Cementing made these weird crystals (and cant drop)

[1mysurveymail]

Long time no see Au chasers. I hope this message finds everyone healthy, wealthy, and happily making .999

I should have "inquarted" my carat jewellery by smelting with silver or copper down to 6 carat before trying to dissolve it in "poorman's AR." This is certainly ONE of the main problems I created for myself.

My supply of scrap has been intermittent and other pursuits have come to the fore. However recently I came upon some Carat scrap (old jewellery) that was 14-18 carat, weighing in at 30 grams. I used poorman's AR, denoxxed with a teaspoon of sulfamic acid crystals from 2 years ago (do they go bad?) and go a nice drop with SMB. Oddly there are flecks of a shiny silvery metal in the Au drop. Platinum or Palladium?

Then THIS odd color happened.



I have never seen this color solution from Carat jewellery before. A little more SMB has no effect. Maybe it is too basic, should I add HCl ? It has been a few years since I used anything other than AP on foils, and HCl and Bleach to dissolve.

After my fist successful drop, I had gently heated the solution and let it cool overnight for a second drop. I put a 3/4" copper plumbing coupler in (using fishing line). I pulled it out today and nice black powder had begun to cement, and these weird crystals too. Have a look.




This was OLD jewellery, could these crystals be Lead (Pb)?

My stannous tests did not work, my testing solution was too old because even my AuCl (gold test solution) did not register a positive.

Hope someone can explain and perhaps remind me what to do next. I have forgotten some of the tricks taught by the old dogs. I slept with a copy of Hoke under my pillow, but nothing happened. I should have stayed in a "Holiday Inn Express."

Cheers and thanks

 

[1mysurveymail]

I just made a new batch of stannous testing solution. I used 3 inches of lead-free solder in 100ml of HCl to make new stannous test solution.

Until then I will continue to cement out the Au and PGM's(?) with a copper coupling on a piece of fishing line.


Any other advice?

Could this be silver I decanted from my first run with poorman's AR? Since the original material was 14k-18k old gold jewellery. Some was definitely a silver nitrate (it turned purple/black in the sun). This next bit of spongy material came after cleaning my first drop with HCl + Bleach so I think it is silver chloride...



I separated the silver salts in a small pyrex cup. just a few ounces. Now if I can just remember how to get it back to metallic silver again?

 

[Lino1406]

Add concetrated NaOH to AgCl (after good wash), it will give you silver oxide which can be melted directly

 

[1mysurveymail]

Today I found this weird bit of material that survived digestion in HCl and bleach. The weirdness continues.



The fleck of "gold" are most likely Titanium Dioxide or Zirconium? from some junk jewelry that snuck into my run.

Thanks to "lino1406" for the tip on converting AgCl back to an oxide for direct melting! I had forgotten that trick.

 

[1mysurveymail]

Cementing Dropped Poorman's AR is eating lots of Cu

I need advice about continued cementing with copper. My solution "ate" the first 3/4" coupling down to paper thin.



I was clearly way too enthusiastic with my application of Nitrates (Spectracide Stump Remover) into my HCl. My Au was ~35g of carat jewellery 14k and 18k. I denoxxed with sulfamic acid crystals (1 teaspoon) and added a bit of water to dissolve the remaining crystals. We are only talking about less than 2 liters (including the water) diluted by half. My first drop was great. I reheated the solution and added Cu plumbing couplings to cement out any remaining gold, and got quite a bit more. My stannous test shows there is still Au in solution. This morning the 3/4" copper coupling was all fallen apart. So I put in another one. My guess is that there is still free acid in the solution, although it remains a "tea color" not going green from the copper.


Any clues or hints about cementing? Does heating gently accelerate the cementation? Ambient temp here is about 90f so should I just keep adding copper until it won't eat anymore?



This cemented material is just in HCl

 

[Yggdrasil]

Why have you created a new thread about this?
Keep it all together and it will be cleaner and
make it easier to help you.
And one teaspoon of sulfamic to that amount of liquid
seems too little to me.

 

[FrugalRefiner]

I've just combined the two threads. As Yggdrasil said, don't start new threads on the same subject problem. Keep your posts in the same thread so members can see the full context.

Dave

Edited to correct spelling of "context"

 

[1mysurveymail]

Why have you created a new thread about this?
Keep it all together and it will be cleaner and
make it easier to help you.
And one teaspoon of sulfamic to that amount of liquid
seems too little to me.

Sorry about the faux pax. I did add a teaspoon of sulfamic to denoxx. noticing undissolved crystals I added small amounts of water until the crystals all dissolved...

Now it just keeps cementing onto copper. Is this better done at ambient temp (85f) or with gentle heating. Should I continue to feed copper into the solution until no more cementing occurs ( I think "yes")?

 

[Yggdrasil]

I just reread the thread.

Did you inquart your karat scrap?
If not, the AgCl could have stopped the dissolution of
gold.
So the weird lump that was left in the bottom, may be a lump of AgCl and gold.

 

[1mysurveymail]

I just reread the thread.

Did you inquart your karat scrap?
If not, the AgCl could have stopped the dissolution of
gold.
So the weird lump that was left in the bottom, may be a lump of AgCl and gold.

"YGGDRASIL" (cool username) THANK YOU for chipping in. I am baffled how long this cementing may continue, LOL. Does heating the solution make cementing go faster?

No I did not inquart my carat scrap. It was a few rings and bracelets that went right into the "poorman's AR." There were precious and semi-precious stones not easily removed so I did not want to melt and inquart it first.

I think you may be right about the AgCl because the copper always gets a silver sheen before the black cement starts. You can even see it in one of the above photos.

