Refining Gold from Gold Filled Jewelry

[butcher]

Oneal, I sure hope you get to feeling better, be careful about laying in bed too much with pneumonia, your lungs need exercise to keep fluids in the lungs from buildingup. if this is so bad for so long maybe seeing a doctor, is not a bad Idea.

I would think that the sodium metabisulfite would wash out with hot water and dilute HCl.
If gold was already reduced to metal, (brown gold powders), I cannot see the SMB chemically reacting with the gold.

Using sterling silver to in-quarter the gold with is great, it helps me get my silver purity up and helps me in first steps of refining my gold.

Get better soon.

 

[Oneal58]

Hi Butcher, thank you for your concern and advice. I will take it. I have been at the Dr. twice this past week and at the hospital having X-Rays done. I only have it in 1 lung so I am fortunate or blessed I meant to say. I just got to be more careful with my health, working in the cold rain just isn't going to cut it anymore with the condition of my body.
Question 1-Butcher, if hot Nitric will not dissolve these powders in the vessel after several tries can't I safely assume I found my missing Platinum brooches. I haven't tested to see if the powders are platinum yet but is there anything else these powders could be? Because boiling in Nitric several times for hours does not faze the powders?
Question 2 Butcher, if these powders are in fact platinum will I have a small amount of platinum in my gold drop from this material?
Question 3-And if so, do I have to inquart and re-refine to seperate the platinum and gold or is there another way to seperate the two PM's before inquarting? Going through Harold's (Making Gold Pure) process will not help any here, will it?
I can't wait to get back on this lot, I feel I will learn a lot here. But the weather is nasty and I have learned my lesson. I have been house bound for almost 9 days now. This is getting old, I have watched enough news these past 10 days to make anyone sick. Especially watching the politicians who do nothing but waste good air time. We could have Larry the cable guy as President and he could get as much done with this congress we have running this country! Just rediculous, just rediculous. No common sense to be found in them, anywhere!
Thanks Butcher in advance for your answers,
Oneal

 

[butcher]

Oneal,
I will answer the best I can; some of our other members could give much better advice.

I try not to assume what a powder is, but I may try different methods and try to get a good idea as to what it is, for all we know these could be silver chloride, although right now I do not remember what these powders were from (gold fill or plated) and what they have been exposed to up until this point without going back and reading all of the posts up until this question, and we have discussed so many things and with my pea brain memory I will just post some things.

I am supposing if your trying to dissolve these powders in nitric acid you have already eliminated any chlorides, (chloride salts of previous acid treatments using HCl), or (have not used chlorides), and you had no trouble filtering nitric (tin problems), if any of these we would need to change our approach here.

These powders will not dissolve in nitric (without considering silver chloride), or very few other metals, this is a good indication of possible gold and platinum group metals.

(Some palladium may show up in our earlier nitric digest as well as silver, (and base metals) the solution can be tested to see, or these can both be cemented from nitric solution with copper)

Gold dissolves easily in cold Aqua regia, platinum will not as far as practical purposes, (some traces of these metals may go into solutions or stay behind, so this is always taken into consideration), so we can dissolve gold from the platinum (if this is what we have), with cold Aqua Regia, leaving possible platinum group and other insoluble substances as powders, this gold solution decanted, denoxxed, diluted, and let sit 24 hours for anything to settle before decanting and filtering then to our precipitation vessel to retrieve gold (traces of values to stock pot). (Using your stannous chloride tests you can follow your values in solution, your eyes as to what you have where),

Now we can dissolve platinum in boiling hot aqua regia. Powders go into solution easier than solid metals, but it may take some time even for the platinum powders to dissolve, so adding some water, or acids (with their water content a little at a time while heating), can let you heat strongly without concentrating off the acid into fume’s before it has a chance to dissolve the metal powders. (A few drops of this solution can be denoxxed in test tube using hot air heat gun or other heat source, or using small glass vessel jar on electric coffee mug warmer or Mr., Coffee hot plate, in white spoon, or spot plate with ferrous sulfate for gold, letting brown gold precipitate in test and move remaining liquid to next spot on spot plate or to another white spoon (or Q-tip) to test with stannous for platinum looking for orange), depending on tests, gold can be precipitated with ferrous sulfate (copperas), or sodium metabisulfate, after separating liquid from any brown gold powders, the platinum can be precipitated using Ammonium Chloride.

I still find it hard to believe you would have broken any platinum down to powders, during your processes, I have not worked with platinum except for traces, but from my understanding if in metal form of much volume it is close to impossible to get it to dissolve to any extent with out working hard at it. So I would use testing solutions, and these test can be preformed on very small amounts of powder before processing whole batch, this can also help you to decide what steps to take before you begin.

