.


note more holes are drilled in the original showerhead for better exposure of honeycomb to AR


the first few mins i got a positive result for Pt.



comments and advice r welcome. 

Kev


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## Barren Realms 007 (Apr 9, 2011)

You should get you an acid resistant pump. Any kind of impeller that is metal will eventualy fail with the solution you are using. And your impeller housing will go out at the most inopertune time.


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## bubba (Apr 9, 2011)

reminds me of us 20 years ago. AR is not going to pull the Rh. You will make more money, much more, selling those cats whole to a reputable buyer.


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## Harold_V (Apr 10, 2011)

Metallic pump and a shower head?
My advice to you is to start over, using materials that are acid resistant. Nylon isn't. You are heading for a huge failure. 

Harold


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## kjavanb123 (Apr 13, 2011)

ok the last water pump as expected was dissolved, the engine still works just the propeler needs a replacement :-, so i started it with smaller pump, made from plastic parts, and had to hose the cats down, as you can see from the below pics, i think i could dissolve most of the PGM in the cats in less than 30mins. because as this was the 3rd times I was leaching the same set of cats, i got a tiny amount of Pt which indicates most of it got extracted during the first 2 leach. I suggest this pump since it lower the AR usage and zinc, plus dissolving the PGM from cats would be done in a lot shorter times.

new system, with new water pump, a funnel which is glued to the bottom of bucket



the AR hot and with some PGM



stannous shows small amt of Pt in the solution



Keep u posted 
Kev


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## 4metals (Apr 13, 2011)

I've worked with these chemicals long enough to realize one thing, if it's mechanical it will break.
So if I can eliminate a pump, I will. This system will work for the scale you appear to be working on and at least simplify life while you work out the bugs.

I call this a 2 stool system, and the working ingredient is gravity, it's always there and never fails. 


The working acid is put in the bucket without the spray arm. (The acid holding bucket) The spray arm is detailed by my very crude drawing



The important step that is required for the spray arm is to drill a small hole in the bottom elbow to allow the acid to drain back to the acid bucket when it is lowered from the high stool to the floor. 

All you need to do is place the converters in the leach bucket and with the acid storage bucket on the floor add the acid mixture. When you lift the bucket to the high stool, the acid will pour over the work. You can leave it there for a while and then lower the acid bucket to the floor and it will slowly drain out the little weep hole back into the acid bucket. 

This is simple, effective for multiple pieces together, and can process parts until the acid is exhausted. Still be cautious and check the hoses and fittings frequently for signs of embrittlement from the effect of the acid, just to be safe.

Plus it can be used to grow some kick butt hydroponic strawberries.


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## element47 (Apr 13, 2011)

Absolutely love it!!! Multiple stools vs. electric pumps. Brilliant!


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## lazersteve (Apr 13, 2011)

I use two buckets, one slightly smaller inside the larger with the inner bucket containing the combs. The inner bucket has holes (1/8" ) drilled in a drain pattern in the bottom of it to allow the liquid to drain through it and the combs when it is lifted. The inner bucket is lifted every so often to circulate the leech through the combs.

The acid solution goes in the larger bucket up to the level of the tops of the combs. The combs are stacked whole with the vanes (holes) facing up so the acid flows through them as the inner bucket is lifted. 

Same principle as the Acid Peroxide set up.

Steve


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## Barren Realms 007 (Apr 13, 2011)

Steve,

I started drilling a couple of rows of holes on the side of the small bucket about 3"-4" up from the bottom and it stops some of the stagnation of the solution on the outside of the small bucket. It especially stops the heavy reaction that can occour when you lift the small bucket out of poor man's AR.


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## 4metals (Apr 13, 2011)

Either way, no pump, no maintenance.


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## kjavanb123 (Apr 14, 2011)

Guys,

excellent ideas, I guess i need to heat the hcl first then pour it to the bucket, and the 2 stool system. i usually bring the hcl to a boil, then lower the temp and circulate the hot hcl through the pump then add the nitric in small increments. i use hcl and hno3 and no water, is h2o required to make AR or can it be done without? how long do you guys let the AR through the cats to get most of the PGMs out?

I could only produce 0.860grams of Pt from the 4 cats i processed using this pump system. lots of AR solution got sprayed out or wasted due to pump and showerhead failures, so i ordered another 4 cats, and going to work on it one by one this time. 

does 4parts water + 5 parts hcl and 1 parts nitric dissolve all the pgms?

Thanks
Kev


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## Lou (Apr 15, 2011)

Probably most of your precious metal got reduced onto the surface of the base metal components of your system.

Get some FEP tubing and a PTFE diaphragm pump and have another go!


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