Sciencemadness Discussion Board

Metal from phone in HCl (nickel?)

Random - 31-10-2010 at 07:01

I opened few mobile phones and took some metals from inside of them, the metals looked like that:

I took those metals with dots on them. (this is electromagnetic shielding?)

Then I put them in HCl and no bubbles were observed. I left them outside in a glass bottle for a few days and the solution became a little bit yellow, but the metals weren't dissolved much. Yesterday I put into that like 15 mL of ammonium nitrate solution, in the evening the solution was only a little bit more yellow with metals undissolved. In the morning I checked it and I saw a green solution exactly like this with everything dissolved (check the time 2:00):

There was also some condensed water all over the bottle and it's unscrewed cap that was laying on top. I am not sure if there was a large cloud of NO2 there in the night.

Now, is this nickel chloride mixed with some nitrate or something else? I tried to catch these metals with magnet and nothing happened. But then I accidentally left them on a drop of NH4NO3 solution and corrosion was greenish, like patina of copper, but the metal is gray like in the picture. Maybe this could be nickel? If it is nickel, can I precipitate it from solution as metal powder by using citric acid like it's said on BromicAcid's page about nickel:


Nickel powder can be formed in a number of ways, most notably by the reduction of a soluble nickel salt in an aqueous medium by zinc powder or citric acid. Additionally it can be formed as is shown at left by the decomposition of nickel oxalate formed by the displacement reaction between sodium oxalate and a soluble nickel salt.

But then, I could also extract nickel from cupronickel coins in hcl and some nh4no3 solution by citric acid, then I could take out that nickel powder and I could precipitate copper (ii) carbonate with baking soda (if it really works on nickel with citric acid, but not on copper too). Could someone explain to me how citric acid does that and to which solutions?

blogfast25 - 31-10-2010 at 09:55

That behaviour is quite consistent with nickel. By far the best solvent for nickel is nitric acid with which it reacts very vigorously. It's similar to copper in that respect: quite unresponsive to HCl and H2SO4 but very soluble in HNO3...

What's your purpose for the nickel metal? Because if you want to make lump metal (and not powder) there are better methods...

metalresearcher - 31-10-2010 at 10:09

Maybe it is stainless steel which also dissolves in HNO3.
To get pure nickel there are enough affordable sources on ebay.

unionised - 31-10-2010 at 10:19

"I tried to catch these metals with magnet and nothing happened. "
" Maybe this could be nickel?"

cyanureeves - 31-10-2010 at 11:05

true. i have pre 2000 canadian(90+%) nickel quarters and they are ferromagnetic. stainless steel is more likely what it is.also nickel is pretty tough to tube shows nickel dissolving in nitric acid but the acid had to be heated.i have to do that with stainless steel also.however aqua regia will dissolve it pretty quickly. which is what you eventually made hcl +ammonium nitrate solution +metal.

madscientist - 31-10-2010 at 11:30

Concentrated sulfuric acid and 30% H2O2 will dissolve nickel without... external... heating. I tried it 8 years ago so my memory may be hazy, but from what I remember nothing much happened at first, so I left it unattended overnight, and woke to find the nickel completely dissolved, liberally distributed across the walls and ceiling. :D

[Edited on 31-10-2010 by madscientist]

unionised - 31-10-2010 at 11:57

Have I missed something here?
We seem to be discussing nickel chemistry in a thread about something that isn't magnetic; why?

Random - 31-10-2010 at 12:44

Actually, this could be also an alloy of nickel and copper which makes it non magnetic.
This isn't stainless steel because it can't be attracted to magnet.

Which metal or alloy could this be which shows that type of corrosion like patina, but its gray?

matei - 31-10-2010 at 13:58

Most of stainless steel alloys are non-magnetic. To be more specific, austenitic stainless steel, which is about 70% of the stainless on the market is non-magnetic. Only martensitic-type and ferritic alloys (which are low in nickel) have magnetic properties.
Austenitic stainless contains up to 10% nickel.

[Edited on 31-10-2010 by matei]

Random - 31-10-2010 at 17:09

But if it would contain iron air should oxidize it to iron (iii) orange/brown color and it's not happening. And there should be also some type of iron orange rust forming instead of blue/green corrosion.

Also the metal it very easy to cut and I can even take it apart with fingers into pieces.

[Edited on 1-11-2010 by Random]

peach - 31-10-2010 at 22:11

Some of the crappy stainless steels have some degree of magnetic ability to them.

The higher grades shouldn't do anything around a magnet. Even though they have some quantity of iron in them, they won't rust like normal steels due to all the chrome, vanadium and molybdenum in rust free alloys.

The fact you can tear it with your fingers suggests it is not stainless. As even thin stainless is extremely tough.

