# What chems dissolve what metals?



## wop1969 (Mar 19, 2009)

I know this is info is scattered on the forum somewhere but I wanted to know if anyone could answer some questions in this format to help us noobs see a better picture. Keep in mind that when you are a noob at this reading all this info from 20 diffrent post becomes overwhelming and I am sure I am not the only one that needs these answers in one post as these questions are ones that I have come up with while doing hands on learning and I am ready to go to the next level.. 



> I will update the answers I have found in other post (as I find the info) to answer questions 1 and 2. Please correct me if I am wronge or add to this list and I will adjust it


1:what metals with HCL/peroxide desolve?


> HCL/PX will desolve GOLD/PLATINUM/PALLADIUM/COPPER/ZINC/IRON/ALLIMINUM/LEAD/NICKEL/TIN/?



2:what metals with HCL/clorox desolve?


> HCL/CL will desolve GOLD/?



3:I saw this on steves vids and just needed clarafication. Can you 
drop gold from the HCL/peroxide soulution that is pregnet with copper using SMB? if so how well does it work and can you skip the HCL/CL step if all the gold is dropped from the HCL/peroxide solution?

4oes the SMB and HCL/peroxide need to be at a certain temp to work as fast as they do in Steves Vid? My SMB worked but I am yet to have a reaction like the one in steves Vid.

5:How long does StainousCL need to sit after the heating and addition of tin befor it can be used? If so how long


Lazersteve said:


> I add the tin (about 1-2 grams) to 20 mL of HCl and heat it up until the tin begins to dissolve. Once the tin starts to fizz I stop heating and let it stand for 5-10 minutes. The solution will clear up as the tin dissolves. A little extra tin doesn't hurt as it keeps the solution fresh.


6:when melting gold mud using a dish like steves and borax, what is wronge when the gold seems to get stuck in the borax?


Noxx said:


> It seems that you put too much borax. Only a small coat is needed.
> The trick is, when the gold bead is still red hot (but solid), use a pair of stainless tweezers to remove it from the borax, and drop it in cold water.
> Harold wrote=Take note that the flux shouldn't change color unless it takes on a pink or purple hue. Any other color is a sign of contaminated gold.
> 
> If your button isn't fully cleaned by dropping in water, you can give it a boil in dilute sulfuric acid, which will dissolve the flux completely. It takes a few minutes. Rinse well afterwards, otherwise traces of the dissolved flux will re-deposit on the button when the solution evaporates.





7: when dropping gold from HCL/CL using SMB can other metal get dragged down with the gold and persay, contaminate you pure gold?
If so what metals are they?


Harold said:


> Dragdown is a function of dirty solution sticking to precipitated particles. It is not reliant on the precipitant, although some may actually precipitate unwanted elements. Zinc is an example of one that is not selective.
> 
> As the precipitated particles of gold agglomerate, they trap the unwanted elements, which can be difficult to remove by washing alone. Washing is always recommended, but it should not be relied upon alone to yield pure gold. A second refining will improve the quality considerably, because the entrapped elements are well diluted by the new solution, so very little can be dragged down in the second precipitation. In all cases, a prolonged washing of your precipitated gold should be routine, even if you intend to re-refine. The less contamination you include in your solutions, the better you can expect the quality to be.



8:What Chems precipitate what metals?


> SMB precipitates gold but also traces of PGMs.
> Ammonium chloride precipitates platinum.
> Oxalic acid precipitates gold but also traces of copper.
> Zinc, there is no selective precipitation>
> ...


Thanks in advance


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## Noxx (Mar 19, 2009)

> Keep in mind that when you are a noob at this reading all this info from 20 diffrent post becomes overwhelming and I am sure I am not the only one that needs these answers in one post as these questions are ones that I have come up with while doing hands on learning and I am ready to go to the next level..



My advice would be to take written notes, like at school 
This way your information will be easily accessible. If you refine outside, I suppose you don't have a computer on you, don't you ?

I can answer question 6 lol.



> 6:when melting gold mud using a dish like steves and borax, what is wrong when the gold seems to get stuck in the borax? Smile yes I melted some today and got a very smalll bead from my first run but it did not want to get out of the borax, the borax keep sticking to it??



It seems that you put too much borax. Only a small coat is needed. 
The trick is, when the gold bead is still red hot (but solid), use a pair of stainless tweezers to remove it from the borax, and drop it in cold water.

Fast cooling of the bead will remove most of the borax on it.

Good luck !


