Report on performance, mass and energy balances and design criteria for gas-diffusion electroprecipitation and electrocrystalization

This deliverable is linked to Task 3.2 under which The key points of investigation are: Concepts for selective, highly efficient and negligible-electricity-consuming process: • Calculations of thermodynamic equilibria in aqueous solutions for mixed metal matrices in ambient pressure processing conditions • Characteristics of the porous cathodes and anode materials to be employed • Physicochemical conditions of the electrolyte (simulated or real geothermal fluid) such as applied potential, pH, T, mixed metal composition, presence of other elements (especially silica), oxidant gas composition, flow conditions of the electrolyte and oxidant gas) • Characterization of mechanistic and kinetic features (electrochemical response, characterization of metal removal and recovery, characteristics of the solid precipitates and crystals formed) • Effect of the presence of metal-containing flowing carbon particles (see WP 2) and their regeneration through GDEx Generation of design criteria to improve process performance and control • Framework of conditions of applicability of the technology to the removal and recovery of the metal content of geothermal fluids (expected i.e. hundreds to thousands of m3 per day, inlet pH between 2 and 3, high salinity in the range of 30–300 g L-1 NaCl equivalents, highly diluted metal content in ppm range) • Establishment of reactor design criteria for further scalability • Process simulations based on experimental data (multiphysics calculations based on electrochemical engineering concepts) to increase the knowledge of the process • Mass and energy balances (model compositions and real geothermal fluids)