Electrowinning, or 'metal farming', is the extraction of dissolved metal ions from seawater. Electric current transmitted through a wire or pillar attracts positively charged metal ions, which form a solid plate on the wire.
Due to the high metallicity of Proteus, the seas contain near limitless quantities of dissolved metal. The Axum apparently developed electrowinning to gather metals long ago, well before fire or high-temperature smelting. They may have been inspired by bacterial fibers which attract metal ions as insulation and armor. If the Axum possess an electrical sense (like many ocean organisms) they would be able to detect electrical current running through these fibers, which would lead them to the development of wires and basic generators.
Operating instructions: —Ensure the metal farm is powered —Insert a sample of the desired metal into the unit as a catalyst —Wait for a deposit to form —Shatter the deposit and collect the deposited metal