Refining Gold from Gold Filled Jewelry

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butcher said:
Also I would put the magnetic materials the magnet picked up in my stockpot as it may also collect some gold powders or some gold could be mixed with Iron.
Click to expand...
Excellent advice. Especially when processing filings from the jeweler's bench, which always contain bits of iron.

When dealing with items such as watch bands, unless you can strip them with cyanide, you're best served to dismantle them. Items such as the stainless backs and springs should be discarded.

I would suggest that a conventional (ALNICO) magnet be used when sorting items that have iron within. Many objects that contain gold also contain nickel, which may be attracted to super magnets, at least to some degree. By using a weak magnet, only objects that have the potential to be troublesome should be detected. Those that are strongly attracted to the magnet make great material for the stock pot, where it will be used to cement values.

Harold
 
Thanks Harold,
I have noticed that (some) of the items that my rare earth magnet will pick up will not be picked up by a large refrigerator magnet my wife keeps her groceries list pinned to the frig. with. So, you have answered that question for me. Also, the pieces that's barely magnetic that I mentioned in my previous post is another question I have no longer thanks to you and Butcher.
I have a couple of other questions.Hoke mentions in her book, when you make a pour and the gold button pour developes a dimple in the top of the drop? Hoke says this is a reliable indicator for telling you whether you have a good quality pour or not? She says this indicates that the button is going to be soft, pliable,easy for the Jeweler to work with. She says this indicates that the button has little or no tin or lead.
So, how reliable is this dimple forming in helping you determine the purity of the gold button you have? Is this a reliable method of telling if you have a pure or near pure gold button? What are some of the other signs to look for when you pour a button to let you know you have a good high grade button without having to assay or test the button?
Do you use crushed glass on the final melt as Hoke mentioned to do? If so, will you not have to break/crush the button to get the glass coating off to weigh or sell? She also mentioned you can use Saltpeter (KN03) and or soda ash. She also says you need to use Borax each time to coat the crucible before applying heat. I guess what I am asking is, are any of her methods outdated or changed/updated since she wrote her book? Does anyone use these materials in the final melt? I know of course to use Borax coating on your curcible but not sure about the glass, soda ash, or saltpeter?
Hoke also says to use Copperas to drop the gold out of solution. Most everyone on the site here says to use Sodium MetaBisulfate now. That it works much better than Copperas. I looked for a full1/2 day to find a bag of Copperas, finally found some at a Tractor Supply Store, 40 miles away from home. So I was wondering if any of the other information in the book has been outdated/updated and if so what are some of the main things that she says in her book that is no longer used because a new updated process was introduced or a little better refining method was found?
Does anyone still use Copperas anymore? I bought a 4 pound bag of pure copperas for $22. I haven't used any of them yet so I could take them back if they are not going to be used. I have to carry the Draino I bought back because I checked the MSDS Sheet on Draino and it has other fillers in it besides the Sodium Hydroxide. I found Liquid Fire at Ace Hardware, the MSDS Sheet says it's 99% pure Sodium Hydroxide. So, is this good to use, Am I thinking correctly here, that the Liquid Fire is pure enough to use without cleaning it up or trying to purify something that is 99% pure already? Thanks for your help. Oneal58
 
Oneal58,

Copperas is an old chemical name for ferrous sulfate (iron sulfate) (FeSO4), it works very well to precipitate gold from solution, many times I even prefer it over SMB, the crystals need to be green, if they are oxidized brown they will not work, I make my own (copperas) ferrous sulfate, using soft iron laminates from old transformers or motors I burn the shellac off them cut them to small pieces and heat them in dilute sulfuric acid about 10%H2SO4 dissolving the iron into a green solution, this green solution is filtered and concentrated down to crystals, kept slightly wet and acidic for storage, I will use the green crystals or the concentrated liquid.

The ferrous sulfate crystals also are handy for testing purposes in a spot plate to test for gold and also to separate gold in solution in the spot plate to test for other valuable metals, Harold has made several posts explaining how to do this.

Make sure your ferrous sulfate (copperas) is green before using, if it is brown (oxidized) you can use it in the garden and make you some, there are more details about it on the forum.

The Impure sodium hydroxide should be ok for waste treatment, to neutralize the acids.

I thought I have bought liquid fire before and it was concentrated sulfuric acid, are you sure your jug is sodium hydroxide?

If this is liquid fire sulfuric acid it is usually sold with the gallon jug wrapped in plastic and is good for the concentrated sulfuric cell.

Look again at what you have in the liquid fire bottle.

