# Making "Copperas" - ferrous sulphate



## austexjwlry (Jun 18, 2007)

Copperas - is an iron salt, chemical name ferris sulphate. In Hoke's book on pg. 64 it says one way to make it is to dissolve iron in sulphuric acid, then crystalize out the salt that forms.
I cut up some cast iron scrap, put them in old cast iron frying pan, mixed
up some dilute sulphuric acid , covered the pieces in pan. It went to work right away. Started to stink real bad like rotton eggs. Stank up my whole shed! It stank for two days straight! Managed to clean frying pan really well before I gave up due to smell!
I read somewhere else to make away from light. Does anyone know a proper way to do this?

Thanks
Wayne


----------



## butcher (Nov 3, 2008)

Ferrous sulfate (copperous) also called green vitriol.used to precipitate GOLD.
I make mine by putting dilute sulfuric acid glass jar, take transformer laminates (IRON) burn of surface contaminate, rinse,cut to small pieces put in jar of H2SO4, let disolve (can heat if in hurry),solution looks light green and metal Iron in bottom is good. 
I keep slightly acidic if storing.
{do not stopper as gasses would build preesure causing potential dangers},adding a little sulfuric acid or iron pieces as needed and to keep acidic, 
this can be decanted and used to precipitate gold or evaporated to copperous salts (pale green yellow)for long term storage. 
this makes a very good chemical to precipitate Gold chloride from solutions and doesn't seen to drag down the copper(from high copper solutions) like sodium metabisulfite does.


----------



## Ignatz61 (Nov 17, 2008)

I just tried making Ferrous sulfate (copperous) but I did not get a green reaction. My steel is disolving very slow and the acid is a light brown.
I cut the Sulfuric about 50/50 with water. It's been more than a week and my steel is still in pretty good shape. I used strips of sheet metal and expected them to disolve rather readily.
Am I doing something Wrong?
John


----------



## lazersteve (Nov 17, 2008)

John,

I use the crystal that form in my silver chloride reduction setup. The acid is between 5-10% and slowly (1 week) dissolves the iron and forms nice big green crystals in the bottom of the flask. I'll post some photos when I get home tonight.

The copperas crystals is just a by product of the silver chloride reduction for me. Depending on how long you let the solution sit, you can grow some very large crystals.

Steve


----------



## Lou (Nov 17, 2008)

The rotten eggs reek is from sulfide impurities in your iron source.

Ideally, you should use just pure iron and dissolve in hot dilute sulfuric acid.

Lou


----------



## Harold_V (Nov 17, 2008)

Lou provided some excellent advice. Cast iron that was created in a cupola will generally have a fairly high sulfur content due to the sulfur content of the coke used. I would suggest you avoid using cast of any description for that reason. 

Steel, particularly mild steel, such as angle or channel iron, is low carbon, under .2%, and low sulfur as well, so it is one of the more desirable sources. The best one is laminations from transformers. They are made of carbon free iron, as are laminations in motors. 

I would think that filtering the resulting solution before allowing the crystals to grow would be adequate to remove traces of carbon. 

Harold


----------



## OMG (Nov 18, 2008)

Electricity will help it dissolve quicker.

I was fooling around with a citric acid and potassium persulfate electrolysis cell, and had a copper and iron anode. I let it run for a quite a while to see if anything would happen, nothing much did. Then it sat there for a couple weeks and when I went to clean it up, the copper pipe was half transformed into copper sulfate crystals. It looked cool, copper at one end and big blue crystals on the other end.


----------



## cloomis (Nov 19, 2008)

so can napa acid be used out of the box without dilluting?


----------



## butcher (Nov 19, 2008)

NAPA acid ? 
if by napa acid you mean sulfuric battery acid, it can be used for ferrous sulfate, 
if you want to concentrate sulfuric battery acid it can be done by boiling till white fumes appear(approx98%) 
never use used battery acid,


----------



## Harold_V (Nov 19, 2008)

Yeah, what butcher said. Used acid can contain traces of lead (sulfate), which is death on the quality of gold.

In order for the ferrous sulfate crystals to grow, you may have to condense the solution until it nears saturation. 

The acid can certainly be used dilute, and is actually preferred. For example, slimes from silver cells were commonly boiled in cast iron kettles in concentrated sulfuric acid to recover the silver that was enclosed. The sulfuric had little effect on the iron unless it was diluted. 

