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

[IsaacUS]

How does it work?
Also when gold is at the level, it's size and weight is extremely small. Does the melting/boiling point of gold change at the nanoparticle level?

And why does gold and most other metals operate differently in the nanoparticle level? It's still gold, but what I get confused with is, does it have the same properties as a regular 1g gold particle?

 

[butcher]

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No matter how small the cluster of precipitated atoms of gold are they are still elemental gold with the same properties as the metal, can we melt them easier yes, but the melting point and boiling point is the same.

Colloids are gold atoms (elemental metal gold), clustered together to form clumps of atoms of these metals, as the clump grows it can also develop a polarity to these small clusters of gold atoms, so that they repel each other and cannot join with other clusters of these elemental gold cannot come into contact with each other to form large enough cluster to precipitate.

Boiling in a strong acid like H2SO4 will break this colloidal bond removing the polar charge, so these cluster stop acting like a bowl full of magnets, and can then the clusters can bang into each other and form larger clusters of gold atoms we normally can see as the solution going brown and small brown tan or black gold precipitating from solution.

The color of the colloidal solution is an indication of how large the cluster of gold atoms is.
The purple of Cassius in our test for gold is a colloid with certain size clusters of gold atoms moving around repeling each other.

 

[IsaacUS]

https://goldrefiningforum.com/phpBB3/search.php?keywords=colloidal+gold&terms=all&author=butcher&sc=1&sf=all&sr=posts&sk=t&sd=d&st=0&ch=300&t=0&submit=Search

Try a search under other Authors or using other keywords.

No matter how small the cluster of precipitated atoms of gold are they are still elemental gold with the same properties as the metal, can we melt them easier yes, but the melting point and boiling point is the same.

Colloids are gold atoms (elemental metal gold), clustered together to form clumps of atoms of these metals, as the clump grows it can also develop a polarity to these small clusters of gold atoms, so that they repel each other and cannot join with other clusters of these elemental gold cannot come into contact with each other to form large enough cluster to precipitate.

Boiling in a strong acid like H2SO4 will break this colloidal bond removing the polar charge, so these cluster stop acting like a bowl full of magnets, and can then the clusters can bang into each other and form larger clusters of gold atoms we normally can see as the solution going brown and small brown tan or black gold precipitating from solution.

The color of the colloidal solution is an indication of how large the cluster of gold atoms is.
The purple of Cassius in our test for gold is a colloid with certain size clusters of gold atoms moving around repeling each other.

Why does the solution turn from red to brown after boiling with sulfuric acid? Isn't the gold amount so small? How would it become visible?

Is there a "safer" way to break the colloid rather than using sulfuric acid to boil?

Previously I added a couple tablespoons in a half cup of colloidal gold. The result was that the solution turned from red to clear.
What would have happened had I boiled it?

 

[butcher]

Why does the solution turn from red to brown after boiling with sulfuric acid? Isn't the gold amount so small? How would it become visible?

Gold can colloid in solutions, take for example with where tin is dissolved with gold, the dissolved gold ions will be reduced to gold atoms (we cannot see) many of these atoms of elemental gold are coming into contact with each other and join in clumps (we still cannot see), these clumps come into contact making larger clumps of gold atoms (we cannot see), before growing large enough for us to see this reduced gold clumps will develop a static charge, now they begin to repel from each other (now we have a colloidal gold solution, (we may not be able to see that it is a colloidal solution unless we shine a light through it (Tyndal effect). the colloidal gold is already elemental gold but these clumps will not settle in solution, because of the static charge.
We cannot test for the gold a colloids in the solution, these tests rely upon the gold being an ionic salt and the stannous chloride or ferrous sulfate, in the tests reducing the gold to elemental gold, as a colloidal gold solution of purple of Cassius with stannous chloride, and elemental gold in a brown ring of gold around the ferrous sulfate crystal.

It would depend on how much gold (as colloids) was in solution whether you would see the brown precipitated gold from solution after breaking the colloidal bond, small amounts of gold you would have to search hard to find any sign of gold, but if a fair amount of gold was in solution you could find it easy in the beaker after settling as brown or black powder...

Is there a "safer" way to break the colloid rather than using sulfuric acid to boil?

Electrolysis can be used to break the colloidal bond.

