I can't tell if I messed up or what???

[Grelko]

Did you look up and see what trituration is?
I believe its much more in depth than just beating up the silver chloride :lol:

Who knows, maybe all you need to do IS smash it together? I might try this someday. I noticed while grinding up small wet pieces of broken ICs, that the pressure/friction did cause them to dry out pretty fast. Maybe it's possible that the Cl bonds are broken and move to the Zn, sort of a "dry" version of the reactivity series?

I read the part about lactose and other medical definitions for the word, except this isn't organic chemistry. I just figured since the research was from 1820, It would use the definition of it from back then.

http://www.merriam-webster.com/dictionary/triturate (since 1828)
1. crush, grind.
2. pulverize and comminute thoroughly by rubbing or grinding

Origin and Etymology of triturate
Late Latin trituratus, past participle of triturare to thresh, from Latin tritura act of rubbing, threshing, from tritus, past participle — more at trite
First Known Use: circa 1755

Silver chloride can be converted with HCl and aluminum, or sulfuric acid and steel.

Thanks Geo, all I knew about was Karo and NaOH. I'll most likely go with HCl and aluminum, instead of using sulfuric for now.

 

[g_axelsson]

Yes, it is just grinding and smashing the silver chloride together with something else to get the reaction going.

The article can be found at sci-hub.ac by searching for the doi number. The author uses a ball mill, and after 20 minutes have a 97% conversion rate of their 6g sample. In the end they had silver, silver chloride, zinc, zinc chloride and zinc oxide. The reaction is compared to the thermite reaction but not as violent but the energy released is enough to create localized melting driving the conversion forward and a sudden jump in temperature.

Instead of zinc a number of other metals can be used, for example copper, iron, chrome, tin. It seems like the conversion rate has little to do with the energy released but is more dependent on the hardness of the metal, chrome gave very low conversion rates while copper and especially tin powder gave higher rates, almost as high as zinc.

I think it is an interesting reaction but nothing practical for refining. There are too much contamination compared to the rather clean conversion with NaOH and sugar.

Göran

 

[Grelko]

Yes, it is just grinding and smashing the silver chloride together with something else to get the reaction going.

The article can be found at sci-hub.ac by searching for the doi number. The author uses a ball mill, and after 20 minutes have a 97% conversion rate of their 6g sample. In the end they had silver, silver chloride, zinc, zinc chloride and zinc oxide. The reaction is compared to the thermite reaction but not as violent but the energy released is enough to create localized melting driving the conversion forward and a sudden jump in temperature.

Instead of zinc a number of other metals can be used, for example copper, iron, chrome, tin. It seems like the conversion rate has little to do with the energy released but is more dependent on the hardness of the metal, chrome gave very low conversion rates while copper and especially tin powder gave higher rates, almost as high as zinc.

I think it is an interesting reaction but nothing practical for refining. There are too much contamination compared to the rather clean conversion with NaOH and sugar.

Göran

You'd still need to rinse the material, plus dissolve the zinc or other metal away with HCl at the end to be able to separate your silver "metal". Still, getting a 97% conversion rate isn't bad for just smashing it together.

Could someone please explain how the HCl and Aluminum process would work? Is it just a simple conversion, dropping the silver out as powder "elemental silver" or is it more involved than that?

The reaction is compared to the thermite reaction but not as violent but the energy released is enough to create localized melting driving the conversion forward and a sudden jump in temperature.

Göran

Nice. 8) It's almost like rubbing 2 sticks together to start a fire.

 

[Topher_osAUrus]

That IS interesting stuff...I am quite curious now.. And have much reading to do about it.

Göran, what do you think is the best method for AgCl conversion when there is PGM contaminates as well as lead sulfate?

I was planning on iron and sulfuric, but, a thread i recently viewed, gsp mentioned a book that had 100 or so different conversion methods for silver. So, I figured, out of that many...there has to be one that is better suited for my needs.

 

[g_axelsson]

I have never liked to work with silver chloride and all my tests of converting with sugar have been failures or at least messy. Since I have plenty of copper from scrapping and found reasonable cheap nitric I prefer to treat the silver chloride with lye, converting it to silver oxide and then dissolving it with nitric and cementing on copper.

Lead sulfate should stay undissolved by the nitric and if it dissolve it doesn't cement on copper.

PGM:s should only exist in trace levels since their chlorides are soluble and can be washed away. If there are some PGM:s after cementing on copper it will be sorted out in the cell.

