Copperas won’t green up

[ARMCO]

OK I’ve always ordered ferrous sulfate online. I thought I would try Copperas from the hardware store. It won’t green up. I’ve used more than enough HCl so I’m not sure what the issue is. Photos attached






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[ARMCO]

Btw, started out nice and green but I left it on the heat with the spinner going to make sure it was very well dissolved and a saturated solution and when I came back it looked like the picture above.


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[Shark]

Hi Yield is all I have ever used, and I have never seen that happen here. The only thing I can think of is that I don't use heat. I just add my copperas to a beaker, add the needed water to a coffee pot, and brew it like coffee. I add the hydrochloric usually after to cools slightly. I am using the same bag I bought three years ago, but I do store it in a vacuum container.

 

[ARMCO]

Hi Yield is all I have ever used, and I have never seen that happen here. The only thing I can think of is that I don't use heat. I just add my copperas to a beaker, add the needed water to a coffee pot, and brew it like coffee. I add the hydrochloric usually after to cools slightly. I am using the same bag I bought three years ago, but I do store it in a vacuum container.

OK, interesting thing. And I was able to recover it back to a greenish state by adding more cool water. Maybe it has something to do with temperature maybe it was supersaturated or something but more Copperas and more hydrochloric didn’t do the job but cool distilled water did. You can see the difference in the two-tone where the cooler water was added.





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[ARMCO]

Hi Yield is all I have ever used, and I have never seen that happen here. The only thing I can think of is that I don't use heat. I just add my copperas to a beaker, add the needed water to a coffee pot, and brew it like coffee. I add the hydrochloric usually after to cools slightly. I am using the same bag I bought three years ago, but I do store it in a vacuum container.

OK, interesting thing. And I was able to recover it back to a greenish state by adding more cool water. Maybe it has something to do with temperature maybe it was supersaturated or something but more Copperas and more hydrochloric didn’t do the job but cool distilled water did

View attachment 2
View attachment 1


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The photos are out of order but the one that is two-tone was where I had poured the water in cooler and more dilute on top and warmer and more concentrated on the bottom.



Now that picture below the one on the left that’s greenish was about 90° and the one on the right was about 151°F


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[ARMCO]

So here’s the epilogue on this Copperas adventure.

It greened up with the cooler distilled water. Ended up having a much greater volume of liquid.

I have only used ferrous Sulfate that I purchased online.


And it appears very different than the Copperas

Side by side comparison:

View attachment 1


Copperas on the left, ferrous sulfate online on the right.




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[anachronism]

I always use the pure ferrous sulphate not a garden product. It's purer and frankly for larger dirty drops I stir the crystals directly into the de-noxxed AR solution. Not something I'd recommend when you're learning the process though because if you have left any Nitric in then it can react quite strongly as you precipitate/redissolve/precipitate in a loop. I found that one out the hard way, with Patnor also in the lab. 8)

I do it this way because it adds no volume to your waste.

Using purer base chemicals will always get you a better result and Ferrous Sulphate is one of those chemicals you can get just as cheap in pure form as in a "shop" compound so I would recommend that people do that. Then again if you're caught short and need some in a hurry then home depot is a lot faster than ordering online.

Don't get hung up on the ferrous sulphate solution being a bit cloudy because when you clean your gold properly it will be clean and have nothing left in it from your precipitant. You can literally mix it in hot water, add a bit of HCl and let it settle and pour off the top into your AR. I do recommend saturating your ferrous sulphate solution too.

Edit: Armco it will still work when it doesn't look green but as you've found out the copperas stuff isn't as pure or good as the "real thing."

 

[Shark]

I would not recommend using the Hi Yield Copperas directly into the solution. It just is not clean enough to be used that way.

 

[anachronism]

I would not recommend using the Hi Yield Copperas directly into the solution. It just is not clean enough to be used that way.

Yep that's correct. I should have made that clearer in my post. Thanks Shark.

Jon

 

[ARMCO]

I would not recommend using the Hi Yield Copperas directly into the solution. It just is not clean enough to be used that way.

Yep that's correct. I should have made that clearer in my post. Thanks Shark.

Jon

I always run it through a filter. Is that what you’re referring to? Should I run through a filter more than once?


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[ARMCO]

I always use the pure ferrous sulphate not a garden product. It's purer and frankly for larger dirty drops I stir the crystals directly into the de-noxxed AR solution. Not something I'd recommend when you're learning the process though because if you have left any Nitric in then it can react quite strongly as you precipitate/redissolve/precipitate in a loop. I found that one out the hard way, with Patnor also in the lab. 8)

I do it this way because it adds no volume to your waste.

Using purer base chemicals will always get you a better result and Ferrous Sulphate is one of those chemicals you can get just as cheap in pure form as in a "shop" compound so I would recommend that people do that. Then again if you're caught short and need some in a hurry then home depot is a lot faster than ordering online.

