Enhancing extraction in ion flotation using the boycott effect

Abstract

While Ion Flotation is highly effective in recovering ionic species at very low concentrations, the approach has struggled to find economically viable application due to hydrodynamic constraints. Recovery and upgrade decline very rapidly with increases in the volumetric feed flux (volumetric rate per unit of vessel area), largely due to the direct coupling of the liquid product flux with the input gas flux. We demonstrate a way to overcome the hydrodynamic limitations using the Reflux Flotation Cell (RFC), a system incorporating parallel inclined channels. These produce a powerful increase in the bubble-liquid segregation velocity, allowing decoupling of the liquid product flux and input gas flux. The system achieved an increase in the feed flux by up to four-fold for the same recovery and upgrade, with the adsorptive extraction rate up to three times greater than achieved by conventional ion flotation. Ultimately bubble coalescence limited the final performance in part due to the significant volume reduction (ratio of feed to product flux) that was targeted.