# please help me with refining my gold



## mohd (Jul 28, 2012)

Dear Sir, 
Firstly I would like to thanks to the Forum Admistrator and to all forum members.

I am mohd from malaysia and i am totally new here.I need some asistance
on refining my gold sand just recovered from river.

First step i have done quite well to smelt the gold sand with using boric acid and sodium carbonite.

After i have a few gold button weight 45.55 g, i have cheked and the contant of the gold is 89.5% gold.

later on i have bring the gold to a jewls shop to sell the gold but the price which i got is usd 46.15 /g on 26/7/2012 which is less than expated.

My question is how to refine my gold (89.5%) to (99.9%).
All chemical is ready bought by me and it is :-

A.Nitric Acid 70%(2.5l)
B.HCL acid 37%(2.5l)
C.Sulfuric Acid
D.sodium bicloride
E.Stannous Cloride
F. all equipment nassery

I have follow the Youtube on refining gold but TOTAL FAIL.When i add up nitric acid 50ml to my gold button and put on hot bricks it did not react and nothing happen.After that I took off my gold ring and do the same as first experiment ALSO FAIL.WHY the acid has no reaction.

Please help me what is going wrong with my experiment.

MILLIONS THANKS TO ALL OF THE FORUM MEMBERS.


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## jimdoc (Jul 28, 2012)

mohd said:


> Dear Sir,
> Firstly I would like to thanks to the Forum Admistrator and to all forum members.
> 
> I am mohd from malaysia and i am totally new here.I need some asistance
> ...




Download this book, it has the answers;

http://goldrefiningforum.com/phpBB3/download/file.php?id=2480

Jim


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## qst42know (Jul 28, 2012)

Your pay out for the gold content of 89.5% is very near all the value that was there. 

Why did you expect more?

$1620 / 31.1 = 52.09 per gram pure

52.09 x .895 = usd $46.62

What was the spot price when you cashed in?


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## jimdoc (Jul 28, 2012)

His post says 26/7/2012, two days ago. So I think it was still a bit under $1600 then?

Jim


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## goldsilverpro (Jul 28, 2012)

According to Kitco, the price on that date was $1618. Therefore, you received 99.1% of the value. This is more than excellent. To me, the big question is, how was the 89.5% determined?

Nitric only attacks the base metals in the alloy and not the gold. When the gold content exceeds about 40%, or a little higher, it blocks any attack on the base metals and, therefore, no reaction occurs.

Download the Hoke book that Jimdoc gave a link for and read it. It is written simply and is very readable. It will answer all your questions and give you the best head start on refining that you could possibly get.


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## qst42know (Jul 28, 2012)

> A.Nitric Acid 70%(2.5l)
> B.HCL acid 37%(2.5l)
> C.Sulfuric Acid
> D.sodium bicloride
> ...



Your list is incomplete. Don't continue attempting to put your gold in solution until you have an appropriate precipitant on hand.


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## mohd (Jul 28, 2012)

To All of the forum member,Thank You for the advice.I will follow trough the book first and thanks for reply to my question.

But the book stated (This book does not cover the refining of virgin ore or crude metal, nor
any phase of mining engineering).

In my case the gold is from virgin ore Recovered in lime stone.
I check the gold at famous gold store (Habib Jewels) in malaysia using deci meter.The put the gold in water on top of weight meter .The meter automaticaly culculate the caret and gold percentage.In one of other shop they chaked with laser machine which in both testing i am not sure how it works.

Anyway Thanks Again.


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## mohd (Jul 28, 2012)

goldsilverpro said:


> According to Kitco, the price on that date was $1618. Therefore, you received 99.1% of the value. This is more than excellent. To me, the big question is, how was the 89.5% determined?
> 
> Nitric only attacks the base metals in the alloy and not the gold. When the gold content exceeds about 40%, or a little higher, it blocks any attack on the base metals and, therefore, no reaction occurs.
> 
> Download the Hoke book that Jimdoc gave a link for and read it. It is written simply and is very readable. It will answer all your questions and give you the best head start on refining that you could possibly get.


