Refining Gold from Gold Filled Jewelry

[Oneal58]

Thanks Geo,
I will put this to use, I really appreciate your response. I am printing all my replies and making a notebook of the replies for references. Thanks,
Oneal58

Making ferrous sulfate (FeSO4), also called copperas or iron sulfate.

Copperas is green in solution or in crystal form.

Ferrous sulfate is good to use to precipitate gold from acidic solutions.
2AuCl3 + 6FeSO4 à 2Au (s) + 2Fe2(SO4)3 +Fe2Cl4

Iron sulfate will also precipitate platinum from boiling hot solution if pH 7.

FeSo4 crystal can be used to detect dissolved gold in solutions in the spot plate,
This is useful also if the gold is in solution with another precious metal, we can use the copperas crystal to test for gold in one dish of spot plate (brown ring) this precipitates the gold and remaining solution moved to another dish in spot plate and tested for other precious metal.

Copperas crystals (green) these crystals will oxidize easily if not stored properly, dry (acid low) and exposed to air (turning brown) the brown crystals will not precipitate gold, most all copperas I have found in garden centers has oxidized and is useless for our needs here.

The green copperas crystals, when made should be kept fresh in storing, I will keep them wet, few drops of sulfuric acid to keep them acidic, store in air tight plastic container (screw on plastic lid with seal an old stump remover bottle is what I use), they have a very long shelf life this way.

It is as easy to make a large batch of ferrous sulfate, as it is to make a small batch of copperas.

You need as pure iron as you can get (not steel), soft Iron laminates from old transformers, or electric motors, is what I use.

An old transformer cut iron laminate welds (hacksaw or angle grinder Etcetera), remove copper winding an save (to rewind another transformer, old motor, use as wire, or throw in your copper scrap metal pile), separate the iron laminates, cut into small pieces (with tin snip’s), use torch to burn off shellac and oils, add this Iron to dilute sulfuric acid (10% H2SO4), (the dilute acid is best as iron can passivate (not dissolve) in strong sulfuric acid), you can dilute battery acid (one part 32% battery acid to two parts water), or dilute the drain cleaner in water.

:shock: Always add the concentrated sulfuric acid to water slowly watching the temperature rise from reaction).
Never add water to concentrated sulfuric acid it will boil out and splash all over you burning you severely or blinding you}

The iron will dissolve slowly in cold solution, heating will speed the reaction, you can boil this solution of iron metal and dilute sulfuric acid because the sulfuric acid has such a high boiling point so gases evolved are mainly just water in fumes.
I use a Pyrex Mr. coffee pot, or white corning ware casserole dish on solid iron metal burner electric hot plate.

After as much iron as will dissolve (dissolves into the concentrating acid) lower temperature and pour this green solution into another jar, letting un-dissolved iron metal and carbon settle well.

Filter solution back into evaporating dish and boil down to crystals, when you get a few inches of crystals cool solution somewhat then pour into a clean jar let cool more and crystals settle, decant liquid back into boiling vessel and make more crystals, this concentrated solution can be used also.

i dont mind being corrected and really appreciate someone taking the time to point out any errors i may make in my comments as im still learning.the laminates your referring to can not be pure iron or even close to it.pure iron is a crystal and does not bend easily without breaking such as castiron.the soft laminates from transformers is an alloy that can be searched on the web.(i did) so i wouldnt look foolish saying this but can contain as little as 85% iron with Ni or Co these can be bent double and be flexed many times before breaking,iron will not stand up to these stresses.

the crystals i spoke of look more like aqua-marine but according to wiki copperas crystals are green if pure.

 

[qst42know]

I put my gold filled items into a 500ml flask and covered with 150 ml of water. I poured out 150ml of Nitric into a beaker.

In a 500ml flask, 300ml of solution pretty much guarantees a fountain. It doesn't leave much room for expansion.

A beaker or coffee pot filled no more than perhaps 1/3 full is much safer. A watch glass or other glass cover condenses some of the fumes.

Cover and leave outside. Put the whole thing inside a bucket or plastic storage container with lid if there is a chance someone or something might spill it in the night.

