Love gold refining, not so much silver

[mlgdave]

I know its me not the processes.
I have tried converting AgCl using sulphuric and iron and got a rusty solution (I suspect I had unused nitric that wasnt completely washed off)
I did AgCl and sulphuric washed really well and used aluminum to precip and got these waxy clear crystals in the solution

and when I melt the resultant "silver" it smokes BAD and takes a long time with an oxy/acet torch to melt and I seemingly have a low yeild (a 20 ounce melting dish full to top melted results in about 4 oz silver)
I just did my first ever AgCl using lye and karo corn syrup, the AgCl seemed to convert to metal right away and I thought "do I need corn syrup"? I added it, the stuff got pretty warm, the water got black, and the resultant wet material filled a 10 ounce melting dish and then when melted i got 7 grams total and a lot of green "slag"

any tips or "to try" ideas?

mlgdave
ps.........Im still loving the refining aspect just struggling with the silver

 

[skeeter629]

After converting to silver metal using lye and syrup, you have to wash and stir the silver multiple times with distilled water. Pour off the dirty water each time, and repeat, until the water is clear. This should eliminate the green slag.

 

[goldenchild]

First. Don't use aluminum to drop anything. Anything... The smoking sounds like the AgCl wasnt fully converted to elemental silver. Torching AgCl is a sure fire way to lose a substantial amount of silver. Up in smoke so to speak.
I think you were saying that you were putting wet silver powder in the crucible. Don't do that Silver powder is also extremely fluffy. It looks like much more than it really is especailly when the dried clumps are huge. And lastly try to estimate how much silver is in solution so your not second guessing on your yeild.

P.S. you can simply use HCL to drop AgCl. Super fast and gets it all.

 

[mlgdave]

I know im getting all the AgCl using HCL, I add HCL until no more white cloudiness occurs. The question I have I guess Im impatient (a bad trait I know) is after I wash the AgCl numerous times until the water comes clear do you have to dry the AgCl to correctly proportion the amount of lye to put in or can use just "add extra" lye and corn syrup as required?

I have about 2" of AgCl in a 5 gallon bucket now, Im also cementing out some silver right now but it seems as if the silver cements out and then dissolves again (I diluted the 35% AgNO to about 17%)

mlgdave
ps.......I did figure out an incredible incredible incredible method to make some natural gold specimens absolutely FLASH! Hugely stoked about that!

 

[goldenchild]

When you are rinsing AgCl make sure to really agitate and crush those clumps. Contaminants always get trapped in clumps. Many rinsings may be necessary. Don't dry out AgCl.

When your AgCl is sitting in nice crystal clear water add enough lye to 100% convert the AgCl to silver oxide. Then after it's all converted add enough kyro to convert all the oxide into elemental silver. Add both the lye and syrup in small increments.

I have a few ounces of silver laying around. I think I may be making a video soon.

 

[samuel-a]

Dave

I have warned you about it... :mrgreen:
What you are experiencing is a growth of Al(OH)3 crystals. I bet you left the Al in with the AgCl for long time... (?)

Anyway, the converted silver from using sulfuric+Al should be washed very (very very) well to rid the Ag powder from Al compounds...
3-5 water wash
2x boils in acidic solution (5-10% HCL)
3-5 more water washes

and takes a long time with an oxy/acet torch to melt

Al(OH)3 when heated to >1100C is reduced to alumina and really mess up your melt.

Al(OH)3 ----1100-1200C----> Al2O3 + 3H2O


You have seen my experience with lye+sugar... i don't remember if i mentioned that but on later experiments with AgCl i used excess lye and left it over for the night on a magnetic stirrer to ensure complete conversion to oxides, only the day after i have added sugar and left it again for the night on the magnetic stirrer to ensure full conversion to elemental silver.
The thing that i disliked the most is, that you can't actually tell when the conversion is complete... both of them...

As Mario mention, you probably didn't fully convert and left a significant amount of un-reacted AgCl that blow up in the smoke.

One more thing on my "to do" list, is try and melt silver oxide rather then convert it to elemental with sugar.
I don't suppose it will be such a good idea though, since silver oxide is very fine powder and hard to handle.... but i have to try.
It should decompose at around 280C to silver metal and oxygen gas. I'm not absolutely sure but, 2.1gram of silver oxide should yield about 1 gram of elemental silver.

Edit: terminology.

 

[goldenchild]

Samuel,

I dont think melting Ag oxide will be much different than melting AgCl. I think it will smoke just as bad as AgCl with just as much loss. Let us know what you find.

 

[4metals]

Not so, silver chloride melts it does not decompose. So it gets nasty when it is reduced by the fluxes when you melt it. When the Cl cracks off the smoke is heavy and quite toxic.

Silver oxide on the other hand decomposes at 230 C (a relatively low temperature when you're melting) So the silver is simply reduced by the decomposition of the AgO to silver metal and oxygen. Easy to do and not at all messy or smoky.