 Dear Sir,

When the gold content exceeds about 40%, or a little higher, it blocks any attack on the base metals . 

In my case 89.5% gold did not react with the acid which is right as you explain. How do i overcome the problem and how many silver needed to add in 45.55 g (89.5%) gold.

Any how thanks friend.


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## mohd (Jul 28, 2012)

qst42know said:


> Your pay out for the gold content of 89.5% is very near all the value that was there.
> 
> Why did you expect more?
> 
> ...


Dear Sir,

IF the gold purity sows 99% than the guy is willing to pay USD 51.9 or RM 161 on the rate USD 1 = RM 3.1.
On that day gold bar seling price 99.9 shows USD 61.2/g.

Thank Friend for reply.


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## qst42know (Jul 28, 2012)

The book that was recommended will explain how much silver and many other things. 

If you read it and still have questions you will get the help you need.


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## mohd (Aug 3, 2012)

Dear Friends,

Please help and i am totally confuse after reading the artical.

What is best process to refine my gold button 89.5%.

Do i have to refine using AR only or using nitric acid after mix the gold button with culculated silver until gold % below 40%.

Thanks Again


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## nickvc (Aug 3, 2012)

Mohd I and virtually all who have replied to you can tell you what to do but we can't be there to make sure you recover all your values hence the admirable suggestion to reds Hoke. Your gold once melted is the same as any other it just assays at around 20 k and the book details how to refine it and how to know where your values are, do you want to lose 10grams to gain a few dollars?
We are not been awkward but trying to show you what you need to know to be successful and not lose your gold. Please take the advice and read Hoke it's in simple terms and your command of English will be sufficient I'm sure to understand it, if not ask questions on points you don't understand. We don't hold your hand here and give simple instructions you need to learn for your own benefit not ours.
Good luck and welcome to the forum.


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## Harold_V (Aug 3, 2012)

mohd said:


> Dear Friends,
> 
> Please help and i am totally confuse after reading the artical.
> 
> ...


The ideal concentration of gold, AFTER INQUARTATION, is 25%. If your gold, as recovered, contains 429 grains, pure, you can assume that the balance would be 51 grains, possibly silver. Based on that, in order to achieve the ideal gold concentration (25%), you would add 80 grams of silver for each troy ounce of gold to be inquarted. It should be melted and stirred well, to create a homogeneous alloy. That alloy would then be poured in to water, creating what I call corn flakes. Those corn flakes would then be parted (dissolved) in dilute nitric acid, leaving behind the gold as a bronze colored pellet, still in the same form as it was created when poured in water. I prefer to NOT break them up, as it's harder to separate the solution from the solids. 

The remaining bronze colored pieces are almost pure gold. They can be elevated to a higher degree of purity by dissolving in aqua regia, which is then evaporated and filtered before precipitating the gold. All of this is covered in Hoke's book. It does not address gold recovered from mining, but the principles remain the same, you simply adjust the math to reflect the higher percentage of gold contained in the material.

Study Hoke's book until you understand what she teaches. Once you gain that understanding, you will be able to refine your gold without questions. 

Harold


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## mohd (Aug 3, 2012)

Dear Sir Harold,

Thankyou for the explaination. I will follow trough the Hoke's book.By the way i will make a test to dissolve 89.5% 10g gold aloy in nitric acid 75% to see how much gold reduce and what is the percentage of the gold recover without doing further process in AR.

Do you have any Idea what is the % of gold adhere in nitric acid process alone.

Best Regards

Mohd


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## Harold_V (Aug 4, 2012)

mohd said:


> I will follow trough the Hoke's book.By the way i will make a test to dissolve 89.5% 10g gold aloy in nitric acid 75% to see how much gold reduce and what is the percentage of the gold recover without doing further process in AR.


