Defeating the Grey Goop

[au-artifax]

Au-artifax - 2, Grey Goop - 0

Well this snow in the northeast has given me enough time to ponder and plan my attack against the grey goop that likes to strike while trying to recover PMs from gold filled jewelry and e-scrap.

As I illuded to in another thread I had declared war against the unknown grey goop.

I had enough time on my hands to experiment and had success in two ways so I thought I would pass it on as a potential method others can use, and also open the door for any concerns I did not think of as far as additional thoughts and jeers perhaps for unforeseen hazards.

First attack:

After watching the grey goop multiply the more I tried to rid base metals from my recovery batch using nitric acid, and then trying to use water, HCl, h2so4, ammonia, more hno3, heated and cooled to various degrees, the thought occurred to me that possibly I didn't necessarily want to actually lose the grey goop; that maybe this grey goop was PMs that decided to go and get oxidized to a state where it became insoluable.
So I did a couple of rinses with distilled water after filtering the whole mess, put the material all together in a flask with 400ml distilled water, added an equal amount of corn syrup, boiled it for twenty minutes, let it cool, then filter and rinsed it again. At this point though the volume of grey goop had diminished by about 50%, which tells me that some of the material that was previously oxidized became soluable in the water after the oxygen molecules were taken on by the glucose.
And as far as there being any danger of nitrates combining with the glucose, I checked on that first and any reaction between the two would not have produced anything hazardous.

BUT, there was still this grey goop...insoluble before...but now?

So round two, after seeing if the rest would go away by dissolving in more DW, I tried a couple different things to no availe. So I thought if half of it went away when I went after the oxides, maybe the other jalf would go away if I went after any chlorides....and it worked...but witha surprise finish! What DID work though was this:
I again filtered and rinsed finally ending up with the batch in the same flask with again 400ml DL. To this I added 200 ml of ammonium hydroxide solution. Of course this resulted in a complete unfilterable (the grey suspension passed right through the filter) which I expected from dealing with ammonia washes. But it was what I had learned here on the forum that had me do the rest. I heated the solution just to advance the reaction that that ammonium hydroxide was doing, let it cool overnight, then I did a complete reversal of the pH and added 500ml of HCl (please don't ask me molarity questions...I just started learning about normality and molarity).
Upon heating this time though, the suspension cleared up and the grey goop was G. O. N. E. The solution was still a little cloudy but I noticed that what was clouding the solution partially was fine dust-like flakes of metal that was settling.
Now here's the surprise...,
I hung a piece of copper in the flask and right away it got all grey and fuzzy and was cementing like crazy. Seems there were values in the grey goop.

As of yet I think I should filter, rinse (remove all the chloride), then hit the whole batch again with nitric (not knowing if there is metallic silver or palladium). I kinda expect both silver and palladium, as the stuff that came off the copper seemed to look different than plain silver I had cemented before.

That's where I am with this. Comments and advice is of course always welcome. I learn so much from everyone here and everyone is so generous with what they know. Thanks, and hopefully I will be able to pull my own weight here someday as you all do.
Matt
Au-artifax

 

[au-artifax]

Update:

I filtered everything and all my gold is sitting in a flask, (covered with grey "pricipitated" metal) bathed in plain DW waiting to be prcessed. Again, I wanted to wait for input before adding the nitric to isolate the gold. And the solution that filtered clear from my last procedure has a piece of copper hanging in it and is still dropping metals out of the solution like crazy.

 

[Rick_J]

Hello, Matt.
Your "grey goop" might be what old time Arizona miners referred to a "ghost gold". Ghost gold reputedly would form as a by product of processing cyanide leaches. Your comment that they are insoluble concurs with reports of ghost gold being much less reactive than the crystalline metal. Rumor also has it that it does consist of Au and/or PGE's, but not oxidized. I have talked about this with a chemistry PhD who is expert in metal extraction processes. He has worked with ghost gold in the past, has refined them to high purity and is absolutely convinced that it is an allotropic form of Au and/or PGE's. It is interesting and noteworthy that, if this is indeed ghost gold, you have been able to drop it back into metal. It is supposedly very difficult to do so. Last week I sent inquiries to the Library of Congress and the Arizona Dept of Mines requesting they search their archives for more information on this substance. If I receive anything worthwhile back, I will post it on this thread.
Regards, Rick.

