# how do i get the black powder (gold) nice gold color



## trisedem (Jan 8, 2013)

Hi, after the last process i end up with the black powder (gold).
So , now i dont wanna smelt it, but i wanna bring it to its original (yellow) gold color.How do i do this ?
Thank you


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## niteliteone (Jan 8, 2013)

We need a lot more information than you have given so far.

What material did you start with ???
What process did you use to remove base metals and recover the gold ???
What process did you use to "REFINE" the recovered gold ???
What reagent did you use to drop the gold from solution ???

And any other information you can give to let us know what you have done to get that black powder.


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## butcher (Jan 9, 2013)

Gold power should be tan-brown color, if it is black it is impure and needs refined.

Pure tan gold powder when crushed with a glass stir rod will turn back into the yellow gold, impure (black powder will not).

Pure tan powdered gold when melted will give gold of high purity, black powder melted can look like anything from copper to impure gold.

We would need details, just stating you have black powder (gold), does not tell us anything of what you have, so we cannot give advice on what to do next.


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## jimdoc (Jan 9, 2013)

Is this black powder from a sulfuric cell?

Jim


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## trisedem (Jan 16, 2013)

Hi everyone,actually the color that i obtained is dark brown ...(sorry for the inaccurate description)...
I used ceramic cpus ....First in Nitric Acid to get rid of all other metals than gold,silver .
After in AR ...heated a little and waited until there was no gold on the cpu ...about 3h.
Than i add water to rinse a few times and i did filtered it and left over night.
Than filtered it and add urea.
I tested the solution with Tin Dichloride.
Than added the SMB...and left it over night.
I have dark brown powder now.
But i dont wanna smelt it ...that is why i would like to know how can i obtain the original yellow color.
Thanks


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## butcher (Jan 16, 2013)

See Harold's gold washing procedures in the thread getting gold pure and shining, this will help to turn the dark brown powder to a light brown (tan) powder (removing the base metals that darken the powder).
Re-refining can also remove impurity. Refining the second time is similar to re-crystallizing salts to purify them, and is normally fairly easy to do the second time.

The light brown powder is gold, if you crushed it with a glass stir rod it would look like gold, (or smeared in under pressure onto a piece of paper it would leave a gold streak), the pure powder will do this where impure gold will not do this or as well.


To get the brown powder look like gold it is melted, it has something to do with particle size and reflection of light as to why this fairly pure brown power does not look like gold.

I do not know how you could change the particle size or form that the brown gold precipitate to make it to look like gold power, without pressure to smash the fine powders together into metal, or by melting the powders back to a lump of gold metal, both of which would join the powders together into another shape, I have seen when melting just before the gold melts the powders join together under the torch and begin to look like gold, I have assume this was the fine powder melting and beginning to melt together.

Gold can be precipitated using oxalic acid, on the second refine.
The second refine (using the different reagent) will improve gold quality as the different reagent will not have the drag down or precipitation of metals the first reagent used will include in the precipitated gold.

http://www.youtube.com/watch?v=o165tgxFMYM

The carbon based reagent's used to precipitate gold seem to precipitate gold with more of the golden color.


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## Gratilla (Jan 16, 2013)

Because pure(ish) gold is very malleable, you can press it into whatever shape you have a mold for.

To test whether it is pure enough, put a small amount of the powder on a hard surface and try smearing it with a spatula or flat of a knife. If you get a nice yellow smudge, compressing it in a mold using a vice or similar should be no problem.

This is the preferred method for turning brown powder into gold "coins" in the Mintek iGoli process.


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## nickvc (Jan 17, 2013)

In your first treatment for the material you used nitric, this will dissolve any silver or palladium in the material so use a copper bar to cement any values before you dispose of the solution and check with stannous to make sure it's barren of values.


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