Review of my Process before I start A-Z

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naboobo2000

naboobo2000

Member
Joined
Nov 10, 2011
Messages
8
Sorry for sounding like a complete noob, but I would like some feedback before I begin this weekend. Below is what I'll be working with and the process that I'll be doing. ( with the forums feedback first)

E-Waste 250 Cell phones

1. Fill single layer vertical of cell phones in 3 gallon bucket placed into a 5 gallon bucket with several holes in bottom of 3 gallon bucket.
2. Cover phones with Muratic acid to depopulate the boards. I have already removed all tin and extras that I could. Cover 5 gallon bucket for 2-3 days.
3. Remove cover and drain 3 gallon back into acid. Place acid phones into empty 5 gallon bucket for AP later. Reload 3 gallon bucket with the next load of phones and place back into acid. Add more acid if process slows. Recover and wait.
4. Clean all depopulated boards with putty scrapper in water bucket.
5. Drain Depopulation bucket through a filter to recover mono caps, flat-packs and junk.
6. Run Depopulated boards in AP using fresh Muratic acid and Peroxide.
7. Remove, filter, clean, wash and repeat
8. Process Gold in AC and drop with SMB. After settle test with Stannious Chloride.
9. Combine all waste into one. Recover Silver by cementing from waste acid using copper plates.
10. After gold drop drain AC through filter and recover all gold mud. After test with Stannious Chloride.
11. Using another copper plate place in this acid to cement out any PMG.
12. Raise PH to 2.5 and place iron plate to recover copper.
13. Neutralize waste and dispose.
14. Become a Millionaire :)

Woof that's some tough reading. Thank you if you got though it and please comment good or bad. Suggestions Please.

Thank you again
Chris
 
Item 9.
Combine all waste into one. Recover Silver by cementing from waste acid using copper plates.

As you don't mention the use of nitric acid in your proposed process you will not have dissolved any silver to recover in this step.
If you use nitric to remove the tin before you start the proposed process then you should cement the silver from that acid. Remember if you are switching from nitric to hydrochloric and don't want to dissolve values in the next step of the process, you should incinerate the material between acids.
 
OK, It looks like I am stuck. I'll keep looking but I am not sure I can recover silver without Nitric?

And if I didn't dissolved any silver in the AP then my gold will be mixed and not pure?
 
naboobo2000:
Sorry for sounding like a complete noob, but I would like some feedback before I begin this weekend. Below are what I'll be working with and the process that I'll be doing. (With the forums feedback first)

E-Waste 250 Cell phones

1. Fill single layer vertical of cell phones in 3 gallon bucket placed into a 5 gallon bucket with several holes in bottom of 3 gallon bucket.
2. Cover phones with Muriatic acid to depopulate the boards. I have already removed all tin and extras that I could. Cover 5-gallon bucket for 2-3 days.
(I see no problem so far, except maybe remove any plastic and magnetic material before using HCl)
3. Remove cover and drain 3 gallon back into acid. Place acid phones into empty 5 gallon bucket for AP later. Reload 3-gallon bucket with the next load of phones and place back into acid. Add more acid if process slows. Recover and wait.
(Heat or using old crock-pot may help)
4. Clean all depopulated boards with putty scrapper in water bucket.
(Save these parts neutralize them, incinerate and crush to powders, treat separately removing base metals, tin will still be trouble, incinerate fine powder again, wash in hot HCl rinse well, neutralize again with NaOH, wash out salt water, dry incinerate, treat with nitric acid, decant nitric solution (recover Pd & Ag, from nitrate solution, cementing on Copper metal), dissolve values in aqua regia, decant solution and precipitate values, using stannous to test solutions).
5. Drain Depopulation bucket through a filter to recover mono caps, flat-packs and junk.
(See above without removing tin you may have problems filtering and recovering values)
6. Run Depopulated boards in AP using fresh Muriatic acid and Peroxide.
7. Remove, filter, clean, wash and repeat
8. Process Gold in AC and drop with SMB. After settle test with Stannous Chloride.
9. Combine all waste into one. Recover Silver by cementing from waste acid using copper plates.
(Silver will be chloride insoluble white powder, if HCl used, this will be mixed with lead and other white salts like copper chloride)
10. After gold drop drain AC through filter and recover all gold mud. After test with Stannous Chloride.
(I assume you are referring to HCl/sodium hypochlorite to dissolve gold, you can use this instead of aqua regia as I stated above)
11. Using another copper plate place in this acid to cement out any PMG.
(Start a waste crock for trace values)
12. Raise PH to 2.5 and place iron plate to recover copper.
13. Neutralize waste and dispose.
14. Become a Millionaire
(Maybe just be happy to pay for your chemicals)’
(it is hard to add changes in the middle of your procedure without changing the whole thing, there are other ways to deal with these metals using some of the other methods or acids than I stated)

naboobo2000:
I see many places here where you are starting to understand a working process, but I also see many holes in your theory, it would be hard to tell you all of them I see, but incineration should be included and removing tin and other troublesome metals that will give you much trouble, some of your value will be inside the parts, so incineration and crushing will expose these, removing as much magnetic metallic before treating with acid,

I do not want to throw monkey wrench into your work here (you almost got it) but I say (they way I see it) back to the drawing board.
 
If I may add something, I ran a trial batch that were depopulated in HCL and I noticed that on some areas of the board ( especially where the number buttons would be ) that some of the gold was removed. As if it had dissolved. I'm.not sure what happened. I know I skipped the nitric part. The only reason I had done this was to have first hand experience to see what would happen if I skipped steps. But I still don't know why it appeared that the gold was removed from only HCL.
 
jrmycooke said:
If I may add something, I ran a trial batch that were depopulated in HCL and I noticed that on some areas of the board ( especially where the number buttons would be ) that some of the gold was removed. As if it had dissolved. I'm.not sure what happened. I know I skipped the nitric part. The only reason I had done this was to have first hand experience to see what would happen if I skipped steps. But I still don't know why it appeared that the gold was removed from only HCL.
Click to expand...

Part of the problem with adding a broad spectrum of base metals to a process is your processes don't act predictably, far too many variables.
 
Gold plating on some materials can be so thin, (very thin), that when base metals under plating dissolve into solution, gold could be left in a very fine (brown) powder (or fine particles), so fine that it seems to have disappeared, or dissolved, these powders may be mixed in with all of the other waste in the bottom of the jar

If atmospheric air enters the HCl, there is slight chance it can put some gold in solution temporarily, (same when adding 3% peroxide in the acid peroxide method), this gold will cement back out onto remaining copper or can be left as very fine brown powders (when all base metals are dissolved).
 
I was able to complete the processing of my 250 cell phone boards. Well almost!

The straight HCL covered bath for 3 days worked. Everything that was soldered in came off ether in the bath or by my scraper on one pass. It appeared with my eyes that I lost nothing. The only things that did not come off where the "dpacks" These are the chips that are soldered from the bottom. I ran the board just like this and will come back for those that had not been removed later.

After boards came out of AP I had to scrub each one with a tooth brush to remove the micro size gold floating around. This part too several days because I had so many boards. I also had the problem with some boards laying on top of each other so the AP didn't work on covered boards. My next batch will not have so many boards in at once. I will also separate the boards with zip ties loosely tied around the boards to keep the boards from laying on-top of each other. I figured that this will also help with the gold to fall off instead of removing with the tooth brush.

IF boards from LCD TVs are the next thing to try.
 

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