Please I need your advise/help!

[kurtak]

you have an excess of hydrochloric acid.
you needed to dry your gold foil.
multiply its weight by 5 and make classic aqua regia
3 parts hydrochloric acid/1 part nitric acid.
For one gram of material there is 5 ml of aqua regia.
an excess of hydrochloric acid does not allow gold to coagulate.

I can assure you that if you dissolve gold foils with "classic" AR (3 parts HCl to one part nitric - or 3ml HCl to 1ml nitric per gram gold) you will end up with excess/free nitric in your AR

Depending on the conditions under which you dissolve the gold you can dissolve a gram of gold foils with as little as 1/2 a ml nitric or less

Example; - under the right conditions (closed reaction vessel & heat) you can dissolve 30 grams of gold foils with only (between) 12 - 15 ml nitric ("sometimes" even as little 10 ml nitric)

on the other hand - if you are trying to dissolve a 30 gram "solid" chunk of gold it will likely take a full ml of nitric per gram gold &/or even as much as 1.5 ml nitric - depending on conditions

The HCL still has to be the same as "classic" AR --- 3 ml HCl (or more) per gram gold --- but the amount of nitric can very (by a lot) depending on the condition under which you are dissolving the gold

Advising new members (beginners) to use "classic" AR to dissolve gold foils is almost always (if not always) why we get new (beginning) members asking why they can't get there gold back out of solution - when they have used classic AR to dissolve their gold foils

Every time - it is because by using classic AR - on foils - they end up with way too much free nitric in their AR so their gold "will not" drop when they add their SMB

Kurt

 

[anachronism]

I can assure you that if you dissolve gold foils with "classic" AR (3 parts HCl to one part nitric - or 3ml HCl to 1ml nitric per gram gold) you will end up with excess/free nitric in your AR

Depending on the conditions under which you dissolve the gold you can dissolve a gram of gold foils with as little as 1/2 a ml nitric or less

Example; - under the right conditions (closed reaction vessel & heat) you can dissolve 30 grams of gold foils with only (between) 12 - 15 ml nitric ("sometimes" even as little 10 ml nitric)

on the other hand - if you are trying to dissolve a 30 gram "solid" chunk of gold it will likely take a full ml of nitric per gram gold &/or even as much as 1.5 ml nitric - depending on conditions

The HCL still has to be the same as "classic" AR --- 3 ml HCl (or more) per gram gold --- but the amount of nitric can very (by a lot) depending on the condition under which you are dissolving the gold

Advising new members (beginners) to use "classic" AR to dissolve gold foils is almost always (if not always) why we get new (beginning) members asking why they can't get there gold back out of solution - when they have used classic AR to dissolve their gold foils

Every time - it is because by using classic AR - on foils - they end up with way too much free nitric in their AR so their gold "will not" drop when they add their SMB

Kurt

Correct. If youre using AR for foils, heat the HCl and add Nitric by the drop. Takes very very little....

 

[anarxi]

I can assure you that if you dissolve gold foils with "classic" AR (3 parts HCl to one part nitric - or 3ml HCl to 1ml nitric per gram gold) you will end up with excess/free nitric in your AR

Depending on the conditions under which you dissolve the gold you can dissolve a gram of gold foils with as little as 1/2 a ml nitric or less

Example; - under the right conditions (closed reaction vessel & heat) you can dissolve 30 grams of gold foils with only (between) 12 - 15 ml nitric ("sometimes" even as little 10 ml nitric)

on the other hand - if you are trying to dissolve a 30 gram "solid" chunk of gold it will likely take a full ml of nitric per gram gold &/or even as much as 1.5 ml nitric - depending on conditions

The HCL still has to be the same as "classic" AR --- 3 ml HCl (or more) per gram gold --- but the amount of nitric can very (by a lot) depending on the condition under which you are dissolving the gold

Advising new members (beginners) to use "classic" AR to dissolve gold foils is almost always (if not always) why we get new (beginning) members asking why they can't get there gold back out of solution - when they have used classic AR to dissolve their gold foils

Every time - it is because by using classic AR - on foils - they end up with way too much free nitric in their AR so their gold "will not" drop when they add their SMB

Kurt

I have urea and copper for this case

although you are right, I did not dissolve the foil.
I would make these fingers in parts, in two liter glasses, with one solution.

 

[kurtak]

I have urea and copper for this case

Or don't over use nitric in the first place

Kurt