This might seem like an odd way to treat silver chloride but it works for me and my situation. I usually work in grams rather than kilos of silver chloride (from gold refining and MLCC:s). Most of my silver comes from keyboard films and contact points. But I'm just a small time hobby refiner and if my situation or type of scrap changes I might reconsider how I work.

I must put up a warning though, dry reduction of silver chloride with zinc powder is an exothermic reaction and if scaled up too much it might literary blow up in your face. The researchers compared that reaction to thermite and surface area (=heat dissipation) and volume (=stored energy) doesn't scale at the same rate. 8 times the mass have only 4 times the surface area so the heat buildup in a big batch will be larger than in a smaller batch. At some point the heat won't dissipate fast enough and you got a runaway reaction and a potential explosion.

Göran

 

[Topher_osAUrus]

Yes, silver chloride is kind of annoying. I can see why Hoke spoke of it with such disdain. I should have been a more "serious student" in the beginning, and been careful to not create as much....but, i have a large pickle jar half full of it that needs done, and I am certain there are values. I think I will try the lye method you spoke of.

Thanks for the tip G

 

[anachronism]

Yes, silver chloride is kind of annoying. I can see why Hoke spoke of it with such disdain. I should have been a more "serious student" in the beginning, and been careful to not create as much....but, i have a large pickle jar half full of it that needs done, and I am certain there are values. I think I will try the lye method you spoke of.

Yes I would define half a pickle jar of silver chloride as values too. You're better off with the sulphuric/nails approach by a country mile over the lye thing.

 

[Topher_osAUrus]

Yes I would define half a pickle jar of silver chloride as values too. You're better off with the sulphuric/nails approach by a country mile over the lye thing.

:lol:

Yeah, it's been collecting for a couple years..

I have much, much more cemented silver than silver chloride now.. And much more sterling and scrap silver to process. I don't advertise that I buy silver, just gold. It just seems that everyone who sells me bulk goldfilled, always has a little bit of sterling they want gone too.

I have sulfuric, and I have nails.. Ill give it a whirl.

 

[Grelko]

After filtering the jar with AP in it, the total material from both jars combined was ~7.8g

I decided to go for the gold first, so I went ahead and incinerated the dry material, that was left after dropping it with copper.

There was a small amount of white smoke, which must have been the silver chloride.

After refining this 1 time (then needing to drop it with copper) and "completely" incinerating it, it now weighs 2.862g (I bought a better scale)

The dry powder after incinerating still looks pretty dark brown, but I was still going to refine this atleast 2 more times.

I may re-dissolve this later tonight. It's already dry and in my 50 ml beaker.


Sadly, I don't have a graphite crucible, so I had to use my stainless one.
I'm not sure if this would contaminate the powder with iron again or not?

 

[Grelko]

So apparently, I have Platinum in my material.

First things first. Stannous stain is nice and purple.

Nothing else in the beaker seems like it will dissolve. There is now almost 2-3x the amount of "fluffy" material in the bottom. It looks like an actual black sponge, but it's mixed with copper in HCl/Cl, so it looks a bit green also. Some of it is floating also.

After decanting a bit of the solution, I tried adding more HCl/Cl to it and tested with stannous again. It looked nice and orange for about 2 seconds, then went black.

I was going to filter the solution, to catch the sponge material (no idea what to do with this yet, dry it out?), then heat the solution to remove the Cl and drop the gold.

 

[Grelko]

I finally got a chance to drop the gold and rinse it. It was medium-light brown after it dried.

I decided to re-dissolve and clean it once again, since I'm trying to get 999...

Of course, like always, something goes slightly wrong...

Did you know that HCl/Cl evaporated until it's dry, looks like scrambled eggs?

Well, now you do :|




I'm guessing that I should either add a little distilled water, or HCl to it now, and re-dissolve it yet again.

I'm wondering why the outside turned orange?

Edit - distilled water worked great, the dried salts went right back into solution.

 

[nickvc]

That IS interesting stuff...I am quite curious now.. And have much reading to do about it.

Göran, what do you think is the best method for AgCl conversion when there is PGM contaminates as well as lead sulfate?

I was planning on iron and sulfuric, but, a thread i recently viewed, gsp mentioned a book that had 100 or so different conversion methods for silver. So, I figured, out of that many...there has to be one that is better suited for my needs.

