Electrochemistry Copper Sludge

[ctgoldbuyer]

Hi Folks,

I have a question. After I complete the process of Gold recovery from Gold Filled material, I store the initial spent nitric & water solution until I have about 5 gallons.

Then, I add copper to drop any silver and filter that silver out to process. Next, I add iron to drop the copper.

I collect the copper sludge or whatever it is called and let it dry.

What can I do with it at this point? If I wanted to make a copper anode to further refine it, how would I do that?

Thank You,

Joe

 

[nickvc]

Joe the copper isn't worth the effort or cost to further process it, if the copper is fairly pure you could use it again to drop values from other solutions but the chances are its a mix of metals that will cause problems. If you can get an xrf scan done to determine the actual metals present then perhaps you can find a use for it failing that it's junk that needs disposing of, if you had huge volumes it has a value but in small volumes it will probably cost you to dispose of it.

 

[NoIdea]

Hello - try adding sulphuric after the silver, boil and collect nitric acid for re-use, concentrate sulphuric acid copper sulphate, cool and crystalise out copper sulphate, filter and wash copper sulphate with cold water, heat copper sulphate in a vessel that can strongly heated, cool and collect the sulphure trioxide over ice-bathed sulphuric acid for re-ue, the resulting copper oxide is place in a double ended vessel in which DRY hydrogen is introduced at one end, with the other end being an exhaust exit where excess hydrogen burns. The copper oxide is reduce to copper and water when heated over 300 deg C, higher temperatures result in quicker reaction times.

Note: dry hydrogen burns whereas wet hydrogen EXPLODES, dry over concentrated H2SO4


Deano

 

[Macleight]

Hi Folks,

I have a question. After I complete the process of Gold recovery from Gold Filled material, I store the initial spent nitric & water solution until I have about 5 gallons.

Hello. Soon I will have a similar situation. After removing tin and lead, I will have a solution of copper, with spent HNO3 (not really HNO3 anymore) H2O and maybe some other stuff.

Here are my assumptions:

1) When you say "Gold recovery from Gold Filled material" you mean scrap that you have reacted with HNO3. You then processed this material further.

2) When you say "initial spent nitric & water solution until I have about 5 gallons." you are talking about your wash water, after filtration, that should contain copper.

I collect the copper sludge or whatever it is called and let it dry.

At this point, you have a solution you are assuming is mostly solubilized copper. It is probably aquamarine in color? I should think a this point, if it contains all of the waste from your previous actions, and you have pulled out all the metals except copper, the copper should exist as a nitride or chloride salt.

What can I do with it at this point? If I wanted to make a copper anode to further refine it, how would I do that?

I want to know this also. Not as an exercising in casting copper anodes, but academically, what then? I know how to dispose of copper impregnated solutions. What if I wanted to gather that metal?

Joe the copper isn't worth the effort or cost to further process it

But what about just for fun?

Then comes Deano's post. Which sounds like a major pain.

Is this really the way to recover the copper leftovers? Excluding cost, assuming a perfect system built to scale (lab, bench top, industry) is this the only way to recover copper? Not being a precious metal, it's of little use to the small scale refiner. But thinking about where all the copper comes from, what would be done in industry?

 

[nickvc]

The big boys no doubt have ways to sell their waste or at least to move it on to base metal refiners as they have large volumes which make it worthwhile.
The problem for small scale refiners is that we just can't create that volume even over a lifetime so it can become another cost, we can neutralise the solutions and recover all the metals dissolved in the solutions but further recovery or refining just isn't feasible economically.
There are further processes that can be done at home but not without extra cost and added time that could be more better used recovering and refining precious metals.

 

[NoIdea]

Then comes Deano's post. Which sounds like a major pain.

:lol: Not at all, if you use the same vessal for both copper oxide reduction and copper sulphate decomposition, hydrgen is produced by reacting waste non-recyclable aluminium [electrolytic capacitor] and sodium hydroxide, collected over conc. H2SO4, I promise to post pictures of my unit, well cumbersum work model 8)

Deano

 

[butcher]

Deano
You promised, :lol:
I like to do similar things, find a use for an otherwise waste product. I am interested in hearing more about this one.
Although I may not try your ideas I always enjoy reading of them.

 

[kurtak]

Deano
You promised, :lol:
I like to do similar things, find a use for an otherwise waste product. I am interested in hearing more about this one.
Although I may not try your ideas I always enjoy reading of them.

