oily residue in AP of brick cleaner

[pesco]

Hi,
I have few litres of old B&Q brick cleaner left over some building project and wanted to use it out to free up some space. It is HCl based (around 20%).

All great, mentioned brick cleaner + H₂O₂ + some pins and connectors.
Base metals dissolved, liquid green, gold foils floating around.

As it was brick cleaner it wasn't just HCl and there were some detergents, inhibitors or similar stuff and as result there is a layer of oily substance floating on top the beaker. Quite a bit of gold flakes is trapped in it.

Now, the question is what would be the best way to get rid of it ?

I was thinking to use acetone to dissolve the oil and free up the gold foils, so they could drop to the bottom of the beaker. Two problems with this :
- acetone doesn't destroy oils, just dissolves it, as soon as acetone evaporates the oil will be back as visible pools
- acetone + acid + salts could be a bit risky business, however should be safe while in the solution


Have you got any suggestions guys?

 

[Oz]

Filter it, then incinerate.

 

[martyn111]

I use exactly the same brick cleaner from B&Q, the way I deal with floating foils is to spray them down with a wash bottle, this pushes them down below the surface of the liquid where they sink to the bottom of the vessel, once they are all settled I decant the liquid out of the vessel, incinerate the solids and proceed to dissolve the foils using the acid bleach method.

 

[pesco]

Thanks for replies!

The oily stuff clogs up the filter media in no time :x
Even when I tried to keep water column high hoping that the oily stuff will go up immediately after entering the funnel.

Lots of foils are very small and are trapped inside the "oily bubbles".
Martyn111, I don't know if you have noticed, but the foils when very small sort of glue to the oily stuff :x


All pins and connectors dissolved.
I dropped in some Cu to cement any values which could have dissolved by H₂O₂+HCl.
Liquid condensated by evaporation from around 3-4L to 700ml.
On top of the liquid in 1L beaker there is around 4-5mm layer of this oily gunk.
Best way I found is to place paper towel on top of the liquid and soak up the oily stuff.
Paper towel will get incinerated when it dries out.
The liquid will get processed as usuall :mrgreen:

 

[pesco]

It wasn't the "oily stuff" what clogged the filter media - it was the gold :mrgreen:

I found out that the "oily stuff" are definitely detergents and they go through the filter with no problems. First the droplets are so tiny you can't actually see them, but when I came back to the solution after few weeks the beaker has "oily" film floating on top.

Spraying works on bits of foils, but the black powder gets trapped in the "oily stuff", however filtering did help and there is no Au left in a solution.