Applications of electrochemical technology involving low reactant
concentrations require electrodes with high mass transport rates and specific
surface areas to increase cross-sectional current densities and optimise capital
and operating costs. Experimental results will be compared with model
predictions for two such reactor types, which facilitate adherent and coherent
deposit morphologies: a) cathode feeder electrodes contacting unconsolidated
beds of moving, conducting particles that can grow, and enable continual
harvesting of the metallic product by hydraulic transport from the bed of the
particles; b) mesh cathodes in fluidised beds of inert particles, to enhance mass
transport rates; used for metal recovery from: i) low concentrations of platinum
in aqueous iodide solutions; ii) acidic aqueous chloride solutions, produced by
the leaching of waste electrical and electronic equipment, containing precious
metals in low concentrations and base metals in high concentrations.