If I understand you correctly, you intend to dissolve the 89.5% gold in nitric. If so, that won't work. That's why you were told to inquart. If you do not inquart, you won't be able to dissolve the button you have now. It most likely won't dissolve in aqua regia, either, as it most likely already contains silver, and that will prevent the material from dissolving in aqua regia, too. However, once you have inquarted, you will be able to remove all of the silver, leaving behind gold. It won't be pure, but it will be very close, assuming you digest all of the base metals (including silver), and rinse well. 

Please read Hoke's book, even if you must have it translated. It will provide you with enough information that you will then gain an understanding of what you must do, and how it must be done. 



> Do you have any Idea what is the % of gold adhere in nitric acid process alone.


I'm sorry, but I do not understand your question. Can you phrase it differently?

Harold


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## mohd (Aug 4, 2012)

Harold_V said:


> mohd said:
> 
> 
> > I will follow trough the Hoke's book.By the way i will make a test to dissolve 89.5% 10g gold aloy in nitric acid 75% to see how much gold reduce and what is the percentage of the gold recover without doing further process in AR.
> ...


Dear Sir Harold,

Actually i am wendering and would like to know if i have mix the gold with silver and get the aloy sufficient to dissolve with nitric acid. If the aloy has been process to get the gold at the bottom of the acid ! then the collected gold didnt went for AR process , I just melt it to button shape, Do you have any idea how much is the gold purity by percent recovered by nitric acid process.


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## samuel-a (Aug 4, 2012)

mohd said:


> Actually i am wendering and would like to know if i have mix the gold with silver and get the aloy sufficient to dissolve with nitric acid. If the aloy has been process to get the gold at the bottom of the acid ! then the collected gold didnt went for AR process , I just melt it to button shape, Do you have any idea how much is the gold purity by percent recovered by nitric acid process.



I don't know if it is a language barrier or a lack of basic understanding, so i'll try to make things clear.

Pure gold or a high gold content alloy will not be attacked by Nitric acid alone. 
It will dissolve in AR.

Silver (and most other base metals) will get dissolved in Nitric acid. 
Silver will react to AR to from an insoluble solid silver chloride that will hinder further dissolution.

An alloy of gold and silver will be attacked by Nitric acid alone up to a certain threshold as stated by GSP, being around 40% Au/60% Ag. Gold will remain untouched as 'solid' sponge. But at these proportions, dissolution of silver will be very slow and uneven. 
If we change the proportions to 25% Au/75% (inquarting), we will get faster dissolution rate, achieve full dissolution of silver and still get the 'solid' gold sponge.

As mentioned above, high gold alloy will be attacked by Aqua Regia (Hydrochloric acid + Nitric acid). However, Silver content in the alloy plays an important role here and if the silver content in the alloy is above 8-10%, it will render the dissolution process by slowing it down sugnificantly and requires much more acids. To overcome this, agitation and high temp' are used.

If indeed your alloy is made up from 89.5% gold and the rest being silver, then inquarting is the way to go.
If the other ingredients are not only silver then AR will be sufficient.


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## mohd (Aug 4, 2012)

samuel-a said:


> mohd said:
> 
> 
> > Actually i am wendering and would like to know if i have mix the gold with silver and get the aloy sufficient to dissolve with nitric acid. If the aloy has been process to get the gold at the bottom of the acid ! then the collected gold didnt went for AR process , I just melt it to button shape, Do you have any idea how much is the gold purity by percent recovered by nitric acid process.
> ...



Thank you samuel ,

I dont know if my poor assay in english confuse the helper.What i mean is the 89.5% of gold about 5 gram is mix with pure silver at about 10.5 gram for the aloy and just dissolve with nitric acid to get the gold at the bottom of the solution. if the gold is collected and melt become gold button ! what is the percentage of the gold button if anyone have an idea.

