Method to Convert Silver Sulphide Into Metalic Silver

METHOD TO CONVERT SILVER SULPHIDE INTO METALIC SILVER

This work is dedicated to Mr. Chris Owen,better known as GSP.Chris has provided,to all members of the Forum, many valuable knowledge.Also knowledge.Also he has shared,with all of us,his huge experience in precious metal recovering.THANKS,GSP.

SCOPE

Silver sulphide is an important raw material for silver.The most important silver ore is silver sulphide (argentite).Due to its its great insolubility any silver compound can be converted to silver sulphide. When silver is in solution it can be easily precipitate to silver sulphide just adding some alkali sulphide ,i.e. sodium or potassium sulphide.This sulphide.This reaction forms a black mud of silver sulphide. There is a lack of information about how to refine the black mud of silver sulphide.Nitric acid or chloridizing process(aqua regia or ferric chloride) can be used but both processes present drawbacks.Nitric acid process releases toxic fumes and needs many reprocessing steps;chloridizing process converts silver sulphide into silver chloride which needs further treatment. The purpose of this invention is to provide,step by step, a method to convert directly silver sulphide into metalic silver,without using any acid and in a very short time.

MATERIALS

Silver sulphide Potassium nitrate Borax Crucible Metalic rod Gas/oxygen torch 1 Bottle of Whisky (Chivas,Crown Royal,Jack Daniel´s,Jim Beam,J&B or any Whisky you like ) PROCEDURE

Weight the silver sulphide,then put the black mud of silver sulphide,as dry as possible,into the crucible:

Add potassium nitrate to the silver sulphide in 3:1 weight proportion,I mean,for 1 part of silver sulphide add 3 parts of potassium nitrate:

Mix well the solid powders until you get a grey powder:

Now light the torch with a low flame just to rise temperature to 300 or 400 C.Some white fumes will be released so do it below an extraction hood or in a well ventilated area:

The powder starts to boil and a crust is formed on the surface:

With the metallic rod brake the crust and mix well to permit that the solid reaction takes place uniformely.You are told to get an uniform green paste.At this moment you can see some little balls of silver:

Add borax,the proportion is half weight of the original weight of silver sulphide that you have,I mean,if you have 200 gr. of silver sulphide then add 100 gr. of borax,then rise temperature to 1100 C:

The mixure starts to melt and a green fluid is formed,pour off this green fluid carefully into a well dried vessel because if it is wet the fluid explotes and can cause you severe burns.NEVER pour off this hot green fluid into

water: :

Once that you have poured off the green liquid,melt the grey paste which is pure silver:

Finaly melt the silver and pour it off into an ingot.You will get a nice bar of  shiny and white silver:

Well,we have achieved our goal, g oal, now, it is time to celebrate,open that bottle of whisky and say CHEERS!!!! to me. Questions and comments are welcomed. Kindest Regards Manuel