As far as using crushed glass, quartz sand, borax, nitrates, sodium carbonate, flour, charcoal, litharge, and other ingredients, most of these are added as flux when you are melting materials that contain gold to collect or assay the gold or other values, each of these ingredient have specific purpose in the melt, some like glass form slag for oxides of metals to gather into, slag can also shield your melt from environmental oxygen from torch or furnace, nitrates would oxidize base metals in the melt, flour or charcoal remove oxides make CO2 gas, borax also forms a slag and act as flux shield or to help metals from sticking to your dish or crucible, helps to get melt more fluid where powders can melt together better, sodium carbonate also helps with this also and helps remove oxides and can help in conversion of metal salts in the melt to form molten metals (like silver salts when melted)
The use of these and other ingredients in the melt, are chosen by what properties you need them to perform.

Sodium carbonate is hard on melting dish or crucible somewhat attacking it, but can also be used to clean them. I have no proof but it seems to take old slag (glass full of metal oxides) melts them more into metals and glass slag, making them fluid enough with heat to pour them off, it also seems to melt some of the surface coating of the dish and add it to the slag being poured off.

Sometimes people use flux to help improve the looks of their impure gold (or to slightly improve its quality) (in this case re-refining would give higher purity), unless you were just selling it to a refiner as impure, but then why fool with it?

Gold of high purity will melt with only a wet coating of borax to dish so gold will not stick to dish as powders are brought into a molten form, adding too much borax and the gold may be harder to remove from the dish.

The dimple (pipe) and bright color, softness, crystal, and lack of oxide coating does give an indication of purity of the gold.
 
Hi Butcher, you are right, I was thinking one thing and typed another?? I have reallly got to watch this more closely and (proof read), check over what I type. If I can make this type of mistake here, I could also make a mistake under the hood. From what I know now a mistake made with some of the chemicals involved is unforgiving and you will not have a second chance.
You were right, I am after the sulphuric, but I did buy the Draino. I came home and pulled the MSDS Sheet on it and found it had impurities in it. I didn't buy the Liquid Fire yet, I found it at Ace Hardware then came home and pulled the MSDS Sheet on it. I am going to go back to buy it. I just didn't want to buy something else I could not use. I have done enough of that trying to get the right lab glass I needed off Ebay. Another thing, I thought that all products on the shelves of stores suppose to have the contents labeled on them? I have noticed that some of such items (chemicals) on the shelves don't have what the product contains anymore, just a number and website to check the MSDS Sheet on it?
But thank you for bringing this to my attention. I really do need to work on this harder, pay closer attention and proof read more. Hoping this practice will follow me to the shed out back.
So, I will hang onto the Copperas until I open the bag at least. If crystals aren't green and fresh, I just have a good product to use for Iron deficiency in soil. I cannot find a manufacture date on the bag of Copperas I bought anywhere, unless of course I have overlooked it, which is possible. I will look again tomorrow.
A question on the melt of the high purity gold in the crucible. When you say add a wet coating of Borax to the dish so gold will not stick to dish. Do I add just enough (water?) to Borax to make a paste to coat dish with? If so, about how thick should this paste be? Does the Borax completely burn off during the melt? What if you put too much Borax into the crucible? Do you keep heating the gold until you burn it all off or does it form a slag that can be removed? On new crucibles, should I season the crucibles with a coat of Borax on them or cure them without adding anything in the crucibles before use.
The more I ask questions, read and study, the more I realize the depth of what I am attempting to do and how little I still know. I thought I would have been melting gold a month ago. I still haven't fired up my torch to melt any gold yet? I honestly don't feel I am any nearer to doing this now than I was a month ago? I have missed only a few days studying during the last couple of months. I will probably average 4 hours of study, reading, a day. It took me a week and a half to read Hoke's Book alone. I took it slow and easy, double and triple reading many chapters.
I got 1 more question for everyone who reads this post. Was there a lot of anxiety before your first refine/melt or is it just me who feels this way? I just need to get to the place that I feel confident enough to just bite the bullet and get the torch fired up.
Thanks Butcher and everyone else who has helped me so far. I am so thankful I found this site, it's been a life saver, literally.
Oneal58
 
Oneal58
Relax you are getting there faster than you think, patience is a big factor here, my melting dishes I heat them up slowly so I do not crack them to get rid of moisture then just sprinkle some borax powder on the hot dish, just enough to coat it the borax is kind of fluid when hot, and this is what I meant when I stated (wet the dish with borax).

I have heard one member say he painted water wet borax on his dish but I would not do that, as I have had dishes crack just from heating out the moisture of what looked like a dry dish, even though the dishes are not very expensive they are a trouble for me to get and I want to get the most mile's I can out of the ones I have.

