What would cause my AR solution to only drop part of the gold powder?

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When I first started heating solutions pretty hot, I started having problems with drops as well. Adding some hydrochloric acid seemed to be the fix 99.9% of the time. Adding nitric very seldom helped with completing a drop, the hydrochloric almost always worked.
 
Shark said:
When I first started heating solutions pretty hot, I started having problems with drops as well. Adding some hydrochloric acid seemed to be the fix 99.9% of the time. Adding nitric very seldom helped with completing a drop, the hydrochloric almost always worked.
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Sorry i haven't called you back sir. I have been as busy as a long tail cat in a rocking chair convention! I will try and touch base Sunday.
 
Adding hcl makes perfect sense. I typically have tried to use acid volumes that are completely spent at the end of the process. Especially the nitric. That way I don't have to use much urea to neutralize the acid. I have been walking a fine line on having enough to dissolve all the gold or spending more time and money trying to neutralize excess nitric. In several instances I have had to reintroduce product to a new batch of AR because I did not use enough hcl or nitric. I thought I was dealing with excess nitric but now I think is was the other way around and I over neutralized the hcl along with the nitric. Does my theory hold water?
 
Palladium,

I purchased wide range test strips so they go from 1 to 14. So 1 being at the low end of the scale. They do not show a minus number at all. Only 1 to 14.

Mtnman
 
Mountain Man said:
Palladium,

I purchased wide range test strips so they go from 1 to 14. So 1 being at the low end of the scale. They do not show a minus number at all. Only 1 to 14.

Mtnman
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Therefore you might want to do a bit of homework on the pH scale and acidity/alkalinity. It's not hard to pick up but you do need to understand properly what you're looking at. 8)

Jon
 
Mountain Man said:
I am leaning towards introducing the copper strips unless there is a better way from here.
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As was originally suggested by Geo & agreed to by goldenchild this is what you should have done in the FIRST place :!:

doing so "in the first place" you would already have your gold back from the solution & you would have it ALL back :!:

For the life of me I just don't understand why people think copper is considered "the last resort" in situations like this

Copper is your friend !!!

Hoke's, Harold, 4metals, GSP, etc. etc. etc. (ALL the pros) talk about sending solutions to the "stock pot" to cement out any "traces" of gold left (&/or PGMs that may be present) after doing chemical drop

Harold talked OFTEN about how he retired & retired well off - from the "traces" of gold (& other PMs) he recovered over his years of refining by sending his solutions to the stock pot (for cementing with copper) after dropping the gold from his solutions with chemical precipitants - just as Hoke's, 4metals & GSP have ALL talked about - "traces" - recovered by cementing from the stock pot

We are talking about "traces" that show little or NO gold with a stannous test

What does that tell you ??? --- it tells you that coper "is your friend" !!!

It does not matter if you are going after traces of gold or a solution that is loaded with gold

If you are having trouble getting your gold back - copper is your friend - it will get your gold back & it will get it ALL back

If chemicals are not getting your gold back - STOP - adding chemicals --- all you are doing is making a chemical soup that can &/or will cause more problems that can or will interfere with dropping your gold

Problems such as raising the Ph - or precipitating chems (instead of gold) from a warm/hot solution when the solution cools - or not dissolving the chems you are adding (to a cool solution) because you have over saturated the solution with chems

If you have already added so much other chems that raised the Ph of the solution - the ONLY other chem you should add is HCl - then add copper - if you get a "strong" reaction (foaming) wait for the reaction to "stop" - test the solution - if it still test positive - add agitation (air bubbler or stirring)

If free nitric (or other oxidizer) is the problem - copper will use up the nitric (oxidizer) --- copper is your friend

I stopped using chemicals years ago (urea, sulfamic) to denox my AR --- I use ONLY copper

copper gets rid of ALL the free nitric & it gives you back ALL of your gold

You have 2 opptions with using copper to denox your AR &/or recover your gold

(1) copper powder works best for this one & will give you back gold at 995 to 999 (after normal washing of the gold powder) --- in this method put your beaker of AR on the hot plate - add "a bit" of copper powder & stir - the copper will precipitate gold - let the gold settle - if the settled gold is reacting with the AR let the AR dissolve the gold - make additions of copper powder - when the settled gold powder no longer reacts with the AR your free nitric (oxidizer) is used up - at that point you can finish the gold precipitation with SMB (or other chem precipitant) --- with this process (denoxing) you still want to send the solution to the stock pot after the chem precipitation to recover any traces the chem did not drop

(2) Or just flat out cement ALL the gold out with a solid piece of copper (this is basically the same idea as the stock pot to recover traces of gold) but applies in a situation like this one where in there are more then traces of gold but you are having trouble to get your gold with chems - it will denox the solution (if that is the problem) and give you back ALL your gold - but - your gold will have "some" copper contamination - your gold could be as low as 97 - 98 % - or as high as 995

Bottom line - copper is your friend if you are going to play in the refining game - learn when, how & where to use it

Whether refining (option #1) or for recovery (option #2) copper is your friend - especially when dealing with gold from ewaste