And I will second that :!:

Kurt

 

[mike6]

Gentlemen,
This same question has occurred to me. I recall ''Palladium'', in one of his tutorial videos, stating that his process warranted the recovery of copper for re-use. The problem, however, was the iron contamination. In an effort to overcome this problem, I took 20 gallons of spent nitric acid and water from my last silver precipitation, and placed it directly into one of my electrolysis cells. This one has stainless steel cathode and anode plates. I set the rectifier at 4volts and 150 amps and let it run for a few hours. The result was, to my dismay, copper plated stainless steel. It took quite a bit of scraping with a stainless steel spatula, but I managed to get the cathode plates clean. The questions that remain to be answered are numerous. Is the copper leaf uncontaminated?, should I rather use a sheet of copper as the cathode, and wait for enough buildup before harvesting?, what was the electricity cost vs copper yield? I may be able to mitigate the cost factor by running the plant exclusively off-grid with my generator and bio-fuel. The most important question of all is why? Do I wish to recover uncontaminated copper for re-introduction into my silver refining process, or do I wish to decontaminate my spent solutions for responsible disposal....Hmmmm?

 

[butcher]

Laser Steve posted a process similar to what your describing, using a graphite anode (more inert to nitric so as not to contaminate the solution with metal from the anode), lowering the copper in the copper nitrate solution so the nitrate solution could be reused (in this case I believe it was for his silver cell).

With the graphite anode you would not be putting (more), or other metals in solution, which could add more contamination to your electrolyte and thus to the copper that is plated out of solution.

The copper plated out should be fairly pure as long as the electrolyte did not have a high contamination of metals that would also plate out, or would plate out easier than the copper.

GSP has given details of the math to figure how much metal will plate out of solution, with this you could calculate the copper and the electrical power consumed to figure if your spending more on electricity than the copper is worth, solar cells charging a battery or bank of battery's, as a power source for your electrolytic cells would be a conservative way to run your cells.

 

[richard2013]

Mike maybe this will lead to the reuse of your 20 gallon nitric solution,, :lol:

 

[mike6]

Ha, the bounty is magnanimous!. Free copper!, free nitric!, when will it ever end?.. . Thanks for the information gentlemen, I'm off to track down Laser steve's and GSP'S posts.

 

[lunker]

Delano,

with regards to the sulphuric acid, is it added by the drop? And watch for the copper to drop out of solution,How will I know when enough is enough?
And if too much is added. How can it be removed from the nitric so it can be er used.I apologize if these are simplistic questions.would like to clarify before attempting something new. Don't like suprises :shock:
Thanks

 

[butcher]

If you have a solution of copper nitrate (silver cemented from solution with copper), adding sulfuric acid and then distilling off the nitric acid, which can be condensed or collected in a tiny bit of water, or a little water with some 3% H2O2 added.

You will want to add enough sulfuric acid to give the needed hydrogen from the acid, to make the nitric form the copper nitrate in solution, and enough acid to take up the copper ions leaving copper sulfate when distilling is complete.

Cu(NO3)₂ + H₂SO₄
----Distilling gases into H₂O/H₂O₂--->
CuSO₄ + 2HNO₃

From above equation we see we need a mole of sulfuric acid for each mole of copper nitrate in solution.

The copper nitrate solution will have water involved which will pretty much distill off first (before NOx gases), or the nitric will distill off.
We will also collect gases into water (to convert NO₂ gases into nitric acid), the H₂O₂ will help to oxidize the clear NO gas into NO₂ gas, this small amount of water will not dilute concentration of the acid as much as the water involved in the original copper nitrate solution.
NO gas is not soluble, but with oxygen it will form the familiar red deadly NO₂ gas which is soluble.
2NO + O2 --> 2NO2
H2O2 in the water can help to supply oxygen in the solution of water.
NO2 + H2O --> HNO3

This extra water is not much of a problem, even though the nitric acid will be dilute, because with evaporation of our product nitric acid we can concentrate the dilute nitric to 68% if needed.

Distilling a solution is fairly easy but has to be understood and done properly to avoid dangers, breaking glassware of hot acids is dangerous, with distilling we have added dangers of suck back, where if heat is lowered on the boiling flask before breaking the system to the cold condensed solution, we can create a vacuum in the hot distilling flask, sucking cold liquid back into the hot flask of concentrated acids, exploding glass shards and hot acids is not something you would want to be any where near or to have happen in your lab.

Study how to distill properly, and understand how it is done safely, before undertaking the project, make sure to study enough to keep yourself out of danger, Note watching a you tube video is not studying, research the subject well before attempting it.

 

[lunker]

Thank you for the explanation. Makes sense now. I agree, you tube is not a substitute for actually cracking open a book and learning!

 

[butcher]

Lunker,
When I study something, I search all of the possible resources I can find on the subject, even reading redundant information on the same subject, many times small bits of information's are described from one book, or source that will not be included in the seven others I have read on the same subject, this way I can get a better picture of the subject I am studying, many times I go back and study more of what I have researched a dozen times, you will be surprised at what you can learn or what you may have missed.