The borax becomes a clear fluid when hot (and will change color if it absorbs base metals) if you melt gold even fairly pure you may see a light violet color stain which kind of looks like the diluted stannous test, in the borax coated dish after our done, when borax cools it is like a soft glass clear if not tainted with metals, (this soft glass coating which can be chipped or hammered off a metal if you added a lot of borax to the melt), when we melt our refined gold buttons the gold is not really got a coating of borax, sometimes if you add a little more borax than you needed the button may stick in the bottom of the dish when borax glass cools, these can be moved after gold cools down and before borax cools, or most of the time just popped loose with a pocket knife.

I do not see any reason to fear this, just inform yourself of dangers and take the precautions, a lot of it is common sense, and learning before you jump off the bridge (is there water in the river did you even check) you seem to be doing your homework and I feel you will do just fine.

There is a lot to learning all of this, and it gets easier as you go, but you will never learn everything, you are just starting to see why we give the answers to the question, when a new guy ask us tell me how to refine my gold in the next post. And expects us to tell him in ten lines or less.
 
Oneal58, i dont think he meant for you to wet the borax.what he meant was,heat the melting dish slowly to a dull red heat and then sprinkle DRY borax on the inside of the dish a little at a time and reapply the heat to melt and push the borax to a smooth coating on the entire surface of the inside of the dish,dont over do it,just enough to coat it evenly.it will look "wet" when you finish and after it cools it will still shine like it is wet.if you actually wet the dish before you try to heat it up the dish will break from trapped moisture exploding out.all my dishes crack a little at first,its caused from heating too fast or cooling too fast but after you have heated it the first time and conditioned it with borax it should hold together through quite a few melts unless you melt something thats dirty.use the dish you will melt pure gold only for melting pure gold and nothing else.after the fkux gets dirty or the crack gets too big you can use it to incinerate in or to do test melts.
 
Thanks Butcher and Geo,
I understand now.
Another question, I was told by Harold to heat the gold filled watch band tops/cases I have up to a dull red, not melt, just heat them up at 2 seperate times in the process he gave me to burn off all the krud that is on them. I can just imagine what's inside these things after the bands have been worn for years on someone's arm.
Someone has told me to use caustic soda/Lye and boil the gold filled watch band top caps/cases a couple of times on the hot plate. I would prefer to go with Harolds advice on cleaning the watch band top caps and cases than using caustic soda or Lye. Unless of course this alternate method could cause me less trouble down the road. I was looking at these watch band top caps last night. Some of these top caps are nearly 1/4 full of God knows what? The watch cases are not as dirty.
So, I am asking, if the watch band top caps are really dirty will burning them a couple of times as Harold told me to do get all the dirt out/off of them or do I need to boil them up first in some caustic soda/Lye? Do I then burn them like Harold told me to or will they clean up with the Caustic Soda/Lye good enough. I develped a way to get these top caps off quickly but this process that I use squeezes/crushes about 1/3rd of the top cap together, tightly. Maybe tight enough that this Caustic Soda/Lye cannot get to the dirt I traped in there when I squeezed them together. I don't even want to think about having to open each one back up. :shock: It would seem to me to always give them a couple of good burns as Harold has stated anyway to burn this traped krud up. Even if I boil them up first. Also, I wanted to double check to see if this Caustic Soda/Lye does not harm/effect the gold filled band tops and cases. I read this on another site and just wanted to hear what someone thought about this here. I have many days of work taking these top caps off and would not want to destroy the value in them by doing something I am not suppose to.
I got to go to town and get some of the Liquid Fire from Ace Hardware I need. I need to make up some Stannous Chloride Solution. I read on the site somewhere that I can use lead free plumbers solder and dissolve it in a little nitric acid for my tin. Will this be pure tin, pure enough to make Stannous Chloride?
Thanks, Oneal
 
Oneal58,

Always follow Harold's advice, you will not go wrong.
Sometimes there are other way's to do things, but until you understand them stick with known proven procedures,

I cannot say where Harold told you to burn something red hot, we usually refer to that as incineration, it is usually recommended for several reasons, like removing oils and inorganic materials, or carbon-ous materials, incineration is also recommended when we use one acid in a process like nitric acid, and after decanting and rinsing the powders we may incinerate to remove the nitrates formed (removing the previous acid or salts of those acids) because we cannot just rinse out this previously used acid it may effect our next step(like dissolving gold when we do not want it too), so now we can change acids say like washing in HCl (without the previous acid nitric mixing with the HCl and forming a form of aqua regia and dissolve gold) when all we may be trying to do to these powders now is to rid tin and other base metals (see more about tin and incineration)

Another reason we may use incineration, is to oxidize the base metals, this makes them easier to dissolve in acid, one troublesome metal is tin, tin in nitric acid makes a gooey mess, almost impossible to filter, it is also troublesome in chloride solutions, one way to deal with the trouble maker is to incinerate, this oxidizes the tin, which makes it dissolve easier in the HCl (hydrochloric acid) (muriatic acid), this not only helps us to get this trouble making metal washed out of our powders but also improves our ability to filter our solutions. There are other reasons for incineration, but just take Harold's advice he has been there done that, sorry if I new what instruction he gave I may be able to give you more clues as to why he said do it this way, do not miss or skip steps, or change the process unless you understand why and where, even skipping something that seems like why would that matter if I did not do this or that could mean trouble for you later, sometimes these very simple steps are there to eliminate this trouble, and you may not even see why.

