Waste Treatment Question - distilation

[Jonbot5k]

I was browsing YouTube the other day and came across a video by NurdRage on how to recover copper and HCL from copper chloride PCB enchant without creating additional waste. link: https://www.youtube.com/watch?v=FjEoRidvgYE .
The procedure is as follows:
1) filter and dilute solution to below 20% acid concentration
2) distill off H2O and HCL
3) add sulfuric/H2O and distill to drive off HCL and convert chloride to sulfide
4) dissolve sulfide in H2O , electroplate out the copper and recover sulfuric acid

Now i am by no means a chemist but since "AP" is essentially copper chloride wouldn't this be a great way of getting rid of my stock pot? I know copper chloride can be regenerated by adding more HCL and bubbling in oxygen but 5 gal is way too much copper chloride to keep on hand. The HCL could be reused for further gold refining/projects as well as the Sulfuric Acid, and i have always wanted to grow copper crystals through electrolysis. I have 2, 5 gal stock pots, one with just spent copper chloride ("AP") and one containing a mix of copper chloride and SMB solutions. I should also note i used HCL and bleach to dissolve the gold since Nitric is hard to come by here.

My questions are:

1) Hydrogen Peroxide - I've read that one should NEVER distill to dryness a solution containing peroxides as they can become unstable and explode. now the amount of peroxide is low, say 1 Pint of 3% in 5 gal of waste, but I'd rather not take a chance. Is there a way to completely destroy the peroxides? maybe Manganese Dioxide? or have the peroxides already been destroyed by acting on the copper?

2) Bleach - The second stock pot contains the SMB solutions along with the copper chloride. how will this Impact the distillations? will the bleach distill over or has it complexed with HCL to form another compound? does anyone have the chemical formula of what happens when disolving gold in HCL/Bleach? i know its the chlorine gas that actually dissolves the gold but what are the other bi-products of this reaction?

3) SMB - same question as the bleach. will the SMB stay in the reaction flash after distilling, or has it complexed with the HCL/Bleach to form something else. a chemical equation on this would be helpful as well.

again i am not a chemist and this is my first go at gold recovery/refining so any help is appreciated. I have already cemented out and removed all PM's from both stock pots using copper and i am definitely going to try this "waste Free" method on my one stock pot once the weather gets nicer. hopefully i can figure out how to process the second pot the same way and recover the HCL instead of just adding lye to neutralize.


Edit: stoichiometry is the word. 2 Au + 3 NaClO + 8 HCl = 2 HAuCl4 + 3 NaCl + 3 H2O aka gold+bleach+HCl = gold in solution + salt + water. so in theory if i had way more HCl than bleach all the bleach should be gone and in its place is saltwater... right?

edit 2: found this https://www.goldrefiningforum.com/phpBB3/viewtopic.php?f=37&t=13278&p=138219&hilit=smb+stoichiometry#p138219 if i understand correctly the SMB waste should only be more saltwater, HCl, and Sulfuric acid right? if so i shouldnt have a problem processing my second stock pot. albeit theres gonna be a lot of salt?...

 

[snoman701]

It doesn't get much easier than raising the pH with sodium hydroxide to precipitate metal hydroxides. You floc it, then filter it. It filters really nicely. If you haven't used any chelators such as ammonia or sulfamic acid, your filtered solution should be clear, and close to meeting discharge limits.

If you do have chelated compounds such as ammoniacal copper present (it will be a really pretty blue), use calcium polysulfide to precipitate remaining metals as sulfides. You can floc this and allow it to settle and decant, filtration will prove to be troublesome as it seems to slime filters.

I've treated at least a thousand gallons this way. Flocculant used was floccin A or D, can't remember. Calcium polysulfide is available in 55 gallon drums as a Tramfloc product (I think 810), but is also used in veterinary medicine as something called "lyme sulfur dip", so that's a possible source for small quantity. I have not tried to use the latter, but cannot anticipate a reason why it wouldn't work.

 

[goldsilverpro]

It doesn't get much easier than raising the pH with sodium hydroxide to precipitate metal hydroxides. You floc it, then filter it. It filters really nicely. If you haven't used any chelators such as ammonia or sulfamic acid, your filtered solution should be clear, and close to meeting discharge limits.