Oneal, sometimes trying to help someone who is not familiar with all of the processes or variables one can encounter can be very hard, because many times when I work my processes are determined in steps usually governed by my tests or what is needed at that time, it is hard to say do step 1234, as when I work I may find that after a test or some other factor, that steps 1231 then 23423 would work better in the process I am working on, it is also very hard for me to know or remember what you’ve done or where your at in a process, or to be able to give advice of the next steps unless I am doing the work,

I hope your spending some of your rest time in bed with a good Hokes book.
Take good care buddy I worked today and am very tired so I really do not know if anything I wrote here is worth a dime, its about 4 hours past bedtime good night,


your friend butcher

 

[Geo]

Oneal,

i have COPD bad,and if i even get a whiff of chlorine or NOx i cant breathe good for days on end. i get a pneumococcal vaccine every five years and a flu shoot every year. you may ask your doctor about getting vaccinated for both when you get better.

 

[Oneal58]

Thanks Butcher, Geo. That is something I will ask my Dr. about when I go back tomorrow for more antibiotics.
Butcher the sun came out today and it warmed up nicely. Though still feeling terrible I did walk over to the old house just to check on things.
I had dropped the gold out of the last refine of gold filled jewelry before I got really sick. The gold drop was just sitting there in Sodium Metabisulfite. I stuck a Q-tip into the sodium metabisulfite and then put a drop of stannous on the wet Q-Tip. The cotton turned a black color, not purple but black? I didn't do anything else with the solution, just covered it back up and came back in the house.
Butcher do you know what could have caused the cotton swab to turn black when stannous was added? If the metabisulfite wasn't holding any metals shouldn't I have gotten a negative test result? The gold had settled nicely on the bottom of the pot and the solution was clear but had a bluish tint to it?
I might had stumped my toe with the stump-out when dropping the gold. I usually dissolve the metabisulfite and then add to drop the gold. This was the first time I just used the stump-out straight out of the container and had far less control on the amount I put in. I will not do that again though. If I had an excess of sodium metabisulfite would this have caused the cotton swab to turn black? I just made a fresh batch of stannous right before I got sick so the stannous is fresh. Any ideas?
It seems that my thinking is not clear enough yet to mess with anything, especially these acids. The cough medicine I am taking must have something in it, makes me woozy! :?:
Thanks My Buddy,
Oneal

 

[Geo]

false positives are brown and are mottled and not uniform. sounds like you have a positive for gold. take a small sample (just a drop really) and dilute with about three drops of water and test again. this diluted solution should give the purple color you are used to seeing.

 

[Oneal58]

Hi Geo, tried that but got the brown color???? Thanks Geo, Oneal

 

[Geo]

I've seen AR do that when the solution runs out of hcl first before the nitric is spent. this may not be the solution to your problem but if the dilute sample showed negative then its pretty safe to say you have dropped all the gold.

 

[Oneal58]

Thanks Geo, got the brown color on the swab like you said was a false positive. I didn't take the solution down as far as I normally do when I was evaporating the Nitric off this last time. I very well could have had a little nitric left in solution. I broke my container last time I took the solution down to a thick syrup so I didn't take it down as far this time. I guess I depended to heavily on the HCL to drive off the Nitric if any was there. Short cuts, but I see now there are no short cuts.
Thanks Geo,
Oneal

 

[Oneal58]

Hi Butcher or anyone who knows the answer to this.
Can I use a large stainless steel container to cool my homemade nitric in? Instead of cooling the nitric in a closed container, such as a coffee pot I thought I might have less nitric locked up in salts if I used a large round open bowl that is made of stainless steel. How quickly will the acids attack the stainless? It will have to be left in the bowl for hours while bringing the temperature down in the freezer. I thought I would make the Nitric as usual in the coffee pots but then pour into the large open stainless steel bowl. Thinking a lot less nitric will get locked up in the salts this way. I am losing a lot of Nitric from fluid being locked up in the salts after making it. This large bowl is open and flatter and maybe the salts will not be able to lock up as much nitric. I thought I would give it a try? Or how about a thick plastic bowl, tupperware maybe? Will tupperware hold up? Haven't made it back to work yet but feeling better today. I know I have to make some new batches of Nitric first though. Maybe in a couple of days or so?
Thanks Butcher,
Oneal

 

[Geo]

if the stainless is the ordinary kitchen stainless it will attack it immediately on contact. stainless series 300 or better is used for nitric.

