Chapter 19, Problem 19.141SP

Interpretation Introduction

Interpretation:

The constant current that required to produce aluminum by the Hall-Heroult process at a rate of $\text{40}\text{.0 kg/h}$ should be determined.

Concept introduction:

Hall-Heroult process widely used in the extraction of aluminum. Pure ${\text{Al}}_{\text{2}}{\text{O}}_{\text{3}}$ is mixed with ${\text{CaF}}_{\text{2}}$ or ${\text{Na}}_{\text{3}}{\text{AlF}}_{\text{6}}$ in Hall-Heroult process. Graphite act as the anode and the carbon lining acts as the cathode.

Following reactions occurred at the cathode and anode;

Cathode: ${\text{Al}}^{\text{3+}}{\text{+3e}}^{\text{-}}\to \text{Al}$

Anode; ${\text{O}}^{\text{2-}}\text{+C}\to {\text{CO+2e}}^{\text{-}}$

Overall reaction; ${\text{2Al}}_{\text{2}}{\text{O}}_{\text{3}}\text{+3C}\to {\text{4Al+3CO}}_{\text{2}}$

$Z=E/F$

$m=Zit$