If you do have chelated compounds such as ammoniacal copper present (it will be a really pretty blue), use calcium polysulfide to precipitate remaining metals as sulfides. You can floc this and allow it to settle and decant, filtration will prove to be troublesome as it seems to slime filters.

I've treated at least a thousand gallons this way. Flocculant used was floccin A or D, can't remember. Calcium polysulfide is available in 55 gallon drums as a Tramfloc product (I think 810), but is also used in veterinary medicine as something called "lyme sulfur dip", so that's a possible source for small quantity. I have not tried to use the latter, but cannot anticipate a reason why it wouldn't work.

The solution can maybe be dumped. What do you do with the metal hydroxides? Most of the metal hydroxides are considered, by the EPA, as toxic as the solutions they came from. Why? Because most are soluble in weak acid (pH 2, I think). You can't just dump them. To treat them, one must redissolve them in an acid. So now, you're back to square one. Iron and aluminum hydroxides may be an exception. Copper is definitely not an exception. I found out many years ago that dropping out metal hydroxides is not the way to go. Also, different states have different rules.

 

[Jonbot5k]

The solution can maybe be dumped. What do you do with the metal hydroxides? Most of the metal hydroxides are considered, by the EPA, as toxic as the solutions they came from. Why? Because most are soluble in weak acid (pH 2, I think). You can't just dump them. To treat them, one must redissolve them in an acid. So now, you're back to square one. Iron and aluminum hydroxides may be an exception. Copper is definitely not an exception. I found out many years ago that dropping out metal hydroxides is not the way to go. Also, different states have different rules.

excatly goldsilverpro. I'd rather, if safely possible, distill off any usable acid and not have to deal with hydroxy slime. even if it takes more time and effort, i feel better knowing I'm not dumping out hazardous material. the peroxide is my biggest concern right now. the waste is primarily Cu, any other metals will be minimal after electroplating the Cu and can be dealt with later.

 

[4metals]

What Chris is referring to is the fact that the metal hydroxides may fail the EPA testing requirement of TCLP (Toxic characteristic leaching procedure) this process simulates the effect of acid rainwater on solids likely to end up in landfills. There are 8 RCRA metals they look for with this test.

Metals dropped from a mixed metal waste treatment by what is called the classic destruct process (precipitation of metal hydroxides by raising the pH) are likely to contain at least 1 of the metals contained in this waste solid. There are chelating agents which can be added in the process to keep some of these metals from leaching out of the solid form and thereby pass the TCLP testing. But on any commercial scale the material should be tested by a certified lab at least once annually to confirm (or deny) compliance. Then the waste can be shipped as non hazardous unless, of course, the metals cannot be successfully chelated with your process.

The 8 RCRA metals and their allowable concentrations are;
Arsenic (As), 50 ppm
Barium (Ba), 100 ppm
Cadmium (Cd), 1 ppm
Chromium (Cr), 5 ppm
Lead (Pb), 5 ppm
Mercury (Hg), 0.2 ppm
Selenium (Se), 1.0 ppm
Silver (Ag). 5 ppm

The one exception to this is the exemption afforded to refiners for shipping wastes for precious metal recovery. Most refiners dry, (usually by incineration) crush, and sift, their hydroxides and ship the material to a refiner in Europe who will pay for all PM's and copper. It never fails to result in a payable return despite the fees for processing. A refiner that treats his or her waste stream, tests the effluent, and ships their processed hydroxides to a refiner, does not generate any wastes and is only responsible to prove the efficiency of their system if the proper authorities request.

 

[Jonbot5k]

i don't intend on shipping or sending waste somewhere if possible. i enjoy the chem and would like to render all waste into safe, hopefully usable, material myself. if im going to recycle e-waste, why not recycle what chemicals i can too.

 

[g_axelsson]

I did some research on the RCRA metals a while ago, there are some links on the wiki.
http://goldrefiningwiki.com/mediawiki/index.php/RCRA_8_metals

I still have to do more research, but it's a beginning.

/Göran

 

[snoman701]

You are very correct chris, the hydroxides may not pass tclp.

The copper smelter was happy to take them though. They are a sellable product in the right quantity.

Liquid waste is just saltwAter and can be sent off for around $1/gallon + freight on a non-hazardous liquid (so call it $2/gallon)

It should reach discharge levels with the sulfide precipitation, but without appropriate permitting in place I wouldn't dare dump them.