Example say I told you to wash some white powders in boiling hot water and then decant, and you figure that heating the water is not important, too much trouble, and you just used cold water, then at the end of the process, you find your gold is full of lead and then you do not understand why, (lead chloride is much more soluble in very hot water, and almost insoluble in cold water), by skipping the part about using hot water (something that would seem unimportant) could mean success or failure, or having to start all over again and possibly making the same mistake again.

Stannous chloride is made with tin (95% tin solder will work) and Hydrochloric acid, also called HCl or muriatic acid.
(Stannous chloride is NOT made with nitric acid, which would give you that gooey stuff I was talking about above, and would not work to test for gold in solution)
 
Hi Butcher, you are right. Harold didn't use heat/burn in the manner I stated. He used incinerate just like you said he would have. I still am working on the technical language, it's slow in comming but I have tunnel vison now and we will get there with your and everyone else's help. All of you have taken your time to answer my questions and that really means a lot to me. I promise to play it back one day down the road with other first timers like me. Only when I become competent to do so.
I am building my tray/screen for my sulphuric cell now in the den. I am using #10 bare copper grounding wire to build the frame. I am using stripped telephone wire to build the basket by basket weaving the telephone wire to the #10 copper frame . I am doing so in a way not to make any solder joints at all in the sulphuric acid. The only place there will be a solder joint is (1) outside of the cell. Does that sound like it should work to you? I will send you a picture of it when I finish it. I am going to start on the lowest end material I have before I go to Harold's procedure on the gold filled material. I am going to start with some necklaces ( gold plated). Seems to me that the necklaces I chose will have more plating on them than just the run of the mill plated Jewelry. I am going to start with the necklaces that have a lot fine openings (holes) in them. Surface area should be at least twice as much on these than just the flat Herringbone type Necklaces with no openings in them.
I bought my Liquid Fire (Sulphuric) today from Ace Hardware, I bought a gallon to get started.
Butcher, another question tonight is, can I use brick cleaner which has I believe 31.45% muratic (hydrochloric) acid when it's time or do I concentrate it? Also, I saw a method of taking a few drops of concentrated peroxide, just a few drops and cleaning up the muratic. Is this step necessary to do? I also found my tin solder, it's 98% tin and 2% silver. Will the 2% silver be a problem? You have already answered this in a previous post about the tin solder for the stannous Chloride but I didn't mention the 2% silver? I am going to start with Industrial grade Nitric Acid. But trying to get ahead of the game I tried to order some Potassium Nitrate and the Farm Supply said they were not going to order anymore untill the spring, when they sell pretty much all their fertilizers. Same story at the other fertilizer dealers I called, can't get the Potassium Nitrate untill next spring. Do you prefer Potassium Nitrate over Sodium Nitrate? I remember you saying you made your Nitric?
So, can I use the 31.45% muratic to make my Aqua Regia when it's time or do I need to concentrate it? Thank you Butcher, you have really been bending over backwards to help me and it has not gone unnoticed and I am truely greatful.
By the way I copied Harold's Post, the directions he gave me on the gold filled material when I feel I am ready for that one. It's below.
Thanks Butcher,
Oneal58

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November 14th, 2011, 6:20 am by Harold_V
Re: modified reverse electroplate theory
Oneal58 wrote:
Hi Everyone, is it best to try and reverse electroplate the gold filled items I have
Not a good idea. The nature of stripping cells is such that they are very effective on pure gold, but not so good on alloyed gold, which is what you have with gold filled items.


or just melt the watch cases and make some shot and then drop a small test batch into Aqua Regia just to see is it worth the effort and expense in acids.
Also not a good idea. Have you read Hoke?

If not, why not?


I don't understand how Gold Filled items which are (mostly antique) are put together yet.
Read Nick's post. He covered it very well, in just a few words.


Is there enough gold in them to go this route or would it be a waste of good Aqua Regia and time.
If you used that approach, yeah, it's a waste of time. You clearly don't understand how such material should be processed. If you were to approach the project from that perspective, there'd be no end to the problems you'd encounter, all of which can be easily avoided.

