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Preparation And Investigation Of Metals And Metal-Al2O3 Inert Anodes For Aluminum Production

Posted on:2005-01-10Degree:DoctorType:Dissertation
Country:ChinaCandidate:Z N ShiFull Text:PDF
GTID:1101360185978929Subject:Non-ferrous metallurgy
Abstract/Summary:PDF Full Text Request
Research and development work on inert anodes is the hot point and emphasis of the world's primary aluminum production industry nowadays. In this doctorial dissertation, some novel materials as inert anodes were developed and investigated for aluminum electrolysis.In the first stage of research works, Cu-Ni base alloys and Fe-Ni alloys were selected for candidate metal anodes. In succession, Fe-Ni(-Co)-Al2O3 anodes were developed. In electrolysis, the current increased gradually from several amperes to 100A and 300A, finally, the electrochemistry properties of the anodes were investigated.XRD analysis was applied to study the phase of anode surface after the Cu-Ni-based alloy anodes being oxidized in air and oxygen and corroded in lower temperature electrolysis. Cu-Ni-Al anode possesses excellent resistance to oxidation and corrosion than that of Cu-Ni-Fe anode. During electrolysis, the cell voltage of the Cu-Ni-Al anode is affected most by the concentration of alumina in cryolite molten salt. Cu-Ni-Fe anode exhibits good corrosion resistance in electrolyte molten salts. Comparatively, the Cu-Ni-Cr anode shows poor resistance to oxidation and corrosion. The tests find that further studies are warranted on the use of Cu-Ni-Al and Cu-Ni-Fe as inert alloy anodes. Low temperature electrolysis can improve the metal anodes properties, and decrease the wear rate of metal anodes.The electrolysis tests were conducted with different weight ratio of Fe to Ni in the Fe-Ni anodes under the same condition. The results showed that the wear rate of Fe-Ni anode decreased with the increasing of the weight ratio of Fe to Ni. When the weight ratio of Fe to Ni was 1.42, the wear rate decreased to the lowest point of 20.75mm/a. Hereafter, the wear rate of Fe-Ni anode increased with the increasing of the weight ratio of Fe to Ni. The anode surface cross section after electrolysis was checked and analyzed by scanning electron microscope and X-ray diffraction apparatus. The results showed there is an oxide film formed on the anode surface, which consisted of NiO, Fe2O3 and...
Keywords/Search Tags:Aluminium electrolysis, Inert anodes, Superalloys, Metal matrix composites, Osat apparatus
PDF Full Text Request
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