Secondly for 89.5% of gold what is the best way to refine it with:

A. mix the gold with silver and dissolve with nitric acid just that process and melt remain gold ,

or

Just put the gold 85.5% purity 5 gram into AR to further refine it and drop the gold with oxilic acid or sodium bisulfate.

I am total confuse becose the gold has 89.5% purity and i would like to refine it to 99 % . I know there is few way to refine it but dosent know which process refine batter for the gold till 99%.

Best regards

Mohd


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## Westerngs (Aug 4, 2012)

Mohd, if you do this:
A. mix the gold with silver and dissolve with nitric acid just that process and melt remain gold ,

The resulting purity of the gold will be dependent on how well the gold nitric acid dissolved the base metals and silver. It can range from 90% to 99.x%. Using several nitric acid washes will produce cleaner gold, but it is my experience that it is very difficult to achieve 99.9% gold.

If you do this:
B. Just put the gold 85.5% purity 5 gram into AR to further refine it and drop the gold with oxilic acid or sodium bisulfate.

This may or may not work.

If the remaining 14.5% is silver or mostly silver, the gold will have a difficult time dissolving in AR because the silver will convert to silver chloride and coat the surface of the gold thereby stopping the reaction.

If the 14.5% gold is mostly base metals, then yes, this would work well. Make sure to wash the gold precipitate well to remove impurities left by the solution.

If you find that the 14.5% is mostly silver, then step A followed by step B is the way to go.

Good luck.


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## mohd (Aug 4, 2012)

Westerngs said:


> Mohd, if you do this:
> A. mix the gold with silver and dissolve with nitric acid just that process and melt remain gold ,
> 
> The resulting purity of the gold will be dependent on how well the gold nitric acid dissolved the base metals and silver. It can range from 90% to 99.x%. Using several nitric acid washes will produce cleaner gold, but it is my experience that it is very difficult to achieve 99.9% gold.
> ...




Dear Westerngs,

Well guide and it is lound and clear. This is what answer i am realy looking for.

Best Regards

Mohd


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## Harold_V (Aug 7, 2012)

mohd said:


> Actually i am wendering and would like to know if i have mix the gold with silver and get the aloy sufficient to dissolve with nitric acid. If the aloy has been process to get the gold at the bottom of the acid ! then the collected gold didnt went for AR process , I just melt it to button shape, Do you have any idea how much is the gold purity by percent recovered by nitric acid process.


So then, what you hope to learn is how pure the gold might be if you simply parted the inquarted gold, and then melted the remains. 
If you've done your work well, I expect you might achieve 99% purity. The gold would likely contain traces of silver and copper, neither of which would harm the quality, assuming that's all that might be present. If, however, you happen to have traces of lead present, or some other elements (iron, for example), you risk gold that is brittle, and can't be rolled or fashioned, aside from casting. 

If you choose to process ONLY by nitric acid, not dissolving the gold, I strongly suggest you subject the gold, at the final operation, to a hard boil in dilute nitric, then follow that by a hard boil, at least two times, with water. When you do the final rinse, the solution should be absent of color. If it is not, repeat the rinse cycle. 

While I generally recommend gold be dissolved, if you're working with clean waste, this may yield excellent gold. If you're melting filings, it is my opinion that you are making a mistake by not dissolving the gold. I know from personal experience, over many years of refining, that gold quality from filings is always suspect, due in part to the presence of iron. 

Harold


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## mohd (Aug 14, 2012)

Harold_V said:


> mohd said:
> 
> 
> > Actually i am wendering and would like to know if i have mix the gold with silver and get the aloy sufficient to dissolve with nitric acid. If the aloy has been process to get the gold at the bottom of the acid ! then the collected gold didnt went for AR process , I just melt it to button shape, Do you have any idea how much is the gold purity by percent recovered by nitric acid process.
> ...


