Soda ash, carbon powder, and borax are the components of a silver chloride flux. Not something I love working with (silver chloride melts) but if you have to, use the right flux.
retrieving fine silver metal from silver chloride solution
- Thread starter jam353wih
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I posted those ingredients from memory because I could not find them on the forum. But, after digging through my old notes (yes I am old enough to have hand written notes) I found the procedure which can range between very effective for clean silver chloride and nasty for very dirty chlorides.
But here goes;
1.Dry the chlorides well.
2.Weigh the chlorides and add the following components based on the start weight.
3. Add 70% of the start weight as soda ash (sodium carbonate)
4. Add 10% of the start weight as carbon powder. (white baking flour works as a substitute for carbon)
5. Weigh out 40% of the start weight of anhydrous borax and add approximately half of the borax, along with the other ingredients and the silver chloride to a mixing drum and mix well. The efficiency of this process depends on the silver chloride reacting with the other ingredients of the flux to be effective.
6. Put the well mixed material in a crucible and add the remaining borax as a cap. If the crucible is too small for the entire charge, slowly add more material as the melt proceeds and shrinks down and at the end of the additions add the borax cap.
I always prefer to melt in a clay bonded crucible in a gas furnace. Important for 2 reasons.
Melting in a clay graphite crucible because the graphite assists in the reduction. Unless you have a low frequency induction furnace where clay graphite crucibles work. The graphite liners of high frequency induction furnaces will be eaten by the reaction.
The circular circulating flame of a gas furnace spirals any smoke efficiently with the help of a length of extender duct pipe the smoke can be delivered well up into your hood.
But here goes;
1.Dry the chlorides well.
2.Weigh the chlorides and add the following components based on the start weight.
3. Add 70% of the start weight as soda ash (sodium carbonate)
4. Add 10% of the start weight as carbon powder. (white baking flour works as a substitute for carbon)
5. Weigh out 40% of the start weight of anhydrous borax and add approximately half of the borax, along with the other ingredients and the silver chloride to a mixing drum and mix well. The efficiency of this process depends on the silver chloride reacting with the other ingredients of the flux to be effective.
6. Put the well mixed material in a crucible and add the remaining borax as a cap. If the crucible is too small for the entire charge, slowly add more material as the melt proceeds and shrinks down and at the end of the additions add the borax cap.
I always prefer to melt in a clay bonded crucible in a gas furnace. Important for 2 reasons.
Melting in a clay graphite crucible because the graphite assists in the reduction. Unless you have a low frequency induction furnace where clay graphite crucibles work. The graphite liners of high frequency induction furnaces will be eaten by the reaction.
The circular circulating flame of a gas furnace spirals any smoke efficiently with the help of a length of extender duct pipe the smoke can be delivered well up into your hood.
