Just Confused about my weird problem

[Mostafa nezhad hasan]

hi everyone, I am new in goldrefining forum and I try to explain my problem quickly first of all, thank you for your attention in your reply.
I have some rocks that contain gold and silver and other metals as iron and copper . I use aqua Regia to extract gold from rocks. Everything is doing as handbook procedure. I smell rocks first and threw it into aqua Regia after rising temperature dissolving of metals starts, and when I test the solution deep black spot is appear. So until this time there is no problem when I separate aqua Regia (for precipitating) then test the solution and black spot is not apear, honestly, my solution turn from red-yellowish to no color. I use SnCl2 as gold indicator. My problem is why this happened.
When I continue to settle down gold with metabisulfite nothing happened this happen for iron sulfite too. If I cement with Cooper, some metal settling down and after dissolving those, same problem is persisted.
Please someone help thank you

 

[Martijn]

Welcome to the forum.

Aqua regia is a process not meant for rocks, so which handbook are you referring to?
Depending on what the rock is made up of, the fumes could be the last you breath. Arsenic, cyanide, mercury, ....not good for your health.

I suspect you make the AR with 3:1 HCl HNO3?

Assuming you in fact have gold in your rocks, that dark stannous stain could be copper, could be gold, but it disappears after a while because there probably is free nitric still in solution or it cemented out on basemetals left inside the rock.

Silver does not dissolve much in AR. The HCl turns the top layer into silver chloride, 'protecting' the silver and possibly gold underneath.
The gold deep inside the rock will not be touched much by the acid.

If you want to know what is in your rock, mill it to a fine powder and pan it. Roast that concentrate and test a bit for silver with nitric, after dissolving filter and add salt water to see any AgCl forms.

Then test the remaining solids with AR, made by covering in HCl, heating to 60 to 80 degrees Celcius and then adding drops of nitric at a time, waiting for the reaction to stop before adding more.

Then test a drop with stannous to see what you have. If the stain is too dark, dilute with drops of destilled water until you see brown(copper) or purple(gold).

Then you need to get a cross sample of your ore material and have it assayed. If you find any values.

Martijn.

Edited for spelling

 

[Mostafa nezhad hasan]

Welcome to the forum.

Aqua regia is a process not meant for rocks, so which handbook are you referring to?
Depending on what the rock is made up of, the fumes could be the last you breath. Arsenic, cyanide, mercury, ....not good for your health.

I suspect you make the AR with 3:1 HCl HNO3?

Assuming you in fact have gold in your rocks, that dark stannous stain could be copper, could be gold, but it disappears after a while because there probably is free nitric still in solution or it cemented out on basemetals left inside the rock.

Silver does not dissolve much in AR. The HCl turns the top layer into silver chloride, 'protecting' the silver and possibly gold underneath.
The gold deep inside the rock will not be touched much by the acid.

If you want to know what is in your rock, mill it to a fine powder and pan it. Roast that concentrate and test a bit for silver with nitric, after dissolving filter and add salt water to see any AgCl forms.

Then test the remaining solids with AR, made by covering in HCl, heating to 60 to 80 degrees Celcius and then adding drops of nitric at a time, waiting for the reaction to stop before adding more.

Then test a drop with stannous to see what you have. If the stain is too dark, dilute with drops of destilled water until you see brown(copper) or purple(gold).

Then you need to get a cross sample of your ore material and have it assayed. If you find any values.

Martijn.

Assuming you in fact have gold in your rocks, that dark stannous stain could be copper, could be gold, but it disappears after a while

Edited for spelling

Hi Martijn
So thankful for replying, you are absolutely right. I apologize for my pervious description that turn to misunderstanding. I first smell rocks beside Na2CO3. After that a black crystal-metal form and drop it in aqua regia.
“Assuming you in fact have gold in your rocks, that dark stannous stain could be copper, could be gold, but it disappears after a while” no I mean when I ‘m dissolving I can see black spot (deep purple) , but when I leave solution for 10 minute to be cold and test again, surprisingly no color change happen. You see, it seem nothing exist in solution.
I am extracting gold and silver from cellphone’s board, and in my first attempt in rocks I so confused about that

 

[Yggdrasil]

hi everyone, I am new in goldrefining forum and I try to explain my problem quickly first of all, thank you for your attention in your reply.
I have some rocks that contain gold and silver and other metals as iron and copper . I use aqua Regia to extract gold from rocks. Everything is doing as handbook procedure. I smell rocks first and threw it into aqua Regia after rising temperature dissolving of metals starts, and when I test the solution deep black spot is appear. So until this time there is no problem when I separate aqua Regia (for precipitating) then test the solution and black spot is not apear, honestly, my solution turn from red-yellowish to no color. I use SnCl2 as gold indicator. My problem is why this happened.
When I continue to settle down gold with metabisulfite nothing happened this happen for iron sulfite too. If I cement with Cooper, some metal settling down and after dissolving those, same problem is persisted.
Please someone help thank you

As Martijn have said, AR is "never" used for rocks/ore.
The reasons are many.
It is obviously the dangers of unknown substances in the ore itself, like Arsenic, Mercury, Cadmium or others.
Next it is more expensive than other options,
especially when taken into account that you have to dissolve ALL metal from the Ore to prevent the Gold from cementing out again.
This creates much more waste that gave to be treated and so on.