Don't get hung up on the ferrous sulphate solution being a bit cloudy because when you clean your gold properly it will be clean and have nothing left in it from your precipitant. You can literally mix it in hot water, add a bit of HCl and let it settle and pour off the top into your AR. I do recommend saturating your ferrous sulphate solution too.

Edit: Armco it will still work when it doesn't look green but as you've found out the copperas stuff isn't as pure or good as the "real thing."

Apologies. I hadn’t seen that I had a couple responses above that last response. Thank you for your reply it’s good information and I appreciate it.

Problem I have with the pure stuff that I ordered online is that it came half oxidized and brownish so I always made a saturated solution and green it up with the hydrochloric. But you’re right it expands the volume of waste tremendously.

I think what you said up there is that even if it has gone kind of brown you can still put the pure crystals directly in.

And thanks again for your reply I really do appreciate it. Thanks to you shark as well.


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[butcher]

Most of the copperas, ferrous sulfate from the sack is no longer a pure salt of iron (II) sulfate, most of the dried product was further oxidized to form ferric sulfate, from drying the salt and exposing it to atmospheric air Oxygen and moisture changes during storage.

Note that the dried product was whitish brown, not a clear green salt.
Note the brown solution which formed when hydrating the salt, not the bright green color of iron sulfate, possibly even some insoluble iron hydroxide may also form.

Fresh copperas is a green crystal:

ferrous sulfate
https://en.wikipedia.org/wiki/Iron(II)_sulfate


which can oxidize further to a white/Brown salt:

ferric sulfate
https://en.wikipedia.org/wiki/Iron(III)_sulfate

 

[g_axelsson]

Most of the copperas, ferrous sulfate from the sack is no longer a pure salt of iron (II) sulfate, most of the dried product was further oxidized to form ferric sulfate, from drying the salt and exposing it to atmospheric air Oxygen and moisture changes during storage.

Note that the dried product was whitish brown, not a clear green salt.
Note the brown solution which formed when hydrating the salt, not the bright green color of iron sulfate, possibly even some insoluble iron hydroxide may also form.

Exactly! Ferrous sulfate is matched with one sulfate ion for each iron, while ferric sulfate is two iron and three sulfate ions. There is a third iron atom that is combined with oxygen and water and forms undissolvable iron oxides or hydroxides. That's why the solution is so turbid and not clear.

I must admit that I don't know how addition of hydrochloric acid to ferric sulfate can reduce it into ferrous sulfate. Isn't the result just a lowering of pH so iron hydroxides can dissolve and the color change is a result of the pH change?

I made my own ferrous sulfate from the wash water and diluted sulfuric that was left from my sulfuric cell experiment. I added a couple of pieces of iron from a computer case until there was no other reaction. There was some carbon released from the steel, but I filtered it easily off. The solution was saturated so there were a lot of crystals, added some water until it all dissolved.
The resulting blue clear solution was stored in a bottle and still after a year it is as fresh as when I made it. To use it I just open the top and pour off some of it, I don't need a lot as it is saturated.

I did a re-crystallization and made these beauties... just out of pure luck.


Here is the dirty crystal mess with carbon from the steel.


Filtering off the carbon.


Göran

 

[Shark]

I would not recommend using the Hi Yield Copperas directly into the solution. It just is not clean enough to be used that way.

Yep that's correct. I should have made that clearer in my post. Thanks Shark.

Jon

Not a problem Jon. Sometimes the beginner will miss that detail and then wonder why they have dirty gold. I bet you can't guess how I know that, :lol:

 

[aga]

Stuff from garden suppliers generally contains a lot of junk - the plants do not care, maybe benefit by it.

Things like ammonium sulphate, urea, copper sulphate etc you can just dissolve them in the minimum amount of hot water, filter out the junk, maybe boil down a little, then leave to crystallise into a Much purer version.

Doesn't work with Copperas.

Copperas, aka iron(II) sulphate can only really exist without any oxygen (or other oxidiser) hanging around to boot it up to iron(III) sulphate, which means that if you leave it out in air, it goes 'off'.

The small amount i made (<30g) is stored as a green solid under a small amount of sulphuric acid.

Basically the bulk of it remains green 'copperas', but when some oxygen hits it, it becomes iron(III) sulphate, which then gets reduced by the acid back to iron(II)sulphate : an equilibrium is happening.

Won't last forever, but it's still green with brown acid on top about 2 years later.

 

[ARMCO]

I would not recommend using the Hi Yield Copperas directly into the solution. It just is not clean enough to be used that way.

Gotcha. Thanks!

 

[ARMCO]

Stuff from garden suppliers generally contains a lot of junk - the plants do not care, maybe benefit by it.

Things like ammonium sulphate, urea, copper sulphate etc you can just dissolve them in the minimum amount of hot water, filter out the junk, maybe boil down a little, then leave to crystallise into a Much purer version.

