What to pay for gold plate and gold filled?
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Harold said:
Harold,
It's not too often that I disagree with what you have posted, but in this instance I have seen the results with my own eyes. I am merely reporting what I have observed first hand. I have repeated the results on multiple batches.
The key difference from the 'normal' AR process and the modified version of poor man's AR (nitrate salt and HCl) may be that with the modified Poor man's method the HCl is added first and allowed to react with heating before adding any nitrate salt. This colors the HCl deep green with dissolved iron and some copper [edit] if present [/edit].
The best that I can figure is that the dissolved base metals in solution prevent the gold from being attacked to larger extent when the nitrate is added this way. The nitrate salt does not form nitric immediately, typically there is a delay as it dissolves in the hot acid. Another difference may be due to the fact that the nitrate is added in very small portions and allowed to react completely.
To a slight degree the gold shells are attacked, but not like they would be when normal AR is used. I use this modified process all the time and every single time I do, more than 50% of the shells remain intact. The remaining shells, along with any thin items dissolve and re-precipitate as the familiar brown powder.
I'll be dissolving a batch this weekend (or sooner) and I'll post a few photos of the process with the results.
Steve
Gnatz,
I use roughly 3.5 mL of 70% nitric per gram of copper based scrap.
Dilute the nitric with an equal volume of water.
You know it's done when nothing except hollow gold shells, gold flakes, and/or dark powder remains in the bottom of the beaker.
I use a pointed bamboo skewer to test the shells, if the skewer pierces the shell easily the shell is stripped. I also go by the sound the shells make when the liquid is swirled in the beaker. They will move about the solution easier and make a tickle or tinkle sound.
My experience with GF wires is that the gold shell tends to break apart more as the core is dissolved. With watch cases, rings, and other larger gold filled items the shells will remain intact to some degree.
Steve
I use roughly 3.5 mL of 70% nitric per gram of copper based scrap.
Dilute the nitric with an equal volume of water.
You know it's done when nothing except hollow gold shells, gold flakes, and/or dark powder remains in the bottom of the beaker.
I use a pointed bamboo skewer to test the shells, if the skewer pierces the shell easily the shell is stripped. I also go by the sound the shells make when the liquid is swirled in the beaker. They will move about the solution easier and make a tickle or tinkle sound.
My experience with GF wires is that the gold shell tends to break apart more as the core is dissolved. With watch cases, rings, and other larger gold filled items the shells will remain intact to some degree.
Steve
Thanks Steve,
So 350 ml + 350 ml water for 100 grams of wire.
I don't know how to convert Molar to %. Is the 6 Molar Nitric I got close to 70%?
Also the foils that will be left should be free of pretty much all base metals and any silver alloyed with the gold. So if I weigh the foils I should be able to calculate to amount of gold in larger batches ( allowing for melt loss) right?
john
So 350 ml + 350 ml water for 100 grams of wire.
I don't know how to convert Molar to %. Is the 6 Molar Nitric I got close to 70%?
Also the foils that will be left should be free of pretty much all base metals and any silver alloyed with the gold. So if I weigh the foils I should be able to calculate to amount of gold in larger batches ( allowing for melt loss) right?
john
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I don't have a problem with that, Steve. My experiences have all come from the use of commercially prepared nitric, so I did not take into account that you may have been reporting on circumstances totally different from those I experienced.lazersteve said:
I know that what I said holds true in the circumstances I described, having used the particular system purposely when refining a large batch of mixed dental wastes. It was faster and easier to eliminate the unwanted metals that way than to test each individual piece, a long, slow process.
Harold
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Well-known member
I would finish the refining before calculating your potential yield. A small amount of base metals remaining could add up to a large error once multiplied.
Yes I agree a small error could be come larger as the multiples increase.
My main objective is to determine the best method for me and to verify the formulas given here.
My results:
10 grams of14k goldfilled wire cut to 1/2" lengths
formula-(14/24)*(10 grams)*(1/20)=grams of pure gold
.583*10*.05=.291 grams pure gold
Test 1- 10 grams of material in dilute NItric acid, after all base metals disolved foils washed and dried then weighed
Yield=.345grams (Some brown fibers remained as well)
Test 2- tumbled 10 grams of wire until gold was stripped off
yield=.2 grams
So I think (allowing for the insoluble fibers) I will use .25 grams per 10 gram batch
That means 1 oz of material would be
31.1 grams / 10 x .25=.778grams/oz of pure gold
Do these number seem right to you guys?
My main objective is to determine the best method for me and to verify the formulas given here.