Lou or Steve could better advise you on growing crystals. What little ferrous sulfate I used was purchased, some even from a gardening center. I preferred SO2 from a cylinder, but ferrous sulfate works well, too. 

Harold


----------



## cloomis (Nov 19, 2008)

was just wondering since the napa sufuric acid was already dilluted ,and definately use new acid in this process.


----------



## cloomis (Nov 22, 2008)

So do we rince ,dry or use the crystals as is ,


----------



## butcher (Nov 22, 2008)

ferrous sulfate, if crystals I add water and few drops sulfuric to make sure its a little acidic (I have read where some people add few drops of HCL to get acidic).
I have used it without making it into crystals, and I only make the crystals if I want to store some of it.


----------



## qst42know (Nov 22, 2008)

Steel freight banding is low in impurities. The black finish burns off quickly. And coiling it around a pair of needle nose pliers removes most of the heat scale. An equal weight of banding provides a great deal of surface area to the acid and it dissolves pretty quickly. 

What is it about cementing silver that dissolves iron so much faster though? 

Would a small amout of HCL speed things up?


----------



## lazersteve (Nov 22, 2008)

The only reason I mentioned the silver chloride conversion relevance is because the ferrous sulfate is usable by product of the reaction. It's always nice to have uses of the leftovers of a reaction.

Many of the left overs from silver reactions lend themselves to recycling and/or reuse.

Steve


----------



## allanwcoty (Dec 19, 2008)

Just wondering what the by product of dissolving motor laminae in the dilute sulfuric is besides copperas? Fumes? Will the reaction still continue in the cold, just slower? I'm talking 20 degrees below F.


----------



## qst42know (Dec 19, 2008)

I would guess if your car battery doesn't freeze in such weather, you could try it. 

As the acid gets used up it may freeze, (just guessing here) and I suspect it will take a long time. Time may take the place of heat.

I would not try this in glass but in a plastic container set in a larger bucket in case it freezes and splits. I may try this myself though I don't have 20 below.


----------



## jimdoc (Dec 19, 2008)

A battery that is not fully charged will freeze,
so I would think that fresh acid not used in a 
battery would probably freeze. The reaction
should build up some heat, don't know if it
would be enough to keep it from freezing.
It is cheap enough to just try it out, as long as 
you use a container that won't break.
Jim


----------



## Harold_V (Dec 20, 2008)

qst42know said:


> I would not try this in glass but in a plastic container set in a larger bucket in case it freezes and splits. I may try this myself though I don't have 20 below.



Plastic buckets at such low temperatures are no better than glass. 

Harold


----------



## Platdigger (Dec 20, 2008)

You may want to take a look at this link. It has the freezing points of sulfuric at different concentrations. http://www.resistoflex.com/sulfuric_graphs.htm

Randy


----------



## allanwcoty (Dec 20, 2008)

Thanks for all the posts. If I'm reading the charts right I don't have much room for the sulfuric to loose strength. Anybody with an answer to the by-products?


----------



## qst42know (Dec 20, 2008)

I don't know what the byproducts of making copperas are but if you must make some you could use an electric crock pot. If your amount is small you may be able to use one of those electric potpourri cookers. Still Copperas is quite cheap it may be difficult to justify paying for heat in 20 below weather for a low price compound.

I quit processing when it got cold to keep my electric bill down. I'm definitely suffering from the refiners form of cabin fever


----------



## allanwcoty (Dec 20, 2008)

Put 10 cups of new battery acid with about 10 small strips of iron out at 1pm at 10 degrees below F. Just checked at 3:30pm and has some slight bubbles that are forming a scum on the surface of the acid. Could be they are trying to freeze. Remaining solution has no sign of freezing.


----------



## allanwcoty (Dec 22, 2008)

Lots to learn. First batch was not with transformer or motor laminae but with some laminae that come out of old dial phones, about 12 in a stack that goes through copper coils. They are having some action but not much. I got impatient with it out in the cold and brought it indoors and put a plastic bag over bucket and secured to allow for expansion & gasses? Inside it still is working slow but better. 
Started a second batch with 10 cups new sulfuric and 2 chunks of unseperated laminae and they went to work pretty fast. Used up all of the sulfuric and crystals actually seperated the laminae and may be expanding too much for the coffee pot? Added second batch of sulfuric and will look at later. Coffeepot was very warm from the reaction. Any ideas as to the gasses being given off yet. Have a Merry Christmas everyone. allan


