So I decided to refine some 585 gold. Just for fun and to educate children.
I bought 10g 585 gold from pawnshop, and 14g of 925 silver. I melted them and mixed them together. I extracted silver and copper with the help nitric acid. I cemented silver out with copper and melted it back to a chunk of silver.
Then with aqua regia I dissolved the remaining stuff after washing in distilled water few times. I filtered the liquid. I got very nice dark orange colored liquid.
As I had no urea at hand, so I neutralized aqua regia with sodium bicarbonate. Then I wanted to get rid of eccessive sodium bicarbonate that I added too much. I heated the solution up close to boiling point, so that half of sodium bicarbonate converted to water and CO2 and the rest to Sodium carbonate, which is 3x more soluble. After bubbling was done, the solution became feculent orange. Lighter in color. I tried to filter it out, but for some reason it did not filter well, and I left half of the solution unfiltered, as they looked pretty much the same. then I made sodium metabisulfite solution and poured it into filtered part of solution. There was just some bubbling and nothing really happened. But then suddenly there was precipitating gold after like 30 seconds.
So I continued with unfiltrated solution. But to my horror, orange color disappeared completely, and it became clear. The filtered solution looked like some of the precipitated gold returned back to solution. Only very small precipitation patches remained in the bottom I cleaned the precipitate and melted it into a small drop of gold. like 0,3g.
Tin Chloride test shows that gold is still there. In both solutions. Also, it looks like small metal glitter is floating inside the solution.
One more point that Na2S2O5 was not of laboratory grade. But there must clearly something else wrong, as in unfiltered part of solution nothing participated out.
And that filter, I looked at later, contained some metal like powder.
Any ideas what is not right here?
I bought 10g 585 gold from pawnshop, and 14g of 925 silver. I melted them and mixed them together. I extracted silver and copper with the help nitric acid. I cemented silver out with copper and melted it back to a chunk of silver.
Then with aqua regia I dissolved the remaining stuff after washing in distilled water few times. I filtered the liquid. I got very nice dark orange colored liquid.
As I had no urea at hand, so I neutralized aqua regia with sodium bicarbonate. Then I wanted to get rid of eccessive sodium bicarbonate that I added too much. I heated the solution up close to boiling point, so that half of sodium bicarbonate converted to water and CO2 and the rest to Sodium carbonate, which is 3x more soluble. After bubbling was done, the solution became feculent orange. Lighter in color. I tried to filter it out, but for some reason it did not filter well, and I left half of the solution unfiltered, as they looked pretty much the same. then I made sodium metabisulfite solution and poured it into filtered part of solution. There was just some bubbling and nothing really happened. But then suddenly there was precipitating gold after like 30 seconds.
So I continued with unfiltrated solution. But to my horror, orange color disappeared completely, and it became clear. The filtered solution looked like some of the precipitated gold returned back to solution. Only very small precipitation patches remained in the bottom I cleaned the precipitate and melted it into a small drop of gold. like 0,3g.
Tin Chloride test shows that gold is still there. In both solutions. Also, it looks like small metal glitter is floating inside the solution.
One more point that Na2S2O5 was not of laboratory grade. But there must clearly something else wrong, as in unfiltered part of solution nothing participated out.
And that filter, I looked at later, contained some metal like powder.
Any ideas what is not right here?
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