 

[au-artifax]

Hello, Matt.
Your "grey goop" might be what old time Arizona miners referred to a "ghost gold". Ghost gold reputedly would form as a by product of processing cyanide leaches. Your comment that they are insoluble concurs with reports of ghost gold being much less reactive than the crystalline metal. Rumor also has it that it does consist of Au and/or PGE's, but not oxidized. I have talked about this with a chemistry PhD who is expert in metal extraction processes. He has worked with ghost gold in the past, has refined them to high purity and is absolutely convinced that it is an allotropic form of Au and/or PGE's. It is interesting and noteworthy that, if this is indeed ghost gold, you have been able to drop it back into metal. It is supposedly very difficult to do so. Last week I sent inquiries to the Library of Congress and the Arizona Dept of Mines requesting they search their archives for more information on this substance. If I receive anything worthwhile back, I will post it on this thread.
Regards, Rick.

Thank you Rick
I am attempting to attach pics to the forum but do not know how to quite yet. Give me a half hour and I will have it figured out. In the mean time though let me try to describe the metals that cemented out of the once grey goop/now solution.
The metals that cemented out of the solution has taken on two separate characteristics; upon jiggling the container the sediment separated into the familiar fine silver and also a second heavier patch of large black clumps that appeared like largely ground pepper. I could not get the camera to capture the sheen from the specs in the paper but they reflected yellow when I shone my flashlight on them. Anyways, these (pepper specs) were definitely heavier than the silver and were last to leave the settling flask as I filtered the substances. I had to use my spray bottle on solid stream to get them to wash out into the filter completely.

anyways, let me have a go at posting the pics, and thank you for the neat info. I will do some research also into your suggestion and we will see what happens. I should actually keep the cemented metals separate, dissolve them in AR (the grey goop I've encountered in the past had always been nonreactive in AR or AP), sncl test them, and if positive for anything try standard precipitation depending g on what the test shows. I will make sure I have a fresh batch of sncl ready. It may take a few days because of my day job of course.

 

[au-artifax]

This is how the whole filter looked with all the cemented product together.





These are the pepper-speck clumps that cemented out of the solution.


There! I got the pic posting thing down.

Thanks for looking.

I am so tempted to just get lazy now and throw it back into the original batch. Curiosity though says no, me getting tired says yes..,grrr....patience Matt....patience!

PS: after the filtering was complete the bottom of the filter paper was loaded with the black pepper clumps. So there was more than just a little bit.I would say volume-wise there was only about 75-100 cc of the grey goop that finally went into solution. Half of the cemented substance went into the main batch I was processing before I decided to isolate the solution and continue cementing in a different container.

 

[au-artifax]

PPS:

Like my funnel setup? It shows 0% of corrosion after two years of use. I cut plastic rain-gutter screen and inserted it in the funnel after heat-shaping it. It works awesome and the whole filter paper gets used, not just the tip at the bottom of the funnel.

 

[Geo]

Are you working with electronics or concentrates? If you are working with electronics, I would say it's tin oxide. Any electrical connector that holds tension (springs, slot connector pins) are more than likely made of phosphor bronze. Bronze is an alloy of copper and tin while brass is copper and zinc. digesting these types of materials in either hcl (AP) or nitric acid will create tin oxide. AP will create tin oxide through two phases. tin metal to stannous chloride to tin oxide. nitric acid creates hydrated tin oxide in a single phase. tin metal to metastannic acid.

 

[Loito]

Good morning,

au-artifax can you please add a picture from your starting material? I don´t know what you mean with "grey goop"? Thanks

 

[au-artifax]

Geo, in this case I was working with gold filled jewelry. Also, note that the metals in question cemented out on copper, so I doubt there would be tin cementing out.

As far as the grey goop, I don't have a pic of it. It looks just like any pic I've seen on this forum with a mystery grey sediment that wouldn't dissolve for others. I didn't bother taking a pic also because I noticed this material has been produced by quite a few members without anyone really having any success changing it's state.

I can and will recreate the whole process next time I do a batch recovery on gold filled jewelry or e-waist recovery. I will make sure I take pics. Note that this grey goop did not show any reaction to sncl testing, suggesting there possibly was allotropic metals in the GG.

 

[Geo]

Gold filled scrap can contain a substantial amount of tin.

 

[Palladium]

Are those coffee filters your using and how long did you leave it in nitric the first time?

