Has anyone seen this?

[Starting out]

I decided to process my waste bucket for the first time which contained HCL and H2O2 with whatever metals made it through the filter or were in solution. Following Sreetips' advice, I had left some copper fittings and pipes for at least a week. I am puzzled by the white creamy looking substance that formed on the copper. I can scrape most of it off with a knife and after a day, the copper is covered again. could this be a passivation layer of silver chloride? The material I was processing was from computer PCBs and some pins pulled from motherboards. If you've come across this or have advice on what to do next, please let me know. Thank you all very much.

 

[Martijn]

Are you treating your AP (copper chloride leach) as waste or is this waste from HCL / H2O2 gold leaches?
Pins and PCB's generally don't have a lot of silver in them. If any.

Waste containing HCL will only have insoluble silver chloride which would not pass a filter.

So i guess you are cementing your AP, and if you use a bubbler, you are dissolving the copper and depleting any free HCL, leaving you with insoluble (in water) copper 1 chloride.
If you are not using a bubbler, there can be free HCL left and the copper 1 chloride can not turn into copper 2 chloride. Or very slowly.
Test if a bit dissolves in HCL. This reaction needs time and air. Stir or shake the test tube every now and then. Or use a bottle with an air bubbler for the test.

You can reuse AP indefinitely by the way. It's not waste.

And only use clean red copper pipe or electric wire to cement, leave soldered fittings out!!

Martijn.

 

[Starting out]

Are you treating your AP (copper chloride leach) as waste or is this waste from HCL / H2O2 gold leaches?
Pins and PCB's generally don't have a lot of silver in them. If any.

Waste containing HCL will only have insoluble silver chloride which would not pass a filter.

So i guess you are cementing your AP, and if you use a bubbler, you are dissolving the copper and depleting any free HCL, leaving you with insoluble (in water) copper 1 chloride.
If you are not using a bubbler, there can be free HCL left and the copper 1 chloride can not turn into copper 2 chloride. Or very slowly.
Test if a bit dissolves in HCL. This reaction needs time and air. Stir or shake the test tube every now and then. Or use a bottle with an air bubbler for the test.

You can reuse AP indefinitely by the way. It's not waste.

And only use clean red copper pipe or electric wire to cement, leave soldered fittings out!!

Martijn.

Thanks for the advice Martijn,

That stuff didn't go through filter. It was precipitated after I filtered out the gold foils from fingers and pins. I also reused the AP to remove the enig from larger pcbs. After filtering, I poured the solution into a bucket and added the copper to precip any PMs that were still in solution. It only turned that way after adding the copper. I believed that the solder wouldn't hurt at that point since the reactivity series would still precip out the silver, gold and pgms. I was thinking silver chloride because of the cloudy white appearance and how it looks like Sreetips' AgCl. Maybe because I threw in a lot of stuff that still had solder. If copper chloride looks similar to silver chloride then I guess it makes sense. I've managed to isolate quite a bit of the white stuff by letting it settle and decanting. Could I test it with Lye and sugar? would CuCl turn to Cu oxide the to CU metal the AgCl does?

Maybe there's a thread on reusing your AP that I can check out. I haven't had a lot of time to search everything.

I really am just Starting out and have so much to learn. I'm grateful for your help.

Thanks

 

[FrugalRefiner]

I would test it by putting a bit of the white precipitate in a test tube and adding a bit of HCl. If it's CuCl it will dissolve. If it's AgCl (not likely) it won't.

Dave

 

[Starting out]

I would test it by putting a bit of the white precipitate in a test tube and adding a bit of HCl. If it's CuCl it will dissolve. If it's AgCl (not likely) it won't.

Dave

Thanks Dave

 

[Starting out]

I would test it by putting a bit of the white precipitate in a test tube and adding a bit of HCl. If it's CuCl it will dissolve. If it's AgCl (not likely) it won't.

Dave

I got the white precipitate into a filter and left it overnight. It was pretty cool that it turned from white and creamy to this green, dried cake. When I saw the color I figured you were right and that it's copper chloride. I put a few crumbs into a small flask and added some HCL and yes it dissolved slowly. I attached a photo of the cake.

Thank you very much for your help.

 

[jadedalex]

Start, Just wanted to add that I notice that you used Soldered joints in your cementing bucket. Shouldn't you be using PURE Copper? Lead does create havoc in more ways than one...

 

[Starting out]

Start, Just wanted to add that I notice that you used Soldered joints in your cementing bucket. Shouldn't you be using PURE Copper? Lead does create havoc in more ways than one...

Yeah, thanks Jade. My reasoning was that after filtering out the gold foils from the fingers, my solution would contain only the base metals. The copper with fittings that I added are all above silver, gold and PGMs on the reactivity series and were only added to cement out any minute amount of precious metals. Once the solution is saturated and precious metals cemented out, I add Iron to get the copper. Its a lot of fun melting the copper too. I don't know why lead creates havoc but I will heed your advice and use only pure copper from now on. I'm also hoping to distill the remaining solution to get my HCL back to new. If it's a bad idea, please explain as if I'm a 2 year old lol..

Thanks much