Refractories and Carbon Cathode Materials for the Aluminum Industry. Chapter 2. refractories and carbon cathode blocks for electrolytic production of aluminum

摘要

In the commercial manufacture of aluminum, the electrolyte performs three major functions: (i) as a current conductor between the anode and the cathode; (ii) as a solvent for aluminum oxide, and (iii) as a physical interface between aluminum formed on the cathode and carbon dioxide formed on the anode. The electrolyte typically used is cryolite Na_3AlF_6 (T_(m.p)= 1010 deg C) with aluminum oxide dissolved in it and additives (up to 16 - 18 percent) of aluminum, calcium, and magnesium fluorides. The additives serve to reduce the melting point to 930 - 960 deg C.