Many Au/Pt/Pt precipitate failures over and over

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ZiegenSauger

Well-known member
Joined
May 18, 2020
Messages
73
Greetings!

I have been "watching" in silent mode since I joined for learning purposes. Over the last year, I have been studding formal sources, browsing the web, watching videos and buying tools, chemicals, scrap, and so forth.

First I started to work with base metals to train melting, pouring. Then I moved to Silver until I was able to pour my first bar (now I have accumulated slightly under 1Kg of cement silver, in "cleaning" process right now).

Over the last month, disaster after disaster: All my (gold, platinum, palladium) precipitates failed.

In summary, I have one back Stannous positive for Gold, one batch Stannous positive for Palladium and possible traces of Platinum, one batch Pl with possible traces of Pd.

For all this, in separate time frames and processes, I cleaned base metals with HNO3, dissolved Gold foils in Acqua Regia, dennoxed, reduced to syrup. Failure one, two and three. Now it is in liquid form since I cannot understand how many wrong things I am doing.

For Pd and Pt in summary I had almost a pound of Silver/PGM that I processed somewhat similar to above.

I dennoxed using 2 different methods, the continued evaporation 2x. I use SMB for Gold precipitation and for PGM, Nh4Cl, DMG, NaClO3 and NH4Cl, used in different situations. During one of the disasters (2 Gold disasters, one of them I lost equivalent to 25% to the syrup Gold) and a handful of PGM disasters (I lost under 5% of total combined syrup) I dropped the Pt batch and the Pd with Aluminium, and managed to obtain the powder. However after Acqua Regia, it is all in liquid form again. I added Sodium Chlorade to five small test tubes. All of them reacted and the liquid became crystal yellow (about 24hrs and no precipitate but chlorine gases still being released).

Is there any information I need to add? Any clue for a dumb newbie who is certainly repeating the very same stupid mistake over and over?

Thnx in advance (in desperate mode)

Regards
 
Hello,
I think you did not denoxx correctly or at least you did not remove all the excess nitric acid, this certainly makes the precipitation process a total failure.
Second option is that your solution is not concentrated enough. if so, try to concentrate the solution by evaporation then retry your precipitation.
Usually I don’t use aqua regia to dissolve my metals for further refining because I hate denoxxing and if denoxxing did not go well nothing will work. So I suggest you cement, then dissolve your metals with HCl/H2O2( it doesn’t need denoxxing) then try to precipitate your metals.


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Thank you so so much @Inter Refiner, really appreciate your advice.

Let me try it now: so I am going to radically syrup the beakers - I have five in liquid format. And you are right. After first failure of each batch, I syrup'ed to the point where the precipitation chemicals were crystallized at the bottom but the liquid was not really that concentrated.

I think I will start a new batch, I have a couple of ounces of Silver/PGM.

One of my first failures was with HCl/H2O2, so I got traumatized. Now I will try again, first dissolving in HNO3 and then refining with HCl/H2O2 as you said. With this clean slate I will have a better sense of the specific mistake with this process (again, which was my very first for the upper metals).

THANK YOU VERY MUCH INDEED!!!!!!!!
 
UPDATE 2:

(1) I had already one small batch of PGM filters for the times I boiled and filtered the crystallized precipitation chemicals I spent. I got it in 100mL HCL and incremented by 0.5mL Nitric until brown fume was minimal. Waited to boil some more, added 50mL HCL and I am filtering now. Next I will syrup again as far as I can go.

(2) I have now a 1000mL beaker full of PGM (traces of gold) dissolved liquid on slow heat. Also, on the other heat source, I have about 300mL of dissolved Platinum (apparently traces of Pd) on slow boil too.

(3) I left for a week 4 Tupperware worth of filter paper with filtered PGM precipitate crystals with a bit of HCL and water. Now I am filtering this large batch. I will get slightly under 1L (assumption) of this dirty liquid and put it to slow heat later. I am squeezing these (almost clean) filters to a 500mL flask for later burn.