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## Harold_V (Mar 20, 2009)

I will not reply to your first few questions, leaving them for those that have experience working with the work-arounds chemicals. I have none. 



wop1969 said:


> 6:when melting gold mud using a dish like steves and borax, what is wronge when the gold seems to get stuck in the borax?  yes I melted some today and got a very smalll bead from my first run but it did not want to get out of the borax, the borax keep sticking to it??


Noxx has provided you the key to success. Your melting dish should have nothing more than a thin film of borax applied. The only time you should use more is if you intend to pour the contents to a cone mold. 

Take note that the flux shouldn't change color unless it takes on a pink or purple hue. Any other color is a sign of contaminated gold. 

If your button isn't fully cleaned by dropping in water, you can give it a boil in dilute sulfuric acid, which will dissolve the flux completely. It takes a few minutes. Rinse well afterwards, otherwise traces of the dissolved flux will re-deposit on the button when the solution evaporates. 



> 7: when dropping gold from HCL/CL using SMB can other metal get dragged down with the gold and persay, contaminate you pure gold?
> If so what metals are they?


Dragdown is a function of dirty solution sticking to precipitated particles. It is not reliant on the precipitant, although some may actually precipitate unwanted elements. Zinc is an example of one that is not selective. 

As the precipitated particles of gold agglomerate, they trap the unwanted elements, which can be difficult to remove by washing alone. Washing is always recommended, but it should not be relied upon alone to yield pure gold. A second refining will improve the quality considerably, because the entrapped elements are well diluted by the new solution, so very little can be dragged down in the second precipitation. In all cases, a prolonged washing of your precipitated gold should be routine, even if you intend to re-refine. The less contamination you include in your solutions, the better you can expect the quality to be. 

Harold


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## wop1969 (Mar 20, 2009)

Tnx Noxx I will be greedy on the borax next time 

far as notes I cant read my own writing half the time 
I do print stuff out and hang it on the walls of my lab but these are new questions that have risen from on hand trials and I think most probably come to the same place I am at in the adventure of on hands learning.

Problem is, like question one by reading I would be lead to think PT,PD and RH will not disolve in HCL/PX but in steves vids there is a few mentions of PT,PD being in the HCL/PX solution and after getting out the gold putting it aside to test for those and recover later, so I ask some of these questions to cliarify what seems to be contradictions in my mind, but I might be wronge I will not say I win the Nobel prize for paying attention some times


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## wop1969 (Mar 20, 2009)

wop1969 said:


> 5:How long does StainousCL need to sit after the heating and addition of tin befor it can be used? If so how long





lazersteve said:


> I add the tin (about 1-2 grams) to 20 mL of HCl and heat it up until the tin begins to dissolve. Once the tin starts to fizz I stop heating and let it stand for 5-10 minutes. The solution will clear up as the tin dissolves. A little extra tin doesn't hurt as it keeps the solution fresh.



I answered my own question via another post by steve , very detailed directions.

Thanks Harold, now that I have got past the first run and know what to do I will probly make it a practice to do a second HCL/CL on the gold dust as I want to produce high purity, it seems the right thing to do.
Harold when you say washing are you talking about a good rinse with plain HCL?

Also you talked about zinc not being selective, will zinc desolve into an HCL/CL solution like gold will? If so would you remove the zinc with a good HCL wash then water rinse of the foils after HCL/PEROX befor the HCL/CL bath?


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## Harold_V (Mar 20, 2009)

wop1969 said:


> Harold when you say washing are you talking about a good rinse with plain HCL?


Washing is an involved process. It includes water rinses and an ammonium hydroxide boil, along with HCl washes. Here's a link that will provide some guidance. 

http://goldrefiningforum.com/phpBB3/viewtopic.php?t=325&start=0



> Also you talked about zinc not being selective, will zinc desolve into an HCL/CL solution like gold will?



Yes. Zinc will readily dissolve in nitric, sulfuric or HCl. It does so with a vengeance. 



> If so would you remove the zinc with a good HCL wash then water rinse of the foils after HCL/PEROX befor the HCL/CL bath?


You may have misconstrued what I meant to say. I was talking about having used zinc to precipitate values. It brings down everything---copper included. You aren't likely to encounter any zinc that is troublesome. Any that may be present when you do preliminary processes to access gold will be in solution and will be filtered away with the solution. Remember----the pins you dissolve are made up of copper and zinc. They're typically yellow brass, which runs approximately 30% zinc. 

