Energy Balance for Aluminum Production

Worldwide, the electrolytic production of aluminum is the second largest consumer of electrical energy for electrochemical processes. It is a molten salt process at high temperature ( 1250K). Consumable anodes are used and the overall reaction is  

The use of carbon anodes is primarily due to the lower open-circuit voltage of Eq. 2.91 compared to the straightforward reduction of AI2O3 to aluminum and oxygen. Equation (2.91) represents an oversimplified view of aluminum production a number of side reactions occur. One of the more important is the formation of CO  

FIGURE 2.18. Cell for the extraction of aluminum (after Pletcher ). 

THE PROBLEM Determine the wall thickness that will keep the fused salt temperature at 1250K. 

THE SOLUTION First, calculation of the cell voltage V. V , the voltage drop through the electrolyte, is  

---