Liquid Bipolar Electrode for Extraction of Aluminium and PGM Concentrate from Spent Catalysts

摘要

Liquid bipolar electrodes (LBE) were proposed for the extraction of noble metals from spent catalysts by the electrometallurgical method with the production of aluminium and oxygen. The two-sectioned electrolysis cell divided by the LBE for the one-step extraction was designed. The first section acts as the aluminium reduction cell; the second one plays the role of the aluminium refinery cell. The noble metals are collected in the LBE, while the carrier (Al_2O_3) is decomposed to oxygen and aluminium which is transferred through the second section to be collected in the cathode. The effect of the spent catalysts content in the melt on the electrode processes and carrier dissolution kinetics was studied for molten fluoride systems at 800 °C. The dissolution rate lays in the range from 0.0123 to 0.0291 g kg~(-1) s~(-1). The extraction of Pt to the LBE reached more than 99%. This method can be applied for the treatment of catalyst based on γ-Al_2O_3 carrier with a minor content of other oxides (SiO_2, Fe_2O_3, MgO, TiO_2, CeO_2).