Electrolysis of the molten salt sample using high current. For example if you melt NaCl, then electrolyse it, the sodium will be reduced from Na+ to Na(l) - thus the alkali metal has been produced separate from its salt. An example of this process is the Downs Cell used to get sodium.
Note this won't worth with an aqueous solution of the salt as water will be reduced instead of the metal ion.
Note to the answer above, that would just leave the salt of the metal, you wouldn't get the metal by itself.
Answers & Comments
Verified answer
Electrolysis of the molten salt sample using high current. For example if you melt NaCl, then electrolyse it, the sodium will be reduced from Na+ to Na(l) - thus the alkali metal has been produced separate from its salt. An example of this process is the Downs Cell used to get sodium.
Note this won't worth with an aqueous solution of the salt as water will be reduced instead of the metal ion.
Note to the answer above, that would just leave the salt of the metal, you wouldn't get the metal by itself.
guessing it is in a liquid solution you could boil it at a certain temperature and the alkali will be left over. Or by process of sublimation