Gw. Stevens et Hrc. Pratt, Solvent extraction equipment design and operation: Future directions from an engineering perspective, SOLVENT EXT, 18(6), 2000, pp. 1051-1078
The operation of solvent extraction plants involves optimisation of conditi
ons to minimise loss of solvent and maximise recovery. Because of these com
peting goals there are a number of different geometries of contactors that
have evolved for different services; in the future, lower feed concentratio
n and higher recoveries will lead to a consideration of new ways of contact
ing the two phases. The potential of some of the newer devices is compared
with more traditional contactors.
The current methods used for design and scale up of column-type solvent ext
raction devices are reviewed. This covers both the hydrodynamic factors whi
ch determine column cross-section and throughput, and mass transfer perform
ance through the influence of drop size, holdup, mass transfer coefficient,
axial dispersion, and drop interactions (coalescence and breakage). The cu
rrent techniques for scale up are limited and rely on extensive pilot testi
ng before final designs can be confidently achieved. A discussion of the po
tential for more sophisticated models for performance evaluation is also in
cluded.