 

[au-artifax]

To reply to geo and palladium:

Geo, thank you for your input. Although I stressed using nitric to remove base metals, I usually hit my batches of mixed raw materials first with HCl to go after tin, ferrous metals, and any stainless that sneaks by. As always a thurough boiling rinse in DW comes before switching over to nitric so I can remove stuff like copper, silver and palladium. (I went after the palladium but am pretty sure any there got locked up into the grey goop). In fact I am pretty sure there was palladium in the batch, and it would jave showed up when adding the HCl to the Ammonia given enough time.

Any tin that may have created some of the grey goop, if there was any, went away after the glucose step and became soluable. As for before, being very very familiar with the yellow filter-clogging tin, none was produced and it would have clogged my filters the first time I filtered the whole batch coming out of the nitric. Note also there is no yellow at the top edges of the filter which is where the tin usually shows up first.
To risk using the statement too much, yes, "there's more than one way to skin a cat" ( or peel an apple... for the ASPCA buffs), so If you had or have a solution to converting or dealing with this common grey sediment I am all ears.

Palladium, yes they are coffee filters. I prefer them because they are quick and inexpensive, even though I have to re-run some things through more than once to capture all the solids. I know they can cloud solutions when filtering solutions with nitric, but never have I seen them produce grey mud or "goop" as I call it. The goop started before the filtering processes.

As far as the treatment with nitric itself, I used 50% diluted again by 50% distilled water, and heated to 80-85°C until the solution would dissolve no more. Each batch of spent solution produced a measurable amount of AgCl that I am stockpiling. Of course the last treatment produced the least amount of AgCl, and inversely the most grey goop/slime/mud.

I hope I answered all your questions.

 

[Palladium]

Let me say what i see wrong here is the best way to explain it i guess. Gold filled should be run in a 50-50 nitric treatment first to remove anything that will dissolve. The only thing that should really be left after that process is stainless, aluminum, and gold. Wash that with water and then on to ar. Any aluminum will react vigorously when you add the hcl and will let you know that you need to do a better job of segregating. Any stainless will dissolve in ar slowly. This will be controlled by how much nitric you add to the ar solution. High nitric will take longer to dissolve the stainless. You want the solution of ar to consume all the nitric early on before all the gold dissolves causing a shortage of nitric and resulting in a solution high in chlorides. The stainless will start to dissolve because without an excess oxidizer the metals will start to cement out causing the stainless to dissolve in the process. You add a little nitric and repeat the process over and over in small steps like that until the stainless dissolves. If you leave gold filled in nitric and heat it to long what happens is after the base metal dissolves that the gold layer is attached to it starts to dissolve the gold layer which is karated. This break down in the foil thickness results in gold that is very finely divided and will turn the same purple as silver chloride but is gold in a metallic state and not a salt. Theirs a thin line between what is enough time in the nitric and what is not. If you heat it slowly over a longer period of time you will have less processing issues than if you tried to do it to quick. I use medium heat and keep in just below a simmer boil for a 24 hour period. This will eliminate any silver chlorides from showing up in the ar process and causing problems also. Second thing is your filters. Coffee filters run anywhere from 5 microns up to 25 microns and are not uniform in how they are made so one side off the same filter could be 5 microns and the other could be 25 micron. That purple gold will travel through a 5 micron filter easily and you need to either go down to a 1 micron filter or filter through a 5 micron until it packs the filter and starts filtering the fine particulate out. I use bounty paper towels and a colander for noodles to filter the foils once they come out of nitric. It will catch the fine gold as well as the foils. Incinerate that and then process with straight ar.

 

[au-artifax]

Well I use HCl before nitric. HCl is cheaper, can even catch and dissolve stainless, and it doesn't leave clingy aluminum chloride residue "iffin Ize done midst sum" (in my best "dummer than lint phraseology).

I am not even at the first refine yet so of course I am not going to toss in the AR yet. I am still collecting everything. Why dissolve base metals in nitric that you can dissolve in cheap and much more readily available HCl? Note in the following pics the layers of PMs in my flask... the top two layers came mostly out of the cementation of the reprocessed grey goop. I will be doing another nitric treatment before going after the gold in the bottom.

Also is a pic just taken of more PMs that cemented over night from the solution. There were also some recognizable minute crystalized gold particles mixed in.

As for the filters, I guess me and hundreds of other folks just rely on our senses at whatever moment we are living in and hope not to lose too much value.

After all this thread/topic was started with the objective to pass on a way to reclaim some values unseen and passed by in some cases. Now let's hear it from those out there that never lose or never lost values in their processing.

