Metallurgy of Key Minerals - Thanatia: The Destiny of the Earth's Mineral Resources - page 205

Scrap
metallics, alloys

Sweeps
minerals

Photographic
materials

Melting Incineration Shredding

metallics

slag

Homogenisation
crushing, grinding,
blending

Analysis

Incineration Washing

Analysis Analysis

hydro-
metallurgy

pyro-
metallurgy

high Au
low Ag

high Ag
low Au

high Au
low Ag

high Ag
low Au

slag
matte (Cu 2 S)
flue dust

Smelting
(extraction)

chlorine

PbO or
Cu 2 O

bullion

Smelting
(Miller)

Cupellation

flue dust

Gold

Dore - Ag, Au, PM

nitric acid nitric acid

Chemical
refining

Chemical
treatment

Electrolysis
Moebius or Balbach

Silver

PGM
solutions

Ag, Pd
solution

Au, PGM
slime

Au, PGM
slime

aqua regia
or HCl/Cl 2

Electrolysis Wohlwill
or
Chemical refining

Silver chloride
separation

silver
refining

Gold

Pd solution PGM

slime

Gold PGM refining PGMs

Fig.8.9Generalflowsheetforpreciousmetalrecovery(IPPC,2009)

8.9.1 Silver process

Perhaps surprisingly, silver ores are not the most important source of Ag. The
present economic limit of the exploitation of such ores must contain at least 0.01%
Ag (100 ppm) with the most important ones being argentiferous lead and lead-zinc
ores. Argentiferous copper ores can, additionally, contain variable amounts of Ni
and Co. Indeed most of the world's silver is taken from the byproduct of Pb=Zn (31-
50%), Cu,(25-30%), Ag (10-28%) and Au (10-14%) bearing deposits. After the ore
beneficiation, a typical feed for smelting may have a composition of Au (0.0007%),
Ag (0.034%), Pb (0.34%), Zn (4.43%) and Cu (28.3%) (Ecoinvent - Classen et al.
(2007)).