Presence of silver chloride in a solution of king's water

[RogerBack33]

I wish everyone a good day. As I said in the title, I have king water with gold content. During the filtering phase of the king water, which I had previously processed, it looked like in the first photo. After mixing, the color became greenish yellow. When I took a small sample for precipitation and tried hydrazine hydrate, a problem arose as seen in the 150 ml beaker. Can you help me ? What should I do after this step?

Aqua regia was diluted with water while filtering. It was liberated from nitric while hot before filtration with sulphamic acid. The white precipitate disappears again in solution with slight stirring. Thank you in advance for your help and comments.

 

[Yggdrasil]

I wish everyone a good day. As I said in the title, I have king water with gold content. During the filtering phase of the king water, which I had previously processed, it looked like in the first photo. After mixing, the color became greenish yellow. When I took a small sample for precipitation and tried hydrazine hydrate, a problem arose as seen in the 150 ml beaker. Can you help me ? What should I do after this step?

Aqua regia was diluted with water while filtering. It was liberated from nitric while hot before filtration with sulphamic acid. The white precipitate disappears again in solution with slight stirring. Thank you in advance for your help and comments.

What was the start material?

Why are you using Hydrazine?
It is carcinogenic and a much more toxic and dangerous chemical than SMB, Ascorbic acid, Oxalic acid or Ferrous Sulfate?
Almost nobody is using Hydrazine of the same reasons.
Even if there is Silver in the feed stock there should be negligible Silver in the AR.

What do you men by this?

It was liberated from nitric while hot before filtration with sulphamic acid.

Did you mean deNOxed with Sulfamic acid?

My guess is that it is some kind of clear glassy Hydrazine salt almost invisible wen dispersed.

 

[lazersteve]

I have extensive experience using hydrazine to reduce metal salts to their parent metal. I start with hydrazine sulfate and add it in dry form with vigorous stirring to a slurry of the salt (eg platinum ammonium/potassium chloride) suspended in a basic solution (ammonium/sodium hydroxide). The basic solution works in two ways: 1) it acts as a slight solvent for the metal salt we are trying to reduce, and 2) it frees the sulfate ion from the hydrazine which becomes the hydrogen source for the basic pH reduction.
It appears to me that you added a solution of a hydrazine salt to your acidic AR which doesn't release any hydrogen. Secondly I've never attempted to use free base hydrazine (or it's salts) to reduce dissolved metals in solution directly so I can't speak if this is a viable route or not.

I suspect you are looking at your hydrazine salt.

What pH was your hydrazine "hydrate" at when you added it? Hydrazine hydrate appears as a clear to slight yellow oily sheen on the surface of the reaction solution.

What is the final pH of the resulting solution?

Steve

 

[Yggdrasil]

I have extensive experience using hydrazine to reduce metal salts to their parent metal. I start with hydrazine sulfate and add it in dry form with vigorous stirring to a slurry of the salt (eg platinum ammonium/potassium chloride) suspended in a basic solution (ammonium/sodium hydroxide). The basic solution works in two ways: 1) it acts as a slight solvent for the metal salt we are trying to reduce, and 2) it frees the sulfate ion from the hydrazine which becomes the hydrogen source for the basic pH reduction.
It appears to me that you added a solution of a hydrazine salt to your acidic AR which doesn't release any hydrogen. Secondly I've never attempted to use free base hydrazine (or it's salts) to reduce dissolved metals in solution directly so I can't speak if this is a viable route or not.

I suspect you are looking at your hydrazine salt.

What pH was your hydrazine "hydrate" at when you added it? Hydrazine hydrate appears as a clear to slight yellow oily sheen on the surface of the reaction solution.

What is the final pH of the resulting solution?

Steve

Do it have any upsides with respect to precipitating Gold from solution?
For instance Cyanide solutions and such?

 

[lazersteve]

Never used hydrazine sulfate on cyanide solutions, zinc dust is the cheaper, safer, less problematic method with CN.

I used hydrazine sulfate in PGM salt reduction as an initial step to purification of dirty PGM salts followed by a final refining of the clean PGM Blacks to high purity metal. I have since developed new more direct and environmentally friendly processes which eliminate the need for hydrazine, but it's still in my "toolbox" if the need ever arises for it.

Hydrazine is very fast and forgiving as it's added to the slurry in small increments until the reaction kicks off, then it's nearly instaneous with a large evolution of gas and foaming once the reaction starts. High purity metal is attained with second refining of the dirty Blacks. The final metallic product is a fluffy mass which resembles a brain when pure. The resulting solution is typically crystal clear. Waste solutions need to be kept separate and properly disposed of. The waste occasionally contains trace PGMs as well.
It's also worth noting that hydrazine is not a selective reducing agent. It will reduce most any metal salt below hydrogen to the parent metal as far as I am aware.

Steve

 

[Yggdrasil]

Never used hydrazine sulfate on cyanide solutions, zinc dust is the cheaper, safer, less problematic method with CN.

I used hydrazine sulfate in PGM salt reduction as an initial step to purification of dirty PGM salts followed by a final refining of the clean PGM Blacks to high purity metal. I have since developed new more direct and environmentally friendly processes which eliminate the need for hydrazine, but it's still in my "toolbox" if the need ever arises for it.

Hydrazine is very fast and forgiving as it's added to the slurry in small increments until the reaction kicks off, then it's nearly instaneous with a large evolution of gas and foaming once the reaction starts. High purity metal is attained with second refining of the dirty Blacks. The final metallic product is a fluffy mass which resembles a brain when pure. The resulting solution is typically crystal clear. Waste solutions need to be kept separate and properly disposed of. The waste occasionally contains trace PGMs as well.
It's also worth noting that hydrazine is not a selective reducing agent. It will reduce most any metal salt below hydrogen to the parent metal as far as I am aware.

Steve

Thanks Steve