Harold


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## wop1969 (Mar 20, 2009)

> Quote:
> If so would you remove the zinc with a good HCL wash then water rinse of the foils after HCL/PEROX befor the HCL/CL bath?
> 
> You may have misconstrued what I meant to say. I was talking about having used zinc to precipitate values. It brings down everything---copper included. You aren't likely to encounter any zinc that is troublesome. Any that may be present when you do preliminary processes to access gold will be in solution and will be filtered away with the solution. Remember----the pins you dissolve are made up of copper and zinc. They're typically yellow brass, which runs approximately 30% zinc.
> ...



So, With collected foils there will most likly not be any zinc, but if you precip gold from HCL/PX thier my be some copper in the precid with the gold?

Also, can I use zinc to precip copper from the waste acid (HCL/PX) once I get all the other PGM's out?


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## wop1969 (Mar 20, 2009)

I have started to edit the first post in this topic to list the answers with the questions in an easy to understand format


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## Harold_V (Mar 20, 2009)

wop1969 said:


> So, With collected foils there will most likly not be any zinc, but if you precip gold from HCL/PX thier my be some copper in the precid with the gold?


This matter would be best addressed this way. Zinc is almost never used as a precipitant for refining. It is used frequently for a recovery, however. For example, if you had a batch go bad, you may choose to use zinc to precipitate everything, which could then be incinerated so you could start over. It is usually far more desirable to use a precipitant that is selective, so it will cause only the desired element to be precipitated. 



> Also, can I use zinc to precip copper from the waste acid (HCL/PX) once I get all the other PGM's out?



Yes, you could, but the recovered copper is generally of no value, so you can use scrap steel instead. It's far more economical than using zinc, unless you have an endless supply of zinc and don't care if it's used for recovering copper, which, ultimately, is likely to be thrown away. 

Harold


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## wop1969 (Mar 20, 2009)

Harold could you post a list of what chems precip what metals so I can add it to the first post?

I could attemp it but it would be incomplete I am sure :?


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## Noxx (Mar 20, 2009)

Here are two commons:

SMB precipitates gold but also traces of PGMs.

Oxalic acid precipitates gold but also traces of copper.


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## wop1969 (Mar 20, 2009)

Im going to take a guess and say their is probly not any 100% selective precipitates?


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## Harold_V (Mar 20, 2009)

wop1969 said:


> Harold could you post a list of what chems precip what metals so I can add it to the first post?
> 
> I could attemp it but it would be incomplete I am sure :?



Sigh! I'm the wrong person to ask. I don't have a chemical background--I'm nothing more than a trained monkey with experience in refining. 

Ferrous sulfate is an excellent precipitant, by the way.

Harold


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## Oz (Mar 21, 2009)

Harold_V said:


> I'm nothing more than a trained monkey with experience in refining.Harold



You are too humble. You may have gotten your start with a book, but it was your many years of trial and error that caused you to take it much farther. I see you give advice time and again that is nowhere to be found in Hoke. Your needs caused you to learn and develop in ways that were innovative on your part beyond a book and you give advice that is spot on. Hard won real world experience is the greatest gift you give the forum besides your time.


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## Platdigger (Mar 21, 2009)

Tiz true......


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## Harold_V (Mar 21, 2009)

Thanks, guys. 

Harold


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## wop1969 (Mar 21, 2009)

Oz said:


> Harold_V said:
> 
> 
> > I'm nothing more than a trained monkey with experience in refining.Harold
> ...



Ditto


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## The Refiner49er (Mar 21, 2009)

I haven't posted to the Forum in a long time, but couldn't help but give credit where credit is due.

Harold, among others here; have been instrumental to my development as a refiner. It is a fairly complex process, particularly if you are processing many different types of materials. The proof of good refining practices are clearly evident in the final product.

I must express my sincere appreciation for all his contributions and advice... Harold is a key player whose contributions have been to the benefit of countless precious metal refiners; both beginners and those who have thought to be otherwise. Hokes book is a great foundation for methodology, but there is nothing that replaces practical experience. 

Hats off to Harold!!!


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## Platdigger (Mar 21, 2009)

Hey 49er, long time.....
You pour those buttons?
Randy


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## The Refiner49er (Mar 21, 2009)

The buttons are from some California placer gold I refined last year, about 920 purity. The big one was just short of 82 grams.

How are things with you, Randy?


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## Platdigger (Mar 22, 2009)

Real good John.
You know, after I posted that question, I got to thinking that I had asked you that before.......they still look good tho.....
Randy


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## wop1969 (Mar 25, 2009)

anyone have any more answers to the questions in I listed?


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