Gold not dropping - why is it my sulfamic?

[Ellias]

Hello folks.

I keep running into the same issue over and over again and for some reason i keep getting the white residue and absolutely demolish my gold recovery (despire clearly seeing gold and testing gold). I documented everything this time and taken pictures

1. I have incinerated 10 CPU pinned chips, and 100 grams of IC chips. And 3 BGAs

2. Grind with mortar and pestle

3. Reburn

4. Wash with hot water until no more carbon

5.2x boiling HCL bath

6. Wash with water 9x

7. 2x nitric acid bath

8. Wash 9x hot water until clear

9 Poorman aqua regia with 125 ml hcl, 28g sodium nitrate, 68 ml water (tap)

10. Tested gold (positive) spread out between 5 hrs apart

11. At 80c added pinches of Sulfamic acid until no reaction (3 pinches)

12. Waited 5 hours

13. Filter solution

14. Tested gold (color became lighter but still positive

15. Added stump out to 50ml tap water and mix in to AR.

15. Waited 7 hours and i get this cloudy non brown color. What is going on here. Why am i not able to get any return. Im so perplexed.

 

[Ellias]

Hello folks.

I keep running into the same issue over and over again and for some reason i keep getting the white residue and absolutely demolish my gold recovery (despire clearly seeing gold and testing gold). I documented everything this time and taken pictures

1. I have incinerated 10 CPU pinned chips, and 100 grams of IC chips. And 3 BGAs

2. Grind with mortar and pestle

3. Reburn

4. Wash with hot water until no more carbon

5.2x boiling HCL bath

6. Wash with water 9x

7. 2x nitric acid bath

8. Wash 9x hot water until clear

9 Poorman aqua regia with 125 ml hcl, 28g sodium nitrate, 68 ml water (tap)

10. Tested gold (positive) spread out between 5 hrs apart

11. At 80c added pinches of Sulfamic acid until no reaction (3 pinches)

12. Waited 5 hours

13. Filter solution

14. Tested gold (color became lighter but still positive

15. Added stump out to 50ml tap water and mix in to AR.

15. Waited 7 hours and i get this cloudy non brown color. What is going on here. Why am i not able to get any return. Im so perplexed.

I have added my end result now.

What am i doing wrong here.

 

[BGDOCK]

Chemists of the group can I take a guess, Could the white reside be Salt ?
NaNO3 + HCl → NaCl + HNO3
Is your tap water chlorinated ?
Shouldn’t the solution be diluted ?
How about using ferrous sulphate ?
Edited for clarity

 

[Ellias]

Chemists of the group can I take a guess, Could the white reside be Salt ?
NaNO3 + HCl → NaCl + HNO3
Is your tap water chlorinated ?
Shouldn’t the solution be diluted ?
How about using ferrous sulphate ?
Edited for clarity

Added water to clean but im still getting the white build up. Where has my gold gone is the question. Every step with stanneous seems to be okay. Im thinking of completely going away with the sulfamic acid to see if anyrhing would be different. Here is the picture of the white substance dried.

It turned dark grey.

 

[BGDOCK]

I would not give up the Sulfamic Acid
It can do 2 things.
De-Nox HNO3 and precipitate out lead.
“When in doubt, cement it out “ with copper : tubing, pipe fittings or wire and an air bubbler.
After cementation recover your values and try again .
I prefer dropping gold w/ iron sulphate it seems to drop cleaner gold .

 

[BGDOCK]

Could be lead or silver chloride hard to say
lead chloride is soluble in hot water , silver chloride isn’t and if it goes from white to grey ,in sunlight I told lean towards silver chloride


*chapter 8 page 77 (bottom of page) C.M. Hoke

 

[Shark]

Heavy copper has the ability under the right conditions to reform into the oxidizer in AR. It is possibly the one case where the use of both sulfamic and urea could be the answer. But again, did you heat the AR to the point of killing the HCl as well as the nitric? Did you check the PH? This is another example of where I would use copperas as a first round precipitant. But even then having enough active HCl may be needed and is why I often mix copperas up with some HCl before using it.

 

[Ellias]

Heavy copper has the ability under the right conditions to reform into the oxidizer in AR. It is possibly the one case where the use of both sulfamic and urea could be the answer. But again, did you heat the AR to the point of killing the HCl as well as the nitric? Did you check the PH? This is another example of where I would use copperas as a first round precipitant. But even then having enough active HCl may be needed and is why I often mix copperas up with some HCl before using it.