 

[Oneal58]

Thanks qst42know for your respones.
Question 1- Do I dilute the nitric down to 50/50 and add to the beaker or do I just keep adding full strength to the beaker now. I have since changed over to a large 1800ml beaker. But do I gradually keep increasing the strength of the Nitric in the beaker if I still have base metals that are not dissolved. Or just keep adding the 50/50 nitric? Thanks,
Oneal

 

[qst42know]

i dont mind being corrected and really appreciate someone taking the time to point out any errors i may make in my comments as im still learning.the laminates your referring to can not be pure iron or even close to it.pure iron is a crystal and does not bend easily without breaking such as castiron.the soft laminates from transformers is an alloy that can be searched on the web.(i did) so i wouldnt look foolish saying this but can contain as little as 85% iron with Ni or Co these can be bent double and be flexed many times before breaking,iron will not stand up to these stresses.

Geo

I did look these alloys up, and some discussions on their use. I see they are many times more expensive and used for more critical applications than the low alloy 1020 steel which would be common in small transformers and fractional HP motors.

I was previously unaware of these special alloys. Thanks for finding this it could have been a mysterious contamination in a gold precipitation.

 

[qst42know]

Thanks qst42know for your respones.
Question 1- Do I dilute the nitric down to 50/50 and add to the beaker or do I just keep adding full strength to the beaker now. I have since changed over to a large 1800ml beaker. But do I gradually keep increasing the strength of the Nitric in the beaker if I still have base metals that are not dissolved. Or just keep adding the 50/50 nitric? Thanks,
Oneal

I have only used poormans nitric which is 50%.

Anyone else?

 

[butcher]

Geo,
I am also still learning,
And as you, I also want to be corrected or shown the best way to do this if there are better ways, I would also like to learn as much as possible about the Iron alloy's and their use.
As far as I know the laminates is fairly pure iron,

I have not seen where cobalt or nickel was used in this type of laminates in transformers; there are many different types of metals used in electro magnetic core metals(electical metals), used in electronics and electrical industry, and may be many different types used for this or other purpose depending on the magnetic reaction needed in their use.

I have heard of small amounts of silicon and other metals in laminate, but this has not given me any problems in the copperas that I know of.

The ferrous sulfate from your garden supply I would say has more metal contaminates, but if green will work well for use.

Most all iron or steel will have contaminates.

I have not seen where cobalt or nickel was used in this type of laminates; I would like to see the composition (the document you spoke of reading), just out of curiosity.

The transformer laminates are the best Iron I have found to make ferrous sulfate with, I thought they were fairly high purity soft easy to work with thin and makes great ferrous sulfate. (Without using my blacksmithing stockpile).

Real iron is hard to come by since we do not use blacksmith shops any more, I do have some railroad iron or horseshoe iron that may be fairly close.

Iron can be very soft and flexible, or made to be hard brittle and crystallized and break like glass. This is usually done with heat treatment or can also be from other materials like carbon, silica and so on in the metal or added to it.
Cast Iron I thought has much more contaminates, I do not know if these would affect the copperas if it were made from cast Iron, I do not think they would but I do not know.

http://www.aksteel.com/pdf/markets_products/electrical/Mag_Cores_Data_Bulletin.pdf

http://en.wikipedia.org/wiki/Cast_iron

I also make ferrous sulfate using sodium bisulfate (the byproduct white crystal salts saved from making nitric acid) the sodium bisulfate act very similar to the dilute sulfuric acid in water with heat.

 

[Geo]

this is a company that makes laminates with special alloys.my point being unless you have the specs for each individual transformer or motor stator your playing Russian roulette with your processes. www.magmet.com/lamination/materials.php wiki states that the electrical steel is an alloy but only list Si as the other component but there are others.would you use something your not sure about that may contain a contaminant or something you know for sure whether it does or not and if it does whats in it and what you can expect.

 

[Oneal58]

Hi Everyone and Anyone,
I have just got back in from adding more nitric acid to the lot of gold filled material (jewelry) I am dissolving the base metals from.
I have added nitric and each time I get a reaction telling me there is more metal to be dissolved.
I add more nitric, full 70% nitric now in 100ml increments since I moved the batch to large 1800ml beaker.
I have added nitric now for the fourth time and am still getting a reaction and the flask heats up each time.
From what I have read I keep adding the nitric untill the reaction ceases. Telling me I have dissolved all base metals.
In total, I have put 450ml of nitric into the batch of gold plated material.
I started with 3/4 pound of gold filled items, rings, necklaces, Etc;.
I am still getting reaction and heating of the vessel.
I am going to stick with this routine untill I can add the nitric and not get the reaction and heat.
I am into this process now about 2-1/2 hours.
Am I following procedure or have I left something out?
Thanks, Oneal58

 

[Geo]

Oneal58

it takes 1 gallon of 70% nitric to digest 2 pounds of copper.you have 3/4 pound of material and not all of that is copper.you should use 1404 ml 70% nitric acid for this process. cover with a watch glass or any glass cover and add a little heat.

