Precipitate Gold Using Zinc powder

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Franciz

Franciz

Well-known member
Joined
Nov 21, 2011
Messages
135
Location
Vietnam
Hello All,
I have ordered and received my M-nbss white powder today.
I have dissolve 20g of it and 30g of NaCN to 1liter of hot water,The solution turn light yellow.
I put gold plated pins to the solution and the solution turns dark yellow/orange.
After all gold has dissolved i then combine the solution and rinse water and rise the ph to 12.
After i have rised the ph i stirred in some zinc powder the zinc powder turn black, i kept adding bit by bit until i saw grey zinc on the bottom. With stirring the solution seems like turning to a clear solution but after 1min or so it slowly turn back to dark yellow solution.

May i know it this normal? And what is the color of the solution should be after the gold has all out?

I hope someone can help to answer my question here....

Kind Regs
Francis.....
 

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goldsilverpro said:
Looks alright to me.
Click to expand...

Dear Master Chris,

So happy to get your reply. Do you mean the yellow color of the solution is normal?
And do you mean the solution will remain yellow in color even after all the gold has drop out?
May i Know when is the best time to filter, Should i leave the solution overnight until its turn clear or i can filter now....

Thanks Master Chris.....
Francis
 
Francis if you leave the gold in the solution too long it can redissolve some of it, to counter this hang a piece of zinc in the solution, decant the solution when it's settled and only filter what's necessary saves time.
 
The solution color can depend on other things and I never pay much attention to it. However, the color of your solution looks normal. I mainly stir enough to create a little foam on top and look at the color of it. It should be white when everything is dropped.
 
nickvc said:
Francis if you leave the gold in the solution too long it can redissolve some of it, to counter this hang a piece of zinc in the solution, decant the solution when it's settled and only filter what's necessary saves time.
Click to expand...

Dear Nickvc,

Yes, I have hang a piece of zinc plate in the solution, But i can still see the zinc still react with the NaOH and the solution is not clear yet. But all the powder has settle on the bottom.
Should i ignore the reaction and just decant and filter the powder?

Please anyone here could tell me should the solution remain yellow in color even after the gold has been all drop out?


Thanks and best regs
Francis
 
Even when all the gold is out, the solution won't be colorless. It will have a light straw color.

It worried me when you said the m-NBSS you bought was white. All that I have used was tan colored flakes. Just like this MSDS says.
http://apps.risd.edu/envirohealth_msds/Textiles/prochemflakesludigolf.pdf
 
goldsilverpro said:
Even when all the gold is out, the solution won't be colorless. It will have a light straw color.

It worried me when you said the m-NBSS you bought was white. All that I have used was tan colored flakes. Just like this MSDS says.
http://apps.risd.edu/envirohealth_msds/Textiles/prochemflakesludigolf.pdf
Click to expand...

My solution turns dark Orange color.
When i called up the supplier and asked for meta nitrobenzene sulfonic acid sodium salt, They told me they called it resist salt.
And the cas no is 127-68-4. When i got it it is in powder form and is white in color.
Any idea?
 
I have post the picture of the powder.
It look the same as here--> http://ultrachemicalworks.tradeindia.com/Exporters_Suppliers/Exporter7571.491110/Resist-Salt.html

Thanks
Francis
 
This is confusing. There are so many of those nitroaromatic compounds, many of which will work. The more I search, though, the more I think this is the one I used - CAS 827-95-2.
http://www.chemicalbook.com/CASEN_827-95-2.htm
 
goldsilverpro said:
This is confusing. There are so many of those nitroaromatic compounds, many of which will work. The more I search, though, the more I think this is the one I used - CAS 827-95-2.
http://www.chemicalbook.com/CASEN_827-95-2.htm
Click to expand...

Yes Master Chris, This is confusing. I have search and found the ludigol link http://www.pburch.net/dyeing/FAQ/ludigol.shtml.
It says is m-nitrobenzene sulfonic acid, sodium salt. For m-nitrobenzene sulfonic acid, sodium salt i am sure the cas no is 127-68-4 But if the cas number is 827-95-2 then it is m-NITROBENZOIC ACID SODIUM SALT, Means it is not ludigol?

Do you think for my cas no 127-68-4 powder will work, There is now 25kg with me.?
Supplier refuse to sell me less than that... :cry: :cry: :cry:
When it dissolved in water the solution became yellow.
Issit the same?

