solar_plasma
Well-known member
I don't know, if this topic is placed correct in Help Needed, since I don't need help, but rather would like to hear some advices.
I have dissolved all´my 7g recovered gold (from my first ceramic cpu experiments to my last more skilled experiments) in AR and used goldbutton method to get rid of excess nitric, though the gold button was not pure,but from my first ceramic cpu recovery. I let it sit for a week with the gold button.
I precipitated with potassium metabisulfite and got a light brown precitation at first, later more dark, almost black. So, obviously and like expected I had some impurities in it.
Then I decanted until the wash water stayed clear and decanted 2 times more.
Finally I let it sit for 2 weeks in 33% HCl, which got a coffee brown colour. This makes me wonder, since the first solution in AR was strongly yellow, as I would expect from a properly done gold solution.
Today I made a first and quick test on q-tips (later I will make better tests on spotplate when I am in the lab) with DMG 1% in alc. and SnCl2-solution, which was old, but still showed positive on my standard gold solution. DMG turned brown, SnCl2 at first yellow, after 30 min almost discoloured but in good light very slightly pink.
Before I go on, I will make fresh and better test solution: DMG/NaOH instead of alc. and fresh SnCl2.
At this point I like to believe the coffee brown colour might indicate Pd/Pt, which ofcourse has to be tested. But my question at this point is, why has it been yellow in AR before? Or maybe I haven't worked properly enough at any point?
This fairly poor description leaves room for speculations, but maybe some of you like to give their two cents...
I have dissolved all´my 7g recovered gold (from my first ceramic cpu experiments to my last more skilled experiments) in AR and used goldbutton method to get rid of excess nitric, though the gold button was not pure,but from my first ceramic cpu recovery. I let it sit for a week with the gold button.
I precipitated with potassium metabisulfite and got a light brown precitation at first, later more dark, almost black. So, obviously and like expected I had some impurities in it.
Then I decanted until the wash water stayed clear and decanted 2 times more.
Finally I let it sit for 2 weeks in 33% HCl, which got a coffee brown colour. This makes me wonder, since the first solution in AR was strongly yellow, as I would expect from a properly done gold solution.
Today I made a first and quick test on q-tips (later I will make better tests on spotplate when I am in the lab) with DMG 1% in alc. and SnCl2-solution, which was old, but still showed positive on my standard gold solution. DMG turned brown, SnCl2 at first yellow, after 30 min almost discoloured but in good light very slightly pink.
Before I go on, I will make fresh and better test solution: DMG/NaOH instead of alc. and fresh SnCl2.
At this point I like to believe the coffee brown colour might indicate Pd/Pt, which ofcourse has to be tested. But my question at this point is, why has it been yellow in AR before? Or maybe I haven't worked properly enough at any point?
This fairly poor description leaves room for speculations, but maybe some of you like to give their two cents...