(4) I have other 4 (almost clean) small Tupperwares from first filtration. I will combine with this flask to later burn and proceed. There are some 3 or 4 dark brick red filters (marble sized) I will most likely separate and precipitate with whatever else I might accumulate with perceived more materia.

That's all for now folks.

@Inter Refiner, the beer is on me. When first successful drop happen, the 6-pack is on me :D
 
UPDATE 3:

Building my work journals to help learning!

Just found out why my HCl/H2O2 tentatives never worked: my H2O2 bottles are all 3% ...

I am being able to revise everything.

Great!!
 
ZiegenSauger said:
UPDATE 2:
@Inter Refiner, the beer is on me. When first successful drop happen, the 6-pack is on me :D

Hahahaha, waiting for that


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ZiegenSauger said:
UPDATE 3:

Building my work journals to help learning!

Just found out why my HCl/H2O2 tentatives never worked: my H2O2 bottles are all 3% ...

I am being able to revise everything.

Great!!
Get at least 12% H2O2


Sent from my iPhone using Tapatalk
 
UPDATE 4:

First off, @ Inter Refiner, I owe you a 12-pack. Serious man, let me know how can I send you.

Because of all I told before, I am working with 5 batches: four of them come from a 2-pound pack of high end Monster Cable connectors from the early nineties. They were part of my audio system and then I stored in a large bin while moving all these years. They were gold filled, hard to say they were not pure gold, and some silver but a lot of PGM as it came out. I could never imagine that (a couple of dozen did not have the gold layer, but they were almost solid palladium and Cu).

The fifth batch is from a watch band that would not dissolve with anything. I have been tucking it in all those processes but they kept pristine. After talking to InterR I decided to separate it and cook it alone in Acqua Regia ... comes out it was WHITE GOLD ... ouch.

1) Batch one, legacy. Mostly Pd dissolved in 900mL solution with Au and Pt. Evaporating now. Note that for batches 1, 2 and 3 the reality is the same. I am on 3rd-4th evaporation. All sample tests I did were unsuccessful. Apparently because of the so many times I added so much of different chemicals that now nothing works. I am evaporating to minimum volume possible last time. If does not work, I will precipitate with Al or Zn (for the Pd batch I did 3 sample tests with Al and recovered around 2 grams of black Pd).
2) Batch 2, legacy. Mostly dissolved Pt in 800Ml solution with Au and Pd.
3) Batch three: legacy. Mostly PGM dissolved in 500mL solution with gold.
4) Batch four, legacy. pure gold solution being recovered from crystallized chemicals. Shows traces of PGM too. I have not decided what to do. For now I am separating the dissolved metal from the crystals patiently and will eventually evaporate. From there I will see. Most like will drop with pure Cu.
5) Batch five, new. Gold, Gold, Gold from a white Gold watch band. Evaporating. Already separated a test sample and tried SMB, IT WORKED LIKE FREAKING MAGIC. Already washed with HCl and have the most beautiful gram of brown gold powder. My eternal love hehehe

Thank you guys. Patience has been the added spice to @ Inter Refiner advice.

I am excited now

@ Inter Refiner, I am serious about the 12-pack
 
ZiegenSauger said:
UPDATE 4:

First off, @ Inter Refiner, I owe you a 12-pack. Serious man, let me know how can I send you.

Because of all I told before, I am working with 5 batches: four of them come from a 2-pound pack of high end Monster Cable connectors from the early nineties. They were part of my audio system and then I stored in a large bin while moving all these years. They were gold filled, hard to say they were not pure gold, and some silver but a lot of PGM as it came out. I could never imagine that (a couple of dozen did not have the gold layer, but they were almost solid palladium and Cu).

The fifth batch is from a watch band that would not dissolve with anything. I have been tucking it in all those processes but they kept pristine. After talking to InterR I decided to separate it and cook it alone in Acqua Regia ... comes out it was WHITE GOLD ... ouch.

