Gelatin encapsulated metal powder for silver recovery from processing solutions

摘要

The present invention relates to the use of fine metal particles for the recovery of silver from a silver-bearing photographic waste solution. In particular, the metal particles are encapsulated in a hydrophilic colloid that allows for the permeability of water and silver ions. When contacted with the silver-bearing photographic waste solution, the hydrophilic colloid will imbibe water and swell. At the same time, the silver ions can permeate the colloid matrix and come into contact with the metal particles, preferably iron particles, at which point a metal-metal exchange reaction takes place.