IMHO


Well here are the pics....

Day two and more cemented product testing + for gold and a little palladium. Yesterday's had some silver too.




This pic shows what I have collected from this batch in a 2lt flask. Notice the layering.





This pic shows the clear layering effect. Yes they are all PMs and the solution clear where once it had a thick layer of grey gooh and cloudy unfilterable solution. Whatever might have gotten through the filter was either reclaimed or just plain worthless.

 

[Westerngs]

I tend to agree with Palladium that you had tin oxide and silver chloride which trapped some gold in it upon filtering.

First off, no amount of rinsing will remove traces of HCl, the only way to do that is by incinerating the material prior to the nitric treatment, so you created some silver chloride. Secondly, I know from first hand experience, that tin present in material being dissolved in nitric will cause some gold to break up into very small particles which will then filter out with the tin oxide. The tin oxide then has to be treated for gold recovery.

Secondly, I believe Rick_J may have been talking with good old Dr. Poe. As an assayer, I have run across many claims of "this ore will cannot be assayed correctly via conventional fire assay methods and the values can only be correctly assayed via our own special method". There is no such thing, and there is no such thing as "ghost gold", unless you consider gold lost in filtration "ghost gold". This has been proven many times and can be found in accepted literature and assay manuals.

I would recommend that if you continue to treat the material with HCl first, to incinerate the material prior to continuing with nitric acid treatments. I believe the HCl first step to be a mistake however, unless there is some sort of tin bearing metal brazed onto the gold filled material. Most tin that is contained in gold filled is there as an alloy with the gold filled and would not be attacked by the HCl treatment.

 

[au-artifax]

I will gladly accept any shipments of grey goop the forum members come across and cannot convert to values. You guys seem to be missing the point. I am suggesting a way to reclaim values, not how to be perfect supermen and never end up with a botched batch.

Nobody has even discussed the recovery, just tin tin tin. Oh... And filters. For example, I discussed the temp I used with nitric 75-80°C, (light below boil simmer) then palladium throws the same thing in as if I never said I did the same thing. Did I really ruffle that many feathers coming up with a viable method for recovering PMs that people were losing? What gives? Also in the same breath I hear HCl won't touch tin alloyed in the gold, then that it WILL and leave your gold too fine to filter.

AgCl? The ammonia didn't dissolve any of the GG. SnO2? The glucose would have sucked up the weakly bonded oxygen from the tin right away and left tin behind for the HCl to go after when I added HCl to the ammonium hydroxide wash.

And if it matters, yes I DO believe gold may take on a different crystalline structure in certain environmental conditions whether natural or man made. Carbon for example, how many different allotropes does it have?

Isn't this chemistry thing all based on things we cannot see? So who do you know that can prove there is no such thing as different structures of PM crystals? Is there nothing left to discover or has mankind won the game and learned all there is to know?

C'mon guys!
Is there a scientist in the house? And by "scientist" I mean someone hell-bent on "discovery".

 

[Palladium]

Continue with doing things outside of the procedures that work and you will continue to have problems. Hcl first is your problem. What i just gave you above is the road map to gold filled. With the "god knows how much" gold filled i've ran it's not like i haven't figured it out. But hey! It's not my gold.

 

[Westerngs]

Yes, we just have no interest in re-inventing the wheel.

 

[Palladium]

For example, I discussed the temp I used with nitric 75-80°C, (light below boil simmer) then palladium throws the same thing in as if I never said I did the same thing.

God forbid i explain it so someone who is not you will come along later and understand the value in it and not mess up their gold and refuse to listen to unsound logic. How dare i !!!! My bad! Let me leave you with this thread.

 

[au-artifax]

Yes, we just have no interest in re-inventing the wheel.

The wheel started off being made of stone...
Then reinvented using wood...
Then reinvented with metal hoops...
Then reinvented using natural rubber on wood spooked rims...
Then reinvented with natural rubber on metal rims...
Then reinvented with tubes...
Then reinvented with synthetic rubber...
Then reinvented to different types of synthetic rubbers...
Then reinvented to nylon....and all different kinds of wheels....and the quest to reinvent the wheel continues to this day.

Who keeps reinventing things? Innovators, engineers and scientists! I was hoping to have this topic advance to other fresh ideas, but nope. I am disappointed, and would never presume I was an expert because I knew Hoke better than the next guy. That's not being good, that's just being a copy-cat. What you know should be a starting point, not an end.