One could use either chemical or physical separation technique.
Physical techniques could be atomic vapor laser separation or mass spectroscopy.
Chemical simply means converting the alloy to some chemical form, precipitating each species (element) and then processing them back to metal form. This is essenially how ores are processes. One could use an electrochemical process.
However to separate an alloy into its constituent elements requires a lot of energy. It would be less expensive to purchase the pure elements.