Doesn't work with Copperas.

Copperas, aka iron(II) sulphate can only really exist without any oxygen (or other oxidiser) hanging around to boot it up to iron(III) sulphate, which means that if you leave it out in air, it goes 'off'.

The small amount i made (<30g) is stored as a green solid under a small amount of sulphuric acid.

Basically the bulk of it remains green 'copperas', but when some oxygen hits it, it becomes iron(III) sulphate, which then gets reduced by the acid back to iron(II)sulphate : an equilibrium is happening.

Won't last forever, but it's still green with brown acid on top about 2 years later.

Thanks. Interesting. I still have plenty ferrous sulfate heptahydrate but I thought I'd buy the bag of Copperas just to see. i didn't realize I was already working with the superior form. And as you said (or someone else above, can't remember) it was pretty cheap for a large bag of the stuff online.

I AM out of SMB however and also bought a small bottle of Bonide Stump Out to see how that works in comparison. I need to order some SMB online however.

Ascorbic acid is probably my next attempt.

Someday I'll try oxalic acid.

I have also been interested in trying hydrazine, particularly for my stock pot solids which I dissolved in AR and which I have been struggling with. I have some hydrazine sulphate powder. I have only found one place online that instructed to dissolve it in distilled water and HCL. I did zinc in the past but that drops EVERYthing as you know. Unfortunately I have an inordinate amount of waste (stock pot) I am trying to reduce and process. And after zinc I have a bunch of dried solids, mostly copper powder laced with precious metals. I need to review Hoke on the stock pot again. lol

Thanks again gentleman.

 

[ARMCO]

Most of the copperas, ferrous sulfate from the sack is no longer a pure salt of iron (II) sulfate, most of the dried product was further oxidized to form ferric sulfate, from drying the salt and exposing it to atmospheric air Oxygen and moisture changes during storage.

Note that the dried product was whitish brown, not a clear green salt.
Note the brown solution which formed when hydrating the salt, not the bright green color of iron sulfate, possibly even some insoluble iron hydroxide may also form.

Fresh copperas is a green crystal:

ferrous sulfate
https://en.wikipedia.org/wiki/Iron(II)_sulfate


which can oxidize further to a white/Brown salt:

ferric sulfate
https://en.wikipedia.org/wiki/Iron(III)_sulfate

Thank you;.

 

[ARMCO]

Most of the copperas, ferrous sulfate from the sack is no longer a pure salt of iron (II) sulfate, most of the dried product was further oxidized to form ferric sulfate, from drying the salt and exposing it to atmospheric air Oxygen and moisture changes during storage.

Note that the dried product was whitish brown, not a clear green salt.
Note the brown solution which formed when hydrating the salt, not the bright green color of iron sulfate, possibly even some insoluble iron hydroxide may also form.

Exactly! Ferrous sulfate is matched with one sulfate ion for each iron, while ferric sulfate is two iron and three sulfate ions. There is a third iron atom that is combined with oxygen and water and forms undissolvable iron oxides or hydroxides. That's why the solution is so turbid and not clear.

I must admit that I don't know how addition of hydrochloric acid to ferric sulfate can reduce it into ferrous sulfate. Isn't the result just a lowering of pH so iron hydroxides can dissolve and the color change is a result of the pH change?

I made my own ferrous sulfate from the wash water and diluted sulfuric that was left from my sulfuric cell experiment. I added a couple of pieces of iron from a computer case until there was no other reaction. There was some carbon released from the steel, but I filtered it easily off. The solution was saturated so there were a lot of crystals, added some water until it all dissolved.
The resulting blue clear solution was stored in a bottle and still after a year it is as fresh as when I made it. To use it I just open the top and pour off some of it, I don't need a lot as it is saturated.

I did a re-crystallization and made these beauties... just out of pure luck.
Copperas-1.jpg

Here is the dirty crystal mess with carbon from the steel.
Copperas-dirty.jpg

Filtering off the carbon.
Copperas-solution.jpg

Göran

Awesome. I like that you made that your self. I have had some of those crystals just like that after supersaturating a solution with the (online) ferrous sulfate, bottling it, and letting it cool. After it cooled some crystals just like that formed in the bottom of the bottle.

Just for fun, can the turbid Copperas be, for lack of a better word, "refined" and obtain some good clean solution or crystals? I think Aga above said "no" but I thought i'd ask [edited: for more opinions, no offense Aga].

 

[Shark]

Just for fun, can the turbid Copperas be, for lack of a better word, "refined" and obtain some good clean solution or crystals? I think Aga above said "no" but I thought i'd ask [edited: for more opinions, no offense Aga].

I have never tried it so I am not sure. I have a small amount in a solution that is getting pretty old, I will try and get it out soon and see what happens with it. This week is a bit crazy here, so it might take a day or three yet.