Welcome New Members !

Gold Refining Forum

Help Support Gold Refining Forum:

This site may earn a commission from merchant affiliate links, including eBay, Amazon, and others.

Noxx

Well-known member
Joined
Feb 24, 2007
Messages
3,365
Location
Quebec, Canada
Welcome to this forum ! I hope you will pass good time over here.
Please follow those rules:
-Do not use Racism/Sexism/Bad Taste/Violent language.
-Do not spam.
-Do not write like when you are on MSN/ICQ
-Try to correct spelling mistakes.
-Post in the good section
-Do not write in capital letters.
-Be sympathic.

Thanks and I hope this community will grow a lot !

Copyright 2007. All rights reserved. No part of this website may be reproduced or transmitted in any form or by any means, electronic or mechanical, without written permission from both the website owner, Jean-Nicolas Allaire (salut151@hotmail DOT com) and the author of material in question. For personal only use by individuals only. This material may not be linked to from any other website, computer, or server unless written permission is obtained from this website's owner and the author(s) of the material to be displayed. This copyright notice must appear on any content that is approved for external use. All content is not for resale, reproduction, or distribution by any business in whole or in part without the written permission of the author(s). Violators of this copyright will be prosecuted to the fullest extent of the international copyright laws.

Individuals using this website and performing the experiments described herein accept full responsibility for all that results directly or indirectly from these activities. Jean-Nicolas Allaire, all co-authors and GoldRefiningForum.com shall be absolved of any and all responsibility for the result of activities conducted from information and instructions provided in this website.

By logging in to this website you confirm that you agree to all terms and conditions outlined above.
 
Hello--

The site promises to be of value to those that are learning the art of refining, so I applaud your effort. Perhaps I'll be able to contribute as time allows, or the opportunity presents itself.

Harold
 
Great site, thanks for setting it up.

I have been tinkering with refining for over a year, as time permits.
Harold has been a great help to me (through other means of communication).
Thanks, Harold!

I picked Technic's Techni-Strip AU for stripping gold off of PC board connectors and other concentrated gold-plated scrap, as it is supposed to remove "only" the gold, and leave the base metals behind. It works great at removing the gold, but it doesn't want to let it go. I've been experimenting with different ways to get the gold back out of the cyanide solution, with varied results.

I've tried the zinc precipitation method. I think I need to add more lye to raise the pH more, and that's why I'm having trouble with that.

I've tried something that is essentially electrowining, using stainless steel electrodes. I get a lot of mushy gold this way, and some plating of gold on the cathode. This has yielded the most gold so far, and I keep going until something else starts to plate out on the cathode. I haven't built a pulsing system for the plating supply yet, some articles indicate this makes the concentrated material a higher purity by keeping copper, etc. from also
plating out. This won't matter if there isn't much copper in there, anyway.
When I'm done with this process, the solution has turned to mud, but that stuff is NOT gold in suspension. I haven't figured out what it is, but it just burns away.

I have tried activated carbon extraction, and it seems to work very well, judging by the fact that the solution will then accept more gold. But, I must have used too much carbon, as the gold was not very dense when I burned it. I need to try again with just a tiny amount of carbon, and see what can extract.

I had one solution that I'd mucked around with too much for any of the above techniques to extract the gold from, so I let it dry out and just burned it all in a crucible. That took forever, but it is finally done. I did get a few more grams of gold out of it. It seems like I should have about twice the gold that I actually got, but I shouldn't complain. I've got something like 10 grams of gold out of total scrap so far. At today's prices, that's about $220, if it is pure. Some of it looks really great, some has base metals in in. Ahh, into the crucible again!

But, it seems like it is a LOT of work to process this stuff for just a couple bucks an hour! Maybe I'm doing something wrong. I will be starting another batch of the Techni-Strip Au maybe this weekend, and maybe it will work better.

Jon
 
I'm glad you share your experience.
I don't know much about renverse electroplating...
Also, I strongly recommand not using cyanides copounds. They are very very toxics and nobody should never manipulate them.

Yes, you can precipitate gold from your solution with Zinc. I used to precipitate my gold with copper or Sodium Metabisulfide.
But I always use the Aqua Regia refining method.

I never heard the activated carbon extraction technique... What is it ?

If you wanna know if your gold is pure, put it in Concentrated Nitric Acid. If the acid boils and takes color, your gold is not pure. If nothing happens, you have pure gold or nearly pure (+95%).

Good Luck !
 
Noxx said:
Also, I strongly recommand not using cyanides copounds. They are very very toxics and nobody should never manipulate them.
Well, obviously not for the careless, some steps can't be done without proper ventilation, can't be done in large scale without special permits, etc. etc.