 

[Oneal58]

Hi Geo, thanks for your reply.
Is there a way of telling what series stainless you have? My sister works for this School District. She makes the purchases to keep the kitchens in the schools supplied and running. She also gets (for me) the old stainless steel items that get bent up, mixer funnels, Old Hobart Mixers, grinders, slicers, such stuff, that has worn out or needs repair. I will fix what I can and sometimes get lucky and make a few dollars. I have just got back from her house and she says that the school buys the high grade stainless but doesn't know what series the stainless would be? Says she doesn't ever remember seeing what grade of stainless it is she purchases on her paperwork. But what the school pays for these pots, pans, Etc;, is rediculously high! The pieces I have are thick and heavy, much thicker and heavier than anything you would see in a retail store that I have found.
Can I assume that this stainless is a high grade stainless because of the thickness and weight? If not, is there a way to test it to see what grade it is other than putting the acid in there and waiting to see what happens?
Thanks Geo,
Oneal

 

[butcher]

The way I understand concentrated will not attack higher grades of stainless steel.
But dilute nitric acid may attack it.
The concentrated acid will oxidize and passivate a layer, so the acid is blocked from further attacking the article.

I would study this more as I may be mistaken if dilute nitric will attack it.

I usually use glass, although I have bought nitric 70% in some white plastic jugs it looks like thick walled (HDPE), I really did not check the type of plastic and can be wrong of the type, I will look tonight and see what letters are on them.

I have let my potassium nitrate cool in empty brown 3% hydrogen peroxide bottles, these worked good as the brown plastic kept light from decomposing the acid, after decanting (or pouring off) the chilled nitric solution, I could bang the bottle to break up the salt brick in the bottom, sometimes adding some water and a little peroxide to these salts would free a little dilute nitric from the potassium sulfate salt.

The higher grades of stainless are non-magnetic.

Thickness of the metal will not give any clue to its composition or type.

Harold has posted some information about stainless; he also understands these metals well, a search of stainless steel and Harold, as author would be an interesting read.

 

[Oneal58]

Hi Butcher, bigger problems now. I mentioned a couple of weeks ago about me not being able to get some powders to dissolve in the last batch I ran, (lost brooches). I also had some gold that the first run with AR didn't dissolve so I put the batch back through another AR treatment. Then I got sick, from time to time I would walk out to the old building and heat up the AR just to try and get the remaining gold to dissolve. One day I left the batch on heat most of the afternoon. I felt good enough today to go back out and inspect this batch. This batch is nearly 3 weeks old now. Has been sitting in either hot or cold AR for nearly 3 weeks. I tested the batch to see if the gold had made it to solution. What I found is below. Powders are still in the vessel also that will not dissolve. But I am suspicious I found my missing platinum brooches. But now it is mixed in with the gold. I don't have a clue where to go from here? Platinum and Gold mixed in AR. How in the world do I seperate the two.
Thanks for any help here Butcher.
Oneal

 

[Geo]

Oneal,

Hoke tells us to precipitate the gold first with ferrous sulfate (copperas). it will selectively react to the gold, it may drag down a trace amount of other metal but its only a trace.

 

[freechemist]

Hey Oneal58,

If you really have platinum and gold as a mixed solution in AR, you can separate them by precipitating gold with oxalic acid:

1.) Eliminate HNO3 by repeated evaporation and addition of fresh HCl the usual way.
2.) Dilute the residual concentrated "denoxxed" solution with water and a few ml of HCl.
3.) Add a 10%(weight)-solution of oxalic acid dihydrate; 12 ml per gram of dissolved gold.
4.) Mix well and let the loosely covered beaker stand on a nearly boiling waterbath, at least over night.

After this time of hot digestion, precipitation of metallic gold usually is complete. Platinum will not be much affected and remains in solution, from which it can be recovered by cementation.

Good luck and regards, freechemist

 

[butcher]

Decant solution from well-settled powders, siphon aqua regia with suction bulb, solutions can be tested after small sample denoxxed. use the spot plate test we discussed earlier in the thread, with ferrous sulfate for gold, and then testing barren(for gold), solution tested for platinum.

The aqua regia solution if tests show a positive for values.

You can de-NOx solution using evaporation methods, (dilute to precipitate silver), the values in solutions precipitated from the aqua regia solution, ferrous sulfate for gold, from dilute solution then concentrating and ammonium chloride for platinum (only if these show up in your tests), if only traces (stockpot).
I did not go into detail about letting settle overnight, decanting solutions from precipitated powders and filtering before using the next reagent to precipitate the next batch of metals.

Another alternative is cement values from aqua regia using copper buss bar.

Which of these two methods I would decide to use, depends on test results and how much base metals I had in the aqua regia solution, and value content of metals in solution.

The powders I would wash well with boiling hot water, noting color of water washes, and letting decanted water cool in jar to see if lead compounds formed when hot water wash cooled (depending on what I see would give me clues as if I would need to remove other base metals from these powders. (Also how well the aqua regia filtered can give me clues of tin content)

If powders were just pretty much values (low in base metals), dissolve the gold in cold aqua regia, leaving insoluble powders (possible platinum), treat normally as you would gold in solution, after precipitating gold using ferrous sulfate take small sample of dilute solution and test for platinum if hardly any in solution it can be retrieved in stock pot.