Sent from my iPhone using Tapatalk

 

[kernels]

If you follow the "4 metals" waste treatment process, you cement out (to metal) anything less reactive than iron and end up with mainly Iron Hydroxide, which I believe turns into 'rust' when left in contact with air, but Wikipedia also states that Iron Hydroxide is sometimes added to contaminated waterways to clean up some other metal salt.

 

[goldsilverpro]

If you follow the "4 metals" waste treatment process, you cement out (to metal) anything less reactive than iron and end up with mainly Iron Hydroxide, which I believe turns into 'rust' when left in contact with air, but Wikipedia also states that Iron Hydroxide is sometimes added to contaminated waterways to clean up some other metal salt.

That's the best, simplest way to do it, in my opinion.

 

[Owltech]

https://clu-in.org/download/contaminantfocus/dnapl/Treatment_Technologies/SS-Handbook.pdf

 

[EMRE]

If you follow the "4 metals" waste treatment process, you cement out (to metal) anything less reactive than iron and end up with mainly Iron Hydroxide, which I believe turns into 'rust' when left in contact with air, but Wikipedia also states that Iron Hydroxide is sometimes added to contaminated waterways to clean up some other metal salt.

That's the best, simplest way to do it, in my opinion.

Cant we just increase the ph to 9 and drop all metals as hydroxides and filter them out? Why do we drop all metals with iron in acidic state and drop iron as hydroxide in alkaline?(this is after cementing pgms with copper of course). I would appriciate it.

Emre

 

[butcher]

EMRE,
A quick study of waste treatment should answer the question better than I can in a simple post.

Cementing values with copper, we can recover more noble or valuable metals from solution.

Cementing metals from solution using iron metal drops copper as well as other metals from the solution such as cadmium, cobalt, nickel, tin, lead, antimony, arsenic, bismuth, as well as reduce some of the acids (note hydrogens place in the metals reactivity series).

With this iron solution, we can remove or precipitate many other metals from solution as metal oxides or hydroxides by adjusting the pH, leaving us with a much less toxic solution of saltwater. We can not remove all of the metals, but we can make it much less dangerous to dispose of.View attachment pH metals chart.rtf

 

[snoman701]

If you follow the "4 metals" waste treatment process, you cement out (to metal) anything less reactive than iron and end up with mainly Iron Hydroxide, which I believe turns into 'rust' when left in contact with air, but Wikipedia also states that Iron Hydroxide is sometimes added to contaminated waterways to clean up some other metal salt.

That's the best, simplest way to do it, in my opinion.

Cant we just increase the ph to 9 and drop all metals as hydroxides and filter them out? Why do we drop all metals with iron in acidic state and drop iron as hydroxide in alkaline?(this is after cementing pgms with copper of course). I would appriciate it.

Emre

If you read the above, the answers are pretty well laid out. As to what method you choose, it's more preference and technical capability and what you want to do.

The guidelines put forth on the board to cement the metals are there for people who are going to get rid of the clear liquid through whatever method they have to. It creates a filtrate that is pretty environmentally acceptable and doesn't require investment in equipment. It sends all of the waste stream in responsible directions that meet disposal requirements, even if they aren't being disposed of within the letter of the law.

In order to precipitate all of the metals as hydroxides, instead of cementing them, you pretty much have to have a filter press, which will then require a pump to feed it and an air compressor to feed the pump. Basically, you are looking at an investment of about 7 grand if you are good at scrounging stuff. You will still have to have the filtrate analyzed to ensure it meets discharge requirements, THEN, in order to discharge it, you have to be permitted....or pay someone to haul off the filtrate.

There are no shortcuts in waste treatment....and there are a lot of options and a lot of opinions. All of them have merit.

One very very consistent opinion is however, don't let it get away from you before you adopt a solution, and stick to it. Don't let your waste get away from you.

 

[FrugalRefiner]

Cant we just increase the ph to 9 and drop all metals as hydroxides and filter them out? Why do we drop all metals with iron in acidic state and drop iron as hydroxide in alkaline?(this is after cementing pgms with copper of course). I would appriciate it.

I'll add a bit to what others have said based on my understanding. When we cement with iron, we drop nearly every metal that is in solution as a metal. The metals are pretty stable. The iron can be dropped as an oxide/hydroxide which is fairly safe.

If we just turn all the metals into oxides and hydroxides, they are not as stable and some can be redissolved by nothing more than our slightly acidic rain. They cannot be safely disposed of in that state.