 

[Oneal58]

Thanks Geo, I appreciate that. So, I have a long way to go yet to get all the base metals dissolved. I will bring the heat plate outside tomorrow and start adding a little heat to get more work out of the nitric? I just didn't know how close or how far I was away from the goal of getting the base metals out. Thank you for answering that question. Live and learn. I should have looked that up before I got started, saved me a lot of worry.
Can you overshoot with the nitric and cause yourself problems? What I mean is can you overwork the material with nitric?
Thanks, Oneal59

 

[butcher]

Oneal,
Your 70% nitric should be diluted with water, for each gram of copper it would take about 4.2ml of 70% HNO3 and 4.2ml of water.
It takes about 130ml HNO3 70% and 130ml of water to dissolve an ounce of copper.
It takes about ½ gallon 70% Hno3 and ½ gallon water to dissolve a pound of copper.
(Thanks GSP, I hope I did not screw up the numbers here).

If your using 70% nitric and heating without water, much of your nitric is being lost to fumes, as the nitric is already at its azeotropic mix, adding water will help to keep nitric in your pot dissolving the copper. I find adding some 3% H202 hydrogen peroxide is also beneficial in solution.



Geo,
Thank you for that document, I have not found 80% nickel transformer laminates or inductor cores but I will search for them now, I would like a source of that white metal for other purposes.

Most all of the transformers and motors I have run into have soft iron laminates.

As I stated earlier there are many alloys and metals used, "electrical steels” used for their magnetic properties in the industry.
Some very exotic mixtures also inductors and choke’s also can have a wide variety of compounds.

I do not believe you would be playing Russian roulette using the iron transformer laminate or old motor laminates, My crystals of ferrous sulfate seem really pure, I have had no trouble using them (I could be washing the trouble (if any) out when I wash the gold powders I really cannot say), but as long as I achieve good results with the process I will continue to use it.

I would sure hate to post a process to make your own chemical if it would cause other's problems in there processes, and if that is the case I will not post it, and-or remove it.

Iron can be softer than aluminum and cut with a knife, although you will not run into much soft pure iron nowadays, blacksmithing a lost art they used a lot of it long ago, but modern steel has replaced its use, even our modern Iron is actually steel.

 

[Oneal58]

Hi Butcher, hope you are doing well today. Thank you for your post, this is good information to know. I realize I do not have the knowledge and understanding of the process yet. But to be competent it will take many, many, years, not months. You have to start somewhere and be hungry to learn, which I am. Just like understanding electrical properties, how it's made, what makes it do what it does, what characteristics it displays when certain loads are applied and componets are placed into a circuit. It has taken me a lifetime and many years of study and I still only scratch the surface on the subject of what I know. Just as some my think that wiring a house, calculating the loads, Etc;. May seem complicated, but honestly it's the most simplest thing to do in the electrical field. It is #1 on a scale to infinity! I say this because I am sort of like in that stage with refinning right now, it seems complicated. But I know down the road somehwere everything will click and the light will go off in my head. I will then build upon that base. I am full of questions but I have to learn how to ask them first, if you are following me. But I am a person that has to get his hands on something, try it, learn from my mistakes. But also try and prepare myself enough that I don't do damage or harm myself or others in the process. The electrical field can be dangerous, it killed my brother. You have to respect it, just as I respect this field. Carelessness can kill you! I feel confident that I can make a decent refinner. I realize I will be weak in the technical areas of the field just as I am weak in areas of the electrical field. But I made a decent electrician even though there is tons of things I didn't know and still don't know.
So, when I ask all these questions that may sound dumb, consider where I am right now and please be forgiving and understanding. I am at #1 on a scale to infinity.
Thanks Butcher
Oneal58

 

[Oneal58]

