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Title:
METHOD FOR MANUFACTURING A COOLING ELEMENT, COOLING ELEMENT AND METALLURGICAL FURNACE
Document Type and Number:
WIPO Patent Application WO/2015/144985
Kind Code:
A1
Abstract:
The invention relates to a method for manufacturing a cooling element (1) for at least partly lining an inner space (2) of a metallurgical furnace (3). The method comprises a providing step for providing a cooling element (1) having a surface (4) that is to be arranged turned towards the inner space (2) of the metallurgical furnace (3) and a hardening step for hardening at least partly the surface (4) of the cooling element (1) that is to be arranged turned towards the inner space (2) of the metallurgical furnace (3) to provide the surface (4) with a hardened surface area (5). Any one of the following is used in the hardening step: air hammering, shot blasting, shot peening, pearl blasting, and laser peening. The invention relates also to a cooling element and to a metallurgical furnace.

Inventors:
LINDGREN, Mari (Hiirakkotie 11, Pori, FI-28430, FI)
JÅFS, Mikael (Okatie 2b, Kirkkonummi, FI-02400, FI)
Application Number:
FI2015/050196
Publication Date:
October 01, 2015
Filing Date:
March 24, 2015
Export Citation:
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Assignee:
OUTOTEC (FINLAND) OY (Rauhalanpuisto 9, Espoo, FI-02230, FI)
International Classes:
F27D1/12; F27D9/00
Domestic Patent References:
WO2006040394A12006-04-20
WO2010000939A12010-01-07
Foreign References:
EP1253390A12002-10-30
Attorney, Agent or Firm:
BOCO IP OY AB (Itämerenkatu 5, Helsinki, FI-00180, FI)
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Claims:
Claims

1. A method for manufacturing a cooling element (1) for at least partly lining an inner space (2) of a metallurgical furnace (3) such as for at least partly lining a furnace space of a suspension smelting furnace, wherein the method comprises

a providing step for providing a cooling element (1) having a surface (4) that is to be arranged turned towards the inner space (2) of the metallurgical furnace (3),

characterized

by a hardening step for hardening at least partly the surface (4) of the cooling element (1) that is to be arranged turned towards the inner space (2) of the metallurgical furnace (3) to provide the surface (4) with a hardened surface area (5), and

by using any one of the following in the hardening step: air hammering, shot blasting, shot peening, pearl blasting, and laser peening.

2. The method according to claim 1, characterized

by a covering step for covering the hardened surface area (5) of the surface (4) of the cooling element (1) at least partly with refractory material (6).

3. The method according to claim 2, characterized

by covering the hardened surface area (5) of the surface (4) of the cooling element (1) in the covering step at least partly with refractory material (6) so that the hardened surface area (5) of the surface (4) of the cooling element (1) remains at least partly uncovered by any refractory material (6).

4. The method according to any of the claims 1 to 3, characterized

by hardening in the hardening step the surface (4) of a part of the cooling element (1) that is made of at least one of steel or copper alloy.

5. A cooling element (1) for at least partly lining an inner space (2) of a metallurgical furnace (3) such as for at least partly lining a furnace space of a suspension smelting furnace, wherein the cooling element (1) having a surface (4) that is to be arranged turned towards the inner space (2) of the metallurgical furnace (3),

characterized

by the surface (4) of the cooling element (1) that is to be arranged turned towards the inner space (2) of the metallurgical furnace (3) has at least partly been hardened by any one of air hammering, shot blasting, shot peening, pearl blasting, and laser peening to provide the surface (4) of the cooling element (1) with a hardened surface area (5).

6. The cooling element (1) according to claim 5, characterized by the hardened surface area (5) of the surface (4) of the cooling element (1) being at least partly covered by refractory material (6).

7. The cooling element (1) according to claim 6, characterized by the hardened surface area (5) of the surface (4) of the cooling element (1) being at least partly uncovered by any refractory material (6).

8. The cooling element (1) according to any of the claims 5 to 7, characterized by the part of the cooling element (1) having said surface (4) having said hardened surface area (5) being made of at least one of steel or copper alloy.

9. A metallurgical furnace (3) such as a suspension smelting furnace having an inner space

(2) such as a furnace space at least partly lined by cooling elements (1), wherein each cooling element (1) having a surface (4) that is turned towards the inner space (2) of the metallurgical furnace (3),

characterized

by the surface (4) that is turned towards the inner space (2) of the metallurgical furnace

(3) of at least one of the cooling elements (1) has at least partly been hardened by any of air hammering, shot blasting, shot peening, pearl blasting, and laser peening to provide said surface (4) of said at least one cooling element (1) with a hardened surface area (5).

10. The metallurgical furnace (3) according to claim 9, characterized by the hardened surface area (5) of said surface (4) of said at least one cooling element (1) being at least partly covered by refractory material (6).

11. The metallurgical furnace (3) according to claim 10, characterized by the hardened surface area (5) of said surface (4) of said at least one cooling element (1) being at least partly uncovered by any refractory material (6). 12. The metallurgical furnace (3) according to any of the claims 9 to 10, characterized by the part of said at least one cooling element (1) that has the surface (4) having said hardened surface area (5) being made of at least one of steel or copper alloy.