But, I'm still quite alive, and I have done 3 quarts of the stuff so far, still working out the tricks. Technic wants to buy the solution back from you, but I am not licensed to ship hazmat, so I really CAN'T do that! It never ocurred to me they would sell me this stuff and then not tell me how to do the extraction myself! According to their directions, you should be able to dissolve one Troy ounce of gold per gallon of solution mixed to their recipe.
That is roughly 0.1 % cyanide by weight, but with a lot of other secret stuff added to keep the cyanide from attacking base metals. This really works, too. I did the first batches in an open tray with manual agitation, and it would remove the plating on circuit board fingers in about 10 minutes. The last batch I tried was in a jar on a motorized roller, with some plastic rods on the inside of the jar to tumble the contents like the drum in a clothes dryer. But, the closed jar may have prevented the process from getting the oxygen it needs to "rust" the gold.

Anyway, with 3 quarts I should have gotten 3/4 of a Troy Oz. or about 23 grams of gold. It looks like I've gotten closer to 10 g than 20. So, I'm wondering if I'm doing something wrong. Anyway, I still have several pounds of the Techni-Strip Au left, and will continue working with it. I think I need to raise the pH more before doing the precipitation with the Zinc flour,
and then be patient and let the precipitation finish before filtering.

The process as I have worked it out is as follows :

Once the cyanide has as much gold as it will hold, you add a little more cyanide so some is available. Then, you raise the pH to 12, I use lye. Then, you sprinkle in the zinc flour as one ounce zinc for one ounce of gold.
The precipitation is supposed to happen very quickly, but maybe my problem was the pH was not high enough. Then, you filter the stuff, and you are supposed to get a thick brown mud. If you mash the mud with the side of a knife blade, it will compact into metallic gold. You then slowly burn these filters to an ash in a partially closed container. Harold recommends an old stainless electric skillet, but I don't have one, and use a stainless measuring cup and a propane torch, and it probably heats it way too fast and drives off some of the gold as smoke. When the filter is completely ashed, burn it with nitric acid until it stops fizzing. That is the excess zinc being converted to a metallic salt. This is soluble and can be washed away with water. The remains go in a high temperature crucible and are fired. I use an Oxy-Propylene torch (An Oxy-Acetylene torch with Propylene as the fuel gas, generic brand equivalent to MAPP.) As a flux, I mix a pinch of "anti-Borax" brazing flux, which is basically pure borax, with a couple pinches of sodium carbonate, known as washing soda. it takes a couple of minutes to cook the stuff down and get the flux running, and if everything goes well you end up with one big bead of metal at the bottom. I usually get it pretty hot to drive off any remaining base metals. Sometimes the flux and metal don't "gel" and I end up with a lot of tiny gold beads in the flux and have to fool around picking them out with tweezers.

Yes, you can precipitate gold from your solution with Zinc. I used to precipitate my gold with copper or Sodium Metabisulfide.
But I always use the Aqua Regia refining method.
The problem with Aqua Regia is it dissolves ANY metal, and the scrap has much more base metal than gold. Then, you have to separate all that base metal. The genius of this techni-Strip Au is that it preferentially attacks the
gold. If you monitor the process and pull the boards as soon as the gold is gone, it really works well and pulls very little base metal off.
I never heard the activated carbon extraction technique... What is it ?
{/quote]
I found this in some gold mining articles. When using the cyanide heap process, weak cyanide is poured over a heap of gold-bearing ore. You end up with a lake of weak cyanide solution with a small trace of gold in it. They then run the cyanide solution over activated carbon, and the carbon sucks up the gold. Then, they use a more concentrated cyanide, like 1.0 % to pull the gold back out of the carbon. This can concentrate the gold 1000 times or something. I figured I could just burn the carbon in a crucible, but the results were less than spectacular.
If you wanna know if your gold is pure, put it in Concentrated Nitric Acid. If the acid boils and takes color, your gold is not pure. If nothing happens, you have pure gold or nearly pure (+95%).
I don't have any nitric acid, but muriatic and sulfuric-based drain opener is easily available. The sulfuric is nasty-smelling stuff, and foams like crazy when added to almost anything. When my gold buttons come out dirty-looking, I throw them in a vial of about 50% of that sulfuric drain cleaner and they are bright and look like 24-karat the next morning.
Good Luck !
 
Well, obviously not for the careless, some steps can't be done without proper ventilation, can't be done in large scale without special permits, etc. etc.

When processing gold batch, everything should be done outside or with very adequade ventilation exept for washing the gold powder if you only use water.

That is roughly 0.1 % cyanide by weight, but with a lot of other secret stuff added to keep the cyanide from attacking base metals. This really works, too. I did the first batches in an open tray with manual agitation, and it would remove the plating on circuit board fingers in about 10 minutes.

Interesting results with this technique. A lot faster than the Aqua Regia.


I think I need to raise the pH more before doing the precipitation with the Zinc flour,
and then be patient and let the precipitation finish before filtering.

Do use a gold solution indicator ? You could easily know if there is any gold left in solution.

