Overflow molten metal transfer pump with gas and flux injection

An apparatus for introducing flux to molten metal residing as a bath in a furnace, said bath of molten metal having a bath surface height, the apparatus comprising an elongated tube surrounding at least one rotating impeller, said tube and impeller disposed in the molten metal bath such that rotation of the impeller creates a flow of said molten metal up the tube to a chamber, said flow of molten metal elevating a portion of the molten metal into the chamber and then into a launder located above said bath surface height, and a device introducing a fluxing agent comprising a powdered or granulated salt of chloride and/or fluoride to the elevated portion of the molten metal in said launder, said apparatus further comprising a controller monitoring and controlling simultaneously at least flux feed rate, and a speed at which said impeller is rotated such that the flux introduction rate is correlated to the impeller rotation speed.