WO2009077653A1

WO2009077653A1 - Suspension smelting furnace and method for producing crude metal or matte in a suspension smelting furnace

Info

Publication number: WO2009077653A1
Application number: PCT/FI2008/050738
Authority: WO
Inventors: Pekka Hanniala; Risto Saarinen; Aimo Kurki; Ilkka V. Kojo
Original assignee: Outotec Oyj
Priority date: 2007-12-17
Filing date: 2008-12-15
Publication date: 2009-06-25
Also published as: FI20075924L; CL2008003741A1; PE20091303A1; FI20075924A0

Abstract

The invention relates to a suspension smelting furnace (1), such as a flash smelting furnace, comprising a reaction shaft (2) comprising a burner (3). The burner (3) comprises a solid matter feed arrangement (4) for feeding solid matter (5) into the burner (3), and a reaction gas feed arrangement (6) for feeding reaction gas (7), such as oxygen-enriched air, to the burner (3). The burner (3) is arranged to feed solid matter (5) and reaction gas (7) into the reaction shaft (2) and to burn the solid matter (5) and reaction gas (7) fed into the reaction shaft (2), so that the solid matter (5) and reaction gas (7) react together forming a melt (8). In addition, the suspension smelting furnace (1) comprises a settler (9) arranged at the lower end of the reaction shaft (2), the settler (9) comprising a bottom (10), on top of which the melt (8) is collected, and an uptake shaft (11) arranged to the settler (9) for exhausting combustion gases (12) from the suspension smelting furnace (1). The burner (3) is arranged in the reaction shaft (2), at the distance of 2 to 5 meters from the surface (13) of the melt (8), above the surface (13) of the melt (8). The invention also relates to a method for producing crude metal or matte, such as blister copper, copper matte, fine nickel matte, or nickel matte in a suspension smelting furnace (1), such as a flash smelting furnace.

Description

SUSPENSION SMELTING FURNACE AND METHOD FOR PRODUCING CRUDE METAL OR MATTE IN A SUSPENSION SMELTING FURNACE

Background of the invention The invention relates to a suspension smelting furnace, such as a flash smelting furnace, having a reaction shaft comprising a burner, which burner comprises a solid matter feed arrangement for feeding solid matter to the burner, and a reaction gas feed arrangement for feeding reaction gas such as oxygen-enriched air to the burner, so that the burner is arranged to feed solid matter and reaction gas into the reaction shaft and to burn the solid matter and reaction gas fed into the reaction shaft, so that the solid matter and reaction gas react together and form a melt, a settler arranged at the lower end of the reaction shaft, said settler comprising a bottom on top of which the melt is collected, and an uptake shaft arranged to the settler for exhausting combustion gases from the suspension smelting furnace. The invention also relates to a method for producing crude metal or matte, such as blister copper, copper matte, fine nickel matte or nickel matte, in a suspension smelting furnace, for instance in a flash smelting furnace, in which method solid matter and reaction gas such as oxygen-enriched air is fed by a burner into the reaction shaft of a suspension smelting furnace, the solid matter and reaction gas fed into the reaction shaft are burned by the burner, so that the solid matter and the reaction gas react together forming a melt, and the created melt is collected on the bottom of a settler arranged at the lower end of the reaction shaft.

In known suspension smelting furnaces, it is characteristic that the reaction shaft is high, normally more than 5 meters. Owing to an unnecessarily high reaction shaft, the heat losses occurring through the reaction shaft walls are likewise unnecessarily high, thus resulting in increased operation costs owing to an increased energy demand. A high reaction shaft has a particularly strong influence in the investment costs, because the higher the reaction shaft is, the higher is the location of equipment installed above the reaction shaft, and the higher are the construction expenses focused in said area.

Brief description of the invention

The object of the invention is to solve the above mentioned problems. The object of the invention is achieved by a suspension smelting furnace according to the independent claim 1.

The invention also relates to a method according to claim 7 for producing crude metal, such as blister copper, copper matte, fine nickel matte or nickel matte, of metal concentrate in a suspension smelting furnace.

Preferred embodiments of the invention are set forth in the dependent claims.

A suspension smelting furnace according to the invention is characterized in that the concentrate burner is located in the reaction shaft, at the distance of 2 to 5 meters from the melt surface, above the melt surface. With current concentrate burner types, such as the ones introduced in the publications WO 98/14741 and WO 02/055746, there is achieved a suspension that is more effective than in earlier applications, and the height of the reaction shaft can be essentially lowered, particularly when using oxygen enrichment. The reaction shaft is no longer needed as a heat exchanger/combustion chamber, the measures of which should be designed for the use of external energy. The control of feed and combustion is improved, up to a point where the combination of concentrate burner/reaction shaft can be observed solely as a "burner", especially when applying the solid matter feed method and oxygen enrichment described in the publications WO 98/14741 and WO 02/055746. hi particular when applying the solid matter feed method and oxygen enrichment described in the publications WO 98/14741 and WO 02/055746, it has been found out that the reaction shaft can be made essentially lower than in the known prior art arrangements.