My results:
10 grams of14k goldfilled wire cut to 1/2" lengths
formula-(14/24)*(10 grams)*(1/20)=grams of pure gold
.583*10*.05=.291 grams pure gold
Test 1- 10 grams of material in dilute NItric acid, after all base metals disolved foils washed and dried then weighed
Yield=.345grams (Some brown fibers remained as well)
Test 2- tumbled 10 grams of wire until gold was stripped off
yield=.2 grams
So I think (allowing for the insoluble fibers) I will use .25 grams per 10 gram batch
That means 1 oz of material would be
31.1 grams / 10 x .25=.778grams/oz of pure gold
Do these number seem right to you guys?
??? 31.1g /10x0.25=.778 ??? this equation doesn't make sense to me.
But your approximation seems right with your figures,.
If 10 grams of scrap gave a quarter gram of gold, then a troy ounce of scrap should yield approximate three quarter gram gold.
But your approximation seems right with your figures,.
If 10 grams of scrap gave a quarter gram of gold, then a troy ounce of scrap should yield approximate three quarter gram gold.
A
Anonymous
Guest
Sorry 31.1 divided by 2.5 does not equal .778
31.1/10 times .25 does, I think.
Jiim
Edit messed up 2nd formula removed
31.1/10 times .25 does, I think.
Jiim
Edit messed up 2nd formula removed
No not how I figured it. 31.103 / 39.97 = 0.778 
who cares about the math, Lets just get some gold then see how much we have and how much less it is than we hoped for.
edit yes 31.1/10=3.11 3.11x0.25=.7775
now lets disolve and see.
who cares about the math, Lets just get some gold then see how much we have and how much less it is than we hoped for.
edit yes 31.1/10=3.11 3.11x0.25=.7775
now lets disolve and see.
I am having a hard time disolving it. I cornflaked all the pins to help with exposing the base metals to the acid. I still can't get even 100g to disolve.
it fizzes and I even get a little brown cloud, when that stops I heat to slight boil. More fizzing but the pieces seem relatively unchanged. I am diluting 50/50 with water.
Can someone tell me about how much Nitric acid it should take to disolve 1 lb of 14k gold filled scrap (new)?
thanks,
john
it fizzes and I even get a little brown cloud, when that stops I heat to slight boil. More fizzing but the pieces seem relatively unchanged. I am diluting 50/50 with water.
Can someone tell me about how much Nitric acid it should take to disolve 1 lb of 14k gold filled scrap (new)?
thanks,
john
Standard technical grade nitric is about 15.5 Molar, or a little less. One gallon of it will dissolve about 2 pounds of copper. For maximum speed and the elimination of crystallization, I usually dilute it 50/50 with water. Therefore, one gallon of 50/50 tech grade nitric (about 7.8 Molar) will dissolve about one pound of copper.
If my math is right, one liter of 6M nitric will dissolve about 93 grams of copper.
(6M/15.5M)(2 lb-Cu/gal)(454 gm/lb)/(3.785 liters/gal) = 92.8 gm-Cu/liter of 6M nitric.
After dilution, you had 3M nitric. As Harold said, this dilute acid will work but it will go slow. You probably shouldn't have diluted it. These numbers above are only fairly close approximations, depending on the exact copper alloy - your acid might already be saturated with base metals.
I do sort of agree with shotting the gold filled. The nitric works faster and the copper and silver in the karat gold are also dissolved, leaving a fairly pure gold that is easily dissolved in AR. The problem is that the gold is usually very finely divided, sometimes near colloidal (purple/black slime), which can make settling and filtering very difficult, if not close to impossible. Sometimes the fine particles can be somewhat agglomerated, before filtering, by heating the solution for a period of time. If the solution is heated, replace the evaporated water before cooling. Otherwise, the copper nitrate could form crystals.
http://www.erowid.org/archive/rhodium/chemistry/equipment/molarity.html
If my math is right, one liter of 6M nitric will dissolve about 93 grams of copper.
(6M/15.5M)(2 lb-Cu/gal)(454 gm/lb)/(3.785 liters/gal) = 92.8 gm-Cu/liter of 6M nitric.
After dilution, you had 3M nitric. As Harold said, this dilute acid will work but it will go slow. You probably shouldn't have diluted it. These numbers above are only fairly close approximations, depending on the exact copper alloy - your acid might already be saturated with base metals.
I do sort of agree with shotting the gold filled. The nitric works faster and the copper and silver in the karat gold are also dissolved, leaving a fairly pure gold that is easily dissolved in AR. The problem is that the gold is usually very finely divided, sometimes near colloidal (purple/black slime), which can make settling and filtering very difficult, if not close to impossible. Sometimes the fine particles can be somewhat agglomerated, before filtering, by heating the solution for a period of time. If the solution is heated, replace the evaporated water before cooling. Otherwise, the copper nitrate could form crystals.
http://www.erowid.org/archive/rhodium/chemistry/equipment/molarity.html
Ok,
So I am in need of significantly more Nitric (acid by GSP's calculations about 8 Liters.)
