What is the name of the process used for the purification of aluminum by electrolytic refining?

The process used for the purification of aluminum by electrolytic refining is called the Hall-Héroult process. This method is essential in the aluminum industry and involves the electrolysis of alumina (Al₂O₃) dissolved in molten cryolite (Na₃AlF₆).

During the Hall-Héroult process, aluminum ions are reduced at the cathode, forming pure aluminum, while oxygen ions are oxidized at the anode, producing oxygen gas. This process is highly efficient for obtaining aluminum from its ore and is widely used in industrial applications.

The Bayer's process, referenced in the options, is used primarily for extracting alumina from bauxite ore but does not involve electrolytic refining. The Hoop's process and Spark discharge method are not recognized as standard methods for aluminum purification, further solidifying the Hall-Héroult process as the correct and established name for the electrolytic refining of aluminum.