What else in AP besides CuCl?

[Alentia]

After processing months of computer scrap in AP I end up with foils and grey mud in the bucket. I bet everyone is familiar with the picture.

After washing with HCl, some of the mud dissolved in the HCl, but some remained. I have dried 2 batches, one batch I have treated with H2SO4 (about 5ml) and piece of iron (5gr).

After I have it dried, I had evaporated chloride on slow heat inside oven and received light brown (copper like) powder.

The said powder does not dissolve in HCl, HNO3 nor AR. It melts into small balls at high temp in the dish with torch. Balls do not join together in melting dish but scattering around the dish. What is this material? I did not try to heat AR yet. The yellow liquid in the tube tests "clear" with stannous.

Got pictures in wrong order...

 

[solar_plasma]

I would bet on iron.

Butcher wrote:

ferric chloride will form insoluble iron oxides and hydroxides (especially when heated) which are insoluble yellow or red powders, which are very resistant to acids even aqua regia

http://goldrefiningforum.com/~goldrefi/phpBB3/viewtopic.php?f=48&t=7674#p121562

 

[nickvc]

Alentia may I first say I'm no expert on the AP method but I know what I would do with this powder. The sediment you recovered from your AP was from numerous items I'm guessing so there is a good chance that you have a mix of elements in your powders. I'd wash the powder in boiling water several times then dry and incinerate the powders. Then I would give the powder a good wash in hot hydrochloric acid and repeat until no colour comes from the powder and then dissolve in hydrochloric and bleach. Filter and precipitate, testing all solutions for any values obviously as I go. The gold powder may well not be clean so if high quality is your aim I'd then redissolve in AR and precipitate again
The used filters could ontain values depending on the feed you used so keep and process when the quantity warrants the time or effort.
You could also try washing the powder in hot hydrochloric first but I'd still be tempted to incinerate it whichever method you choose.

 

[solar_plasma]

...I should add, I meant the brown powder, which didn't dissolve at all or in anything.

 

[Alentia]

Alentia may I first say I'm no expert on the AP method but I know what I would do with this powder. The sediment you recovered from your AP was from numerous items I'm guessing so there is a good chance that you have a mix of elements in your powders. I'd wash the powder in boiling water several times then dry and incinerate the powders. Then I would give the powder a good wash in hot hydrochloric acid and repeat until no colour comes from the powder and then dissolve in hydrochloric and bleach. Filter and precipitate, testing all solutions for any values obviously as I go. The gold powder may well not be clean so if high quality is your aim I'd then redissolve in AR and precipitate again
The used filters could ontain values depending on the feed you used so keep and process when the quantity warrants the time or effort.
You could also try washing the powder in hot hydrochloric first but I'd still be tempted to incinerate it whichever method you choose.

Nick,

That is exactly what has been done resulting in brown powder not soluble in AR and therefore will not be soluble in Chlorine.

Solar,

Good call, I will test with magnet small melted piece and will advise. However, I am not fully understand how Iron Chloride would precipitate in AP as grey mud as it should be absorbed by the solution and be removed during washes.

 

[nickvc]

Sorry you didn't mention using heated solutions or incineration some don't do either but both will help in ridding the powder of base metals and with filtering later.

 

[butcher]

There are some metals like tin and Iron that their chemistry can get very complicated.
Iron being one of those metals that its chemistry can be complicated iron can be oxidized into many different oxidation states, even when made int a metal salt by dissolving it in acids it can many hold several different oxidation states of that one metal-acid salts.

Iron chlorides a metal-salt formed with Iron and HCl, can have a two main oxidation states, FeCl2 and FeCl3, (both soluble in solution), but even these can be easily converted to other oxidation states of iron depending on conditions, they can form iron oxides or hydroxides depending on conditions, another thing with solutions we can push iron out of solution with metals higher in the electrolytic series of metals higher in series than iron.

Strongly heated iron salts in solution with water can hydrolyze, and become hydroxides of iron which are insoluble, this can also happen easier if pH of the iron solutions are not very acidic or are changed with bases such as NaOH or other basic solutions...

Most of the different iron salts, when the soluble iron salts are evaporated to crystals and dried can easily be oxidized by air or oxygen, especially if the are not kept acidic, and are exposed to oxygen over time, like the pretty green crystals of ferrous sulfate can oxidize to brown and white iron oxides, heating copperas crystals with a torch in a melting dish would drive off the SO2 gases and oxidize the iron to an iron oxide dust from the oxygen in the environment and or from the torch.

