Abstract: A burner comprises a refractory nozzle body enclosing a cavity and having a plurality of conduits each extending from said cavity to openings in the exterior of said nozzle body, wherein the axes of all said conduits lie in a common plane and the axes of any two of said conduits are either parallel to each other or form an angle diverging from said nozzle body, the nozzle body also having a passageway extending from said cavity to an opening in said nozzle body located on the opposite side of said cavity from said conduits; and a reactant distributor, made of metal, comprising a plurality of feeders each comprising a first tube and a second tube surrounding and coaxial with the first tube and defining an annular space between said tubes, there being one feeder in each of said conduits, wherein the distance from the ends of the first and second tubes of each feeder to the opening of the conduit in which the feeder is located is at least 1.