Microwave enhanced demulsification of metal ion extraction emulsions: From permittivity modeling to proof of concept for solvent extraction processes
Résumé
The demulsification by microwaves of liquid-liquid systems for metal recycling was experimentally and
numerically investigated. Strongly ionic aqueous phases with high conductivities and typical organic phases,
both representative of industrial ones, were used. Experimental microwave demulsification was achieved in both
the W/O and O/W systems at the laboratory scale showing the rapidity and the efficiency of the process. The
dielectric properties of these representative emulsions were measured and modeled using the permittivities
measured in the separate phases and the phase fractions. Taking into account the direction of the emulsion,
permittivities were predicted over a wide range of frequencies, along with microwave penetration depths in the
whole range of phase fractions. Numerical simulations of the electric field distribution and penetration depths
calculations at several frequencies demonstrated that microwave heating is relevant and possible in both W/O
and O/W dense packed emulsions, which should rapidly lead to demulsification, including on a large industrial
scale.