To get good quality return shouldn't I melt everything and then start fresh with AQ and go through all the steps of recovery or is there a simpler route?
One does NOT dissolve everything along with the values when there are options. Gold filled is certainly top of the heap where this matter is concerned. Gold filled is generally 95% base metal, all of which is troublesome. Have you given any thought to NOT melting? Think a moment about this idea. First, remove any parts that are magnetic. Avoid including steel in your refining circuit. Also, remove any aluminum should there be any present. The pieces are then heated to dull redness (but NOT melted). That burns off any oils and other substances that can be problematic. You then go after the base metals with dilute nitric acid. The resulting solution will contains traces of silver, along with several other base metals, and will yield thin sheets of the alloyed gold, along with miniscule particles. The material should be subjected to nitric until all base metals have been dissolved. The remaining solids, including the fine sludge that is sure to be a part of the solids, is then gathered in a filter. When dry, it should be incinerated to redness, but, again, do NOT melt. After incineration, screen and go through the material with a magnet. The material should then be given a wash in hot HCl, then rinsed until the rinse water is clear of color. Only then should you dissolve the gold.

It's all in Hoke (except for the HCl wash after incineration, which is one I developed to aid filtration for such material).

You can run gold plated items the same way, although, with the cost of nitric acid, you're better served to strip such items with a sulfuric stripping cell, or to use the AP process that is well discussed on this forum.

Read Hoke! Then read it again. Read until the things I've talked about here make sense to you.

Harold
 
Oneal58,

The hydrochloric acid you are talking about is what most all of us use, no need to try and clean it up, or do anything to it, as you said.

Some places sell some types that are "green" or something like, that they may have other ingredients, I would not use them.

Just regular muriatic acid is fine, hardware stores or where they sell rock brick or masonry supplies,

muriatic acid, hydrochloric acid, HCl all are describing the same acid, there are even some old ancient names also.

I have not used the concentrated sulfuric acid stripping cell, and only know what I have read about it, although I have a fair understanding of electrical principles, and played with a few other types of cells, and I have a good understanding of batteries, and other cells, I will try and keep my comments to what I do know, sorry I will not be able to help too much with this project, but many members here will be glad to help.

I would not think the silver in your tin solder would give you any problems, the silver may be an insoluble powder or possibly silver chloride white powder, in the bottom of stannous solution, and the solution could be decanted or filtered off if you wanted too, I do not see where it would cause any problem if you did not separate it out.

I have used both sodium and potassium nitrate, to make nitric acid, they both work well, I like them both for differing reasons, they do have a little different results, the sodium sulfate salts seem much more soluble than potassium salts, potassium salts are better for the environment than the sodium salts,

I reuse the byproducts from my home made nitric, so I save the potassium or sodium sulfate salts for other uses.

Here in Oregon we have a lot of trees, which mean a lot of stumps, and so some of our feed and grain co-op, hardware stores, (even bi-mart in season) will sell one pound bottles of stump remover, there are two chemicals they use for stump remover
1. Potassium nitrate,
2. Sodium pyrosulfite (SMB) (sodium metabisulfite),
both of these I use in my recovery or refining.

Hydrochloric acid can be made with rock salt and sulfuric acid, but for now you should just buy yours at the hardware store, just giving you this for information, this I would only use in recovery from ore or low grade material, but also for you remember when you mix sulfuric and salt what you are making.
 
Hi Butcher, thanks. I end up with gaseous hydrogen chloride which I can then bubble through water to get Hydrochloric Acid. I also end up with a soild in the bottom of the reaction vessel that is Sodium Hydrogen Sulfide. I hope I got that right?
Is there a chart offered somewhere that you can use as a guide that tells you how much of each one to use, if you ever need to produce some for any reason. I read a lot of post on the forum but some of them don't give you the quantities involved for some reason?
I have ordered a lot of different sized pyrex beakers and flask, condensers, connector's of different sizes, lids, stpppers, Etc;. My reasoning was if I was going to make a little money at this, which is badly needed to catch up some hospital bills and Dr. bills for me and my wife (both). My wife has had a light stroke on her left side among other issues because of this. Well, we both are almost worn out but we have had a great time the last 40 years.
But I decided I was going to have to make what I needed after pricing some of the chemicals I was going to need on a regular basis. I have put in a lot of time trying to teach myself some basic chemistry. Chemistry is one class I chose not to take in school because of the horror stories other students would tell me about the classes. But I probably would not have remembered any of it now anyway. I went the electrical route in my career and then Auctioneering, which I miss tremendously. Now you are saying, well I see now, Auctioneering, that's why he rambles so much! :lol:
But I will probably give you a break for a few days here Butcher. I finished my copper Cathode basket last night and will be running gold plated material over the next couple of days if nothing pops up. So, wish me luck and a blessing could not hurt.
Another question for you today Butcher, then I will let you rest a couple of days. It's getting a little cold outside here but the sulphuric cell suppose to work better when it's cold anyway.
But, I have a natural gas heater in the shop. It's the open flame unvented type. I wanted to ask you, will the carbon monoxide fumes from the gas heater cause any reactions with any of the acids I will be using? Also this heater puts moisture in the building at times when the temps are right. I know this can't be good the way some acids will suck moisture back into them. Do I need to find myself an electrical heater instead of this gas heater. It's a fairly tight shop but the ceilings are not but about 7 foot. The vent hood does a good job so it may be that I can keep the natural gas heater in place. Just trying to cover all the bases before I begin and get your feelings about it. Thanks Butcher, Oneal
 
