Electrochemistry Is anyone using the Pforzheim Process??

[KCGreg]

I did a search for this on the forum this morning and couldn't find anything. As I understand this process, reading from Electroplating and Electrorefining of Metals by Watt/Philip, an anode consisting of 5-7% gold, 22-50% silver, 40-60% Copper and about 5% lead, zinc and tin is immersed in a copper nitrate electrolyte and a current is applied. The copper, zinc and silver pass into solution and the copper is deposited electrolytically at the cathode while the silver and other metals remains in solution. The gold is captured in the anode bag. The electrolyte must be maintained acid by the addition of nitric, presumably to prevent the co-deposition of silver on the cathode. The silver is recovered by displacement with the copper recovered from the cathode. And, eventually, the solution will become saturated with base metals and has to be replaced. The whole description of the process in the book isn't much more detailed than this but this is my Readers Digest version. I'ld like to give this a go and see how it works but I wanted to get some input and advice from the folks who are more knowledgable and experienced than I.

Here are a few questions regarding this process:
1) My past studies on electrowinning copper have indicated that the proper working current for electrowinning of copper is 1amp and 1 volt per square foot of cathode space. Would this be an ideal current to employ in this instance?
2) Would it be preferable to use a stainless steel (maybe 304 grade SS) or a copper sheet cathode? I'm assuming SS would be preferable but there's enough I don't know about the process to require me to ask.
3) What would be an acceptable amount of free nitric in the electrolyte? And, how would one determine how much free nitric is available as the process progressed? I think that process is called titration??
4) If I started this process what could be some unforseen complications?
5) Would the anode have to have the same amount of sq/ft or sq/in as the cathode?
6) How you would you determine when the electrolyte had been saturated with enough lead, zinc, nickel etc. to require replacement? Would the color of the electrolyte alone be a good indicator?
7) What affect would white gold containing nickel have on the cathodic deposition of the copper? Should white gold be kept to a minimum?
8) What would prevent the zinc from being deposited on the cathode at the same time as the copper?

Thanks in advance for your thoughts on this. I also want to say that for having been back on the forum for less than a few days, WOW! This place just rocks! The amount of information and knowledge on this forum is simply overwhelming. Some of you are some very, very well informed and experienced/educated men! I'm glad to be in such company and thanks for sharing your experience, knowledge and insights with the rest of us.

 

[Lino1406]

Nickel won't precipitate from nitrate solutions

 

[kurt]

Trying to part silver from copper in an electrolytic cell using copper nitrate as your electrolyte is very difficult – I’m not saying it can’t be done just that its very difficult – the reason for this is that silver wants to co-deposit in a nitrate electrolyte cell

For this to work the volt setting needs to be less then 1 volt – more like .35 volts & no more then .7 & yes I believe you need to have some free nitric in your electrolyte (around 10% I believe)

Also I believe the copper content of your anode needs to be more like 93% plus

Amps used in a cell are NOT determined by a setting you adjust but rather are determined by electrolyte concentration – anode/cathode spacing – anode size (surface area) --- these things determine the amount of “current density” delivered from the available amps – if you change the “amp setting” it will change the volts as well – so it’s the volts you want to control

Kurt

 

[jscurlock]

This process is used by larger refiners to recover copper, silver and gold from crushed circuit boards. They crush, burn, melt and cast the alloy into plates then use electrolysis to separate the metals. I, too, would like to know the details of this process.

Skip to about 2:20 in this video and it will show the industrial application of this process:
http://www.youtube.com/watch?v=dB3IvtcN2YI

In this video they use copper to remove copper and steel to remove the silver.

 

[butcher]

Looks like the video left out 99.999% of the information needed for anybody wanting to refine their gold, copper or silver.
Just put the computer chips in aqua regia and what comes out is pure gold powder.

Prepare circuit boards and melt to anodes, plate out copper leaving pure gold and silver, then put in another cell and plate out the pure silver leaving gold, then go to the gold cell and plate out pure gold.

Gosh if only it was as easy as the videos on you tube.

You can learn the processes here on the forum, but it will take learning much more information than that you tube video shows, it is not as easy as they make it look on that video, which really shows us nothing, it is miss-information for the most part if you are wanting to refine metals, they are just taking snapshots of parts of many processes, leaving out thousands of important details and making it look like one simple step, from scrap to gold.

Forget the video if you wish to learn to refine, you can learn the processes here on the forum,( you can learn the processes they are using also), the video is just Bull for the most part (in the video they show the bulls horns and his tail and that is about it, and then show a perfectly cooked steak on a dinner plate, and tell you that is how your steak was made).

PS those anodes from the electronic scrap would have been melted with scrap copper, to get the copper as the majority of the metal in the anode (about 96% copper, with gold and silver or PGM as only a very small portion), the copper anode is refined in the cell, to get refined copper, leaving the very small percentage of more noble metals as sludge, called anode slimes, which can be further treated and refined.

The process would be very hard to do for a small refiner, it would also take a lot of specialized equipment, it would be a high cost way to try and get the gold from the few tons of circuit boards you have, you would spend more on equipment than you would make from the metals, that is if you didn't poison yourself and your neighbors from burning the electronic scrap, or if you did not end up in jail, when authority's seen the toxic smoke coming from the pile circuit boards.

 

[kurt]

Looks like the video left out 99.999% of the information needed for anybody wanting to refine their gold, copper or silver.
Just put the computer chips in aqua regia and what comes out is pure gold powder.

Prepare circuit boards and melt to anodes, plate out copper leaving pure gold and silver, then put in another cell and plate out the pure silver leaving gold, then go to the gold cell and plate out pure gold.