In a preferred embodiment of the invention, the reaction shaft height is less than 4 meters. By means of this embodiment, there is achieved the advantage that the inner volume of the reaction shaft is reduced, which also results in smaller heat losses. By using the arrangement according to the invention, the reaction shaft can be made hot, i.e. the cold spots in the reaction shaft are reduced. Another advantage achieved by this preferred embodiment is that the amount of gas recirculated back into the reaction shaft, i.e. the return circulation back to the reaction shaft is reduced, in which case the reactions, especially the heating of the concentrate particles up to their ignition point, take place in a more controlled fashion, and the degree of over-oxygenation is remarkably reduced, which means that the obtained slag quality is better, for example with respect to the copper separation, and the amount of dust in the combustion gas flowing into the uptake shaft is smaller.

By placing the burner in the reaction shaft at the distance of 2 to 5 meters, advantageously 3 to 4 meters, preferably about 4 meters, above the melt located in the settler and by using a short reaction shaft with a length of less than 4 meters, the share of the cold section in the top part of the reaction shaft is cut as unnecessary, and on the other hand, the very hottest part of the reaction shaft is shifted to the "empty space" in the settler, i.e. nearer to the melt surface. As a consequence, the thermal radiation directed to the reaction shaft walls is in the hottest section of the reaction shaft more moderate than in prior art arrangements, or even extremely low, because the hottest section of the earlier embodiments of the reaction shaft can in the embodiment according to the invention be completely shifted to the settler, in other words to the empty space of the settler, above the melt located in the settler.

The reaction shaft can be vertical, for example rectangular, prism-shaped or cylindrical.

In a preferred embodiment, the reaction shaft is expanded downwardly in the direction of the settler, so that the reaction shaft provides a natural reaction space for the suspension caused by the reactions, without essentially increasing the suspension velocity. For the reactions inside the reaction shaft is a broad upper part of the reaction shaft unnecessary, because the reactions start in the space beneath the burner and especially because of the increasing temperature of the gas its volume increased in the downward direction in the reaction shaft. Therefore it is preferable that the gas has more space to expand especially when moving downward in the reaction shaft. By this is a sufficient residence time achieved for the gas and the material with a remarkable cheaper construction compared to if the reaction shaft would be for example cylindrical and "sufficiently" broad also it its upper end.

List of drawings

A few preferred embodiments of the invention are described in more detail below, with reference to the appended drawings, where Figure 1 is an illustration in principle of a first preferred embodiment of the suspension smelting furnace according to the invention, and

Figure 2 is an illustration in principle of another preferred embodiment of the suspension smelting furnace according to the invention.

Detailed description of the invention The drawing illustrates a suspension smelting furnace 1, such as a flash smelting furnace.

The suspension smelting furnace 1 comprises a reaction shaft 2 comprising a burner 3. The burner 3 is, preferably, but not necessarily the burner 3 described in the publications WO 98/14741 or WO 02/055746. The burner 3 comprises a solid matter feed arrangement 4 for feeding solid matter 5, such as concentrate, flux and flue dust, to the burner 3, and a reaction gas feed arrangement 6 for feeding reaction gas 7, such as oxygen-enriched air, to the feeding burner 3. The burner 3 is arranged to feed solid matter 5 and reaction gas 7 into the reaction shaft 2, and to burn the solid matter 5 and reaction gas 7 fed into the reaction shaft 2, so that the solid matter 5 and reaction gas 7 react together in a way known as such, forming a melt 8.

The suspension smelting furnace 1 further comprises a settler 9 arranged at the lower end of the reaction shaft 2, which settler 9 has a bottom 10, on top of which the melt 8 is collected.

The suspension smelting furnace 1 further comprises an uptake shaft 11 arranged to the settler 9 for exhausting combustion gases 12 from the suspension smelting furnace 1. The burner 3 is arranged in the reaction shaft 2, at the distance of 2 to 5 meters from the surface 13 of the melt 8, above the surface 13 of the melt 8.

The burner 3 is preferably arranged in the reaction shaft 2, at the distance of 3 to 4 meters from the surface 13 of the melt 8, above the surface 13 of the melt 8.

The burner 3 is most advantageously arranged in the reaction shaft 2, at the distance of about 4 meters from the surface 13 of the melt 8, above the surface 13 of the melt 8.

In a preferred embodiment, the height of the reaction shaft 2 is less than 4 meters.

In a preferred embodiment illustrated in Figure 2, the cross-sectional surface of the reaction shaft 2 is expanded downwardly, in the direction of the settler 9. In a preferred embodiment, the lining of the reaction shaft 2 comprises a cooling arrangement (not illustrated) for cooling the lining of the reaction shaft 2.

The invention also relates to a method for producing crude metal or matte, such as blister copper, copper matte, fine nickel matte, or nickel matte of metal concentrate in a suspension smelting furnace 1 , for instance in a flash smelting furnace. The method includes a step where solid matter 5, such as a concentrate, flux and flue dust, and reaction gas 7, such as oxygen-enriched air, is fed through a burner 3 to the reaction shaft 2 of a suspension smelting furnace 1.

