For Sale Does anybody need/want copper sulfate?

[icejj]

I have a few 5 gallon buckets of copper sulfate, which was created by adding sulfuric acid to copper nitrate. The copper nitrate was a result of 50/50 nitric and distilled water boils to dissolve base metals from gold filled material. I added the sulfuric acid in order to reuse the nitric. Could this copper sulfate be of any use to anyone? Pickup would be in or near the northern virgina area.

 

[4metals]

While I don't need any copper sulfate, I am sure we would get some good information from discussing your process to get the extra mile out of your nitric acid.

 

[icejj]

I have a few 5 gallon buckets of copper sulfate, which was created by adding sulfuric acid to copper nitrate. The copper nitrate was a result of 50/50 nitric and distilled water boils to dissolve base metals from gold filled material. I added the sulfuric acid in order to reuse the nitric. Could this copper sulfate be of any use to anyone? Pickup would be in or near the northern virgina area.

Forgot to post pics.... these pics depict a portion of what I have

 

[icejj]

While I don't need any copper sulfate, I am sure we would get some good information from discussing your process to get the extra mile out of your nitric acid.

Okay I'll give details and results when I get a chance

 

[icejj]

Also, I forgot to mention that the copper sulfate is free.

 

[SRM]

You might try Nyrstar. They have operations NE of Knoxville, TN (Strawberry Plains). Copper Sulfate is one of the more expensive reagents in zinc flotation.

 

[icejj]

You might try Nyrstar. They have operations NE of Knoxville, TN (Strawberry Plains). Copper Sulfate is one of the more expensive reagents in zinc flotation.

Thanks!

 

[icejj]

While I don't need any copper sulfate, I am sure we would get some good information from discussing your process to get the extra mile out of your nitric acid.

In order to dissolve the base metals from a batch of gold filled jewelry, I performed 50/50 nitric and distilled water boils on the gold filled material until all metals were dissolved and I was left with gold foils. The resulting solution of copper nitrate (plus any other dissolved metals) is what I performed the nitric recovery on.

First, I cemented the silver from the solution by placing pieces of copper into the solution. In prior cases, I added salt to create silver chloride (I have since stopped using the silver chloride method and only cement silver on copper now.)

Next, I poured the solution off of the cemented silver (or silver chloride).

Next, I added a calculated amount of sulfuric acid to the copper nitrate solution, in order to convert the solution to free/recovered nitric + copper sulfate. I waited until the blue copper sulfate crystals formed, then poured off the recovered nitric for reuse. The recovered nitric was a more lightly tinted blueish/green and clear, vs the not clear dark blue/green look of saturated copper nitrate.

In order to determine how much sulfuric was needed, I took 100ml of the solution and added sulfuric, slowly, keeping track of how much sulfuric I added until a test drop of the solution turned white (as opposed to green/black) when heating the test drop until it dried. White is anhydrous CuSO4, indicating a slight excess of sulfuric. Green/black means there is still CuNO3 in there. I then used the amount of sulfuric needed per 100ml of solution to determine how much sulfuric was needed for the entire amount of the solution.

The resulting recovered nitric was pretty effective. In one particular instance, I started with 5000ml of 50/50 nitric + distilled water. The 5000ml was used to dissolve gold filled material, and was completely saturated with base metals. After recovery I ended with approximately 3600ml of recovered 50/50 nitric + distilled water. I was able to dissolve about 580 grams of gold filled jewelry with the recovered nitric, which amounts to dissolving roughly 1 gram per 3.1ml of recovered nitric.

After performing another recovery on a previously recovered amount of 50/50 nitric (i.e. second recovery), I was able to dissolve approximately 1 gram of gold filled per 3.8ml of re-recovered nitric.

Since I had so much copper nitrate left over from dissolving gold filled jewelry (i.e. gallons), the nitric was definitely worth recovering, as I'm a hobbyist and am not able to get nitric cheap.

 

[4metals]

While you sacrifice purity and concentration by not using any distillation apparatus, you make up for it with simplicity. Thank you for sharing.

 

[icejj]

While you sacrifice purity and concentration by not using any distillation apparatus, you make up for it with simplicity. Thank you for sharing.

Correct. Another drawback is that since the recovered nitric will contain sulfuric, after using the recovered nitric to dissolve base metals, one would need to pour off the solution before it cools, otherwise copper sulfate would form and trap your gold foils and/or partially dissolved scrap. You would then have to dissolve the copper sulfate to proceed. This is a pain, so it's best to not let it cool while your scrap is still in it. Or you could use slightly less sulfuric when doing the recovery method, but for me there still tends to be the issue. So I make sure to pour it off while it's warm.

 

[Martijn]

Correct. Another drawback is that since the recovered nitric will contain sulfuric, after using the recovered nitric to dissolve base metals, one would need to pour off the solution before it cools, otherwise copper sulfate would form and trap your gold foils and/or partially dissolved scrap. You would then have to dissolve the copper sulfate to proceed. This is a pain, so it's best to not let it cool while your scrap is still in it. Or you could use slightly less sulfuric when doing the recovery method, but for me there still tends to be the issue. So I make sure to pour it off while it's warm.

You can evaporate a copper nitrate solution at 60 to 70 degrees C to almost only crystals, but keep the temperature below 80 as it decomposes somewhere above 80 C.
Then convert it with sulfuric and put a bottle of the solution in the freezer.
This will precipitate more copper sulfate and leave a stronger acid with less copper sulfate in solution.

 

[4metals]

otherwise copper sulfate would form and trap your gold foils and/or partially dissolved scrap. You would then have to dissolve the copper sulfate to proceed.

So you do not filter the solution to collect the foils and insolubles, you decant them.

Another drawback is that since the recovered nitric will contain sulfuric, after using the recovered nitric to dissolve base metals,

That is a perk to distillation, no sulfuric carry over.