I think there is a language barrier here to, what do you mean by smelling the rocks?
And I am pretty certain there is NO procedure using AR for ore, until after it has been properly assayed and then gravity concentrated.
How do you perform the Stannous test?
If the Stannous is negative there will be no precipitation, simple as that.

I suggest you send your rocks to proper assay or learn to do your own assay.
And while you wait for the answer start studying, and by that I mean NO youtube studies, but the ones I'm giving you now.

We ask our new members to do 3 things.
1. Read C.M. Hokes book on refining jewelers scrap, it gives an easy introduction to the most important chemistry regarding refining.
It is free here on the forum: Screen Readable Copy of Hoke's Book
2. Then read the safety section of the forum: Safety
3. And then read about "Dealing with waste" in the forum: Dealing with Waste

Suggested reading: The Library

Forum rules : https://goldrefiningforum.com/threads/gold-refining-forum-rules.31182/post-327766

 

[Lino1406]

Hi Martijn
So thankful for replying, you are absolutely right. I apologize for my pervious description that turn to misunderstanding. I first smell rocks beside Na2CO3. After that a black crystal-metal form and drop it in aqua regia.
“Assuming you in fact have gold in your rocks, that dark stannous stain could be copper, could be gold, but it disappears after a while” no I mean when I ‘m dissolving I can see black spot (deep purple) , but when I leave solution for 10 minute to be cold and test again, surprisingly no color change happen. You see, it seem nothing exist in solution.
I am extracting gold and silver from cellphone’s board, and in my first attempt in rocks I so confused about that

Stannous black spot disappears - no or very little pms

 

[Mostafa nezhad hasan]

As Martijn have said, AR is "never" used for rocks/ore.
The reasons are many.
It is obviously the dangers of unknown substances in the ore itself, like Arsenic, Mercury, Cadmium or others.
Next it is more expensive than other options,
especially when taken into account that you have to dissolve ALL metal from the Ore to prevent the Gold from cementing out again.
This creates much more waste that gave to be treated and so on.

I think there is a language barrier here to, what do you mean by smelling the rocks?
And I am pretty certain there is NO procedure using AR for ore, until after it has been properly assayed and then gravity concentrated.
How do you perform the Stannous test?
If the Stannous is negative there will be no precipitation, simple as that.

I suggest you send your rocks to proper assay or learn to do your own assay.
And while you wait for the answer start studying, and by that I mean NO youtube studies, but the ones I'm giving you now.

We ask our new members to do 3 things.
1. Read C.M. Hokes book on refining jewelers scrap, it gives an easy introduction to the most important chemistry regarding refining.
It is free here on the forum: Screen Readable Copy of Hoke's Book
2. Then read the safety section of the forum: Safety
3. And then read about "Dealing with waste" in the forum: Dealing with Waste

Suggested reading: The Library

Forum rules : https://goldrefiningforum.com/threads/gold-refining-forum-rules.31182/post-327766

I am agree with language barrier, and my another issue is my typing dictionary on my tablet!!! for example i type "smellting" but it write smell. so sorry for thoes problem. honestly i will try to explain correctly tonight. thank you for your points.

 

[Yggdrasil]

I am agree with language barrier, and my another issue is my typing dictionary on my tablet!!! for example i type "smellting" but it write smell. so sorry for thoes problem. honestly i will try to explain correctly tonight. thank you for your points.

Seriously drop the acids on ores until you have a proper assay telling it is safe.
Even then, it will probably not be economically sound.

If you drop one l it might get you in the right direction
And if you already have it smelted into an dore bar or something similar, it should be safer.
Just take the bar and have a XRF with complete library done and you will know if it has Gold in it.
Have you found the rocks/ores locally?

 

[Mostafa nezhad hasan]

Seriously drop the acids on ores until you have a proper assay telling it is safe.
Even then, it will probably not be economically sound.

If you drop one l it might get you in the right direction
And if you already have it smelted into an dore bar or something similar, it should be safer.
Just take the bar and have a XRF with complete library done and you will know if it has Gold in it.
Have you found the rocks/ores locally?

yes, in our local exist 3 gold mining, and i found one little mine. my degree of education is MSC chemical engineering, but becouse government policy in iran, i cannot introduce it mine, you see. i send samples to lab and have two kind of rocks and ore. i try to attach pics tonight. still so so thanks for help.

 

[Martijn]

How do you know your rocks contain gold and silver? Sounds like you had it assayed allready. Or is it from a known mine?
Edited to say: i did not read your post completely. you have a mine, so you're looking for ways to extract pm's from the ore, right?

 

[Mostafa nezhad hasan]

ok everybody
thanks for your great answers, @Martijn was absolutly right, some iron powder from my jaw crusher and my ball mill exist that thy persist to exist in smelting procedure, in other word gold cement after dissolving.
thanks a lot.

 

[Martijn]

A magnet should take care of that. Put it in a bag to get the iron out. Check with a loupe if any gold is left in the magnetic portion.

 

[Martijn]

I mean put the magnet in a bag or to catch the magnetic parst.
Pull it out to release the collected iron from your panned concentrates. Then redo the magnetic portion by spreading it out.
For small batches obviously.