Blast Furnace automatically smelts 2 ores into 1 bar (e.g. Quietus Ore into Quietus Bar) and has a chance to produce additional materials. Its speed is 2 operations per second.
It can smelt ores that are Common, Uncommon or Rare. Later in the game it gets replaced by Arc Smelter, which can also smelt Legendary ores, can smelt Metallic Hydrogen and Deuterium Rod, and also produces more additional materials.
Blast Furnace replaces earlier Electric Furnace, which can only smelt ores of Common/Uncommon rarity and produces less additional materials.
Industrial Smelting (Electronics tree).