Elaboración de emulsiones con partículas magnéticas y uso potencial en la industria minera

Abstract

Con el objetivo de presentar a las emulsiones magnéticas como una alternativa para mejorar la eficiencia del proceso de flotación, que se ha utilizado por años para la concentración de minerales valiosos con un tamaño menor a 10 um, se elaboraron dos tipos de emulsiones (A y B). Ambas formadas por una fase dispersa de agua y por A)gotas de queroseno con partículas de magnetita (Fe3O4) en su interior, B)gotas de ferrofluido, respectivamente. Además se evaluó la estabilidad y el comportamiento de las emulsiones magnéticas ante la presencia de calcita (un mineral diamagnético) y también al aplicarle un campo magnético externo. Como resultado, se observó que la calcita adsorbía a las gotas de la emulsión de ferrofluido permitiendo su concentración a través del campo magnético aplicado.

A method is presented for the recovery of diamagnetic fine particles in the presence of an oil in water (O/W) magnetic emulsion. Here kerosene was used as the oily phase. Initially to elaborate the kerosene in water magnetic emulsion We start with a top to the bottom synthesis. Where magnetite particles are introduce inside the emulsion drops by grinding them with hydrophobic surfactants. The size of magnetite particles dictates the diameters around 100 µm which in turns affects the emulsion stability. In addition, when a second surfactant was added at the magnetite surface We observed a self-emulsification that ended breaking up the emulsion. As a result, We change to an alternative synthesis route, where We use the approach bottom to the top. In other words, We synthesized superparamagnetic nanoparticles using the coprecipitate method. In the absence of an external magnetic field a classical emulsion (Brownian motion) behaviour was observed whereas in presence of magnetic field the drops form large chains aligning in the same direction of the applied field. Moreover, We investigated about the interaction between calcite fines (diamagnetic particles) and the droplets emulsion. We conclude that the nanoparticles were absorbed at the calcite surface and for that calcite fines acquiring magnetic properties that allow them to move towards the source field.