Method and apparatus for heating molten steel utilizing a plasma arc torch

An apparatus for heating a molten metal such as steel and comprising

• a vessel adapted to support molten metal such as steel and including an open top,
• at least two plasma arc torches mounted above said vessel, each said torch including a housing defining a forward end positioned adjacent the molten metal supported in said vessel, a rear electrode mounted within the housing, a tubular collimator mounted within said housing forwardly of and in coaxial alignment with said rear electrode, power supply means for generating an arc which extends from said rear electrode through said collimator and to the molten metal supported in said vessel, and vortex generating means for generating a vortical flow of gas at a location between said rear electrode and collimator and so that a vortical flow of gas exits forwardly through said collimator and substantially surrounds and collimates said arc, and with each of said at least two plasma torches being mounted approximately midway between the center and the inside periphery of the vessel and at circumferentially spaced locations with respect to the center of the vessel and also being mounted along a plane that is perpendicular to a radial line from the center of the vessel and at an angle of between about 30.degree. to 70.degree. with respect to the surface of the molten metal in the vessel, and with said torches being oriented in a common circumferential direction about the center of the vessel and such that the mass flow provided by said vortex generating means of said torches impinges at an angle upon the surface of the molten metal in said vessel and so as to impart a common circular movement to the molten metal in the vessel.