Daer Sir,

Today I have a result of success of :-

a.Mix 18k 5g ring with silver and remove the silver using nitric acid.the resuld bottom of the bicar left brownish powder is about 3g.
B.mix HCL with nitric acid 4:1 and boil medium heat and put the brownish powder to the solution.The brown powder is gone turning the AR golden in colour with little amount of partical at bottom than i filtter the solution and get very clear golden colour solution.
c.After i chaked with litmus paper to find out the PH and the solution show 0.I have bought firtiliser urea 42% and add to the solution to neutralise the nitric acid BUT no reaction with bicar become cold and the urea dissolve .I have put might be 15g of urea into 200ml AR with water mix but the litmus paper did not show sign just as earlier PH 0.

Please help me what is going on wrong with the urea process.How much do i have to add in the AR solution.

Thanks

Mohd


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## freechemist (Aug 22, 2012)

Mohd,

You are asking for help: "_Please help me what is going on wrong with the urea process.How much do i have to add in the AR solution._"

Mainly 3 things went wrong in your processing:

1.) Addition of urea is simply unuseful. A lot about this topic can be read in the forum.
2.) 42% urea, fertilizer grade, was really a bad choice. It contains only 42% urea and 58% different substances.
3.) You added much, too much of urea (ca. 6 grams), together with 9 grams of different, unknown material. In other words you made a mess out of your original, seemingly pure gold solution.

To recover your gold, you can proceed as follows:

1.) Test with SnCl2, if gold is really present.
2.) Add 2-5 ml conc. sulfuric acid and ca. 25 ml conc. HCl to your probably gold containing, mixed solution, mix well and transfer into an evaporating-dish, which should become not more than about half full. Put the dish with it's contents on a weakly boiling water-bath or, eventually, a hot-plate. Keep
the contents near the boiling point and let evaporate to a sirupy consistency and/or until different salts begin to crystallize.
3.) Let cool down, add 25 ml water and 25 ml conc. HCl, stir well up and repeat the evaporation procedure.
4.) Take up the evaporation-residue in 100-150 ml water, dissolve completely, and precipitate the gold with SMB. About 3 grams should be sufficient.


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## butcher (Aug 22, 2012)

freechemist, good advice,

but I have one small thing in your advice I would change.

"3.) Let cool down, add 25 ml water and 25 ml conc. HCl, stir well up and repeat the evaporation procedure."

Here I would not add any water, water just dilutes the nitric or nitrate salts (salts which become nitric in solution with added acid), the concentrated HCl is mostly water anyway about 8o%, adding water I feel just complicates and prolongs the evaporation process.

But then again here he did use an excess of urea, so I am wondering if this may be the reason you suggest water here? 

Some sulfuric just a few ml, can help to keep the salts from forming during evaporation and also help with driving off nitrate as nox gas.


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## freechemist (Aug 24, 2012)

*@butcher:*

Urea in aqueous solution, if heated a long time, hydrolyses to form CO2 and ammonia quantitatively. If there is really gold present, and not sufficient acid to neutralize all the ammonia formed, you may enter a dangerous situation.

If concentrated HCl is heated, the first thing evaporating is gaseous hydrogenchloride. Hence my proposition to add water, to come near the azeotropic composition of HCl. Secondly, a high chloride-concentration of the mixture, caused by copious amounts of dissolved/crystallizing chloride-salts may also influence premature HCl-gas-volatilization.

Regards, freechemist


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## butcher (Aug 24, 2012)

Thank You for the reply, and the good information contained, so the urea was the reason, for the suggestion to add the water.


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## mohd (Aug 31, 2012)

freechemist said:


> Mohd,
> 
> You are asking for help: "_Please help me what is going on wrong with the urea process.How much do i have to add in the AR solution._"
> 
> ...


Dear Sir,

Its A great Advice.And I have use the method and the result is I manage to recover 2.7 g pure gold from the solution . The gold has been accepted by the gold shop in indonesia( while i was there for vacation) which pay usd 50.7/g. But i did not sell it cos the gold was from weeding ring and will keep by my wife forever.

Thanks Again

Mohd


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