To the remaining powders use very hot aqua regia to dissolve platinum.

(This could be done with only a small portion of powders and aqua regia for testing purpose so if these powders did not contain values you would not be wasting time and trouble working on the whole batch).

Since we think these powders are mostly platinum I would probably just keep solution fairly concentrated while putting powders in solution adding small amounts of acids as needed, once in solution, denox any free nitric, keeping solution concentrated precipitate platinum using ammonium chloride, (test solution), traces of gold to stock pot.


I can write a process that may or may not work, as in recovery or refining each step taken depends much on what you have, and test results, so following a procedure as step one two three may not work as well, as if you understand the tests and clues you have while working, and the understanding of what step you may need to take when and why, by using your eyes and just seeing which way to go, that way you may not trip on something I cannot see from where I am.

Read Hokes here is where you will learn which steps you may need to take and when and why.

Now is the time to study Hoke's book, while you cannot be out in your cold lab.

Hokes book and some bed rest and fluids and you will be back on your feet in the lab with a whole new insight.

freechemist gives good advice, we each may go about a chore in some different mthod.
Oneal get well.

 

[Oneal58]

Thanks so much Butcher, Geo for your help. I have a general idea of what direction I need to go now. I will get back into Hoke's over the next few days and do some more studying while down and out. I am still prescribed bed rest but I feel good enough to sneak out a few minutes here and there while the wife is in the shower or gone shopping. Will try and get the spot test done and post the results over the next few days.
Thank you all for your help, this is a wonderful site to say the least. Thanks to all of you who guide and direct me through this undertaking. But for me, this endeavor has proved to be somewhat more difficult than I first expected and has gained my respect, as you all have? But everyone knows that anything worth having deserves your best efforts, at least. Will let you know what I find out.
Thanks again,
Oneal

 

[kadriver]

Oneal58:

I just did this procedure. I used ferrous sulfate (copperas) to drop the gold out of the solution containing my PGMs.

I added 1 gram of copperas and the gold precipitated out perfectly.

I allowed it to settle overnight, then drew off the clear golden liquid containing PGMs.

I poured the gold into a filter paper in my vacuum filter and trapped the gold in the filter paper.

I then incinereated the filter paper until it disintigrated in a melt dish with lots of borax to keep the ashes in the dish (otherwise they fly out all over the place - causing lose of values).

I recovered a small bead of gold from theis process!

Here is the post with pictures:

http://goldrefiningforum.com/phpBB3/viewtopic.php?f=51&t=12477&start=40

kadriver

 

[Oneal58]

Thanks Kadriver, I appreciate your post. Kadriver, how did you end up with gold in your platinum, as I did? Was the platinum really hard to get into solution with the AR for you?
Also was your gold/platinum mixed solution a light red color. My solution I put my platinum brooches in has a redish tint but it is not a dark red? It's sort of a yellowish red? What are you going to cement out your Platinum with?
Kadriver, tell me, if you will, what did you think about your Platinum Recovery? Was it worth the trouble it put you through? Do you plan on continuing on the converter's? I have been following your post on your recovery. I see it takes much longer than it does to refine Karat Gold. So I am just curious as to whether you are going to continue with the platinum recoveries.
I bought a bag of Ferrous Sulfate a while back I haven't even opened yet. I will try and drop the gold with that, as you said hopefully monday. I have 2 batches of this solution with platinum mixed in with the gold. I was caught by surprise on the first one and have already added Metabisulfite. The Gold did not drop well at all. I was wondering how do I go about getting the Metabisulfite out of the gold in solution or visa-versa, that I could not get to drop. I get a positive test on both Platinum and gold in these solutions. And now it is mixed with Metabisulfite and still in solution? I shouldn't have tried to mess with refining at all while I have been sick, that was a big mistake and I would advise anyone to never do that. I thought it was my homemade nitric causing the problem about not dissolving the powders in solution. So I boiled and boiled and added AR and boiled and boiled some more, for days. I was bound and determined to dissolve those powders with AR. I never did get them to dissolve completely and they are still in the bottom of the bowl, still. I had blamed my homemade nitric for all these problems but I think it's been the platinum all along. Hopefully I will be able to get back on this monday to try and sort it out. One thing I have learned from this experience, if you are not really sure what is going into the pot to dissolve, don't put it in there to begin with. If done by accident the way mine was, get a safe (that locks) to keep those pieces in. And not tell the wife the combination. I am in Hoke's again now trying to get this sorted out in my head, but I don't think anything is sticking right now, but I will keep trying.
Thanks Kadriver,
Oneal