| The conductive materials resisting against high temperature corrosion and oxidation are mainly used to make inert anodes for aluminium electrolysis in this thesis. Therefore, the fabrication and application of inert anode for aluminium electrolysis are main contents of the thesis.Because the inert anodes have several obvious advantages in aspects of eliminating green-house gas release and saving production cost, many researchers have been of primary concern to inert anodes. But the inert anodes have not been used in aluminium electrolysis up to now because of existing many difficulties.In this work, firstly, author and his colleagues made choice of a coating composite of (WC-M)/316L,(Al2O3-M) and (NiFe2O4-M) from many materials by soaking tests in electrolytes melting, high temperature oxide tests or electrolysis. Then three types of inert anodes made up of the above three materials and completed tests of aluminium electrolysis. Results shown up that (NiFe2O4-M) anode had better corrosive resistance than other two candidates. But when (NiFe2O4-M) cermet inert anodes were tried further with a batch of anodes, the results proved out that when (NiFe2O4-M) was used as inert anodes, many problems were protruded out again, for examples, anode green bodies were often broken down at pattern drawing in press compacting, success rate was less than30%; In addition, cracks or bending of sintered anodes appeared often in the sintering; otherwise present electrolytes were not suitable with (NiFe2O4-M) anode.In order to overcome the above problems, author and his colleagues presented following technical inventions:1. Before mixing with metallic powder, calcined NiFe2O4was ball-milled by high energy grinding to nano or quasi-nano sizes which were late ball-milled together with metallic powder in common ball-mill, which is beneficial to improve wetting characteristics of NiFe2O4towards metallic powders. After the process was introduced, success rate of press-compacting anode green bodies increased to above95%, but was only than30%without high energy ball-mill;2. The (NiFe2O4-M) anodes are mechanical mixture of NiFe2O4ceramic phase and Cu-Ni metallic phase. Generally, the sintered temperatures of the above two phases are different. The synchro-sintering means that the above two phase were sintered at same temperature and in same duration by means of adjusting the ratio of Cu to Ni in metallic phase in order that the above two phases have very near sintering temperature. After synchro-sintering process was introduced, the bending or cracks of sintered anodes were disappeared satisfactorily;3. The mutual appropriation of (NiFe2O4-M) anode with different electrolytes was researched thoroughly by completing many electrolysis tests in different electrolytes. Good mutual appropriation means that (NiFe2O4-M) anodes can keep on better conductivity and lest corrosion for long electrolysis. The tests results pointed out that (NiFe2O4-M) anodes were not appropriated with present electrolytes used commonly and low melting point electrolytes because in the former, the anodes were corroded more rapidly, and in the later, the conductivity did not keep on for long because of producing curdling cathode crust without better conductivity. On the bases of the above results, writer and his colleagues invented a new Na3AlF6Ideal Electrolyte (NAIE) which is composed of Na3AlF6,Al2O3and the others. When electrolyzing in NAIE electrolyte, the (NiFe2O4-M) anode kept on better conductivity and resistance against corrosion for long. Subsequently repeated electrolysis tests were done, the results shown up that for100hs electrolysis tests, the (NiFe2O4-M) anodes were only corroded with trace and were able to keep on ideal electric conductivity in NAIE electrolyte.Presently (NiFe2O4-M) anodes and aluminium electrolysis in NAIE electrolyte have been developed already into pilot test stage with4kA current cell.
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