Incineration : in which step?

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Hi all.
This is the way I do.
first step: nitric acid and water
second step: aqua regia + urea + mbs
third step: clorox, and 3 washes with water
fourth step: clorox, and 3 washes with water
Fifth step: ammonia, and 3 washes with water
sixth step: clorox, and 3 washes with water
Seventh step: aqua regia + urea + mbs.
I want to incinerate the material obtained
after the treatment with nitric acid and water.
It is properly incinerated after the second
step (after aqua regia treatment + urea + mbs)?
This is what's left of my E-scap after the first pass ...

it's wrong? I accept constructive criticism and suggestions.
thank you all.

 

[glorycloud]

Greetings or Ciao!

Where did you get this process from? I haven't seen Clorox required other than
for making auric chloride with HCL and Clorox.

Perhaps you can tell us what material you started with and where this process
that you used came from?

 

[roggiou]

Sorry , for my bad english !
how stupid I am !!
I wrote the wrong thing.
Not CLOROX but HCL
I start from circuit boards - phone part .
I depopulated the boards, and for minimize, or better exclude risk of contamination of silver & base metals + PGM to gold dissolution , I guess , to go in this the way .

first step: nitric acid and water
second step: aqua regia + urea + mbs
third step: HCL, and 3 washes with water
fourth step: HCL, and 3 washes with water
Fifth step: ammonia, and 3 washes with water
sixth step: HCL, and 3 washes with water
Seventh step: aqua regia + urea + mbs.
I want to incinerate the material obtained after the treatment with nitric acid and water.
It is properly incinerated after the second step (after aqua regia treatment + urea + mbs)?
this is my doubt.
Thanks all !
Ciao From Italy (Venice)

 

[glorycloud]

I believe that incineration is recommended between a change in acids
like after using nitric acid and before you use AR.

 

[upcyclist]

To amplify what glorycloud said, I see two main uses for incineration:

1) Roasting: Between stages involving different acids, as he said. Especially when you start with HCl or CuCl₂ and your next step uses nitric, and you want to avoid early formation of AR or silver chloride. Many refer to this step as "roasting" instead of "incineration", when the purpose is to rid yourself of excess chlorides (or nitrates, as the case may be). I may not be fully correct on this, but I consider the primary difference between incineration and roasting to be your intent.

2) Incineration: To convert carbon and complex organics to ash (and water/CO₂/etc). This is used more often in e-scrap recovery than, say, karat scrap refining. Often the best route is actually pyrolysis followed by incineration for this use case, but the small refiner may not have access to pyrolysis.

 

[FrugalRefiner]

Incineration is also useful to eliminate oils and other organics prior to leaching, as well as to convert metastannic acid residues to tin oxide that is soluble in HCl.

If you're going from either nitric or HCl to AR, there is usually no need to incinerate as your purpose is to intentionally create AR, so any remaining nitrates/chlorides are used in the AR.

Dave