Now I understand why there is so much interest here in making your oun nitric.
Can the copper be removed from the spent nitric to breathe new life into it?
So I am in need of significantly more Nitric (acid by GSP's calculations about 8 Liters.)
Now I understand why there is so much interest here in making your oun nitric.
Can the copper be removed from the spent nitric to breathe new life into it?
Yes, copper nitrate can be recycled to nitric acid via decomposition or electrolytically.
GSP's math reinforces the ~3.5 mL (actually 3.66 mL according to Hoke) per gram of 70% nitric as I previously stated. I just did not do the calculations for you based upon your 6M acid. You should have just multiplied the mL I gave you by the molar ratio of 70% to your acid molarity (15.5/6 = 2.58 * 3.66 mL ~= 9.44 mL per gram of copper based for 6M).
Remember about half of your nitric goes up in smoke (NOx= Red Fumes) as it is used so you will lose half of the nitric with each use unless you capture the fumes.
Steve
GSP's math reinforces the ~3.5 mL (actually 3.66 mL according to Hoke) per gram of 70% nitric as I previously stated. I just did not do the calculations for you based upon your 6M acid. You should have just multiplied the mL I gave you by the molar ratio of 70% to your acid molarity (15.5/6 = 2.58 * 3.66 mL ~= 9.44 mL per gram of copper based for 6M).
Remember about half of your nitric goes up in smoke (NOx= Red Fumes) as it is used so you will lose half of the nitric with each use unless you capture the fumes.
Steve
I get back the nitric from copper nitrate, by adding concentrated sulfuric and ditilling it to clear nitric acid, bubbling gas into a small bit of water.
Ok,
I think I have the hot set up for getting the gold out of my gold filled shot.
I have cast anodes and set up a copper cell. I used Ammen's (sp?) formula- 250 g/l copper sulfate, 78 g/l sulfuric acid and distilled water. My anode connected to +6v ~2amp , a copper sheet connected to the cathode. I like this because I can reuse the electolye. I filter it to collect the gold and reuse the clean solution, adding a pinch of acid each time.
This worked good but some of the copper crystals keep breaking off and contaminating the gold slimes. Now I have the anode in a filter bag hopefully this will keep them separate.
I am having a hard time disolving the rouge copper crystals that are mixed with my gold powder. I may not be giving it enough time but I tried AP, Hot HCL, Hot sulphuric acid, now I have dilute Nitric on it.
Are pure copper crystals particularly hard to disolve?
Anybody have any ideas on how to separate the gold and copper once they are mixed? Can I disolve the gold without the copper?
I think I have the hot set up for getting the gold out of my gold filled shot.
I have cast anodes and set up a copper cell. I used Ammen's (sp?) formula- 250 g/l copper sulfate, 78 g/l sulfuric acid and distilled water. My anode connected to +6v ~2amp , a copper sheet connected to the cathode. I like this because I can reuse the electolye. I filter it to collect the gold and reuse the clean solution, adding a pinch of acid each time.
This worked good but some of the copper crystals keep breaking off and contaminating the gold slimes. Now I have the anode in a filter bag hopefully this will keep them separate.
I am having a hard time disolving the rouge copper crystals that are mixed with my gold powder. I may not be giving it enough time but I tried AP, Hot HCL, Hot sulphuric acid, now I have dilute Nitric on it.
Are pure copper crystals particularly hard to disolve?
Anybody have any ideas on how to separate the gold and copper once they are mixed? Can I disolve the gold without the copper?
I would refine it , nitric, then disolve gold HCl/bleach or Aqua Regia.
Thanks, That's the way I was leaning. I tried dilute nitric for 1 hour, Nothing happened. I added HCL turning it into AR and everything disolved and the AR is green.
I will need to get some urea I guess. It will be a few days until all the anodes are digested then I'll put all the slimes in AR.
I expect to see silver, gold and copper and zinc? from the brass wire?
the silver will remain behind when I fliter the AR. SMB should bring down my gold and leave the copper for the most part in solution. Right?
Correct me if I am going about this wrong. But it seems like this will get rid of most if not all of the copper in the gold filled shot. This way I use way less Nitric acid disolving what is left.
I will need to get some urea I guess. It will be a few days until all the anodes are digested then I'll put all the slimes in AR.
I expect to see silver, gold and copper and zinc? from the brass wire?
the silver will remain behind when I fliter the AR. SMB should bring down my gold and leave the copper for the most part in solution. Right?
Correct me if I am going about this wrong. But it seems like this will get rid of most if not all of the copper in the gold filled shot. This way I use way less Nitric acid disolving what is left.
