useful separation scheme for

typical process data

1. Pt Pd Ir trace precipitation from highly acidic spent process liquors / filtrates after aqua regia treatment followed by inefficient classical Pt Pd Ir salt precipitation

=> this is a values recovery process

benefits
no prior neutralization
no additional salination of liquors
replacing unselective cementations avoiding base metal dilution
 

typical pregnant liquor /feed
10 - 100 mg/l Pt, Pd, Ir
10 g/l Cu, Ni, Pb

typical yield
> 99 %  Pt, Pd, Ir recovery
in the precipitate
< 5 mg/l Pt, Pd, Ir each
in the barren liquor
> 95% Cu, Ni, Pb
in the barren liquor

2. Pt Pd Ir trace precipitation in Rh concentrate solutions; process may be part of the Rh refining

=> this is a purification process

benefits
superior simplicity of rhodium purification
 

typical pregnant liquor /feed
3 - 10 g/l Rh
> 10 mg/l Pt, Pd, Ir traces
 
typical yield in purified concentrate
> 95 % Rh