"I end up with gaseous hydrogen chloride which I can then bubble through water to get Hydrochloric Acid. I also end up with a solid in the bottom of the reaction vessel that is Sodium Hydrogen Sulfide. I hope I got that right?"

I am not sure what you are referring to by the above statement?

If you were talking making HCl, forget it just buy it it is very cheap.

If you are talking about making nitric acid then using laser Steve’s method works very well, it uses boiling hot water to dissolve the nitrate fertilizer in then you cool and slowly add the sulfuric acid, let cool again and separate liquid from salts, the liquid is put in freezer and cooled, the salts are again removed (these salts are potassium or sodium sulfate)
100ml H2O
170g-sodium nitrate
Or
200g-potassium nitrate
56ml 98% sulfuric acid

Search for home made nitric acid with Laser Steve

Do not spend much money on materials until you actually need them I use very little lab glass, mostly just jars and kitchenware.

I see no trouble with the heater in your shed, except get the carbon dioxide fumes out of there for your own health, just cover your cell when not in use to prevent it from sucking in moisture, while it is running it generates heat and should discard moisture.

Sorry I lack time to answer more clearly.
 
Hi Harold_V,
Harold, this is Oneal58, you know they guy who has trouble with Etc;. I don't know yet the best way of getting a message to particular members on the site? I have tried not to bother you much but I have a couple of questions about the sulphuric gold stripping cell. Butcher has been kind enough to give me lots of information I am trying to digest now. He has told me that he was not up to date on the Gold Stripping sulphuric cell because he doesn't use that method, at all. He said you would be the man to contact with my questions about the sulphuric cell. You gave me some great information on how to refine my gold filled material and I appreciate it. I plan to use that procedure. You said to use dilute nitric to run the gold filled material. I need to ask you at what % nitric. Would 35% nitric be about right?
I decided to go with the sulphuric stripping cell first to get a little experience and knowledge before I went with the gold filled material I have. Just because the gold filled has a little more gold in it/or on it I should say than the gold electroplated material.
A couple of questions on the gold stripping cell, if you have time to answer them.
Is there a way to tell if you have possibly put a piece of Karat Gold mixed in with the gold plated batch by accident. Will the Karat Gold piece keep it's gold color or will it turn dark just like the gold plated pieces does during the process.
Also you said to keep the magnetic material out of the gold filled material I will be processing.
My question is with the gold stripping sulphuric cell, can you put the pieces that are magnetic ( ferrous metals under gold plate) in the sulphuric cell. I believe the quantity of material I have is about 60%ferrous and the rest is non-ferrous. Looks to me that the higher end ( well made) non-ferrous necklaces and other pieces has brass under the gold plate. Would you seperate these to run through the cell or do you try and strip the pieces that are ferrous and non ferrous together. Or, are the non-ferrous pieces actually gold filled, just not marked? I could not find a mark on non-ferrous pieces anywhere? The GP or GF or any other type mark are not there. I have tested for 10k and they are not 10K. If I dissolve a piece of this material and test with stannous chloride will I get the same results as if I did the same thing with a gold plated ferrous piece?
I have a Rheostat in the circuit of my sulphuric cell. I don't know how to figure the load that the material I am running is going to put on the rectifier, thus determining the amperage flow I am going to get. I have a fluke electrical meter in the circuit to determine amperage flow. Is there a formula that can be used to determine the amperage flow I should get by any other method other than trying to come up with surface areas, Etc;. I know the surface area of the anode and cathode would play a part in the load, how you would go about getting that from all the different types of jewelry would be an involved job. It would seem that this would be almost impossible, too time consuming to do, being that there are so many variables that are involved, such as strength of acid, ambient temperature, acid temperature, surface area of material, distance between anode/cathode and the list would go on and on.
Say for example, I am running 8 ounces of material. The amperage flow is 7 amps through the electrolyte solution. Is this in the ball park of what it should be? I could add more material and bring the amps up. But then as the electrolyte solution gets more saturated with gold with each run the amps would increase. I have read that this increase is due to the increased conductivity of the gold in the electrolyte solution. Where should I try and keep my amperage on 8 ounce runs. I know you would need to know what size cathode, anode, vessel, Etc. But is there a ball park figure when amp flow just gets too high. When the amperage gets to (?) should I let the electrolyte solution settle and decant.
One more question. I ran across some bars at a flea market that were said to have came from a Jewelry Store closing. These bars was said to be made of lead. The 2 thin bars doesn't look like lead to me. My question is, is there a simple test that can be done to determine if the pieces are lead or zinc? If zinc, can this be used in a sulphuric gold stripping cell?
One last question and I will give you a break. Should I try to clean the material before I strip the material in the sulphuric cell. These necklaces and other Jewelry have everything from sweat salts to oils, dead skin and as you have said another post on the forum, this material has a little of everything in and on them.
If I do not clean them first will this effect the process when I get to the point of being ready to melt values. I have read that even a little body oil will cause fine gold to float among many other problems caused by dirty material. Or can I just wait until I have rinsed and filtered off the values and incinerate to a red glow, not melt, but do as you said with the gold filled to clean it before putting it in nitric?
I know this is more than just a couple of questions and I apoligize but thank you for your help.
Thank you in advance for anyone who can help.
Oneal58
 