I left my Nitric Acid covered last night with a larger container on top of the nitric. I added a fresh batch of Nitric before I went to bed around 2:00 A.M.. I walked out the house this morning to where I had the batch of Nitric dissolving base metals on Gold Filled Jewelry. Thinking that any reaction would have been long stopped I lifted the lid before checking the direction of the wind or wearing my air cartridge face mask. I lifted the lid and before I knew it I got a whiff of strong Nitric. The Nitric was still fumming brown smoke. I stopped breathing and backed off from the Nitric container. My question is, how much of this stuff will do damage of some kind?
Thanks Oneal,

 

[publius]

1. NO respirator cartridge will filter out or neutralize Nitric Acid fumes and the associated vapors.
2. Any amount of exposure to Nitric acid and associated vapors will do damage to lung and eye tissue that may or may not heal.
3. Nitric acid reactions should be done under a fume hood or outside where the air can easily dilute the fume/vapors produced.

Play it safe.

Robert

 

[Geo]

this is a story i have told on the forum awhile back.i started dealing with nitric acid about twenty years ago making it for my father and others in the mining community.i had no chemistry knowledge and only knew the process as published in chemistry books.i made nitric for almost nine months forever sick and coughing up blood.i didn't know that i was slowly killing myself.even though i actually breathed the fumes a few times that strike my memory it seemed i was smelling the familiar smell of nitric all the time.now im disabled with COPD and cant walk through Lowe's or Walmart without oxygen.i have never smoked a cigarette in my life.you cant be too safe.nitric acid was called "the red death" by miners for a reason.respirators do not work for nitric acid.you really need to devise a way to vent these fumes away from you or build a fume hood.if your exposed to nitric acid fumes for only a short period of time it can at the least give you pneumonia and at the most it causes pulmonary edema that CAN kill you days after exposure.

please be careful.

Jeff

 

[Oneal58]

I have a fume hood installed. I didn't trust it to keep the fumes out of my enclosed area. I was warned many, many times to do this outside. Which I followed directions. I hope I didn't get enough into my lungs to cause any damage. I did the wrong thing when I held my breath, I should have turned and exhaled instead of holding the fumes in? I just didn't think quick enough. Oh well, I have been knocked silly by electrical jolts, through no fault of my own. Maybe this will get my attention to be even more diligent to stay on guard and stay safe. Thank you fellows for your input, time will tell.
Thanks, Oneal58

 

[Oneal58]

Hi Everyone, just giving an update on my progress with the sulphuric cell.
I diluted sulphuric by 1/3rd and then 5 hours later 1/3rd again. I ended up with what you see in the images I loaded. I will let this settle more and then pour off and wash again and decant.
Question 1- I am considering a Nitric treatment to the black powder or is this necessary Or the right thing to do?
I will then add HCL/CL at 4 to 1 ratio.
Question 2-Am I on base with the process so far, let me know if I have forgotten something?

I have my 3/4 lb. gold filled items I am dissolving base metals by Nitric in it's final stage, I hope. I am warming solution to see if I can get any more reaction but I believe the process is about finished. To dissolve the base metals in this 3/4 lb. lot has taken about 1600ml of Nitric. That's on base with the fromula that Butcher gave me to use to dissolve copper. I am finding that this is an expensive route to take but I don't want to make that call yet, untill I see the returns. I know I will be making my own Nitric from now on. I picked up a couple more bags of Potassium Nitrate yesterday from farm supply. When I transfered the Nitric to the Coffee Pot the gold looked like it was metal free.
Question 3-What are the signs of spent Nitric/how do I tell if it is spent. I have a large crock I will be putting the Nitric in for later processing. I have some Litmus Paper, can I use this to tell? I have loaded a picture of where I am with the gold filled.
Last Question 4-Why can't I save the powder from my sulphuric cell and just put it in with the gold I will be getting from the Nitric Treatment of the gold filled material.
Thank anyone for their response.

 

[Geo]

after you have diluted your sulfuric and reclaimed your powder you can reclaim the sulfuric acid by evaporating the water back out of the solution.

 

[Oneal58]

Thanks, Geo, every little bit of information is a big help. Oneal58

 

[Oneal58]

Could someone tell me why It's a bad idea to run my gold powder that I got from the sulhuric cell through with the values recovered from the nitric treatment of the gold filled jewelry? I know that HCL/Cl of the powdered gold has been recommended. I am fine with that, I just would like to know (why is it best) to use HCL/CL on the sulphuric cell powder and the AR on the values from the nitric process. This is just so I can understand why? Thanks to anyone who will answer. Oneal58