Previously I added a couple of tablespoons in a half cup of colloidal gold. The result was that the solution turned from red to clear.
What would have happened had I boiled it?

Not much, sounds like your gold has precipitated.

You can shine a flashlight through the side of the beaker and look for the Tyndal effect for a colloidal solution...

 

[IsaacUS]

Why does the solution turn from red to brown after boiling with sulfuric acid? Isn't the gold amount so small? How would it become visible?

Gold can colloid in solutions, take for example with where tin is dissolved with gold, the dissolved gold ions will be reduced to gold atoms (we cannot see) many of these atoms of elemental gold are coming into contact with each other and join in clumps (we still cannot see), these clumps come into contact making larger clumps of gold atoms (we cannot see), before growing large enough for us to see this reduced gold clumps will develop a static charge, now they begin to repel from each other (now we have a colloidal gold solution, (we may not be able to see that it is a colloidal solution unless we shine a light through it (Tyndal effect). the colloidal gold is already elemental gold but these clumps will not settle in solution, because of the static charge.
We cannot test for the gold a colloids in the solution, these tests rely upon the gold being an ionic salt and the stannous chloride or ferrous sulfate, in the tests reducing the gold to elemental gold, as a colloidal gold solution of purple of Cassius with stannous chloride, and elemental gold in a brown ring of gold around the ferrous sulfate crystal.

It would depend on how much gold (as colloids) was in solution whether you would see the brown precipitated gold from solution after breaking the colloidal bond, small amounts of gold you would have to search hard to find any sign of gold, but if a fair amount of gold was in solution you could find it easy in the beaker after settling as brown or black powder...

Is there a "safer" way to break the colloid rather than using sulfuric acid to boil?

Electrolysis can be used to break the colloidal bond.

Previously I added a couple of tablespoons in a half cup of colloidal gold. The result was that the solution turned from red to clear.
What would have happened had I boiled it?

Not much, sounds like your gold has precipitated.

You can shine a flashlight through the side of the beaker and look for the Tyndal effect for a colloidal solution...

Why does the solution turn from red to brown after boiling with sulfuric acid? Isn't the gold amount so small? How would it become visible?

Gold can colloid in solutions, take for example with where tin is dissolved with gold, the dissolved gold ions will be reduced to gold atoms (we cannot see) many of these atoms of elemental gold are coming into contact with each other and join in clumps (we still cannot see), these clumps come into contact making larger clumps of gold atoms (we cannot see), before growing large enough for us to see this reduced gold clumps will develop a static charge, now they begin to repel from each other (now we have a colloidal gold solution, (we may not be able to see that it is a colloidal solution unless we shine a light through it (Tyndal effect). the colloidal gold is already elemental gold but these clumps will not settle in solution, because of the static charge.
We cannot test for the gold a colloids in the solution, these tests rely upon the gold being an ionic salt and the stannous chloride or ferrous sulfate, in the tests reducing the gold to elemental gold, as a colloidal gold solution of purple of Cassius with stannous chloride, and elemental gold in a brown ring of gold around the ferrous sulfate crystal.

It would depend on how much gold (as colloids) was in solution whether you would see the brown precipitated gold from solution after breaking the colloidal bond, small amounts of gold you would have to search hard to find any sign of gold, but if a fair amount of gold was in solution you could find it easy in the beaker after settling as brown or black powder...

Is there a "safer" way to break the colloid rather than using sulfuric acid to boil?

Electrolysis can be used to break the colloidal bond.

Previously I added a couple of tablespoons in a half cup of colloidal gold. The result was that the solution turned from red to clear.
What would have happened had I boiled it?

Not much, sounds like your gold has precipitated.

You can shine a flashlight through the side of the beaker and look for the Tyndal effect for a colloidal solution...

So in a 0.8 gallon 100 ppm colloidal gold solution. How much Asorbic acid should I add to precipitate and breaks the colloid

 

[butcher]

https://goldrefiningforum.com/phpBB3/viewtopic.php?t=28006

What are they calculating as part per million in a gallon of colloidal gold which sells for $70?
parts per million of what in what?

Sounds like a great sells pitch, I have 100 parts gold this stuff is real concentrated gold solution......