Once the cyanide has as much gold as it will hold, you add a little more cyanide so some is available. Then, you raise the pH to 12, I use lye. Then, you sprinkle in the zinc flour as one ounce zinc for one ounce of gold.
The precipitation is supposed to happen very quickly, but maybe my problem was the pH was not high enough.

I'm not sure about your technique but in Aqua Regia, you must NOT higher the ph before precipitation. You must neutralise the acid with urea or, when you precipitate, the gold redisolves in the solution ! :shock:
Lol maybe it's what is happening.
It would be interesting if you could put some pictures of your system and results in the appropriate forum section.

The problem with Aqua Regia is it dissolves ANY metal, and the scrap has much more base metal than gold.

It's not a problem when you dissolve those metals before with Nitric Acid. The Aqua Regia method is claimed to give nearly pure gold if everything is done well.

Harold recommends an old stainless electric skillet, but I don't have one, and use a stainless measuring cup and a propane torch, and it probably heats it way too fast and drives off some of the gold as smoke.

Never melt gold in or on any metal surface because it absorbs too much energy (heat) from your torch. Also, you will probably plate the metal you were working on with gold... Not exactly what you want eh ?

Also, heat can NOT «burn» the gold and make it goes in smoke unless your are reaching +2500°C.

Good luck !
 
Noxx said:
Harold recommends an old stainless electric skillet, but I don't have one, and use a stainless measuring cup and a propane torch, and it probably heats it way too fast and drives off some of the gold as smoke.

Never melt gold in or on any metal surface because it absorbs too much energy (heat) from your torch. Also, you will probably plate the metal you were working on with gold... Not exactly what you want eh ?

Also, heat can NOT «burn» the gold and make it goes in smoke unless your are reaching +2500°C.
Not burn the gold, but if there are a lot of chemicals, or even water, mixed with the gold, when they vaporize, they can carry the colloidal-size gold off with the steam/smoke. You don't melt the gold in the skillet, it couldn't anyway. What it does is dry out the filtered out gold and drive off water and remaining chemicals. Also, it burns the paper filter away, leaving little but the gold as dust. then you transfer to a clay (I think) crucible and fire with Oxy-Acetylene torch. (I use Oxy-Propylene because it is safer and easier to store as a liquid than acetylene. It is essentially the same as MAPP.)

Jon
 
Harold recommends an old stainless electric skillet, but I don't have one, and use a stainless measuring cup and a propane torch, and it probably heats it way too fast and drives off some of the gold as smoke.

I worked in a filtered fume hood, so any losses were eventually recovered.

Yes, you can drive off gold under the wrong circumstances, but the amount tends to be rather small. I processed thousands of troy ounces per year and recovered about 8 troy ounces on a two year basis when cleaning out the fume hood. That doesn't take into account that I also changed filters frequently, and recycled them through my furnace, along with other waste materials. The percentage of loss is small, but there is a loss. It's for that reason that almost nothing is discarded in the refinery. It is recycled time and again, so values are not tossed out with the bath water, so to speak.

The skillet I propose is not electric. It is nothing more than a common stainless frying pan. It's heated with a gas fired hot plate and then additionally with a torch until the waste material is free of carbonacious materials. Do understand that my operation was geared to the recovery of values from jeweler's benches, so the processes I used may not make a lot of sense for other operations, although they would work.


Harold
 
I am new to the forum but wise enough to wait to learn how to clean the pure metal from the junk... I am a 58 year old male from Missouri, who as it happens owned a computer repair business for the last 10 years. I have managed to save some 2 or 3 tons of boards and like materials. I have been engaged in the process of separating the goods from the bad. Selling the steel copper and alum. While saving anything that may contain gold silver and the like. I started using pudding containers, now I fill 5lb coffee containers. I do enjoy the work so... I also having realized the value of the scrap business, and have been getting used waste computers from several large concerns.. I always treated my employees well and this has paid off. So the pile never ends so far... I destroy any and all parts including the not so heavy laden motherboards. I am using my spare time reading your (our) forum gleaning all the treasured bits of information I can. I even print the pages if need be and put them in plastic sleeves for reference material. I hope to some time show off my first bit of pure gold. I have also spent the last several years collecting used and broken jewelry for my women co-workers. Like today buying 25grams for $150.00 and the diamonds are free.. What a deal. She wanted the items her X bought her gone at any price. Her loss my gain.
 
heh, this must have been the first post ever. it was fun reading the first posts of "the elite". Maybe I'll be there one day too :D
 
Find the section that best suits your question and click new post.

Before asking try using the search function to see if your question has already been answered before. If you can't find the answer post your question and we'll all pitch in to get you one.

Welcome!

Steve
 
how many gold is on 1 lb goldfingers from old computer
.

Too vague a question. Too many variables. Read up on how to do it and then experiment by recovering the gold from one pound of old computer fingers. Then, you'll surely know, at least from the particular pound of fingers you happened to select.
 
Back
Top