----------



## butcher (Dec 23, 2008)

Made 2 quarts of nice light green / blue crystals ferrous sulfate (copperous), cutup transformer laminates small pieces, torched any varnish rinsed in diluted sulfuric/water, in 5 gallon bucket covered with new battery acid 1 part and 2 parts water, (ok if stonger at first but needs diluted sometime). we want FeSO4*7H2O. when liquid nice blue color. I pull out liquid with suction bulb to get only clean solution, put into coffee pot, not disturbing Iron on bottom, then add more acid and water to Iron for next batch later.( this can be kept going till all Iron gone)
slowly evaporating the blue solution in coffee pot on hotplate, not boiling. and not too hot ( too hot acid seperates making unwanted white powder), I keep adding solution as it boils down after it gets pretty concentrated but still liquid, I pour off in bowl with lid, now cooling most of it crystalizes, I let it settle pour off concentrated liquid back to coffee pot, rinse crystals in sulfuric acid and put them in plastic container, sit them with lid loose by the wood stove to finish drying. this is not much trouble for me as most of this process does not need attention, and can be working while I am doing other things. and I have a good quality precipitant.

edit water does freeze out of the dilute acid (then Ill add lil more acid ) to bucket seems to help by raising specific gravity, and doesnt seem to hurt process, crock pot would also work (but mine are always full of crystalizing other acids to salts)


----------



## allanwcoty (Dec 29, 2008)

First batch with the phone pieces & 10 cups new battery acid has a slight blue grean color with blackish remnants floating just off the bottom. Very little iron started this one.

2nd batch had 2 pads of laminae and 10 cups of new battery acid and has used it and another dose of about 2 cups and has used it but has not dissolved all the laminae. Coffeepot full of light blueish crystals and undissolved laminae.

Took several layers of the laminae from #2 and put in 8 cups of new battery acid and it dissolved leaving greenish liquid. Added several more laminae from #2 and now have greenish liquid and blueish crystals.

Butcher - Are you adding water just to get the acid to go further or is there another reason for the water?

Are there any problems with not burning off the laminae or from not seperating them (except for having an overabundance of product)? I have a coffeepot and a half at this point and thats just from several layers of the laminae.

Any other uses for the "copperas"?

Have a Happy and Safe New Year, allan


----------



## Anonymous (Dec 29, 2008)

The gas would be for the most part hydrogen since the iron is replacing it in the solution.
Jim


----------



## butcher (Dec 29, 2008)

ferrous sulfate FeSO4*7H20, 
water is an ingrediant as far as I am concerned, I start off stronger but add water after it liquid starts turning blueish, I am not sure about this reaction but many metals will actually disolve better in dilute acids, and since sulfuric can be concentrated in Iron vessels (Cast Iron with silicon content) and dilute acid attacks them more than the concentrated acid,so this was my reasoning for the water addition, all I know this really makes nice ferrous crystals for me, and can use without crystalizing, i make the crystals for storage or for testing with. I have had jar of ferrous with Iron in bottom freeze the water (low acid and specific gravity) just adding a little more sulfuric acid will thaw and keep ice from forming Hydrogen bubbles , also if letting a solution sit for several days the hydrogen reacting with Iron the hydrogen gasses out, lowering acid content, adding a few drops of acid every once in a while is important to keep slightly acidic solution.
we have two chemists on the sight maybe one of them will get interested in this and give us a few more things to ponder.


----------



## LittleJohnnyH2SO4 (Dec 30, 2008)

Ill give a very quick explanaton of oxidation and reduction here. Oxidation is a loss of electrons (which have a -1 charge), while reduction is a gaining of electrons.

sulfuric acid is H2SO4. In water, it breaks up into 2 H(+1) ions and an SO4(-2) ion. H(+1) is a decent oxidizing agent. It accepts electrons from iron metal (which has a charge of 0) to make ferrous ions, which have a charge of (+2). By accepting the electrons, 2 H(+1) ions become H2, which is hydrogen gas and has a charge of 0.

Net reaction:

2H(+1) + Fe(0) --> H2(0) + Fe(+2)

H(+1) can't oxidize Fe(+2) any more, but the oxygen gas in air can like this:

O2(0) + 4Fe(+2) --> 2O(-2) + 4Fe(+3)

Fe(+3) is called a ferric ion. As long as there is extra acid in solution, it can dissolve. If there isn't any, your solution will start to get rusty looking, as will exposed crystals of ferrous sulfate. Ferric ion is useless for reducing gold to the metal, which relies on gold(+3) (auric ion) as an oxidizing agent like this:

Au(+3) + 3Fe(+2) --> Au(0) + 3Fe(+3)

The only thing that matters at all is the Fe(+2) being around. You're used to seeing copperas as the heptahydrate, which are the green-blue crystals, but the white powder is just a different hydrate missing a few water molecules. It will perform just as well as the green stuff at reducing your gold.

