Author Topic: purifying silver  (Read 532 times)

Louis Kriedemann

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purifying silver
« on: October 07, 2016, 10:31 AM »
I took a bunch of my old detected silver coins and chemically removed all the junk and copper - leaving me with 99.95% pure silver
dissolved the coins in nitric acid/water solution.  filter the solids out leaving you with a very pretty blue liquid which is silver nitrate with copper in suspension
to drop the silver out of this solution you  dilute the solution with water 50/50 - add hydrochloric acid in small amounts - the results are spectacular - the silver instantly drops out of
solution in the form of snow white clouds of a cottage cheese like substance, which is silver chloride.  you add HCL until the reaction stops
leave to stand and let the silver settle out - syphon off or pour off the blue liquid without losing any silver.  fill up with water and repeat until there is no more copper present. drain water
from the silver chloride
now - that pretty cottage cheese must be transformed from silver chloride to silver oxide.  to go about this you need to put the silver chloride in a pyrex dish or stainless pot for the next
process which involves quite a bit of heat. 
add sodium hydroxide (caustic soda) to the chloride and stir constantly(not with a plasic spoon - it will melt)   the solution will start heating up very quickly.  keep adding caustic soda and stirring
until there is absolutely no more white chloride to be seen. if there are any white specs present - add more caustic soda and keep stirring
when the solution has turned a uniformed black or,  dark brown colour and there is not a spec of white present, you are ready for the next step
this final step is pretty amazing and must be done carefully because of a huge amount of heat and steam present
the silver oxide must now (while it is still hot) be changed from and oxide to elemental silver metal
the addition of syrup (yip - illovo syrup, the one you put on you bread) to the solution will cause a huge reaction of instant boiling of the oxides.  the reaction is short but violent
add more syrup in small-ish amounts and let the reaction take place and settle and keep adding until all reaction stops
allow the solution to cool off somewhat and add water to dilute and again it must settle out. (I leave mine overnight) pour off brown water without losing any silver particles
this must be repeated  many many times until there is no sodium hydroxide left in the solution
once that is all done (and it can take a day or three)  put the silver in a plate or tray of sorts and dry it in the oven
the fine crystals and powder you end up with is very near pure silver -  this can be melted down to silver ingots

my batch of coins that I have just done have left me with 11 ounces of pure silver -  whooohooo
pity silver has no real value ;)

Paul van Heerden

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Re: purifying silver
« Reply #1 on: October 07, 2016, 10:46 AM »
Wow. That is quite a process Louis. I have seen it done on TV before. That is a nice chunky silver bar that you now have
Paul

Metal Detecting Forums South Africa

Re: purifying silver
« Reply #1 on: October 07, 2016, 10:46 AM »