samuel-a
Well-known member
- Joined
- Oct 7, 2009
- Messages
- 2,190
For a while now I'm converting AgCl to elemental using the acid way (10% H2SO4 + Al) and found that with large quantities the process is long and tedious.
I'm producing AgCl from nitric leach of inquarted karat jewelry, the reason i produce AgCl in the first place is because it keeps test slight positive for PGM's that i cement out with Cu slab once the silver had gone out of solution.
So I've been experimenting today with the lye/sugar method with an AgCl sample.
I've pulled the sample while wet so i couldn't weight it but estimate about 10 g of the salt and placed in 250ml Erlenmeyer beaker.
Washed it well with water before, added 200 ml of tap water and placed on magnetic stirrer (set on low), i know i been using way to much water for that sample but otherwise the stir bar will splatter everything all over the beaker.
Start adding 5g of NaOH and after 10 min of stirring noticed only a slight change of color on the powder, i reckon that the desired PH is at about 10-12 to get the the AgCl to oxide completely. I ended up adding increments that totals for about 25g of NaOH to get the oxides and left to stirr for about one hour.
To test the conversion i simply pulled a small sample after each lye addition from the main bulk, washed it with water and added nitric acid to see how much of it dissolve and how much remains as AgCl.
I didn't got a complete conversion before moving on to the sugar step and figure it will eventually will transform to oxide.
Note: The volume of the powder decreased slightly upon the addition of lye and conversion to oxide, i would say about 20-30% of the original salt volume.
Sugar was added to the mix (stirred at all times with magnetic stirrer), one gram per each estimated gram of starting AgCl, total of 10g was added.
Upon addition of the sugar the solution turned darker and into a very thick suspension with nothing settling anymore to the bottom and after 10 minutes or so of stirring, a mirror started forming on the in side walls of the beaker.
This result lead me to understand that i did convert oxide to elemental silver, but not in the known way of gray powder that have been described here on the forum before. the solution left to settle for the night.
Few things to consider:
- The whole process was done at room temp'
- PbCl may very well be present along side the AgCl at small quantities, since it haven't been boiled with water before beginning the process.
- End product purity is not a concern since it will loop back to inquarting new scrap jewelry.
Next time i will defiantly try this process with dextrose and a more control over the PH levels.
Tomorrow i will decant the solution, wash and dry the resulting powder, weight it and dissolve once again with nitric to see how much (if any) AgCl salt is left.
I would like to have your input about this process since i believe it is more suitable for few ounces batches then the acid way.
Any comments and suggestions are welcomed.
Thanks Sam
I'm producing AgCl from nitric leach of inquarted karat jewelry, the reason i produce AgCl in the first place is because it keeps test slight positive for PGM's that i cement out with Cu slab once the silver had gone out of solution.
So I've been experimenting today with the lye/sugar method with an AgCl sample.
I've pulled the sample while wet so i couldn't weight it but estimate about 10 g of the salt and placed in 250ml Erlenmeyer beaker.
Washed it well with water before, added 200 ml of tap water and placed on magnetic stirrer (set on low), i know i been using way to much water for that sample but otherwise the stir bar will splatter everything all over the beaker.
Start adding 5g of NaOH and after 10 min of stirring noticed only a slight change of color on the powder, i reckon that the desired PH is at about 10-12 to get the the AgCl to oxide completely. I ended up adding increments that totals for about 25g of NaOH to get the oxides and left to stirr for about one hour.
To test the conversion i simply pulled a small sample after each lye addition from the main bulk, washed it with water and added nitric acid to see how much of it dissolve and how much remains as AgCl.
I didn't got a complete conversion before moving on to the sugar step and figure it will eventually will transform to oxide.
Note: The volume of the powder decreased slightly upon the addition of lye and conversion to oxide, i would say about 20-30% of the original salt volume.
Sugar was added to the mix (stirred at all times with magnetic stirrer), one gram per each estimated gram of starting AgCl, total of 10g was added.
Upon addition of the sugar the solution turned darker and into a very thick suspension with nothing settling anymore to the bottom and after 10 minutes or so of stirring, a mirror started forming on the in side walls of the beaker.
This result lead me to understand that i did convert oxide to elemental silver, but not in the known way of gray powder that have been described here on the forum before. the solution left to settle for the night.
Few things to consider:
- The whole process was done at room temp'
- PbCl may very well be present along side the AgCl at small quantities, since it haven't been boiled with water before beginning the process.
- End product purity is not a concern since it will loop back to inquarting new scrap jewelry.
Next time i will defiantly try this process with dextrose and a more control over the PH levels.
Tomorrow i will decant the solution, wash and dry the resulting powder, weight it and dissolve once again with nitric to see how much (if any) AgCl salt is left.
I would like to have your input about this process since i believe it is more suitable for few ounces batches then the acid way.
Any comments and suggestions are welcomed.
Thanks Sam
