Process for all desoldered stuff

[marino]

My first post but I'm addicted from this forum.
I separate PC Boards and old board to 3 parts: pins, chips (BG and others) and the rest (all things except the electrolytic capacitors. I know there is some PM inside the ceramic capacitors, transistors and other stuff. I pyrolise it (didn't separate from ash) boil ii in HCl to remove magnetic parts (some left) crush and put to AR. Stanous test was positive until I boiled it. Whats happened? Where the Au and PM are now? In solution or in the mud and how to extract it? Thiosulfphate will help for the mud? There is some process for that kind of stuff?

 

[nickvc]

Welcome to the forum.
If you didn't dissolve all the base metals you may well have cemented your values back out, it's also possible by leaving any carbon in your ash that that has absorbed your values, the advice is to remove as much ash as possible to avoid that happening.

 

[marino]

It's clear, but there is mixed material and I can't imagine that somebody separate so small parts.
I think that 1. pyrolise 2. crush 3. HCl to remove magnetics 4. AR 5. Filtering. Solution SMB with urea and mud thiosulphate for the rest of silver.
It's acceptable way of thinking?
I also put all fingers with the plastic to AP solution and it works quite well. Is there some danger that I lost some gold? Do you do like that or separate from plastic?

 

[kurtak]

I pyrolise it (didn't separate from ash) boil ii in HCl to remove magnetic parts (some left) crush and put to AR.

instead of using HCl to remove the magnetic's from the ash use a magnet - these may (or may not) contain PMs so don't throw them out (yet) they get processed different

then treat your ash with HCl to remove metals like tin, aluminum etc. (non magnetic metals that are effected by HCl)

wash/filter the ash really good to get the HCl dissolved metals out - this is important because HCl dissolved tin (stannous chloride) will cause PM colloids to form which can lead to losses of PMs (do a search on colloids)

Also (as Nick pointed out) after crushing your pyrolized material you need to "make sure" there is NO carbon in it - if there is (& there all most always is) you NEED to incinerate the crushed powders to "make sure" ALL the carbon is turned to "ash" --- or values will be lost to absorption by the carbon --- in other words the organics need to be reduced "completely" to ash before you do ANY leaching

Also (as pointed out by Nick) when you do the AR treatment - if there are any base metals in the mix - you need to use enough AR to dissolve not just the PMs but the base metals as well - other wise the base metals will cement the PMs back out of solution - copper is not effected by HCl - that means if there is copper in the mix when you go to AR you will need a "lot" more AR with a greater amount of nitric to dissolve all the copper

Welcome to the forum

Kurt

 

[nickvc]

It's clear, but there is mixed material and I can't imagine that somebody separate so small parts.
I think that 1. pyrolise 2. crush 3. HCl to remove magnetics 4. AR 5. Filtering. Solution SMB with urea and mud thiosulphate for the rest of silver.
It's acceptable way of thinking?
I also put all fingers with the plastic to AP solution and it works quite well. Is there some danger that I lost some gold? Do you do like that or separate from plastic?

Marino read Kurts post and perhaps you wil understand what the problems could be, other members wash the ash from the metallics by various methods outlined many times here on the forum so they avoid that problem, also trying to remove all values from sludge takes a lot of time and volumes of water which will need to be put with the solution to get at your values and still some will remain trapped. With just metallics to work with makes the job so much easier!

Do some reading here on the forum all the answers are here it just takes effort and time to find them.