Hi,
I started with iodide-iodine method. I bought 500g of KI. Than add 80 ml of HCl and 70 ml of H2O2. I prepare 1000ml solution.
Then the gold dissolved in 40 second.
So I want to precipitate it. I add about 90 g of sodium bisulfate. Then I add ascorbic acid in small portions. I add 300g and Nothing Happened.
So I add more sodium bisulfate, the solution turn brown and reddish. After an hour it turned black again. Then I poured it to another beaker. I remove the sodium bisulfate that didn't dissolved.
Later I try with smb, so I add HCl to ph about 5 and add 100g of smb also nothing happened. So I add 1 g of zinc, also the same.
I came with an idea to add thiosulfate. I add 300g of 5 watered thiosulfate. I left it for a day. Also nothing.
Next I try with the oxalic acid. I add about 80g of 2 watered oxalic acid. The solution was heated to boiling and turn sandy. Later I add about 50g of sodium bisulfate. All goes well but when I came to check the results the solution is black again.
Please help me so much! I don't know what to do now.
The solution contain Gray powder on the bottom which is hardly soluable. Also there are some oxalic acid. And there are now 4000ml of water not 1000ml so it is 4 times diluted
Thanks you in advance, Dominik
I started with iodide-iodine method. I bought 500g of KI. Than add 80 ml of HCl and 70 ml of H2O2. I prepare 1000ml solution.
Then the gold dissolved in 40 second.
So I want to precipitate it. I add about 90 g of sodium bisulfate. Then I add ascorbic acid in small portions. I add 300g and Nothing Happened.
So I add more sodium bisulfate, the solution turn brown and reddish. After an hour it turned black again. Then I poured it to another beaker. I remove the sodium bisulfate that didn't dissolved.
Later I try with smb, so I add HCl to ph about 5 and add 100g of smb also nothing happened. So I add 1 g of zinc, also the same.
I came with an idea to add thiosulfate. I add 300g of 5 watered thiosulfate. I left it for a day. Also nothing.
Next I try with the oxalic acid. I add about 80g of 2 watered oxalic acid. The solution was heated to boiling and turn sandy. Later I add about 50g of sodium bisulfate. All goes well but when I came to check the results the solution is black again.
Please help me so much! I don't know what to do now.
The solution contain Gray powder on the bottom which is hardly soluable. Also there are some oxalic acid. And there are now 4000ml of water not 1000ml so it is 4 times diluted
Thanks you in advance, Dominik