I know that's a huge over-simplification, and 4metals, Lou, and a few others here can quote you the various laws and tests involved, but I think they've already laid it all out in the past.

Dave

 

[snoman701]

I know that's a huge over-simplification, and 4metals, Lou, and a few others here can quote you the various laws and tests involved, but I think they've already laid it all out in the past.

It's hit or miss as to whether the conditions that have been laid out will apply to their situation.

As to oversimplification, most answers given on this forum are huge oversimplifications...but that by no means suggests they aren't the right answers. It's just that the legwork has been done, over and over again, by other people.

For that reason, one thing I can say for certain is that with the questions they have asked, I think it would be a good investment to pay someone who offers consultation to help them develop SOP's for their processes.

I say that mostly in reference to the quantities they have posted in other threads. It is all on the forum if you dig deep enough, but if you value your time, paying someone like GSP, Lou or 4Metals (not sure if he consults) to spend a couple hours guiding you can put you way ahead.

I spent a few months working with someone who really spent a lot of time fumbling around, getting the job done nonetheless, but still fumbling around in the dark. They would have made A LOT more money and faced A LOT less stress if they had made the investment on the front end and paid for someone to teach them.

BUT...one also has to be willing to learn. One thing I haven't seen GSP post about much is how often his refineries went off the books and then screwed up. He seemed to have very compliant students.

*edited to fix formatting

 

[EMRE]

EMRE,
A quick study of waste treatment should answer the question better than I can in a simple post.

Cementing values with copper, we can recover more noble or valuable metals from solution.

Cementing metals from solution using iron metal drops copper as well as other metals from the solution such as cadmium, cobalt, nickel, tin, lead, antimony, arsenic, bismuth, as well as reduce some of the acids (note hydrogens place in the metals reactivity series).



With this iron solution, we can remove or precipitate many other metals from solution as metal oxides or hydroxides by adjusting the pH, leaving us with a much less toxic solution of saltwater. We can not remove all of the metals, but we can make it much less dangerous to dispose of.pH metals chart.rtf

Butcher,
Thanks for the explanation. What about the clearwater after all the heavy metals and hydroxides are out? Is it safe to say that that is a clear enough water that we can just bring down the pH level to 7 and discharge?

 

[snoman701]

Butcher,
Thanks for the explanation. What about the clearwater after all the heavy metals and hydroxides are out? Is it safe to say that that is a clear enough water that we can just bring down the pH level to 7 and discharge?

NO! Read the whole thread that you are replying to, the answers are already in it.

Metals dropped from a mixed metal waste treatment by what is called the classic destruct process (precipitation of metal hydroxides by raising the pH) are likely to contain at least 1 of the metals contained in this waste solid. There are chelating agents which can be added in the process to keep some of these metals from leaching out of the solid form and thereby pass the TCLP testing. But on any commercial scale the material should be tested by a certified lab at least once annually to confirm (or deny) compliance. Then the waste can be shipped as non hazardous unless, of course, the metals cannot be successfully chelated with your process.

The process, if done properly, only brings the liquid to a non-hazardous state.

Just because it's not considered hazardous waste doesn't mean you can dump it down the drain.

 

[silverinstruments]

waste water treatment , you can use mag meter, PTFE liner and HC electrodes, and SST material housing to measure water flow .

 

[nickjam]

I had a gallon of AP and an old distillation rig, so, I watched the video and figured I would give it a try. From my 1/2 gallon of AP I recovered 1/4 gallon "HCl". With standard litmus paper it began red and by the end of the run was instantly turning the paper a deep, dark purple. I need to do some calculations to determine the %. The water I boiled off tested with a pH of about 2. I neutralized that and no precipitation/cementing of any kind. So, that means the metals were all left behind.

I am not going to do the second part to recover the copper, because I really don't care. I am going to save the dried material for a Hazardous waste day, dump the neutralized water (after a quick $20 lab test to ensure it is an effective distillation technique), and reuse the HCl with a splash of old AP to kick off the reaction.

I did have to add some water near the end of the run because the acid concentrated itself into an exploding mess inside the boiling flask. Made me very happy it is an enclosed process.

If my power was not free I would not do this, but it is, so hook up the hot plate, hook up the glassware, and run some old AP just to try and reuse a little more out of my own chemicals while I process new incoming eWaste!