hello oneal58,
Hope your doing well today. I've been following this thread since you started and am glad to see you are still at it.

I'm not able to fully answer the questions you have for Harold but will help a little while you are waiting for an answer to your questions. Study these points and see if you can SEE how these apply.

The current thru your cell will be a result of the voltage applied and the resistance of the cell itself. As the gold removes from the jewellery the amperage will start high and as the gold plating decreases so will the current. When the gold removal is finished the cell amperage should drop close to zero.

Start with one or two pieces at first and watch what happens to the current flow to the cell. By watching the ammeter as it nears zero you have finished removing gold from the piece.

The current thru the cell causes the acid to heat up. Heat is your enemy in the cell. Keep an eye on the temperature of the acid. DO NOT let it go over 120 degrees F or it will start attacking the copper in the jewellery fast.

Also with the dirty jewelery, remember that the acid is a strong solvent and will consume the oils and dirt which will contaminate the acid and you will NOT be able to remove it. Once contaminated the acid will always be contaminated. And this will have an affect on the rest of the process.

Study these points while waiting for Harold to get back to you.

Tom C.
 
Also with the dirty jewelery, remember that the acid is a strong solvent and will consume the oils and dirt which will contaminate the acid and you will NOT be able to remove it. Once contaminated the acid will always be contaminated. And this will have an affect on the rest of the process.

This is why you should incinerate the stuff before you place it in your cell, to burn of the dirt, and oils on it. Make sure all the pieces are red hot, then let it cool down. It should help prevent the contamination. I've seen it in some of Harold's posts before.
 
Hi niteliteone and Jimmydolittle, thank you both for posting and answering some important questions I had. I will be around, not going anywhere. I have had this passion all my life. As I said in an earlier post, I just got the time now to follow up on it.
You have created a couple of more questions for me now that you have the answers to, I am sure. If you don't mind taking the time?
So, what voltage to start with, 6volts, 12volts or other? You said when voltage drops to zero the work is done, stripping of the gold plating has been completed.
Can you explain why that is?
I know that some of the gold plated items I have are made of what looks like brass through and through. Isn't brass a pretty good conductor on it's own? So, why would the amperage drop to zero when the gold plate is gone and it still has the brass there to use as a conductor? Also, I have filed some of the plating on the pieces and I see a thin copper layer there, though very thin it is, it's a copper layer there.
Is the answer to this question is that gold is that much of a better conductor than brass or copper and that is the reason the amps drop to zero?
Are there some gold plated items made of zinc? Also I have many pieces that look like the metal underneath is brass. These pieces are not magnetic, but they look to be made of brass.
Could this be gold filled that isn't marked in any way?
Will a Stainless Steel thermometer be OK to use to check the heat of the electrolyte, if it reads quickly. Or do I need an all glass thermometer?
I would not even mention this because Harold has already told me to incinerate the pieces. I believe wholeheartedly that, I do not question it whatsoever. But, I have some watch band tops that are absolutely dirty beyond belief. They are, what looks to be 1/4 full of krud. On the band tops particularly and only, would a wash in Lye hurt them, only the watch band tops? Or will incinerating get all that krud too?
Could I use enclosed ice packs to pack around my vessel to try and keep the electrolyte cool or is this too dangerous (or too stupid) to have the ice packs (water) too close to the sulphuric acid? Or maybe sit the cell on a seperater of some kind so no water could get to the cell? But, If I had one burst for some reason, I know that would be bad even if it was on the floor! So, this is probably a bad idea, right? Or could be just plain stupid, but I needed to ask?
Thank you niteliteone and jimmydolittle in advance for taking your time to answer my questions, it is very much appreciated.
Oneal58
 