1) Batch one, legacy. Mostly Pd dissolved in 900mL solution with Au and Pt. Evaporating now. Note that for batches 1, 2 and 3 the reality is the same. I am on 3rd-4th evaporation. All sample tests I did were unsuccessful. Apparently because of the so many times I added so much of different chemicals that now nothing works. I am evaporating to minimum volume possible last time. If does not work, I will precipitate with Al or Zn (for the Pd batch I did 3 sample tests with Al and recovered around 2 grams of black Pd).
2) Batch 2, legacy. Mostly dissolved Pt in 800Ml solution with Au and Pd.
3) Batch three: legacy. Mostly PGM dissolved in 500mL solution with gold.
4) Batch four, legacy. pure gold solution being recovered from crystallized chemicals. Shows traces of PGM too. I have not decided what to do. For now I am separating the dissolved metal from the crystals patiently and will eventually evaporate. From there I will see. Most like will drop with pure Cu.
5) Batch five, new. Gold, Gold, Gold from a white Gold watch band. Evaporating. Already separated a test sample and tried SMB, IT WORKED LIKE FREAKING MAGIC. Already washed with HCl and have the most beautiful gram of brown gold powder. My eternal love hehehe

Thank you guys. Patience has been the added spice to @ Inter Refiner advice.

I am excited now

@ Inter Refiner, I am serious about the 12-pack
I am very glad that things worked good with you, spreading knowledge is my 12 pack, thank you bro[emoji16]


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DMG works great for precipitation of Palladium.

I denoxx with sulfamic acid crystals.

Be safe working with PGM salts, they are very toxic.

Steve
 
UPDATE 5:

You are AWESOME guys!! I've been insanely researching the forum, answers to everything. This is really fantastic.

Well, I gave up. :eek:

Many accumulated mistakes and they are being transferred over from one mistake to the other. Not to mention contamination, a lot of.

(1) I have 2L beaker full of slightly humid cement Silver. It seems I have graduated already. Today or tomorrow I will pour first samples (I have an electric furnace).
(2) All Acqua Regia solutions are being filtered with considerable amount of left over dark black mud. Will submerge into Nitric bath next to reset so that I am sure at least Pl and Au are free.
(3) All left over diluted solutions from washing up mistakes are being evaporated. Interesting brick red powder being dropped and filtered off. Will submerge in Acqua Regia next.
(4) 2lb worth of dirt solids from initial mistakes, collected at the bottom of different buckets. Strained off about 50% and bathed in Nitric bath, filtered. Very thick concentrated thick sky blue concentrated solution left. Added pristine new Cu stripes. The solution became a vivid thick brick blood red liquid (different than the other) and a lot of vivid strong red powder. There might be Silver contamination. These "Pd" powders I am just setting aside for now.
(5) PGM filters, residues, crystals are all in Nitric bath. Will split resulting solution in two: filtered solids will go to Acqua Regia together with item (3); liquid part will be reused for any needed Nitric bath. Resulting solid free left over solution will be evaporated for Pd and potential Ag recover.

THE BIG QUESTION I cannot find answer: everything cementing with Cu (basically everything that came off Nitric baths) is yielding a lot of red powder. Solution is still redish black, seems too concentrated. Can I add distilled water so that remaining Cu can react and go into solution? Should I just wait more?

THANK YOU folks!!!

PH
 
UPDATE 6:

Reviewing the thread, I will try to refine the post Acqua Regia and post evaporation solids with HCl and 12% H2O2.

Since the only time I did it I made several mistakes, since for now I have 1/2 lb of the reddish powder plus the deep black powder, I will split apart a small percentage to probe it.

Cheers!

PH
 
Considering all the failures you may find that collecting a small sample of your suspect powders in a plastic baggie and getting an xrf on them could save you a lot of guessing.

I routinely get xrfs of unknowns to help keep me on the right path. Knowing what is in an unknown mixture goes a very long way to figuring out your mistakes.