The best way to separate the PGMs which I think will be in solution is to wash and filter the silver chloride fully till the solution coming from it is literally water, cement that solution with copper and convert the silver chloride with the method of choice. To get the silver totally free of other values a silver cell is the best option and very easy to set up and run, I believe Palladium described and showed his mini silver cell which was excellent.

 

[Grelko]

Well, I think everything is back in order now.

I believe that after I accidently evaporated the solution dry, the auric chloride "AuCl3" turned to salt crystals, and around the edges where it was more orange, was chloroauric acid "HAuCl4" crystals.

I was going to reacidify the solution with HCl, but decided to use a tiny bit of SMB first. I was really surprised to see that it worked and I had the cleanest drop I've seen so far. The wet powder is basically light brown and the stannous test was negative.

Possibly tomorrow, I'll rinse the powder, but I still need to wait until my other melting dishes arrive before I can turn it into a small button.

 

[Grelko]

My new melting dishes arrived, so I took that bit of clean powder I had and made a tiny bead. Well, it "was" a bead, but I pulled it out of the dish too early and squashed it. :lol: It got stuck to the tweezers with borax.

There is still a small amount of black powder in a coffee filter, that may have a little platinum in it, along with at least another .45g of gold (the button from the begining had around .5g). Even though I dissolved everything I could, there was a sponge like material, that I saved to work on later.

All solutions that showed negative, were added to my stock pot for later, so nothing is going to just magically disappear.

You guys are right, it IS hard to take a photo that shows how shiny the gold actually is.

Also, this is my first "real" button. The other bead that I have in the gallery, was just bonding wires "gold panned out" and melted, not refined.

 

[g_axelsson]

Making a pipe with tweezers is to cheat! :mrgreen:

Now you know how good gold is looking after a melt and you will never be satisfied with less.

Good work!

Göran

 

[Grelko]

Making a pipe with tweezers is to cheat! :mrgreen:

Shh :lol: Don't tell anyone, they haven't noticed yet. :wink:

I'm trying to figure out why the rest of the material didn't dissolve. It has to be from the partially burnt filter from the begining, but that has already been re-incinerated to ash, and refined 2 times, filtered and rinsed.

I'm going to see if I can get that black sponge material to dissolve, or I can try to melt it, to see what it actually is. If it does happen to be platinum, I shouldn't be able to melt it with my torch. "mapp gas"

 

[Grelko]

Well, I took that tiny bead to the jewelry store and they tested it with their XRF.
I guess I still need to refine it one more time :roll: I'm pretty sure I refined this 4 times already, 1 more couldn't hurt. :lol:

90.77 Au
2.31 Ag
2.49 Cu

Also, I took down small silver bead from my other thread about mylars (not just keyboard, but microwaves etc.), where all I did was melt them in a small covered crucible on my hot plate for a couple hours, (until it was a mix of black/white ash), then use the "static cling" from a balloon to collect the silver. It turned out at almost 99%. I think it showed 98.92.

 

[anachronism]

Grelko.

Don't keep re-refining it ad infinitum if you're getting such high levels of impurity. You're trying to work with the tiniest of quantities in the spectrum where the losses as a percentage of your gold are the highest, and if you are still getting high levels of Ag and Cu after 4 refines then to be honest you've got something going awry that you need to improve upon. You're learning to get fine gold and that's far less of a frustrating procedure to learn when you're learning to do it with a couple of grammes. I would suggest from experience that one good refine (not recovery) on a few grammes using all the techniques you have learned so far (and executed correctly) would probably get you fine gold.

I'd put this little fella to one side and recover some more. Go grab some more feedstock, learn it with a larger amount and then use what you learn on this first button if you still want to. Of course you may want to put it to one side for ever and say it was your first!

 

[Grelko]

I think I know what my problem was.

Using cold rinses instead of warm/hot.

I didn't filter the solution that final time, I decanted/rinsed it, which would leave the silver at the bottom mixed in with the gold powder, instead of in a filter.

The copper, was most likely not rinsed out good enough. (Because of the cold rinses)

I have enough material that I can keep practicing with. 8) I'll get that 999 eventually.

 

[anachronism]

You can take out the silver and the copper with hot concentrated washes of HCl. There are conflicting opinions on the forum with regards to temperature, however I've always favoured hot. Yes it opens the door to a tiny dissolution of gold however this harks back to my comments regarding the quantity of gold you are trying to refine and the economies of scale.

I have never ever put gold powder in a filter and I don't understand the logic of doing so to be honest. It seems like a pointless exercise to me.