Method of using a suspension smelting furnace, a suspension smelting furnace, and a concentrate burner

1. A method of using a suspension smelting furnace, whereby the suspension smelting furnace comprises a reaction shaft, the method comprising

using a concentrate burner, which comprises

a fine solid matter supply device comprising a feeder pipe for feeding fine-grained solid matter into the reaction shaft, wherein a mouth of the feeder pipe opens in the reaction shaft;

a diffusion device, which is arranged concentrically inside the feeder pipe and which extends to a distance from the mouth of the feeder pipe inside the reaction shaft, and which comprises diffusion gas holes for directing a diffusion gas around the diffusion device to fine solid matter that flows around the diffusion device; and

a first gas supply device for feeding a first gas into the reaction shaft, the first gas supply device opening in the reaction shaft through a first annular discharge opening that concentrically surrounds the feeder pipe for mixing first gas that discharges from the said first annular discharge opening with fine solid matter, which discharges from the feeder pipe in a middle and which is directed sidewards by means of diffusion gas;

the method comprising

feeding fine solid matter into the reaction shaft through the mouth of the feeder pipe of the concentrate burner;

feeding diffusion gas into the reaction shaft through the diffusion gas openings of the diffusion device of the concentrate burner for directing diffusion gas to fine solid matter that flows around the diffusion device; and

feeding first gas into the reaction shaft through the first annular discharge opening of the first gas supply device of the concentrate burner for mixing first gas with fine solid matter, which discharges from the feeder pipe in the middle and which is directed sidewards by means of diffusion gas;

wherein

the method employs a concentrate burner, which comprises a second gas supply device, which comprises a second annular discharge opening, which is concentric with the first annular discharge opening of the first gas supply device of the concentrate burner and which opens in the reaction shaft of the suspension smelting furnace;

second gas through the second annular discharge opening of the second gas supply device;

the first gas and the second gas have different compositions; and

the second annular discharge opening surrounds the first annular discharge opening.

2. A method according to claim 1 , wherein technical oxygen is used as the first gas.

3. A method according to claim 1 , wherein air is used as the first gas.

4. A method according to claim 1 , wherein concentrate particles are added to second gas before feeding second gas through the second annular discharge opening of the second gas supply device into the reaction shaft.

5. A method according to claim 1 , wherein liquid cooling agent is added to first gas by spraying before feeding first gas through the first annular discharge opening of the first gas supply device into the reaction shaft.

6. A method according to claim 1 , wherein liquid cooling agent is added to second gas by spraying before feeding second gas through the second annular discharge opening of the second gas supply device into the reaction shaft.

7. A method according to claim 1 , wherein first gas is caused to spin before feeding first gas through the first annular discharge opening of the first gas supply device into the reaction shaft.

8. A method according to claim 1 , wherein second gas is caused to spin before feeding second gas through the second annular discharge opening of the second gas supply device into the reaction shaft.

9. A method according to claim 1 , wherein second gas is fed through the second annular discharge opening of the second gas supply device at a velocity of 10-200 m/s into the reaction shaft.

10. The method according to claim 1 , comprising using oxygen, technical oxygen, or oxygen enriched air as the second gas.

11. The method according to claim 4 comprising

feeding first concentrate particle fraction, mixed with the second gas, into the reaction shaft through the second annular discharge opening of the second gas supply device; and

feeding second concentrate particle fraction into the reaction shaft through the mouth of the feeder pipe.