Yungang Ban

Electrical conductivity of Na3AIF6-AlF3-Al2O3-CaF2-LiF(NaCl) system electrolyte

Abstract A PGSTAT 30 and a BOOSTER 20A were used to measure cell impedance. Electrical conductivity was gained by the Continuously Varying Cell Constant Technique. Electrical conductivity of KCl was measured for comparison. The results prove that the method is reliable and accurate. The electrical conductivity of Na3AIF6-AIF3-Al2O3-CaF2-LiF(NaCl) system was studied by this method. Activation energy of conductance was obtained based on the experiment results. The experiments show that electrical conductivity is increased greatly with NaCl and LiF added. Increasing 1%LiF(mass fraction) results in corresponding increase of 0.0276 S/cm for superheat condition of 15 °C. For NaCl, it is 0.024 S/cm. Electrical conductivity is increased by 0.003 S/cm with 1 °C temperature increase. The electrical conductivity is lower than that predicted by the WANG Model and higher than that predicted by the Choudhary Model.

Study on Optimization of Anode Structure for Aluminum Reduction Cell

Different top surface anode structures have been studied based on the multi-physics coupling simulation software of ANSYS. The influences on current distribution, temperature distribution, thermal stress distribution and anode voltage drop were compared with different top surface structures, such as the angular, arc, right angle, wave and other top surface structures, which the main purpose is to achieve lower anode gross consumption ultimately. The simulation results showed that the top surface structure with the wave is the best in the distribution of above related parameters, and the anode gross consumption is the lowest.

Cathode Structure Optimization Research for Aluminum Reduction Cell

Different cathode structures were studied with the ANSYS thermo-electric field simulation software. The differences of horizontal current in aluminum pad and cathode voltage drop (CVD) were compared when adopting different techniques, such as partially insulated steel bar, low resistivity steel bar and copper bar technologies. The results showed that the copper bar technology was the best in reducing the horizontal current in the metal and in reducing CVD due to its high conductivity. Furthermore, the current distribution uniformity in cathode is also the best with the copper collector bar technology.

Development and Industrial Application of NEUI600 High Efficiency Aluminum Reduction Cell

As the high amperage aluminum reduction technology is developed in a complicated system, designers should draw special attention to structural optimization, environmental protection and energy saving while overcoming multiple core technical difficulties. NEUI has successfully eliminated a great number of technical bottlenecks hindering the development of high amperage aluminum reduction technologies, such as pot MHD stability technology, 3D thermal-electric field simulation technology, dynamics simulation technology of pot gas flow, etc., and has also developed the NEUI600 aluminum reduction technology, which has been put into extensive application. As of May 2017, 6 NEUI600 potlines with total capacity of 2210 kt/a have been put into commercial operation, the pot voltage can be maintained within the range of 3.90–4.05 V based on actual need. NEUI600 high amperage aluminum reduction technology has become an energy-saving and environment-friendly electrolysis technology with the lowest investment.

Liquidus Temperature of Molten Cryolite-based Aluminum Electrolyte

Liquidus temperature is one of important parameters for aluminum electrolysis. In this study, a new method is introduced; the liquidus temperature is measured with one Agilent 34401A meter connected to a computer. The whole process is controlled by computer software. Firstly, liquidus temperature of NaF and NaCl are measured for comparison. The result is proved to be convenient and accurate. The range of error is {plus minus}1~1.5{degree sign}C at 801{degree sign}C to 995{degree sign}C. Furthermore low temperature aluminum electrolyte composition is related. The liquidus temperature measurement of the system is NaFAlF3(R=2.25)-Al2O3(3%)-CaF2(4%)-LiF(0~6%)-NaCl(0~6%). The result showed that the liquidus temperature is reduced greatly by adding NaCl and LiF. The mathematical model obtained is T({degree sign}C)=947.588-5.907×LiF(wt/%)-6.223×NaCl(wt/%). The authors expected these data are useful for industry production of aluminum electrolysis, since it can provide a scientific basis for choosing suitable low temperature aluminum electrolyte composition.