I did heat it for a while 2-3 hrs (not boiling) So of I'm understanding correctly, I need free hcl to drop with smb?

 

[Yggdrasil]

Added water to clean but im still getting the white build up. Where has my gold gone is the question. Every step with stanneous seems to be okay. Im thinking of completely going away with the sulfamic acid to see if anyrhing would be different. Here is the picture of the white substance dried.

It turned dark grey.

What does the content list of the Stump out say?
SMB or Nitrate?
There are two kinds.
What is your pH before adding the SMB?

 

[anachronism]

Can I ask why you're washing in Nitric yet then using Poor man's Nitric to AR?

 

[Yggdrasil]

Can I ask why you're washing in Nitric yet then using Poor man's Nitric to AR?

Good catch, I missed that part.

 

[Ellias]

Can I ask why you're washing in Nitric yet then using Poor man's Nitric to AR?

I am not using poor mans nitric. The ratio i used was making poor mans AR.

Its very hard for me to get Nitric Acid so after a nitric acid wash, i try to use sodium nitrate and HCl to make poormans AR for the gold recovery bit.

 

[Ellias]

What does the content list of the Stump out say?
SMB or Nitrate?
There are two kinds.
What is your pH before adding the SMB?

May i ask what is the ideal pH before adding SMB? And this is defnitely SMB as i made a gold button with this before.

If my pH is too high? Can i simply add something? What if it is too low (is there such a thing)?

 

[Yggdrasil]

May i ask what is the ideal pH before adding SMB? And this is d3finitely SMB as i made a gold button with this before.

There is no ideal so to speak, but it has to be acidic so the SMB produce SO₂ which is the active ingredient.
So Usually lower than 4 but even better in the 2-1 range.

 

[Yggdrasil]

I am not using poor mans nitric. The ratio i used was making poor mans AR.

Its very hard for me to get Nitric Acid so after a nitric acid wash, i try to use sodium nitrate and HCl to make poormans AR for the gold recovery bit.

This do not make much sense, there is no reason to wash with Nitric at all.
Every change between HCl and Nitric will dissolve some Gold.

 

[Ellias]

This do not make much sense, there is no reason to wash with Nitric at all.
Every change between HCl and Nitric will dissolve some Gold.

Even if i wash like crazy between - on the 9th H20 rinse i even left it in water for a few hours? Is the recommendation to only do HCl washes then AR?

Secondly - even with the AR i created, i was getting postive (per pictures)

 

[Yggdrasil]

Even if i wash like crazy between - on the 9th H20 rinse i even left it in water for a few hours? Is the recommendation to only do HCl washes then AR?

Secondly - even with the AR i created, i was getting postive (per pictures)

There is still Gold, but switching back and forth between HCl and Nitric is almost guaranteed to create losses.
Unless you roast the material in between.
Wash it well in HCl pour the used HCl into a container and add fresh HCl, then drip in Nitric untill all foils are dissolved.

Or even better, use Peroxide or pool Chlorine in stead if Nitric.
No risk of excess Nitric then.

Edit for spelling

 

[Yggdrasil]

Even if i wash like crazy between - on the 9th H20 rinse i even left it in water for a few hours? Is the recommendation to only do HCl washes then AR?

Secondly - even with the AR i created, i was getting postive (per pictures)

Aah, I now saw you are processing Chips.
Much better to gravity separate or smelt them, then process hydrometallurgically.

 

[Ellias]

Aah, I now saw you are processing Chips.
Much better to gravity separate or smelt them, then process hydrometallurgically.

Unfortunately smelting or hydrometal... is not an option for me.

From the recommendations, ive heard:

1. Drip nitric when making AR
2. Test pH(whay is the ideal pH for gold drop?)
3. Do i add hcl since i heard i need free HCl for SMB to work?

 

[Yggdrasil]

Unfortunately smelting or hydrometal... is not an option for me.

From the recommendations, ive heard:

1. Drip nitric when making AR
2. Test pH(whay is the ideal pH for gold drop?)
3. Do i add hcl since i heard i need free HCl for SMB to work?

This was answered in my reply!
And you are going the hydrometallurgical way.
Using acid!