The demulsification by microwaves of liquid-liquid systems for metal recycling was experimentally andnumerically 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.