finger solution colour

hi im curious as to what is giving the gold finger solution this colour as im washing it with hot - almost boiling water?
my thought was something from the pcb board whats soluble in hcl. maybe the masking or a plasticiser.
heres a pic of fingers in hcl solution soaking.View attachment 1

im using 36.6% hcl diluted slightly. just enough to stop it actively 'fuming' and bubbling a little pure oxygen through. i get my o2 free and its silent to run its the only reason i use it.

anyway im curious to what the orangy yellow is so i can dispose of it correctly thats all. there is a slight smell reminds me of a type of plastic resin so i assume thats correct?

edit my post here, does this stuff interfere with further recovery and refining procedures and what point does it usually come out at?

i can just basify this solution to ph12 and steam distill for around 20minutes to remove ovet 99% of it if thats more desirable. i think its actually a polymer. we get it as waste undesirable side products in organic chemistry reactions.

I'm not sure if it is applicable.
But since you used pure O2 it may be wise to check if it has been acting as an oxidiser and dissolved some gold.
Do a stannous test at least.
Do anyone here know if pure O2 can act as an oxidiser with HCl?

Im1badpup1, are you refining in your kitchen?

its straightforward just to dump it back into fresh conc hcl heat then filter again. then use that hcl for the next finger run.
id sprayed the contents out of the container with water causing an initial precipitation i didnt particularly want at that point, lesson learnt.

no but the lights brightest for a picture in the kitchen.

im1badpup1 said:

no but the lights brightest for a picture in the kitchen.

Click to expand...

Where are you doing the refining?

im doing the recovery outside and in the garage, depending on what im doing - that is if running procedures i dont need to sit, watch and babysit. prepwork and workup in the kitchen. but if it involves vapours and gas evolution no. even the small test scale sizes im doing at the minute its done out the house.

when working on full scale ive borosilicate glassware upto 30l and full laboratory sets upto 20l 45/50 29/32
i usually hook up a vacuum with inline gas trap and external venting for reflux/distillations or filtering when necessary, in other words what im doing is contained as well. it has to be really for when doing larger volumes of materials.

and ive a 240m/min3 12in variable speed rvk exhaust vent if needed, and a 9inch backup. thats metres not cm. i turn it on full it slams shut every door in the house whats open even upstairs it sucks so hard. theyre fitted with charcoal filters. in the garage leavjng the car bay shutter up is good enough as like ive already said my reactions are already contained and dealt with.

id already tested the solution with stannous and it was negative, its doubtful pure o2 makes that kind of difference in this instance. it just means i can bubble gently and finish quicker thats all. the precipitates self explanatory really but whatever oiled out ive no idea. il just adjust slightly to suit and have a proper look at the oily stuff when i work up the saturated spent solution at another date.

Why are you washing foils in hot boiling water?

You only need to rinse them after you dissolve the copper underneath them and they fall to the bottom of your vessel.

i dont need to rinse them at all at that point.
ive answered the rest myself in the meantime doesnt matter
cheers

im1badpup1 said:

i dont need to rinse them at all at that point.
ive answered the rest myself in the meantime doesnt matter
cheers

Click to expand...

Do you want to share what you did or found out?

Göran

i rinsed the flask with water - sprayed it to get the bits out, using water which caused a precipitation prematurely of metal chlorides from the acidic solution which when then rinsing the gold foils did the same .
i didnt need to do this since i was going to then put the foils in fresh hcl and heat.
the oiling out, just a small fraction appearing on the rinse water surface which i was initially curious about and what my question actually was isnt anything for me to be concerned of once i realised it doesnt affect working up.

i just shouldnt spray the vessal with water to clear it out. i dont need to rinse the foils at this point either. just put into fresh hcl, heat. no rinsing with water is necessary. im using hcl +hno3 next anyway. if i wanted to dry and weigh the batch or store then perhaps rinse it off at this point.

id used the fingerfoil solution to point of saturation-exhaustion. thats why even a small amount of water would cause precipitation. most people just sling a huge excess of acids in and it would never be something they see.

i used the saturated finger solution to dechip and remove mlccs and flatfilm resistors from another batch of ram memory earlier in another simple displacement reaction. it worked very well. in my kitchen too!

il recover the basemetals when concentrated in sufficient quantity and purity. and convert the chlorides to oxides or maybe straight to the elemental metal, it depends what works best. Also recover the hcl (g) in a water vapour trap for reuse at the end and at the same time.

Thanks! It helps the next person reading this thread. Too many threads ends without the final post of what happened at the end.

Göran