22k button. What am I doing wrong

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GPMR

Member
Joined
Apr 18, 2011
Messages
12
Thanks for a fantastic forum. I learned a lot but not enough yet!
I have used the process described by goldnscrap's inquarting method.
Brought down to 6K, nitric boil, wash, AR dissolve and washed. re dissolved in AR and washed again in HCL and distilled water. Only getting a 22K button, even used a new melting dish :oops:
 
What kind of gold tester did you use?

Your process is kind of sketchy since you didn't go into much detail on your process. I would guess you missed some steps some where. Go into more detail on what you did please.
 
It is the GXL 2400 and test 24 K perfectly.
Have spread the button into a flake in the melting dish.
This now give me some points as 24K some as 23K and even some as low as 17K.
On the top it shows a copper color with perfect gold at the bottom.
Boiled in HCL and copper color is gone but still not 24K
 
It was 9K, 14K and 18K gold rings.
Melted with sterling silver to reduce to 6K.
Boiled in 50/50 Nitric and distilled water for a hour.
Washed with distilled water 5 times.
redid the 50/50 and boiled for one hour.
nitric was still blue green after second boil.
Washed again.
This was then dissolved in AR and boiled for 5 min.
recovered with MSB and left overnight.
decanted and washed with HCL twice and boiled in HCL for 30 min.
5 washes with one boiled in distilled water.
Powder nice light mustard orange.
This was then redissolved in AR and the HCL/distilled water washes followed
The melt followed but you can still see markings running on the top and into the dish
 
You have certainly processed it enough to get it pure. How much karat scrap did you start with? To this you added 3X silver? Sterling or fine silver? Then you digested in 50-50 nitric acid. How much nitric did you use?

nitric was still blue green after second boil.

This is troubling. What I think has happened to you is you didn't add enough nitric acid to remove all of the silver. The excess silver coated the alloy and prevented digestion and you melted it as gold. Did it smoke while melting? A few more details please and we should figure this out.
 
Started with 51.9 gram of scrap at mixed 9, 12, 14 and 18K but 9 being 34g
Calculated 22.87g Au and 29g rest. added sterling 59g. Melted all together and made shot (cornflake). then added 2.5ml per gram silver nitric. 91.5x2.5=230ml nitric and 230ml distilled water .
Then the boil and wash.
I repeated with the same volume of nitric 70% for the second boil.
 

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When dissolving silver and base metal, don't rely on a formula for the amount of nitric required. You are at the mercy of the actual concentration of the acid, plus the unknown elements present in the inquarted material. You most likely have not allowed for the original base metals, and are most likely to not have a clue what they may be, anyway, aside from copper.

If you are in doubt, when you *think* you have eliminated all base metals and silver, pour off the solution and add a small amount of fresh dilute nitric and heat (keep it covered with a watch glass). If you can bring the solution to a boil with no signs of fumes, the job is done. If you see brown fumes, there's still metal to be dissolved. Do not rely on this test if you work without heating.

When you dissolve the resulting gold from inquartation, all of it should dissolve readily---and the color of the solution should be yellow to orange. If you have a green tint, it's obvious you have copper or nickel present---meaning you have either rinsed poorly, or there was still un-dissolved base metal present. If there's un-dissolved base metal, that usually results in some pieces that fail to dissolve in AR--and will be coated with a gray/green layer of silver chloride when you have finished the dissolution process.

There is little reason to expect anything less than about 99% pure gold if you dissolve and filter before precipitation. I can't begin to imagine how you're ending up with such low grade material unless you're melting things that didn't dissolve in AR.

Harold

Edit:
I am not one to support processing by the clock. Heating a solution that is barren of free acid for a prolonged period of time serves no useful purpose. You should become familiar with reactions so you can make visual observations that dictate if you should prolong heating, or if you should add more acid. I stronlgy advise you lose the notion that you have processed for a given amount of time, therefore the work must be done. It may or may not be.
 
As a rule of thumb to determine acid requirements be aware of these facts;

To digest 1 gram of silver it requires 2.34 ml of half 70% nitric,, half distilled water. copper takes almost 3 times as much nitric. The fact that you used 460 ml of the mixture should have been enough. Did you heat the acid? How long did you leave it in the acid?

I prefer to use nitric for parting at 2 parts water and 1 part nitric for the first parting. Still use the calculated nitric, just double the water. For the second nitric I use 1:1.

You should never use concentrated nitric 70% for parting it will take too long. Diluted acid works much quicker.

The button looks good, did it smoke when you melted it? If there were silver chlorides coating any gold you would have noticed the smoke.

You have added enough nitric to do the job, if it was not heated you may have stopped too soon, your reading of 22k, if accurate, can only be from undigested base metals or silver chloride, both of which are easy to detect in your aqua regia digestion. Your purity should have exceeded (by a lot) 22K after the inquarting and parting. If you filtered the solution after the aqua regia digestion, a good practice, you would have eliminated any undigested silver or coated base metals and the gold should have dropped pure. Did you filter the aqua regia before dropping the gold?
 