I found a slab of 7mm thick copper and have switched to using that for cementing out what remains in solution. I cleaned up this heat sink, removed the fins and got a nice 7mm thick piece of copper to cement on.



The fins were pretty thin, so as an experiment I placed them into some "depleted" solution from a previous Poorman's AR drop to observe what happens. Whether something cements onto them, or they just dissolve in the 2 previous solutions. Another day at 85F might yield something observable.

I have been keeping this lumpy insoluble (in HCl + bleach) separate from the very fine silver(?) from my first use of poorman's AR.

I hope I am not chasing just copper. None of the gold jewellery was "white gold" so I thought I would have a minimal amount of silver to deal with.

Based on my calculations there should be 11g of 24k total. Ignoring the low carat stuff. My washed drops from the first solution and they are drying now, so I will have a weight to post by this evening.

My stannous tests are showing less and less indications of gold, yet the cementing continues. I just dissolved this cement in HCl + bleach.



I got more of the same insoluble lumpy stuff.



As instructed by "linno1408" I may treat this material with NaOH. First I think a boil in HCl might help me determine if it is some copper salt or nitrate(?). When this material was first separated I placed it in warm HCl for a few hours to no observable effect. I don't have easy access to inexpensive nitric acid in FL, so I use "Poorman's AR" as a work-around.


I am used to dealing with simple RAM fingers and the AP method, then HCl and bleach, then dropping with SMB. So I am out of my depth.

 

[Yggdrasil]

Then we may have the explanation.
The Silver in the carat scrap is making
a passivating crust of AgCl that protects the Gold from
dissolving.
Silver can not be dissolved in HCl (almost true).
And the Gold protects the Silver from beeing attacked by the Nitric if the item has higher karat then 6.
The way to overcome this is to mix (smelt) gold with Silver or Copper to get the karat down to usable level.
Silver needs 4 times less Nitric than Copper so that is what we use if we can.
But in your case I do not know...
I do not know if Silver can easily be dissolved in Nitrate salts or you have to do some intermediate steps to create weak Nitric.
Can you get Nitric?
Many here use or have used Nitrates so mabe they can chip in here?

 

[1mysurveymail]

A tale of 2 cemented substances:

First the good news. I calculated ~12g of Au. I seem to have gotten most of it on my first drop. The "fudge factor was that there was a small quantity of lower carat gold jewellery that I ignored the weight of. So I am happy.

The weird news:
After the great first drop I used some Copper "couplings" that precipitated "a black powder and a tan powder" from two different volumes of Poorman's AR depleted(?) I dissolved 2 different batches of carat jewellery. I collected small amounts of each cemented powder. One looked black, the other looked tan (like gold precipitate). I put a small amount of each into a pyrex "souffle" cup. All my "lab-ware" comes from thrift stores. HINT, look for UNSCRATCHED glassware. I add a few milliliters of HCl to each cemented powder. The HCl covering the black one turned a very slight green (copper?). The other did not change color but smelled like "rotten eggs," Very much like homemade Stannous does. I feel like I am chasing COPPER (one as a sulfate from the SMB?) at this point.

My huge mistake was that that I must have added way too much "Spectracide Stump Remover" as the source of the nitrates to make my Poorman's AR. Have pity on me.

Now I will keep adding copper metal to see if more cements. Then I will use iron to cement out the copper and see if that works for these solutions.

 

[1mysurveymail]

I failed to "inquart" my carat jewellery. I went straight to dissolving with "poorman's AR." My first grop got almost what I calculated in the way of gold. My fresh stannous solution told me I still had a bit of gold left in solution, so I started cementing my leftover solution on copper. I got a fair amount of cemented black powder on my copper slab especially after adding a bubbler. Thanks guys. So I proceeded to washes from the tutorial by "Lasersteve."

It looked like this at the beginning:







After the boiling water and boiling in HCl this is what I was left with:



After a quick decanting:





So it looks like I was I cementing Silver and PGM's, but NOT GOLD.

What next with this non-gold mystery powder? I put in under water and will keep sleeping with Hoke under my pillow. Any HELPFUL hints?

 

[Martijn]

A bit late reply...
Was there any silver chloride in the filter before dropping the gold? Did you chill before filtering?
If so, the silver should be gone after the AR right?
So i would test a bit by redissolving in AR and test for pgm's with stannous.
If there is AgCl pushed out by the HCL wash, you could test if it turns black with NaOH.
I think it's unlikely any silver cemented out on copper after AR, but i could be wrong. It doesn't look like that to me.


I hope this helps you.

 

[1mysurveymail]

A bit late reply...
Was there any silver chloride in the filter before dropping the gold? Did you chill before filtering?
If so, the silver should be gone after the AR right?
So i would test a bit by redissolving in AR and test for pgm's with stannous.
If there is AgCl pushed out by the HCL wash, you could test if it turns black with NaOH.
I think it's unlikely any silver cemented out on copper after AR, but i could be wrong. It doesn't look like that to me.


I hope this helps you.

Thanks. I have been busy doing recovery. My "refining" keeps adding, and adding. The tricky bit is that I am using "Poorman's AR" for my Karat stuff, and HCl + bleach for my foils. So I keep washing and adding to the "Nice Tan powder," which I NOW keep under a few inches of DISTILLED water, to leach out the chlorides in tap water, and to get me to the lump of 3-4 "9's" eventually when I get to a melt stage. Silver is indeed a "nuisance metal" in my case, not having inexpensive Nitric locally avaialable. Once all of the vaunted washes are done, then my buyer does not seem to care whether it is 3 or 4 "nines," but as a matter of personal progress, I want to get there, albiet without LORDING it over anyone.

Thanks again.