Gosh if only it was as easy as the videos on you tube.

You can learn the processes here on the forum, but it will take learning much more information than that you tube video shows, it is not as easy as they make it look on that video, which really shows us nothing, it is miss-information for the most part if you are wanting to refine metals, they are just taking snapshots of parts of many processes, leaving out thousands of important details and making it look like one simple step, from scrap to gold.

Forget the video if you wish to learn to refine, you can learn the processes here on the forum,( you can learn the processes they are using also), the video is just Bull for the most part (in the video they show the bulls horns and his tail and that is about it, and then show a perfectly cooked steak on a dinner plate, and tell you that is how your steak was made).

PS those anodes from the electronic scrap would have been melted with scrap copper, to get the copper as the majority of the metal in the anode (about 96% copper, with gold and silver or PGM as only a very small portion), the copper anode is refined in the cell, to get refined copper, leaving the very small percentage of more noble metals as sludge, called anode slimes, which can be further treated and refined.

The process would be very hard to do for a small refiner, it would also take a lot of specialized equipment, it would be a high cost way to try and get the gold from the few tons of circuit boards you have, you would spend more on equipment than you would make from the metals, that is if you didn't poison yourself and your neighbors from burning the electronic scrap, or if you did not end up in jail, when authority's seen the toxic smoke coming from the pile circuit boards.

Very well said butcher - when I first started doing this about 4 years ago (going on 5 years now) I was working off info I found here & there on the internet & I couldn't figure out were my gold was going at the end off trying what I found on the net --- then I found this forum & found out why - it was because most ALL the info out there was ether miss-information &/or incomplete information

It was not till I found this forum & spent many - many hours searching & studying "here" that I started to have any real success --- Its been 3 great years of learning here on the forum - & to this day I am still learning - here on the forum!!!

Kurt

 

[jscurlock]

I posted the video just to show that it is the process they use. It is by no means a tutorial. lol I am really interested in how the process works and would like to know the specifics but it seems like no information on it can be found. As for toxic fumes from the incineration of the boards, this can be dealt with by chemical scrubbers. The process could be scaled to moderate sized refiners, however for the home refiner it is simply not worth it.

 

[butcher]

jscurlock,

I have never heard of the pforzheim process, but everything you are wanting to learn, is here on the forum, including the proper methods the video was trying to describe, the video was just terribly inaccurate in showing how the processes are done, or how they work.

Spend some time studying the forum, and you will see what I am trying to say, you will find methods you can use to achieve your goals.
On the forum you will find quite a bit of information on copper refining using electrolysis, after you study that, go back and watch that video again, notice where their anode shows three pure metals copper gold and silver, notice how they show pure copper being dissolved and plated out in one cell and leaving them a pure gold and silver anode to put in another cell, it is just so inaccurate it is almost funny, I am still wondering how they melted those three metal into a bar and the metals did not mix, if I could melt bars like that, then I could just use a hack saw to separate the metals. :lol:.

 

[kurt]

As for toxic fumes from the incineration of the boards, this can be dealt with by chemical scrubbers.

when incinerating circiut boards besides the fumes that need to be chemically scrubed - you also have gases that need to be dealt with - these need to be burned off - so you ether need to have an after burner in place to burn them off - or re-route them back into the burn chamber to burn them off

Then you also need to have a bag house set up in the exit to ether filters or settles out your fly ash or you will lose values (like gold plating) that goes up & out with the smoke

When incinerating C.B.s you have 3 things that need to be delt with in the exiting exhaust

(1) fly ash - which can carry off values
(2) gases (which are different the fumes) that need to be burned off
(3) fumes (which are different the gases) that need to be scrubed

 

[kurt]

Heres what buthcher is talking about - in the video (which I have not looked at) they talk about recovery &/or refining of the copper, gold & silver (& palladium should be on that list) because that is what they pay out on - so they have made a video to impress you on how they recover the metals they pay you for

What they don't show or tell you about is all the other metals in CBs &/or how to deal with them

here are just SOME of the metals involved in CBs - copper, tin, aluminum zinc, lead, iron, nickel, antimony, tantalum - & of course Ag, Au, Pd

And that is not a complete list (I recently had a bunch of CBs come in that had mercury switches on them)

The point is that all these metal need to be dealt with - but there is nothing said about that in video's like the one provided in this thread

Kurt

 

[alexxx]

Kurt,

do you by any chance have a design of such a system that can handle flying ashes, gases & fumes ?

Alex

As for toxic fumes from the incineration of the boards, this can be dealt with by chemical scrubbers.

when incinerating circiut boards besides the fumes that need to be chemically scrubed - you also have gases that need to be dealt with - these need to be burned off - so you ether need to have an after burner in place to burn them off - or re-route them back into the burn chamber to burn them off

Then you also need to have a bag house set up in the exit to ether filters or settles out your fly ash or you will lose values (like gold plating) that goes up & out with the smoke

When incinerating C.B.s you have 3 things that need to be delt with in the exiting exhaust

(1) fly ash - which can carry off values
(2) gases (which are different the fumes) that need to be burned off
(3) fumes (which are different the gases) that need to be scrubed

 

[kurt]

Alex - I have been working on an incinerater design to address all three issues & am hoping to start building it within the next couple weeks.

When I get it done - & if it works as expected - I will be post pic's

Kurt

 

[alexxx]

Can't wait to see it...

Alex - I have been working on an incinerater design to address all three issues & am hoping to start building it within the next couple weeks.

When I get it done - & if it works as expected - I will be post pic's

Kurt