Iron has many oxidization states:
Compounds of iron:
http://en.wikipedia.org/wiki/Category:Iron_compounds

http://en.wikipedia.org/wiki/Category:Iron_oxide_pigments

 

[Alentia]

There are some metals like tin and Iron that their chemistry can get very complicated.
Iron being one of those metals that its chemistry can be complicated iron can be oxidized into many different oxidation states, even when made int a metal salt by dissolving it in acids it can many hold several different oxidation states of that one metal-acid salts.

Iron chlorides a metal-salt formed with Iron and HCl, can have a two main oxidation states, FeCl2 and FeCl3, (both soluble in solution), but even these can be easily converted to other oxidation states of iron depending on conditions, they can form iron oxides or hydroxides depending on conditions, another thing with solutions we can push iron out of solution with metals higher in the electrolytic series of metals higher in series than iron.

Strongly heated iron salts in solution with water can hydrolyze, and become hydroxides of iron which are insoluble, this can also happen easier if pH of the iron solutions are not very acidic or are changed with bases such as NaOH or other basic solutions...

Most of the different iron salts, when the soluble iron salts are evaporated to crystals and dried can easily be oxidized by air or oxygen, especially if the are not kept acidic, and are exposed to oxygen over time, like the pretty green crystals of ferrous sulfate can oxidize to brown and white iron oxides, heating copperas crystals with a torch in a melting dish would drive off the SO2 gases and oxidize the iron to an iron oxide dust from the oxygen in the environment and or from the torch.

Iron has many oxidization states:
Compounds of iron:
http://en.wikipedia.org/wiki/Category:Iron_compounds

http://en.wikipedia.org/wiki/Category:Iron_oxide_pigments

Tested melted ball - it is not magnetic.

 

[solar_plasma]

Is the ball metallic? I never tried, but I don't believe that all iron oxides are magnetic.

 

[Alentia]

Is the ball metallic? I never tried, but I don't believe that all iron oxides are magnetic.

Yeah, that is the one on 3rd picture. Any oxide will convert to elemental metal on melting.

 

[solar_plasma]

That is not true for all oxides and thats even not true for all metal oxides.

 

[butcher]

Iron can form oxides that are non magnetic.
Many iron oxide powders could be hard to melt back into iron metal, in fact it is easier to make a slag of iron when melting than it is to melt many iron compounds back into metallic iron.

Iron oxidizes easily at its melting point, when they make iron they need a carbon source like coke or coal and usually use lime in the flux, to convert the oxides to CO2 gas, and they melt in furnaces that help keep oxygen out of the mix.

 

[SCB]

... and they melt in furnaces that help keep oxygen out of the mix.

Well.. Slight OT but oxygen is a crucial part of both iron and steelmaking.
Oxygen is bubbled through the molten iron/steel to lower the content of some alloying elements such as C and Si. It’s a violent reaction and the molten steel boils vigorously from the CO/CO2 formed, but as long as there are carbon left in the charge very little Fe will be oxidized.
Making oxides from the iron is not a big deal, it’s quite easy to push it back into metallic form again. It's just a matter of adjusting the chemical composition of the slag depending on what one wants to do. Putting elements in the slag and later recovering them from the slag is standard procedure in refining steel.

 

[solar_plasma]

For example Fe₂O₃ will melt at 1565 °C, it will not decompose. Maybe the reducing zone of the torch would reduce the iron if temps are high enough, but that is something else: It doesn't turn to metal because of it melts, but because there is a reducer present, probably CO. And if it is correct what my dad once has tried to teach his youngest son about welding, it will work for the skilled welder.

Still I believe you have made some non-magnetic iron ceramic. I do only see brown slag...is it metallic inside, is it conducting electricity, is it dense and is it thermoconductive? If all four are positive, then I believe you have a non-magnetic metal.

 

[Alentia]

The metal ball dissolved in HNO3. Judging by the color traces of copper are present.

Based on stannous and DMG test traces of Pd (white precipitate) and Pt (orange) are present.

Presence of Pt is kind of strange. Stannous reacts with orange color. I wonder if Pt behaves the same when alloyed with silver (dissolves in HNO3) when alloyed in small percentage with copper and Pd.

It is possible my initial comment was misread. After drying the "mud" I had it calcinated (removed chlorine) in the oven to arrive to the brown powder.

No presence of silver, iron or nickel was identified.

 

[Pantherlikher]

Greetings...
First the novice question.
Would well used or "spent" AP push iron out of solution as suggested?
Being a novice, I'd think iron would push copper out. This would remove tin, iron, and others from solids? Leaving everything above as solids.