Thanks
Francis
 
Franciz said:
goldsilverpro said:
This is confusing. There are so many of those nitroaromatic compounds, many of which will work. The more I search, though, the more I think this is the one I used - CAS 827-95-2.
http://www.chemicalbook.com/CASEN_827-95-2.htm
Click to expand...

Yes Master Chris, This is confusing. I have search and found the ludigol link http://www.pburch.net/dyeing/FAQ/ludigol.shtml.
It says is m-nitrobenzene sulfonic acid, sodium salt. For m-nitrobenzene sulfonic acid, sodium salt i am sure the cas no is 127-68-4 But if the cas number is 827-95-2 then it is m-NITROBENZOIC ACID SODIUM SALT, Means it is not ludigol?

Do you think for my cas no 127-68-4 powder will work, There is now 25kg with me.?
Supplier refuse to sell me less than that... :cry: :cry: :cry:
When it dissolved in water the solution became yellow.
Issit the same?

Thanks
Francis
Click to expand...

If it dissolves the gold, it will work. I can't can't see how it would possibly cause zincing problems, but I've been wrong before.

I found that there are several types of Ludigol and I haven't sorted them out yet. Surely there's an organic chemist on board.

I need to figure out some simple, safe test to tell if all the gold is out of the cyanide solution. Most of the ones I know are not simple or are dangerous. I do have some ideas, though.
 
goldsilverpro said:
Franciz said:
goldsilverpro said:
This is confusing. There are so many of those nitroaromatic compounds, many of which will work. The more I search, though, the more I think this is the one I used - CAS 827-95-2.
http://www.chemicalbook.com/CASEN_827-95-2.htm
Click to expand...

Yes Master Chris, This is confusing. I have search and found the ludigol link http://www.pburch.net/dyeing/FAQ/ludigol.shtml.
It says is m-nitrobenzene sulfonic acid, sodium salt. For m-nitrobenzene sulfonic acid, sodium salt i am sure the cas no is 127-68-4 But if the cas number is 827-95-2 then it is m-NITROBENZOIC ACID SODIUM SALT, Means it is not ludigol?

Do you think for my cas no 127-68-4 powder will work, There is now 25kg with me.?
Supplier refuse to sell me less than that... :cry: :cry: :cry:
When it dissolved in water the solution became yellow.
Issit the same?

Thanks
Francis
Click to expand...

If it dissolves the gold, it will work. I can't can't see how it would possibly cause zincing problems, but I've been wrong before.
Click to expand...


Teacher Chris,
I just do a new batch. I notice something, After dissolved the gold there is many tiny transparent jelly floating around.
This time i keep stirring non-stop i saw yellow foam and kept stirring until the foam turn white. Let it sit for awhile the solution turn from orange to bright yellow color.

DO you think this is a success?

Thanks
Francis
 
After i leave the solution overnight, The solution turn like this------>

Crystal like jelly floating around and solution turn orange in color.

Francis
 

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The situation that you have is interesting. I wish that I had information to relay to you about it but I do not. I did perform various cyanide leaches upon gold bearing ores many years ago but I cannot recall that we ever visually inspected the solution. We extracted a sample via pipet and had that assayed.
------
I would like to point out that the words "chrystal" and "jelly-like/blob'" are almost antonyms in English. The first means something hard and angular whereas the latter two terms mean soft and amorphous.
------
I mean no disrespect in saying this. My knowledge of Viet Namese extends only to ba-me-ba and buc nam tung sigh. Well, and there is a nice bowl of pho to be had in Black Hawk these days.
 
I believe that you have a hydrated form of benzoic acid zinc chelate from leaving the solution over night. The sulfonic acid radical was replaced by the COOH by hydrolysis and the zinc cyanide chelated. Meta pairing (meaning a side atom of carbon as apposed to para meaning end to end) showing from the side to side pairing of the short needles (like the pan flute) making translucent flat flakes, is the reason that I think so. :| Dr. Poe
 
Dr. Poe said:
I believe that you have a hydrated form of benzoic acid zinc chelate from leaving the solution over night. The sulfonic acid radical was replaced by the COOH by hydrolysis and the zinc cyanide chelated. Meta pairing (meaning a side atom of carbon as apposed to para meaning end to end) showing from the side to side pairing of the short needles (like the pan flute) making translucent flat flakes, is the reason that I think so. :| Dr. Poe
Click to expand...


Dear Dr Poe,
The crystal forms before i have enough time to do anything, It just appear when i added in the cyanide.

Thanks..
Francis
 

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