Is there a way to drop gold faster?

Gold Refining Forum

Help Support Gold Refining Forum:

This site may earn a commission from merchant affiliate links, including eBay, Amazon, and others.
This week I tried to use your method 2 times on AR solution about 1 liter, yes it works but the gold sediment came dark brown as the solution color when add about 20 ml sulphuric acid after adding SMB, even after boiling the sediment with HCl and distilled water the color of gold powder still dark, after smelting I got un shiny gold like photos, after test the gold it gives 999 purity but I wonder why it lost its brightness.
 

Attachments

  • IMG-20231129-WA0010.jpeg
    IMG-20231129-WA0010.jpeg
    2.1 MB
This week I tried to use your method 2 times on AR solution about 1 liter, yes it works but the gold sediment came dark brown as the solution color when add about 20 ml sulphuric acid after adding SMB, even after boiling the sediment with HCl and distilled water the color of gold powder still dark, after smelting I got un shiny gold like photos, after test the gold it gives 999 purity but I wonder why it lost its brightness.
This is not a general use technique.
It is what we use when the precipitate is so fine it do not settle well.
 
This week I tried to use your method 2 times on AR solution about 1 liter, yes it works but the gold sediment came dark brown as the solution color when add about 20 ml sulphuric acid after adding SMB, even after boiling the sediment with HCl and distilled water the color of gold powder still dark, after smelting I got un shiny gold like photos, after test the gold it gives 999 purity but I wonder why it lost its brightness.
Most of the time patience is part of the problem.
Not having the patience to wait with refining until recovery concentrated your material enough, or wait for it all to settle, or adding too much smb results in drag down of copper(darker powder) or not taking the time to evaporate the solution.
Are these AR solutions from small tests or your regular gold dissolutions?
Did you wash the powder after SMB?
 
Most of the time patience is part of the problem.
Not having the patience to wait with refining until recovery concentrated your material enough, or wait for it all to settle, or adding too much smb results in drag down of copper(darker powder) or not taking the time to evaporate the solution.
Are these AR solutions from small tests or your regular gold dissolutions?
Did you wash the powder after SMB?
Particle size makes a difference in nanoparticles when it come the color, i imagine very fine powder reflects different wavelengths than bigger clumps.
 
Most of the time patience is part of the problem.
Not having the patience to wait with refining until recovery concentrated your material enough, or wait for it all to settle, or adding too much smb results in drag down of copper(darker powder) or not taking the time to evaporate the solution.
Are these AR solutions from small tests or your regular gold dissolutions?
Did you wash the powder after SMB?
It's regular gold dissolution, second time dissolving in aquaregia, I always add SMB about 3 times gold weight with no issue, as told you gold is 999 but I wonder why its not shinny when use sulfuric acid, for sure I washed the gold powder after precipitating with HCl and distilled water
 
It's regular gold dissolution, second time dissolving in aquaregia, I always add SMB about 3 times gold weight with no issue, as told you gold is 999 but I wonder why its not shinny when use sulfuric acid, for sure I washed the gold powder after precipitating with HCl and distilled water
Just to test, try a 1:1 ratio and test if there is some gold left in solution. To avoid drag down of copper.
Then you can decant and precipitate the rest of the gold in a different beaker. Test the difference between the first 95% and the last bit. If any.
This also tells you how much SMB is actually needed.

And keep the volume of the solution as low as you can, especially for a second refine. This results in a higher concentration dropping the gold faster and cleaner.
You can evaporate the solution with heat to concentrate it, but never boil it.

Overuse of SMB is a cause for fine dust, with copper, that stays suspended in solution.
 
The clumped gold is not shiny after your sulfuric acid or HCl wash/boil because there is no polished surface at that time - just a rough surface that absorbs a lot of light. It is not shiny even if you do not use an acid boil, just multiple distilled water washes.

If the precipitate is pure, then you will have a nice shiny gold mass after melting and cooling.
 
Thanks for the help guys. It worked pretty good. Heating at 50C and stirring about every 15 mins for an hour and then turning the heat off and stirring again a couple times dropped it to a clear solution. Although just as a test I repeated the process with the clear solution and got a couple more grams. It’s not perfect but it better then waiting days. Thanks for the advice. I appreciate.
 
According to gravimetric chemistry, the more nucleii, the finer the precipitate. The object is to promote particle growth rather than the formation of more nucleii. Fast reactions favor the formation of more nucleii and less particle growth. Introduce SMB(precipitant) slowly in the form of your choice so the reaction will favor particle growth...mixing everything at once is not promoting a homogeneous technique, regardless of concentration. Fine particles carry more contaminants as the smaller the particle, the more surface area for contaminants to attach to.
This is very clarifying and makes a lot of sense. Good to know. Thanks!
And it could save even more on SMB use.
 
