ttutone1
Active member
So far everything I have done with gold refining I have succeeded. But this process I messed up. 
I was following these steps:
• Oxalic acid (dehydrate) used at 1:1 weight ratio for the expected gold from solution.
(I use a slight excess Oxalic)
• Dissolve in D. water, water level should not exceed one 1/3 height of the beaker.
• Raise pH with ammonia solution/NaOH to about 6.
• Heat both gold solution and Oxalic solution to near boil.
• SLOWLY add gold solution to oxalic solution, by slow i mean a few drop at a time with a glass pipette. The more concentrated your gold solution is the more vigorous the reaction is. (cover the oxalic beaker almost completely with a watch glass while adding the gold to contain splattering)
• When done adding the gold, give it a good stir with glass rod and keep the reaction beaker 10 more minutes on the hotplate at near boil.
• Remove beaker from heat and allow it to settle over night.
• the following day, Solution should be clear and colorless (assuming it is a second refining), test with SnCl. If negative, filter the solution and discard, if slightly positive, decant the solution to another beaker, add some SMB and let is sit for few more hours or over night.
Where I messed up is I forgot to raise the ph to 6. It didn't look bad but most of the gold would not drop.
So I mixed some more oxalic acid and added about three table spoons of clear ammonia (about 100ml total solution). I didn't think I would have to use all the solution.
Then reheated my auric chloride and oxalic acid. And started adding the oxalic acid solution to the auric chloride. Not much happened. (No fizzing) So I kept adding till the oxalic acid solution that I mixed was gone.
It started to turn clear and some gold was dropping. I thought it looked good.
When the beaker started to cool, the mixed solution started to turn orange. I thought ok this might be normal and let it sit overnight to settle.
The next day the solution is still cloudy orange.
Did I possibly add to much ammonia and raise my ph to high? (My ph test strips are on order so I can't test) :|
Any help would be greatly appreciated. Thank You.
I was following these steps:
• Oxalic acid (dehydrate) used at 1:1 weight ratio for the expected gold from solution.
(I use a slight excess Oxalic)
• Dissolve in D. water, water level should not exceed one 1/3 height of the beaker.
• Raise pH with ammonia solution/NaOH to about 6.
• Heat both gold solution and Oxalic solution to near boil.
• SLOWLY add gold solution to oxalic solution, by slow i mean a few drop at a time with a glass pipette. The more concentrated your gold solution is the more vigorous the reaction is. (cover the oxalic beaker almost completely with a watch glass while adding the gold to contain splattering)
• When done adding the gold, give it a good stir with glass rod and keep the reaction beaker 10 more minutes on the hotplate at near boil.
• Remove beaker from heat and allow it to settle over night.
• the following day, Solution should be clear and colorless (assuming it is a second refining), test with SnCl. If negative, filter the solution and discard, if slightly positive, decant the solution to another beaker, add some SMB and let is sit for few more hours or over night.
Where I messed up is I forgot to raise the ph to 6. It didn't look bad but most of the gold would not drop.
So I mixed some more oxalic acid and added about three table spoons of clear ammonia (about 100ml total solution). I didn't think I would have to use all the solution.
Then reheated my auric chloride and oxalic acid. And started adding the oxalic acid solution to the auric chloride. Not much happened. (No fizzing) So I kept adding till the oxalic acid solution that I mixed was gone.
It started to turn clear and some gold was dropping. I thought it looked good.
When the beaker started to cool, the mixed solution started to turn orange. I thought ok this might be normal and let it sit overnight to settle.
The next day the solution is still cloudy orange.
Did I possibly add to much ammonia and raise my ph to high? (My ph test strips are on order so I can't test) :|
Any help would be greatly appreciated. Thank You.