 

[samuel-a]

Oranges and apples...
But who knows...
When I'll try that i sure will update.

BTW, have you ever try reducing Ag oxide with 30% H2O2 ? that is one more thing on my to do list...anyone with that experience is welcome to chim in.

Edit: Thank you for confirming that 4metlas

 

[4metals]

You have seen my experience with lye+sugar... i don't remember if i mentioned that but on later experiments with AgCl i used excess lye and left it over for the night on a magnetic stirrer to ensure complete conversion to oxides, only the day after i have added sugar and left it again for the night on the magnetic stirrer to ensure full conversion to elemental silver.
The thing that i disliked the most is, that you can't actually tell when the conversion is complete... both of them...

The key to success in the chloride conversion is mixing. I prefer using a tumbler (actually a poly lined cement mixer) If your mixing is good, then it's a matter of adding the proper quantity of caustic and karo.

If you know the volume of the chlorides, determined by putting them in water in a graduated cylinder. For every liter of silver chloride, you will need to add 0.4125 pounds of Karo syrup and 1.32 pounds of 50% liquid caustic. Add the karo first, it seems to make the whole thing more fluid, then when it is mixing smooth, add the caustic slowly.

 

[samuel-a]

The key to success in the chloride conversion is mixing. I prefer using a tumbler (actually a poly lined cement mixer) If your mixing is good, then it's a matter of adding the proper quantity of caustic and karo.

Yes, i figured it out at the time i did that experiment since i knew AgCl is one tough baster...
My stirrer did an excellent job stirring the powders (all night long) and periodically exposing new AgCl to the liquid.

If you know the volume of the chlorides, determined by putting them in water in a graduated cylinder. For every liter of silver chloride, you will need to add 0.4125 pounds of Karo syrup and 1.32 pounds of 50% liquid caustic. Add the karo first, it seems to make the whole thing more fluid, then when it is mixing smooth, add the caustic slowly.

Those looks like very accurate ballpark figures, almost stoichiometric calculated :?:

Thanks again

 

[shyknee]

Oranges and apples...
But who knows...
When I'll try that i sure will update.

BTW, have you ever try reducing Ag oxide with 30% H2O2 ? that is one more thing on my to do list...anyone with that experience is welcome to chim in.

Edit: Thank you for confirming that 4metlas

I experimented with making a silver oxide battery.When I was done I converted the unused silver oxide with just 3% H2O2. luck the vessel was large ,I had anticipated a lot of foaming, but had I not had my spray bottle things would of got out of had fast .
After rinsing and drying it melted beautifully,.. thanks 4metals , Oz or Lou can't remember who had the shirt stains .

 

[Oz]

It was not I that had the shirt stains, but be very careful of using strong H2O2 with silver oxide as it can get rather dangerous/energetic in the right/wrong situations. A chemist would be better than I would to explain this, but please wait before doing this until the safety of it is explained by a professional.

 

[shyknee]

Oz
That is exactly what I imagine, and trying to explain.
If just 3% H2O2 is that reactive then I would say stay away from 30% to dangerous..


But I would do it again given the chance, again just 3% pharma quality.

 

[Lou]

I'd avoid the hydrogen peroxide reduction! It produces a lot of steam and pure oxygen. In fact, silver screening is used with highly concentrated peroxide for rocket propulsion (has a high specific impulse).

The only way to do large volumes of AgCl in my opinion is that posted by 4metals. Although carbonate does work, but one needs to ball mill the carbonate with the silver or it makes an AgCl smokey mess.

 

[HAuCl4]

Put your AgCl in a drum, add a little diluted sulphuric acid, and stir overnight with a rotating copper paddle. Have a good night sleep or 2. Later you can recover the copper with minimum fuss. Not a industrial setup, but it works fine for small quantities. 8)

 

[4metals]

In an effort to keep topics in a place where they can benefit the most members, this topic has been moved to silver.

 

[Goldfinger4]

I usually use NaOH and normal, in water dilluted sugar in a surplus. You can't do anything wrong if you put too much to the silver chloride. It is very important to mix it well.
You should put all the stuff in an bottle or something else that can be closed so that you can shake it. That's more effective than stiring.
Wash the silver afterwards 2-3 times.

 

[4metals]

I wouldn't be putting it in a sealed bottle and shaking it, especially not while adding caustic!

 

[Oz]

I was intrigued by 4metals post adding the Karo before the NaOH as it is in reverse order of what I have seen elsewhere and on the forum.

You can't do anything wrong if you put too much to the silver chloride.

You can indeed use too much NaOH and put silver into solution. I have proven this to myself by taking my “waste” solution and neutralizing with HCl and had silver chloride result.

I cannot say if that would still happen with 4metals procedure as I have not done it and I am no chemist.