That little screen is there to block RF noise coming from the radio frequency circuits, and noise trying to get back in.

Knowing the electronics industry, it's likely it may involve copper and tin plating. That would also be soft enough you could warp it and tear it by hand if it was thin enough.

If you like all things magnetic, check out Permalloy / MuMetal. It's a few hundred times more permeable than steel with regards to magnetic fields, which means it gets used to make magnetic shielding for rooms with MEG scanners in them, or as the casing / cores for very expensive signal transformers. Dropping or bumping said transformers can damage the grain structure and start ruining the effect. The BBC used to buy things like that back in the days of the valve, when transformers were much more important. Now, it's pretty much all solid state, and you can not only go between gain stages without a transformer, but directly into the speakers, so they're not really needed anymore. Super conductors have 0 permeability. The field does enter the superconductor, but stops within nm's (from memory) once within the material, which is likely related to their grain / layer structure and some insight into to how they may be functioning. They're also used as magnetic shields. The metals work by absorbing and grounding it, the superconductors by straight out blocking it (the field immediately induces a perfectly opposite field within the material, counteracting it's self).

MuMetal transformers, from Sowter in the UK

[Edited on 1-11-2010 by peach]

Random - 1-11-2010 at 01:52

So now we have few infos more about this metal alloy:

-blue/green corrosion
-very slowly dissolves in HCl
-Dissolved in poor man's aqua regia
-solution is greenish like on that youtube video
-non magnetic
-easy to tear it with fingers
-it's not stainless steel
-it's gray

Maybe this could be some nickel/copper alloy which is gray. If it is, how could I precipitate nickel separate from copper? Does the citric acid really work? If yes, this could be extracted by this method:

Neutralise to ph 7
add citric acid to precipitate nickel metal (if this is possible)
then remove nickel powder and put baking soda to precipitate copper hydroxide

peach - 1-11-2010 at 02:24

You can precipitate various metals as the hydroxides selectively by choosing a specific pH in the alkaline range.

Precisely which pH you'll need is something you'll have to do a google around, as I don't remember them off the top of my head. Lots of the documents to do with purifying water or leaching metals from ores & soils discuss the pHs specific metals fall out at. They're quite often free as well. Yay!

It may be easier to try leaching it from the other end, selecting an acid / base that will react more significantly more with one component than the other.

Copper is a noble metal, meaning that, unlike the other commonly known ones, it doesn't produce hydrogen when mixed with acid. It also requires that the acid attacking it be an oxidizing acid, like sulphuric or nitric. This is why to generate copper chloride you first dissolve the copper in sulphuric, perhaps mixed with some peroxide to speed up the oxidation. Then treat it with hydrochloric to swap the pretty blue sulphate for the equally pretty green chloride.

Nickel isn't in the noble series, so it will react with none oxidizing acids like HCl.

The simplest method I can think of to test if this is some copper/nickel alloy would be to leave a bit of the metal in a container of some description with some hydrochloric and see if it begins to dissolve. You'll only need to use a tiny bit to test that, a little flake of it off one of the corners will do.

This may take a LONG time given that the electronics people will only be using just enough nickel to keep the possible copper from tarnishing in the open air. It's also a big solid lump, so it will take time for the leaching to work. Hence all the soil, mineral & ore guys referring to it as leaching, as opposed to dissolving.

If there's no visible change after a few minutes -> hours, leave it over night. Still nothing, try a week. By the end of that, if it's going to work, you'll see at least pitting and roughness on the surface, showing the acid is attacking something in the alloy.

How long it takes to do the entire lot is next to impossible to predict. It depends a lot on the strength of the acid, the alloy content, temperatures, blah blah blah. But you may be able to accelerate the process by attaching it to a battery charger or wall adaptor (check it says DC on it, or has a straight horizontal line over a dashed line, not a wavy line). Chloride ions are negatively charged and seek out the anode, the red + lead from a charger.

This wiki page shows the series for metals (top to bottom, reactive to noble, note where hydrogen is, anything below it is a noble metal and won't react with none oxidizing acids).

Mercury is also a noble metal, and right up close to gold / silver / platinum compared to the others. This is why it needs dissolving in boiling 98% sulphuric, and takes a good while to do so. There is an irony here, because that means it's quite hard for it to turn into the super deadly salt forms, but the salts are also so poisonous that only tiny amounts of it need to for it to be a serious health hazard (a brain hazard primarily).

I was dissolving zinc battery casings a lot recently in an attempt to produce zinc sulphide, which I was then doping with manganese salts (made from the paste) to produce electroluminescent paint. I discovered the casings contain traces of iron. But, by using a weak solution of acid and slightly less than I calculated it'd need, the zinc dissolves selectively over a lot of the iron, which is left floating on the surface as mucky gunk.

[Edited on 1-11-2010 by peach]