Hi Butcher, hope you are doing well today. You know, I still do Charity Auctions for the churches around in the area. I can still go for a couple of hours before my breath leaves me.
I live in a farming community and the churches around here raise a good portion of their donations at auctions once a year. It's a tradition that we have fun at. There is a lot of horseplay and we all have a good time. Farmers usually will give once a year instead of paying their tithes weekly or monthly. They usually have an amount their going to spend and really don't care if they get caught with something. They will run the bid on their friends and that goes back and forth. I have sold a bushel of sweet potatoes for $1000.00 before. Two friends bidding against each other. So, you can see how it can be fun. They, (Church) start up the last of Sept. when the crops are mostly out of the fields and run through Oct. Timed just right, while the farmers still have some money in their pockets. Maybe if you're passing through this area in Sept. or Oct. you could attend one of the auctions. All you have to do is raise your hand and keep it their and I would take care of the rest of it. I promise I wouldn't take your bid more than say, 20 times before you could get your hand back down. :lol: Now, you would be embarressed and pay the price or sneak out :oops: . Which one would you do? Just kidding Butcher :twisted: I have never run the bid on anyone but I have been accused of it a couple of times. First time buyer's don't realize there are others in the room bidding against them at first. But they learn quickly after buying a few things. :shock: But I would always give them a refund if they asked for it. I just wanted to teach them how to bid their first time at auction. It's good to hear from you Butcher. I just wanted to talk to you this time instead of bombarding you with questions. Everyone needs a rest every once in a while. Wasn't kidding about the auction, come on down, we will take care of you. If I remember correctly you are in Oregon, right, Oregon has a lot of stumps? If I am wrong about that please forgive me. That's a long, long way from S.C. isn't it. I am going to let you rest Butcher for a couple of days. But please give me a hand when I get through this Sulphuric Cell trials. Then I will be moving to the hard stuff as they say.
Good hearing from you Butcher,
Oneal
 
Oneal58,
I’ll take these one at a time and do what I can.
1. So, what voltage to start with, 6volts, 12volts or other? You said when voltage drops to zero the work is done, stripping of the gold plating has been completed.

A standard 12 volt supply should do fine.
Actually I said when the current drops to zero.

Can you explain why that is?
It is the reaction of the acid on the gold that allows the current to flow, so when the gold is removed from the jewellery the current will drop to “near” zero.
If you leave the jewellery in the cell after the current drops it will slowly attack the base metals dissolving them into solution. This is why you need to watch and remove the jewellery when the current drops near zero.

2. I know that some of the gold plated items I have are made of what looks like brass through and through. Isn't brass a pretty good conductor on its own? So, why would the amperage drop to zero when the gold plate is gone and it still has the brass there to use as a conductor?

Yes brass is a good conductor in normal circumstances. But remember we are dealing with sulfuric acid as the conductor and as long as we keep base metals out of solution the resistance will be very high preventing most current flow.

3. Are there some gold plated items made of zinc?

I’m sure there are some but I can’t say for sure.

4. I have many pieces that look like the metal underneath is brass. These pieces are not magnetic, but they look to be made of brass.
Could this be gold filled that isn't marked in any way?

I don’t know the answer to this question.

5. I would not even mention this because Harold has already told me to incinerate the pieces. I believe wholeheartedly that, I do not question it whatsoever. But, I have some watch band tops that are absolutely dirty beyond belief. They are, what looks to be 1/4 full of krud. On the band tops particularly and only, would a wash in Lye hurt them, only the watch band tops? Or will incinerating get all that krud too?

If it were me, I would mix a little soap and water and with a toothbrush remove as much excess filth as I could before incineration. But that is just me. Wear gloves.

6. Could I use enclosed ice packs to pack around my vessel to try and keep the electrolyte cool or is this too dangerous (or too stupid) to have the ice packs (water) too close to the sulphuric acid? Or maybe sit the cell on a separator of some kind so no water could get to the cell? But, if I had one burst for some reason, I know that would be bad even if it was on the floor!

Is it safe to smoke a cigarette while putting gas in your car? I know I can throw a lit match into a full can of gas and the match will go out. No boom most of the time.

Get the point? You can do it many times with no problem, just like the match and gas can. It only takes that one time, a mistake or accident happens and you will wish you never had water near sulfuric acid. The out gassing can be very fast and cause a lot of injuries before you even know what happened.

What happens if your wife would throw some water on a grease fire on the stove?

Why tempt faith? Just DON’T do it. Take a break when it gets warm.

7. So, this is probably a bad idea, right? Or could be just plain stupid, but I needed to ask?

Bad idea for sure.
The only stupid questions are when you don’t ask when you don’t know!

I would rather spend hours explaining safety to someone than spend a single minute thinking about them in the hospital because I didn’t have the time to explain safe practices to them.

Tom C.
 

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