As I said in the begaining of this post - "I can't figure out for the life of me" - why we are going around & around with try this & try that - when copper was suggested early in this thread - it was the right answer then - & it remains the answer now

if your Ph is to high (from adding all the other chems) lower it with HCl & cement it with copper

Kurt
 
Kurt,
Thank you for your help. I have tried everything except the copper. My ar solution in all my stock pots still show significant amount of gold. I have suspected I was not recovering all my pm's since I started this learning process 3 years ago and have been plagued by this thru out the entire 3 years. I am going to follow your instructions and change my entire mindset about how to recover the pm's and use copper from here on. Fortunately, I have kept all of my solutions from every batch I have done. I actually have close to 100 gallons of ar solution in plastic 50 and 30 gallon drums. The batches I am working on right now all still show high levels of gold in them. All are from ceramic cpu's and so the base metals content should be low making the refining much simpler.

One question. The ones I am working with now are in bottles that are 4 gal jars. Is there any emphasis on how big or how thick the copper strip should be? Also, I got on line to purchase copper powder. I see there is some choices. 1 being copper powder, 2. Copper Sulfate, 3. copper carbonate and 4. atomized copper powder. Which do you recommend and how much is used on a per batch average so I know how much to purchase and which kind?
Thank You again. It may not look like I know much and that would be correct however, I am a fast learner.
Kirk
 
With that volume, absolutely cement it.

Advice is often given based on a single run or smaller amount of solution. At 100 plus gallons your working on a stockpot if your trying to recover missed gold. I am still curious as to why your not getting it to drop cleanly and still giving you a positive test result. I think finding and fixing that problem will move you ahead in whatever process your using.

They way I do my AR runs is basic...get everything in solution, remove nitric(what ever works best for you), drop the gold (which ever precipitant that works best for you) , get my gold powders from the solution. There should be no positive stannous test by now. At this point I move the solution to the side and let it settle for several days. Decant the solution and move it to my stock pot where copper will be introduced to remove any remaining values. I don't recall ever moving my AR from my second settling to my stockpot with a positive test for gold. I have had positive tests for PGM's. They are saved for another time.

All that is just a long way of trying to find why and/or where your gold is getting hung up. Again, it now sounds like copper is your best bet to recover it. Knowing why it is getting hung up is a cure for the same problem in the future.

Let us know how it works out and what you find. We are all still learning as well and this is a puzzle I would like to hear more about.
 
Don't have a lot of time to post right now - but - the heavier/thicker the better - I prefer bus bars - but other heavy/thick copper will work - some people use copper pipe but you need to "split" it (long wise) spread it & flatten it so PMs don't get stuck in the center of the pipe

Kurt
 
The reason I have so much is because I have been dealing with this issue since I started learning how to do this. I have always had a problem with my solution still testing positive after my initial drop. Recognizing that there is still a strong possibility the solution contains pm's I have simply stored it and moved to the next batch. The batches I am working with now still show heavy gold in the solutions in the 4 batches I have done in the last month. I did not want to simply dispose of the others because they test positive for gold as well. I know I have a problem somewhere in my process that is leaving gold in the solutions and I am now at the point that I have to resolve this so I can dispose of the solutions I have built up without loosing what I believe is a lot of gold.

I am determined to learn so I can become an expert also. I will do what ever you suggest to resolve this black hole that exists in my process.

I am very appreciative of all who have taken their time to try and help me resolve this issue. I have been doing it long enough now to realize there is a huge flaw in my recovery technique.

Thank You for your patience and help.
Kirk
 
Okay, I am convinced on the copper and I remembered last year I tried using the copper technique. I thought it did not do anything, but, I went and dug out the copper strips I used to try it with. One side was covered in green like a battery post. I cleaned one side off and to my surprise under all the green was gold cemented to it At least it looks like it is pure yellow gold. It is only on the one side. The other side had no gold on it.

Now my question is how do I get the cemented gold off the copper plate?
 
Pictures of your stannous tests could help a lot. As for cleaning the copper bars, in my small scale environment I use a toothbrush. I just hold the copper under water or the solution I am working on and brush it loose to settle out. I usually start working mine down when I get around 3 to 4 gallons. I don't have room to keep that much waste on hand so I use 5 gallon buckets.
 
After reading your comments about how you can brush it off the copper with a toothbrush leaves me thinking something else is on this copper metal I used. On one side is copper that looks like copper after it has been sitting in acid. Kind of darker colored with some green dry powder from the acid left over on it. The other side though is cleaner and I can see the copper but mostly what I see is what appears to be a layer of yellow metal adhered to the copper and it covers the majority of that side of the copper strip. I will not come off with a toothbrush at all. It is covering 75 to 80 percent of that side of the copper. It looks like it was melted on to it. I thought that is what was meant by cemented to it. It is a layer so thick that you can't see the copper thru it. The only copper I see on this side is where there is not any gold. I will try and get some pics for you all to see. Of it and my stannous tests also.
 
Yes, I will show you pictures of my tests and of the copper strip with what appears to be gold on it. I am working on that right now.
 
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