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Solvation of ions. Some applications. IV A novel process for the recovery of pure silver from impure silver chloride
Journal article   Peer reviewed

Solvation of ions. Some applications. IV A novel process for the recovery of pure silver from impure silver chloride

A.J. Parker, B.W. Clare and R.P. Smith
Hydrometallurg, Vol.4(3), pp.233-245
1979
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Abstract

Silver chloride is exceptionally soluble in dimethylsulfoxide saturated with calcium chloride at 25°C. Solutions containing up to 196 gl−1 silver as Ca(AgCl2)2 have been prepared. If 30–40% by volume of water is added to such solutions, then pure silver chloride is precipitated almost quantitatively. The silver chloride can be easily converted to pure (99.99%) silver metal either by melting at 1100°C with excess sodium carbonate as flux, or by reducing with hydrogen at 300–400°C, or by reducing an aqueous suspension with zinc dust. The water added to the DMSO solution can be recovered by distillation and both it and the CaCl2-DMSO bottoms are recycled for further leaching. This leads to a fast and cheap process for obtaining silver from crude silver chloride, or from materials containing silver in a form that can be converted to silver chloride. Applications to an anode slimes leach residue, a silver halide teaching laboratory residue, and the silver chloride cake from a gold refinery are demonstrated.

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