Hi all fellow gold refiners, this is my first time posting on this forum. I have studied and applied a lot of material within this forum to my personal refining and I have been successful in the area of gold finger gold extraction as well as pcbs. I then attempted the process of gold plating removal using the reverse electrolytic cell with sulphuric acid and this was a success to a certain point. This is where my problem sits, I have added muriatic acid 32% with 5% bleach to the black powder after draining the excess sulphuric acid as much as I could. The problem I face is that the solution stays green after adding HCL and bleach. I have done this at night, no heat and no sunlight and I am seeking solutions to this problem of the solution staying green. I must admit that I have added a bit more bleach than is required with a ratio of 2 HCL to 1 bleach which I used. please help...
HCL and bleach problem
- Thread starter nash@22
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I think you do not have a problem, the colour of the solution is from other contaminants, probably copper, if all the powder has dissolved simply filter and precipitate, if you want high purity gold dissolve the powder after a wash cycle using different reactants and precipitant.
I think you do not have a problem, the colour of the solution is from other contaminants, probably copper, if all the powder has dissolved simply filter and precipitate, if you want high purity gold dissolve the powder after a wash cycle using different reactants and precipitant.
thank you for your response Nickvc, I will filter and precipitate as suggested, my observation was based on my previous experiments where adding HCL and bleach yielded cloroauric acid with a bright gold colour so in a nutshell I was looking for that colour.
Color is not a good indicator, you should use stannous to see where the gold is.
Göran
Göran
As Goran has pointed out colour is a poor indicator once you have various elements in your solutions, the use of stannous,again as Goran pointed out, is your friend. We have had many posts about what is in my solution based on the colour and all we can usually do is guess unless the OP details exactly what has been dissolved.
good day to all, sooo I tested with stannous chloride and found gold in solution, I then proceeded with SMB precipitation and I must say I had to use quite a bit to precipitate the gold, testing with stannous everytime I added SMB, the solution turned a light green but I managed to drop the gold to that brown powder, I then proceeded to clean the powder with HCL and water in repeat and melted the powder to yield 5.2grams of gold.
Great!
Now you just have to study a lot more, for example reading Hoke's book.
One reason that might have caused a problem with needing a lot of SMB is if there were chlorine left. The gold that precipitated would go into solution again until the chlorine is used up. Heating the solution until steaming or just letting it stand a few days is usually enough to remove the excess.
Göran
Now you just have to study a lot more, for example reading Hoke's book.
One reason that might have caused a problem with needing a lot of SMB is if there were chlorine left. The gold that precipitated would go into solution again until the chlorine is used up. Heating the solution until steaming or just letting it stand a few days is usually enough to remove the excess.
Göran
hi, thank your for your help and suggestions which I will most definitely apply in my next extraction 
, I will definitely read a lot more wherever I find information, I do have Hokes book which I am reading as well, loads of good info in there as well at all posts and videos I find. One thing I have noticed is the type of gold plated materials I use for gold plate removal, items containing bit of electronics like gold plated FETS, I try to smash the electronics to expose the gold plated substrates and then clean with alcohol and water. I do find that my rinse water has the green tint after I remove these pieces from the sulphuric acid stripping cell and if these items drop in the stripping cell rinse water container, they have a coat of copper and after removing these pieces from the rinse water container it changes back to the base metal colour. What this means is that the gold plated items should be totally free of other contaminants that can be easily removed before placing into the stripping cell.
, I will definitely read a lot more wherever I find information, I do have Hokes book which I am reading as well, loads of good info in there as well at all posts and videos I find. One thing I have noticed is the type of gold plated materials I use for gold plate removal, items containing bit of electronics like gold plated FETS, I try to smash the electronics to expose the gold plated substrates and then clean with alcohol and water. I do find that my rinse water has the green tint after I remove these pieces from the sulphuric acid stripping cell and if these items drop in the stripping cell rinse water container, they have a coat of copper and after removing these pieces from the rinse water container it changes back to the base metal colour. What this means is that the gold plated items should be totally free of other contaminants that can be easily removed before placing into the stripping cell.
