Process and plant for preheating a metal charge fed in continuous to an electric melting furnace

A plant for implementing a process for preheating a metal charge fed in continuous to an electric melting furnace, comprising:

• a preheating tunnel provided with a horizontal conveyor, wherein said metal charge is hit, in countercurrent, by exhaust fumes or a first gas leaving said electric melting furnace;
• and
• a plurality of nozzles positioned on a hood of said preheating tunnel provided with side walls and said hood, said plurality of nozzles emitting jets of a second gas further hitting said metal charge,
• wherein at least two groups of the plurality of nozzles are provided on the hood of said preheating tunnel, interspaced from each other in a longitudinal direction with respect to the preheating tunnel,
• wherein said plurality of nozzles are distributed transversely and non-uniformly on the hood of the preheating tunnel, with a greater concentration on a top of the hood of said preheating tunnel, and
• wherein the plurality of nozzles generate a turbulence by injecting jets of the second gas to penetrate a stream of the first gas stream passing through the preheating tunnel, said nozzles simultaneously generating a horseshoe vortex structure comprising a descending central gas flow that forms a descending flow, and ascending flows that forms an ascending flow adjacent to the side walls of the preheating tunnel, so as to enable a desired circulation of the first and the second gases.