The only thing I can think of is I don't see any mention of filtering your gold solution which could allow any silver chloride to pass into the precipitated gold, cooling the solution also helps as the chloride will drop out of solution when cold. The other possibility could be lead, were any of the items of scrap repaired with lead solder?
 
Thanks Harold,
Was thinking along the same lines but did not want to break away from the formula for my first.
What will be the easiest process to get this 22 into 24K.
Do I go back to step one or is there a better way to take high K items to 24K

Yes filtered between using whatman#2 and also dropped sulfuric acid in to drop the Pb before filtering
 
No, it did not smoke when melted but had a definite reddish copper on top once cooled the first time.
Yes, had the nitric work till starting to stop and then started heating for one hour but it stoped giving of red fume almost at the end.
 
GPMR said:
Thanks Harold,
Was thinking along the same lines but did not want to break away from the formula for my first.
What will be the easiest process to get this 22 into 24K.
Do I go back to step one or is there a better way to take high K items to 24K

Yes filtered between using whatman#2 and also dropped sulfuric acid in to drop the Pb before filtering
I'm somewhat bewildered by the claim that your gold is so low. It looks pretty good, but then looks may be deceiving.

If you'd like to reprocess, simply melt in the same dish you used to create the button, then pour the metal to a deep container (same thing you did when you inquarted). Recover the cornflakes and digest directly in AR. They won't dissolve as quickly as the finely divided gold from inquartation, but they should dissolve reasonably quickly. Use acid sparingly---a ratio of 4 HCl to 1 nitric, and an excess of HCl is preferred (maybe 4½ :1). That way, you insure that you use all of the nitric. Start with less nitric than you expect you'll need. When dissolution ceases, you will then be able to pour off the solution, leaving behind the traces of gold that have not yet dissolved.

Repeat, using acid sparingly, with a definite excess of HCl. When you have dissolved the last traces of gold, with a little luck, you will have also consumed all of the nitric, so you won't have to evaporate to eliminate free nitric. It is for that reason that you should add nitric VERY sparingly, and allow plenty of time for the acid to do its work before adding any more. Evaporation is a slow process, so the extra time spent in dissolution will be well repaid.

Good luck!

Harold
 
GPMR said:
but it stoped giving of red fume almost at the end.
That can be the results of consuming all of the acid, or all of the metal. Likely you consumed all of the acid.
When you inquart, it's desirable to achieve a low percentage of gold, but not have the gold crumble. If you have added too little silver, it becomes difficult for the nitric to penetrate the resulting honeycomb of gold, slowing dissolution.

Some prefer to crumble the gold to insure complete dissolution. I found that process troublesome (and do not recommend its use) in that it required a waiting period for suspended gold to settle. I didn't have the luxury of the waiting time, so I preferred to give the material a hard boil in covered beakers. You can achieve excellent results, assuming you use enough nitric.

I also used tap water. I was not concerned with the traces of silver chloride that formed. The choice to use tap water is yours. Many don't. I did for all my years of refining. I even washed my gold with tap water. I experienced no problems. I am not suggesting you do the same. Just commenting.

Harold
 
Thanks for all this help.
Will try what you suggest Harold and let you know tomorrow.
 
Harold,
The AR is orange and no undissolved solids in the bottom. with the first run in AR After the sulfuric I had a fine white in the bottom but with the second nothing.
Can it be borax in the dish when melting that might be giving me problems, might have had a bit much in when seasoning the dish. also using LPG and Oxy with the melt.
 
When you re-dissolve your gold, any impurities will be obvious. Silver will manifest itself as a white cloud, which eventually may form some small curds, or not. Copper (or nickel) will yield a blue tint, but that may not be obvious until you have precipitated the gold. It's important to take note of the solution color after precipitation. Silver chloride will have been filtered off, but copper and nickel will remain after the gold is down.

If your solution is not colored, the method by which the gold was tested is faulty. Note that I read you had a surface discoloration. It takes VERY little in the way of a base metal that oxidizes to create that film. When your gold is pure, it will be free of the color. Also, your melting dish, after melting pure gold, should have no color aside from either purple/pink. If the dish you used to melt the button is colored beyond that description, do not use it for melting the re-refined gold. It should either be cleaned fully (too much work) or a new dish employed. The old one can be used for inquartation in the future, so it won't go to waste.

Looking forward to seeing your results.

Harold
 
GPMR said:
Harold,
The AR is orange and no undissolved solids in the bottom. with the first run in AR After the sulfuric I had a fine white in the bottom but with the second nothing.
Can it be borax in the dish when melting that might be giving me problems, might have had a bit much in when seasoning the dish. also using LPG and Oxy with the melt.
If the problem is borax, evidence will be in the coating. Color tells the tale. I just commented on that, above.
The volume of borax will make no difference, so color is the only consideration. If you melt gold under a full borax cover, you won't see the color display you noticed, but not because it isn't contaminated. Flux absorbs oxidation, plus isolates the material from oxygen, so once the oxides are absorbed, no new ones form. The contamination is still there, however, but it's clean metal alloyed with the gold. It is for that reason you should always melt your gold with the surface exposed. If it's pure, no harm is done. If it isn't, it's obvious by the colors you see.

Harold
 

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