Any air oxidation of the ferrous ion is reversible as long as there is iron metal and acid left like this:

Fe(0) + 2Fe(+3) --> 3Fe(+2)

The black grunge at the bottom is probably traces of carbon powder and silicon powder from the iron. Gases coming off are almost entirely hydrogen and _may_ have very, very small amounts of silane.


----------



## butcher (Dec 30, 2008)

Thanks Johnny , I have a question here, maybe I am just confused here, I knew rust can be converted back to Iron metal with electrolisis(pushing electrons), I have used electrolisis to restore rusted antiques,but are you saying it can be done in just a chemical process? looks from equation rust and ferric sulfate converts to ferrous sulfate as long as hydrogen from acid present,if we gained two electrons we would be back to Iron, wouldn't this just be powder? and the electrical current needed for restoring rusted Iron antiques?
sorry if this is hard to understand I have a hard time saying what I mean.
and I am very new to chemistry trying to learn on my own.

Any air oxidation of the ferrous ion is reversible as long as there is iron metal and acid left like this: 

Fe(0) + 2Fe(+3) --> 3Fe(+2)


----------



## maynman1751 (Mar 19, 2020)

Sorry for digging up a very old post buutttt. I am trying to make some ferrous sulfate. I'm using transformer laminates that I burned the impurities off. I'm using sulfuric drain cleaner 98% and diluting it with water 50/50.
AS soon as the reaction starts the solution turns a deep brown color. I've tried two different transfomer plates and diluting the acid further. I've done this before and everything went fine. Any ideas or will this still filter out OK. I certainly don't want ferric sulfate. I'm also using low heat.


----------



## anachronism (Mar 19, 2020)

No disrespect but you can buy it cheaper than you can make it. 

And it's pure 8) 8)


----------



## butcher (Mar 19, 2020)

The sulfuric acid should be diluted to around 10% H2SO4 concentration.


----------



## maynman1751 (Mar 19, 2020)

anachronism said:


> No disrespect but you can buy it cheaper than you can make it.
> 
> And it's pure 8) 8)


Maybe, I don't know. I just like making my own.


----------



## maynman1751 (Mar 19, 2020)

butcher said:


> The sulfuric acid should be diluted to around 10% H2SO4 concentration.



I have since diluted it considerably. Is this batch ruined or is it still salvageable Thanks!?


----------



## butcher (Mar 19, 2020)

You may have iron in various oxidation states, (the reddish or brown sounds like rust) which may be insoluble in the solution...

Iron will passivate in concentrated sulfuric acid.

Iron will dissolve easier in the very dilute acid.

Oxygen in solution or iron exposed to air can also form iron in other oxidation states...


----------



## Geo (Mar 20, 2020)

Iron oxide will dissolve into sulfuric acid easily. I doubt it's iron oxide. Drain opener has inhibitors but I have used it before myself with no issues. It may be the laminates. I found some time ago that some transformer laminates contain nickel. There may be other metals at play. When I make copperas, I use rusty nails. I actually use old pallets as wood for fuel in my incinerator. The nails left behind oxidize rapidly even if they are kept dry. I just toss a hand full in a 2000 ml beaker with 100 ml's of sulfuric acid and 900 ml's of water. Add heat all day and keep topping the solution up with water. There is quite a bit of carbon in steel and will form a black powder that has to be filtered out.


----------



## maynman1751 (Mar 21, 2020)

As usual a big Thank You to Richard and Geo! I split the solution, diluted it further and it just took off. Today I have a nice pale green solution that is growing beautiful green crystals. 
Since my wife was paralyzed in a neck surgery in 2014 I'm pretty much on a hiatus from refining. Forgot some of the details but it's coming back. I'm starting to 'play' around with it again on a very limited basis.
So, Thanks again guys! John.


----------



## butcher (Mar 21, 2020)

John, Some details may get foggy, as you get back into the groove they will become clearer again.


----------



## solarnevo1 (Apr 29, 2020)

Try this looks easy...
https://m.youtube.com/watch?v=sADtR1ytkwc


----------