Ok... Everything and anything goes into the AP so it will have anything.
Incinerate and wash with water, then hot HCL.<(some Sulphuric added here?)
Incinerate again.
Here, I would think to use HCL and a few drops of AP solution. Enough to get the AP running again which would rid alot more base metal if here right? HCL and some peroxide would dissolve alot as an oxidiser is added. Would this be the same as adding alittle AP solution?

Then incinerate again and warm nitric with some sulphuric for any lead? Not sure where to add Sulphuric for any lead but think in early step with hot HCL.

Would this rid the solids of any iron and other base metals?

If so, then AR, filter and test/ drop.
Any solids not dissolved from this should go to AR with hard boil if I'm keeping my steps straight.
Testing along the way to catch PMs as they dissolve.

I need to reread Hoke to get it all straight, but I believe you would want to incinerate between steps while dissolving/ removing base metals followed by the PMs untill you run out of solids.

As a side thought being Novice in the soupy mess. Would using poor man's nitric acid, (Sodium nitrate + sulphuric) play any role in breaking down any complex metals to rid from solids? How about poor man's AR?
Wondering here if different combinations of acids react differently.

B.S.
...Let the learning chastization begin here...

 

[solar_plasma]

@altentia
Maybe I did misunderstand you, since I understood the powder would not dissolve in anything and I believed you had tested the liquids above the solids after each acid treatment.

 

[Alentia]

@altentia
Maybe I did misunderstand you, since I understood the powder would not dissolve in anything and I believed you had tested the liquids above the solids after each acid treatment.

Yes, that is correct. The powder (brown powder) would not dissolve in anything. The brown powder was a result of caclinating grey mud after it was washed several times with HCL and water afterwards.

Once I have melted the brown powder, I was able to create few small metallic non magnetic balls. Obviously I was very confused when everyone suggested it was non magnetic iron, and I still am.

Melting was very annoying as small balls were very stubborn not willing to join into single ball.

One of the balls easily dissolved in HNO3 resulting in the liquid I have posted test results for.

I am assuming I have lost percentage of Pd while melting with oxygen in open dish.

I am more concerned about how to process mud in the future, since calcinate will not dissolve in anything. Well, I did not try alkali.

I can collect brown powder for later Pd recovery, but I do not have equipment to properly melt it and assay to even understand if it's worth it.

 

[Alentia]

Greetings...
First the novice question.
Would well used or "spent" AP push iron out of solution as suggested?
Being a novice, I'd think iron would push copper out. This would remove tin, iron, and others from solids? Leaving everything above as solids.

Ok... Everything and anything goes into the AP so it will have anything.
Incinerate and wash with water, then hot HCL.<(some Sulphuric added here?)
Incinerate again.
Here, I would think to use HCL and a few drops of AP solution. Enough to get the AP running again which would rid alot more base metal if here right? HCL and some peroxide would dissolve alot as an oxidiser is added. Would this be the same as adding alittle AP solution?

Then incinerate again and warm nitric with some sulphuric for any lead? Not sure where to add Sulphuric for any lead but think in early step with hot HCL.

Would this rid the solids of any iron and other base metals?

If so, then AR, filter and test/ drop.
Any solids not dissolved from this should go to AR with hard boil if I'm keeping my steps straight.
Testing along the way to catch PMs as they dissolve.

I need to reread Hoke to get it all straight, but I believe you would want to incinerate between steps while dissolving/ removing base metals followed by the PMs untill you run out of solids.

As a side thought being Novice in the soupy mess. Would using poor man's nitric acid, (Sodium nitrate + sulphuric) play any role in breaking down any complex metals to rid from solids? How about poor man's AR?
Wondering here if different combinations of acids react differently.

B.S.
...Let the learning chastization begin here...

Panther,

I think you are correct on first paragraph.

But the rest is not so easy.

I have incinerated the mud once and resulting powder will not dissolve in anything. So that would stop your process right there.

 

[Alentia]

I think I have an answer to my question and the brown powder I had created.

Pd + 2 CuCl2 → 2 CuCl + PdCl2

Brown powder is PdCl2.

I might have missed a mention anywhere on the forum that AP actually reduces Pd into PdCl2. I was always under impression that Pd settles in AP in metallic form.

I was always wondering what is happening with Pd from MLCC on boards.

Trying to melt brown powder was/is bad idea. It was not alot and it was for discovery anyway.