The method includes a step where the solid matter 5 and reaction gas 7 fed into the reaction shaft 2 is burned by the burner 3, so that the solid matter 5 and the reaction gas 7 react together, forming a melt 8. The method includes a step where the created melt 8 is collected on the bottom 10 of a settler 9 provided at the lower end of the reaction shaft 2.

The method includes a step where the burner 3 is arranged in the reaction shaft 2, at the distance of 2 - 5 meters from the surface 13 of the melt 8 collected on the bottom 10 of the settler 9.

The method preferably includes a step where the burner 3 is arranged in the reaction shaft 2, at the distance of 3 - 4 meters from the surface 13 of the melt 8 collected on the bottom 10 of the settler 9.

The method most advantageously includes a step where the burner 3 is arranged in the reaction shaft 2, at the distance of about 4 meters from the surface 13 of the melt 8 collected on the bottom 10 of the settler 9.

The method advantageously includes a step where the cross-sectional surface of the reaction shaft 2 used in the suspension smelting furnace 1 is expanded downwardly, in the direction of the settler 9.For a man skilled in the art, it is obvious that along with the development of technology, the principal idea of the invention can be realized many different ways. Hence the invention and its embodiments are not restricted to the above described examples, but they can vary within the scope of the appended claims.

Claims

1. A suspension smelting furnace (1), such as a flash smelting furnace, comprising:

- a reaction shaft (2) comprising a burner (3),

- which burner (3) comprises a solid matter feed arrangement (4) for feeding solid matter (5) into the burner (3), and a reaction gas feed arrangement (6) for feeding reaction gas (7), such as oxygen-enriched air, to the burner (3), and

- which burner (3) is arranged to feed solid matter (5) and reaction gas (7) into the reaction shaft (2) and to burn the solid matter (5) and reaction gas (7) fed into the reaction shaft (2), so that the solid matter (5) and the reaction gas (7) react together and form a melt (8),

- a settler (9) arranged at the lower end of the reaction shaft (2), comprising a bottom (10), on top of which the melt (8) is collected, and

- an uptake shaft (11) arranged in the settler (9) for exhausting combustion gases (12) from the suspension smelting furnace (1), c h a ra cte ri zed in that

- the burner (3) is arranged in the reaction shaft (2) at the distance of 2 - 5 meters from the surface (13) of the melt (8), above the surface 813) of the melt (8).

2. A flash smelting furnace according to claim 1, c h a ra cte ri z e d in that the burner (3) is arranged in the reaction shaft (2), at the distance of 3 - 4 meters from the surface (13) of the melt (9), above the surface (13) of the melt (8).

3. A flash smelting furnace according to claim 1 , c h a r a c t e r i z e d in that the burner (3) is arranged in the reaction shaft (2), at the distance of about 4 meters from the surface (13) of the melt (9), above the surface (13) of the melt (8).

4. A flash smelting furnace according to any of the claims 1 -3, c h a ra cte ri z ed in that the height of the reaction shaft (2) is less than 4 meters.

5. A flash smelting furnace according to any of the claims 1 -4, c h a r a cte ri ze d in that the cross-sectional surface of the reaction shaft (2) is expanded downwardly, in the direction of the settler (9).

6. A flash smelting furnace according to any of the claims 1 -5, c h a ra cte r i z ed in that the reaction shaft (2) comprises a cooling arrangement for cooling the reaction shaft (2).

7. A method for producing crude metal or matte, such as blister copper, copper matte, fine nickel matte, or nickel matte, in a suspension smelting furnace (1), such as a flash smelting furnace, in which method - the burner (3) is used for feeding solid matter (5) and reaction gas, (7) such as oxygen-enriched air, to the reaction shaft (2) of the suspension smelting furnace (1),

- the burner (3) is used for burning the solid matter (5) and reaction gas (7) fed into the reaction shaft (2), so that the solid matter (5) and the reaction gas (7) react together forming a melt (8), and - the created melt (8) is collected on the bottom (10) of the settler (9) arranged at the lower end of the reaction shaft (2), ch a r a c te ri zed in that

- the burner (3) is arranged in the reaction shaft (2), at the distance of 2 - 5 meters from the surface (13) of the melt (8) collected on the bottom (10) of the settler (9).

8. A method according to claim 7, c h a r a c t e r i z e d in that the burner (3) is arranged in the reaction shaft (2), at the distance of 3 - 4 meters from the surface (13) of the melt (8) collected on the bottom (10) of the settler (9).

9. A method according to claim 7, c h a r a c t e r i z e d in that the burner (3) is arranged in the reaction shaft (2), at the distance of about 4 meters from the surface (13) of the melt collected on the bottom (10) of the settler (9).

10. A method according to any of the claims 7 - 9, c h a ra cte riz ed in that there is provided a reaction shaft (2), the cross-sectional surface of which is expanded downwardly, in the direction of the settler (9).