Apparatus for melting scrap metal

Claim 1

In a shaft-type furnace for melting charge comprising scrap metal which comprises in combination a hearth portion including a spout, a body portion extending to a substantial height above said hearth portion, a bosh portion flaring outwardly to a substantial height above said body portion and terminating at its upper end in an upwardly extending stack, a plurality of tuyeres located at a first level at the bottom of said body portion just above said hearth portion, a plurality of tuyeres located at a second level near the top of said body portion just below said bosh portion, windpipe means for directing blast air to said first and second level tuyeres, oxyfuel burners disposed in at least some of the second level tuyeres, the nozzle of each said burner being located within its respective tuyere, means supplying fuel and substantially pure oxygen to fire said oxyfuel burners, an opening in said stack for loading charge including said scrap metal into said stack, a supporting media for said scrap metal disposed in said hearth and in said body portion, said media being porous to allow the melted charge to pass therethrough, said second level of tuyeres being located above said supporting media, the tuyeres at said second level being directed and arranged to impart to the gases passing into said furnace at said second level a swirling motion in a given direction about the axis of said furnace, the tuyeres at said first level being constructed and arranged to impart to the gases passing into said furnace at the first level a swirling motion in an opposite direction, said tuyeres being substantially equally spaced around a periphery of said furnace at said first level and at said second level, wherein the position of each of said tuyeres in said second level lies substantially intermediate the position of the adjacent tuyeres in said first level and wherein at one of said levels each of said tuyeres is directed so that the principal axis thereof forms an angle of approximately 15* in a clockwise direction with the radius of said furnace, and wherein at the other said level each of said tuyeres is directed so that the axis thereof forms an angle of approximately 15* in a counterclockwise direction with the radius of said furnace, whereby said charge is preheated in said stack, is melted in the area of said second level of tuyeres dripping down through the supporting media, and is superheated in the area of said first level of tuyeres to a desired spout temperature.