A Contribution to the Recovery of Silver by Cementation from Monometallic, Bimetallic and Trimetallic Nitrate Solutions and from Spent X-Ray Films

Silver is widely used in various industries, which makes it highly demanded. Presently, 20% of the world's silver production originates from naturally occurring Ag mines, with the remaining 80% coming from the Earth's crust, as a byproduct of the production of Cu, Zn and Pb mines. In this study, using a simple stirred reactor, Ag could be recovered by cementation onto Zn from its monometallic and mixed metal nitrate solutions, as well as from waste X-ray films. The recovery of Ag from its monometallic solution increased with higher molar ratios of Zn to Ag, rotational speed and temperature, while the percentage recovery of Ag decreased with increasing acidity. For the sequential recovery of metals from a mixed metal solution, the migration velocities of the cations determined the order in which they were separated. The recovery of Ag from spent X-ray films could be achieved with a purity of 98.3% by mass.