I cannot gather what they have measured, or with what measurement...

Are they counting the colloids in solution, the gold as elemental weight, gold defects/volume, mass milligrams/mass kilograms, milligrams per liter, micrograms per litter...

 

[butcher]

From what information I can gather:

The sell colloidal silver or gold by parts per million a ratio of silver colloid and water.

The manufacturer reports the silver concentration in milligrams/liter an actual measurement of weight to volume.

one liter of water weighs 1000 grams
one milligram is 1/1000 one-thousandth of a gram
1000 milligrams = 1 gram
so:
100 milligrams/liter = 100 parts per million
so we need 10 liters to possibly get a gram of silver from solution

That is if my figures are correct.

My self, I would not like using a carbon-based acid, like ascorbic acid, I would use sulfuric acid.

The gold in the colloidal solution is already reduced to metal, so ascorbic acid cannot reduce the gold, it is the acid hydronium ion (H3O) of ascorbic acid in a heated solution that breaks the polarized bond.
The fact that ascorbic acid can precipitate gold from solution has nothing to do with the fact that with heating strongly and acid we can remove the polar charge that keeps the small clusters of gold growing together to form large enough cluster to form a precipitant that you could see...

 

[IsaacUS]

From what information I can gather:

The sell colloidal silver or gold by parts per million a ratio of silver colloid and water.

The manufacturer reports the silver concentration in milligrams/liter an actual measurement of weight to volume.

one liter of water weighs 1000 grams
one milligram is 1/1000 one-thousandth of a gram
1000 milligrams = 1 gram
so:
100 milligrams/liter = 100 parts per million
so we need 10 liters to possibly get a gram of silver from solution

That is if my figures are correct.

My self, I would not like using a carbon-based acid, like ascorbic acid, I would use sulfuric acid.

The gold in the colloidal solution is already reduced to metal, so ascorbic acid cannot reduce the gold, it is the acid hydronium ion (H3O) of ascorbic acid in a heated solution that breaks the polarized bond.
The fact that ascorbic acid can precipitate gold from solution has nothing to do with the fact that with heating strongly and acid we can remove the polar charge that keeps the small clusters of gold growing together to form large enough cluster to form a precipitant that you could see...

Okay so I'm aiming for that Acid hydronium cation to break the colloidal structure.

I'm planning to boil it on my stovetop. That's the reason why I don't want to use sulfuric acid. Just moved so all my refining tools are shipping out to me next week.

What the optimal temp, and amount of Ascorbic acid
To get the desired result? Also what is the sign that I broke the colloidal structure. The amount of gold is negligible. So will the solution just turn from ruby red to clear or ruby red to darker purple or brown?

 

[butcher]

I suspect the gold amount could be so small that it could be difficult to find the precipitated gold.
You could look for the Tyndale effect, comparing the before and after...

Or maybe set up a small test cell and see if you can get any gold to plate out onto the cathode surface, also testing it before and after...

Electron microscopy (maybe)?
colloidal gold in the wiki:
Colloidal gold is among the most widely used labels for antigens in biological electron microscopy.
In addition to biological probes, gold nanoparticles can be transferred to various mineral substrates, such as mica, single crystal silicon, and atomically flat gold(III), to be observed under atomic force microscopy (AFM).
https://en.wikipedia.org/wiki/Colloidal_gold

https://www.ncbi.nlm.nih.gov/pmc/articles/PMC4188810/

 

[g_axelsson]

If you only want to recover the gold, you could always let it dry out. The gold will be concentrated at the bottom of your vessel and then use a bit of aqua regia to dissolve what's left.

0.8 gallon of 0.1g / liter would only give a few tenths of a gram in the end.

If it was me I would just let it dry out, then wipe it off with a wet tissue and place it with my filters for incineration. I'll get the gold some time.

Göran

 

[IsaacUS]

If you only want to recover the gold, you could always let it dry out. The gold will be concentrated at the bottom of your vessel and then use a bit of aqua regia to dissolve what's left.

0.8 gallon of 0.1g / liter would only give a few tenths of a gram in the end.

If it was me I would just let it dry out, then wipe it off with a wet tissue and place it with my filters for incineration. I'll get the gold some time.

Göran

The gold would be so small that it would practically be invisible.