How is it that sulfuric acid or many other strong acids can break colloidal structure in colloidal gold?

[4metals]

Processing colloidal gold

 

[Yggdrasil]

Am trying to avoid dissolving gold into the solution, I added 75 grams of NaCl, color changed to blue and got precipitate at the bottom, will wait till tomorrow to see how much gold I got.

Salt may supply enough Chloride to dissolve some Gold but I do not see how it can solve the issue with colloids.

 

[Ayham Hafez]

Salt may supply enough Chloride to dissolve some Gold but I do not see how it can solve the issue with colloids.

After denoxing nitric, salt can't dissolve gold.

I read that salt change the ions of colloidal or something like that.

 

[Yggdrasil]

After denoxing nitric, salt can't dissolve gold.

I read that salt change the ions of colloidal or something like that.

It won't break the collodial state but may change the size of the colloids and such the color of the liquid.

 

[Ayham Hafez]

Found this video

 

[Martijn]

If I add sulphuric acid to precipitate gold, I think it will not work cause sulphuric acid will be consumed with copper nitrate to make copper sulphate, and I'm afraid from adding NaCl cuase it will react with silver and not sure if it will precipitate the gold l.

You have very fine gold suspended in solution?
Adding H2SO4 will not precipitate gold, it will clean the surface of the fine gold atom clusters and make them clump together, so they are heavy enough to fall down.

So give your solution a gentle boil with some sulfuric for an hour or so, and this should help the gold fall down.

 

[4metals]

Forming colloidal gold after dissolving mixed metals alloy or copper alloy is well-known, and as told I faced same issue several times specially when silver content is too low, if silver content is high comparing to copper or base metals , colloidal gold will not form

This made me wonder. Does anyone know the necessary concentration of Silver in a copper based alloy needed to allow the gold particles to drop vs. stay in solution as a colloid? The reason I ask is a common question when discussing inquartation is “ can I use copper instead “? We commonly answer yes but you will use a lot more nitric acid to dissolve the copper. We never answer yes but you may form colloidal gold and throw it in with your waste.

Perhaps we should discuss this further?

 

[Ayham Hafez]

This made me wonder. Does anyone know the necessary concentration of Silver in a copper based alloy needed to allow the gold particles to drop vs. stay in solution as a colloid? The reason I ask is a common question when discussing inquartation is “ can I use copper instead “? We commonly answer yes but you will use a lot more nitric acid to dissolve the copper. We never answer yes but you may form colloidal gold and throw it in with your waste.

Perhaps we should discuss this further?

I made inquartation with copper siveral times, gold content between 25% to 30%, colloidal gold not formed, I think it's only form with very small gold content in copper alloy like less than 1%, cause I recovered gold from an copper alloy before and gold content was about 1.8% and didn't form colloidal gold.

Did many gold recovery for less than 0.5% of gold content and all the times colloidal gold formed.

Hope these numbers help.

 

[Ayham Hafez]

I made inquartation with copper siveral times, gold content between 25% to 30%, colloidal gold not formed, I think it's only form with very small gold content in copper alloy like less than 1%, cause I recovered gold from an copper alloy before and gold content was about 1.8% and didn't form colloidal gold.

Did many gold recovery for less than 0.5% of gold content and all the times colloidal gold formed.

Hope these numbers help.

By the way, I recovered the gold of yesterday and got only 4 grams, my rest gold is in the bottom of the copper cell tank, I thought the shopping bags will catch all anode particles but today after investigating I noticed that most of the mud is in the tank.

 

[4metals]

Apparently the shopping bags are the wrong fabric or the wrong mesh and fines fall through.

 

[4metals]

M

Did many gold recovery for less than 0.5% of gold content and all the times colloidal gold formed

I wonder if some colloidal gold formed at higher Gold percentages and was missed. It will pass right through a filter

 

[Ayham Hafez]

Apparently the shopping bags are the wrong fabric or the wrong mesh and fines fall through.

More than one month looking for the best fabric, and didn't find smaller mesh than shopping bags, since also I have issues with oxidization all anode base metals while smelting, so the electrolyte is high contaminated and copper fall from cathode, so now I have to remelt all copper and refine again to get the value

 

[Ayham Hafez]

M
I wonder if some colloidal gold formed at higher Gold percentages and was missed. It will pass right through a filter

Colloidal gold will pass throw any filter, I tried a big cotton filter and its go throw it

 

[Martijn]

This made me wonder. Does anyone know the necessary concentration of Silver in a copper based alloy needed to allow the gold particles to drop vs. stay in solution as a colloid? The reason I ask is a common question when discussing inquartation is “ can I use copper instead “? We commonly answer yes but you will use a lot more nitric acid to dissolve the copper. We never answer yes but you may form colloidal gold and throw it in with your waste.

Perhaps we should discuss this further?

Interesting point. With dirty solutions, you can't see the purple that good after a drop. But if the sulfuric method works, you could use that to make sure you got it all.
The same fine coloidal particles will form in a copper cell, i expect. The sulfuric electrolyte probably prevents them from getting suspended in solution.
I think with any alloy where gold is around 5% or lower, you will leave coloidal atom clusters of gold. If you inquart with copper to 6K, the gold sponge should remian like with silver inquartation, right?

 

[Ayham Hafez]

Interesting point. With dirty solutions, you can't see the purple that good after a drop. But if the sulfuric method works, you could use that to make sure you got it all.
The same fine coloidal particles will form in a copper cell, i expect. The sulfuric electrolyte probably prevents them from getting suspended in solution.
I think with any alloy where gold is around 5% or lower, you will leave coloidal atom clusters of gold. If you inquart with copper to 6K, the gold sponge should remian like with silver inquartation, right?

I think yes.

I smelted the copper anodes slimes before going to nitric acid, so electrolyte has no role in my case

 

[4metals]

More than one month looking for the best fabric, and didn't find smaller mesh than shopping bags, since also I have issues with oxidization all anode base metals while smelting, so the electrolyte is high contaminated and copper fall from cathode, so now I have to remelt all copper and refine again to get the value

I prefer 13 ounce polypropylene anode bags, I know you are outside the US so you may not have a lot of options. Here is a link to an anode bag supplier in the US and it gives information about different fabrics used for anode bags and which baths they work in. HERE Maybe with more information you will have better success locally. I prefer anode bags with a rubberized fabric boot at the bottom which is called a "crap trap". This allows slimes to be siphoned out of the bag without removing the entire bag as the bottom is less likely to puncture when siphoning with a suction wand and contacting the fabric.

 

[Ayham Hafez]

I prefer 13 ounce polypropylene anode bags, I know you are outside the US so you may not have a lot of options. Here is a link to an anode bag supplier in the US and it gives information about different fabrics used for anode bags and which baths they work in. HERE Maybe with more information you will have better success locally. I prefer anode bags with a rubberized fabric boot at the bottom which is called a "crap trap". This allows slimes to be siphoned out of the bag without removing the entire bag as the bottom is less likely to puncture when siphoning with a suction wand and contacting the fabric.

Thanks for your help.

"Crap trap" I searched about it but never find photo, it looks amazing idea, could you please share a photo for it.

 

[4metals]

 

[Ayham Hafez]

View attachment 66365

Wow, I think with this design we can use filter bags many many times, isn't it?

 

[4metals]

Yes they do last a lot longer.