Steve
 
Thank you Steve, that is a great suggestion, much appreciated indeed!!

I actually have a rack of essay tubes from University. I use them for probing. In a nutshell, 4 tubes with 4 different methods (SBM, DMG, HCl, Sodium Hypochlorite, and so forth, depending on the case)!

BIG THANK YOU

PH
 
UPDATE 7: Life After Reset

This is a biggie turn around of events :shock:

Reset pack A: Evaporation of Au, Pt, Pd failed solution with excess everything (SMB, DMG, etc). Already processed 2L.
  • approx. 250g of reddish petroleum black powder left, stored for later processing
  • currently processing one @l beaker from same source and other 1.5L of the last failed batch

Reset pack B: Approx. 2L of Contaminated Pd solution being processed with pure Cu.
  • Already collected (by rigorous filtering) 100G of blood brick red powder, stored for future processing
  • Remaining solution is back with new Cu stripes. The reaction now is vigorous and, finally, liquid is changing color
  • My concern is related to a potential difference between the two drops. The first very concentrated solution took a long to accumulate that amount of powder. After filtering, the diluted solution is moving fast. Guess whether or not I had one PGM drop first and now it is another

Reset pack C: Approx. 2.5L of Nitric washed solids (failed Gold refining), composed of some filter paper, and a lot of SMB and it's cousins. Will move it next to evaporation. Over 1Kg of filter remains and other trash is stored for later burning.

Last legacy pack: Around 150g of Pd brick red powder stored for later processing. The remaining 1L liquid is slightly diluted petroleum color. Will test for Pd in solution. Trying to decide between DMG or Cu/Zn. Will evaporate first.

Silver: everything is rock'n'nrollin'!!!! Already have approx. 2L of cement silver. Will pour my second bar in a zip.

That's all folks!

PH
 
UPDATE 8: Well, well, well!!! :D

Fifteen minutes after this post, I received the delivery of a 2.67 in. x 50 ft. Zinc Strip!! Immediately cut small strips and added to packs C and legacy. Well, well, well, a lot of movement going on.

For the legacy, one concern: I have suspicious of copper. Will keep it in its own.

Cheers.

Excited cheers.

Next step will be to start 100g of gold filled pins to check my learning. I have to make the drop with chemicals work.

PH
 
UPDATE 9:

Hunky dory!

Anti-climatic for now, like fishing salmon upstream during mating season. Zn and Cu worked as expected.

Hoarding 3 "buckets": Black Mud, Pd mud, PGM mud

Stopped everything else, no new batches until the mess is fixed

Not sure what to do next: HNO3 or Acqua Regia for each of these muds? Would it be waste of time be concerned with impurities at this point?

By the way, Ag is doing great, thank you!! first pour was successful, helped me big time to assess volume of cement compared to crucible, compared to final result. Now I am drying Ag mud, actually beautiful Ag mud to keep on melting. With sound expectation that mud volume is far from bar expected weight.

Cheers
 
This is a long thread without any solid information or organization.

- No pictures, not of the starting material, testing or solutions.
- No testing mentioned. You do have stannous and know how to use it?
- No tally of how much material of different kind has been processed.
- Only a vague description of starting material.

And as a result only vague comments offered as help.

You mention monster connectors, last time I checked there are no connectors on monsters (Frankenstein's monster excluded), only teeth. ;-)
Gold filled connectors, never heard of it. Solid gold connectors, that doesn't exist. Larger connectors might have thicker plating to withstand rougher handling but the bigger size means that the bulk material increases faster than plating thickness. So large connectors usually mean lower yield per kg.

How do you know that the watch band was white gold? What testing did you do? What was the weight?

Sounds like a classical mess, or rather three of them. No one can follow what you have done to the various batches so no one can give you solid advice.

You need to shape up, clearly describe what you started with, what you have done in each case and what tests have been done. To me it seems like you are trying to chase metals that are not there.

Göran
 
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