Preparation and preliminary testing of cermet inert anode for aluminum electrolysis
(1. College of Metallurgical Science and Engineering,
Central South University, Changsha 410083, China;
2. State Key Laboratory for Powder Metallurgy,
Central South University, Changsha 410083, China)
Central South University, Changsha 410083, China;
2. State Key Laboratory for Powder Metallurgy,
Central South University, Changsha 410083, China)
Abstract: Recent development of inert anodes for the primary aluminium industry was reviewed. The preparation method of functionally gradient material was introduced into inert anode research area, and a research flow sheet of functionally gradient cermet inert anode was set down. In order to carry out the preparation and optimization of composite oxides as the ceramic matrix of cermet inert anode, the following problems: solid state reaction synthesis of complex oxides, corrosion mechanism of complex oxides in Na3AlF6-Al2O3 melts, effects of NiO content on the corrosion rate and resistivity at high temperature of NiFe2O4-NiO ceramics were studied. The preparation and sintering mechanism of NiFe2O4 based cermets were deeply studied to properly control the sintering atmosphere and temperature system. By efficaciously controlling the sintering atmosphere, the oxidization of metallic phase and the decomposition or deoxidization of ceramic phase are avoided effectively during the sintering process of cermets at various temperatures. By optimizing the composition recipe and sintering temperature system, cermets of relatively high density are prepared without the spillage or asymmetric distribution of metallic phase.
Key words: cermet; inert anode; aluminum electrolysis