Welcome, this is why SO2 gas bubbling through the pregnant AR works so well. It self limits the reaction and allows time for particle growth before forming more nucleii.
The difference is quite obvious. I must admit there are a couple of grams left in solution, but this beautiful light powder was only rinsed with water where the dark usual powder had 2 or 3 boiling HCl washes!!
There are even visible gold flakes or crystals shining in there 😁20231204_231103_mfnr.jpg
20231204_231122_mfnr.jpg
 
The difference is quite obvious. I must admit there are a couple of grams left in solution, but this beautiful light powder was only rinsed with water where the dark usual powder had 2 or 3 boiling HCl washes!!
There are even visible gold flakes or crystals shining in there 😁View attachment 60659
View attachment 60661
Why SO2 gas method didn't precipitate all gold? Is it always behavior or just in your experiment?
 
You are oversimplifying the level of chemical interaction and making incorrect logical conclusions.

The school logic of math doesn't work in chemistry: “In both the first and second cases, sulfur dioxide is used, so the reactions must proceed in the same way".

In inorganic chemistry, everything is much more complicated.

The reaction diagram shows only the approximate reaction products. This is NOT an accurate quantitative diagram of the complete interaction of chemical elements, unfortunately. This often confuses newbies.

It would take quite a long time to list the points on which reactions differ. Therefore, strictly speaking, you will not be able to provide equivalent equality of reaction conditions for SMB and pure SO2. Therefore, the reaction results will always be different.
 
Why SO2 gas method didn't precipitate all gold? Is it always behavior or just in your experiment?
He replied to my message.
This is very clarifying and makes a lot of sense. Good to know. Thanks!
And it could save even more on SMB use.
I did not use SO2 but added smb slowly.
Why SO2 gas method didn't precipitate all gold? Is it always behavior or just in your experiment?
I just left a bit in solution as i was trying to keep the powder clean to experiment. That worked perfectly. The last bit was darker.
I treatet a next batch completely and that last bit was a lot darker.
You should always test with stannous after precipitation or when you think it's done.
 
You are oversimplifying the level of chemical interaction and making incorrect logical conclusions.

The school logic of math doesn't work in chemistry: “In both the first and second cases, sulfur dioxide is used, so the reactions must proceed in the same way".

In inorganic chemistry, everything is much more complicated.

The reaction diagram shows only the approximate reaction products. This is NOT an accurate quantitative diagram of the complete interaction of chemical elements, unfortunately. This often confuses newbies.

It would take quite a long time to list the points on which reactions differ. Therefore, strictly speaking, you will not be able to provide equivalent equality of reaction conditions for SMB and pure SO2. Therefore, the reaction results will always be different.
This done today with SO2، about 5 grams gold, used 20 grams SMB in the flask to generate SO2, stannous chloride test is negative. Took about 5 minutes to finish all SMB.

I watched many videos done by Sreetips that precipitate large amount of gold with SO2, he stopped the SO2 generation after got negative test with stannous, he also done precipitating with short time

Sometimes, I make SMB solution with distilled water, then start to add SMB solution to AR through filter paper drop by drop, it also gives me same yellow precipitate as SO2 precipitating
 

Attachments

  • IMG20231206230955.jpg
    IMG20231206230955.jpg
    1.9 MB
I watched many videos done by Sreetips that precipitate large amount of gold with SO2, he stopped the SO2 generation after got negative test with stannous, he also done precipitating with short time
From some of your questions in the past, I have assumed you were doing some refining on a larger scale. However having seen most of Sreetips videos I know he is not refining large amounts of gold, relatively speaking. Out of curiosity, what is your goal here, a hobby refiner or a small or medium sized commercial refiner?
 
If I remember right by mixing smb with water it converts or changes to sodium sulfite. It still has the ability to drop gold. By mixing smb with an acid it changes it to SO2 gas. Again it still drops gold. The difference might be subtle but they are different. If we drop smb into AR, it is often wasteful of the SO2 by just covering the surface. By mixing with water it can mix into the AR but it dilutes it as well. By mixing smb into HCl it produces SO2 gas that when pumped into AR it mix’s in and drops the gold without diluting the AR solution. By dropping from a concentrated solution the drop can often work somewhat better than from a dilute solution.

They all can work, do so slightly different from each other.

Did I get that right?
 

Latest posts

Back
Top