please help me with refining my gold

[Harold_V]

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

 

[mohd]

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

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

 

[freechemist]

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.

 

[butcher]

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.

 

[freechemist]

@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

 

[butcher]

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

 

[mohd]

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.

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