Description:
METHOD FOR MANUFACTURING A COOLING ELEMENT, COOLING ELEMENT AND METALLURGICAL FURNACE

Field of the invention

The invention relates to a method for manufacturing a cooling element for at least partly lining an inner space of a metallurgical furnace such as a furnace space of a suspension smelting furnace as defined in the preamble of independent claim 1.

The invention also relates a cooling element for at least partly lining an inner space of a metallurgical furnace such as for at least partly lining a furnace space of a suspension smelting furnace as defined in the preamble of independent claim 5.

The invention also relates to a metallurgical furnace such as a suspension smelting furnace having an inner space such as a furnace space at least partly lined by cooling elements, wherein each cooling element having a surface that is turned towards the inner space of the metallurgical furnace as defined in the preamble of independent claim 9.

The invention relates to cooling elements to be used for lining an inner space of a metallurgical furnace such as for lining a furnace space of a suspension smelting furnace. In a suspension smelting furnace the furnace space to be lined with a such cooling element may be the inner space of the reaction shaft, the inner space of the uptake shaft, or a part of the inner space of the lower furnace i.e. of the settler.

Various cooling elements for metallurgical furnaces are known in the art. Publications

WO 2006/040394 and WO 2010/000939 presents cooling elements.

Cooling elements are made of copper because high thermal conductivity is needed. Copper has resistance against corrosive environment but its disadvantage is softness. Previously, steel inserts or steel coatings have been used to increase hardness of a cooling element. Due to lower thermal conductivity of a steel surface compared to a copper surface, the surface temperature of a steel covered cooling element of copper is however higher than the surface temperature of an uncovered cooling element of copper. A result of such higher surface temperature is increased corrosion of the steel covered cooling element of copper. Moreover, complex geometries are difficult to protect with inserts or by coating.

Objective of the invention

The object of the invention is to provide a method for manufacturing a cooling element and a cooling element and additionally a metallurgical furnace which prolongs the service life of the cooling elements.

Short description of the invention

The method of the invention is characterized by the definitions of independent claim 1. Preferred embodiments of the method are defined in the dependent claims 2 to 4. The cooling element of the invention is correspondingly characterized by the definitions of independent claim 5.

Preferred embodiments of the cooling element are defined in the dependent claims 6 to 8. The metallurgical furnace of the invention is correspondingly characterized by the definitions of independent claim 9.

Preferred embodiments of the metallurgical furnace are defined in the dependent claims 10 to 12.

The invention is based on hardening by at least one of air hammering, shot blasting, shot peening, pearl blasting, and laser peening at least partly the surface of the cooling element that is to be arranged turned towards the inner space of the metallurgical furnace to provide the surface with a hardened surface area.

Shot peening is a cold working method for working surfaces of objects, where hard shots are driven by a stream such as compressed gas at a high velocity against the surface to be worked. The hard shots can for example be silica or quartz sand particles, which are driven at a velocity of about 20 to 40 m/s, such as at a velocity of about 30 m/s against the surface of the cooling element.

The invention provided for increased hardness of the surface of the cooling element made of copper, and this improves its erosion resistance without lowering the high thermal conductivity significantly.

In a preferred embodiment said surface area of the surface of the cooling element is at least one edge of the cooling element, preferably at a lower edge of the cooling element. Especially in cases where several cooling elements are used and where the cooling elements are at least partly covered with refractory material such as bricks, the connection areas between the cooling elements i.e. the edge areas of the cooling elements remains uncovered by the refractory material and therefore exposed to the content of the inner space such as to the content of the furnace space of the metallurgical furnace.

List of figures

In the following the invention will described in more detail by referring to the figures, which

Figure 1 shows a metallurgical furnace in the form of a suspension smelting furnace, Figure 2 shows a cooling element,

Figure 3 shows a part of a cooling element that is at least partly covered with refractory material, and

Figure 4 shows a cooling element shown from one side.

Detailed description of the invention

The invention relates to a method for manufacturing a cooling element 1 for at least partly lining an inner space 2 of a metallurgical furnace 3 such as a furnace space of a suspension smelting furnace.

The invention relates also to a cooling element 1 for at least partly lining an inner space 2 of a metallurgical furnace 3 such as for at least partly lining a furnace space of a suspension smelting furnace.

The invention relates additionally to a metallurgical furnace 3 such as a suspension smelting furnace having an inner space 2 such as a furnace space at least partly lined by cooling elements 1, wherein each cooling element 1 having a surface that is turned towards the inner space 2 of the metallurgical furnace 3.

First the method and some preferred embodiments and variants of the method will be described in greater detail.

The method comprises a providing step for providing a cooling element 1 having a surface 4 that is to be arranged turned towards the inner space 2 of the metallurgical furnace 3.

The method comprises a hardening step for hardening at least partly the surface 4 of the cooling element 1 that is to be arranged turned towards the inner space 2 of the metallurgical furnace 3 to provide the surface 4 with a hardened surface area 5. At least one of the following is used in the hardening step: Air hammering, shot blasting, shot peening, pearl blasting, and laser peening.

The method may comprise a covering step for covering the hardened surface area 5 of the surface 4 of the cooling element 1 at least partly with refractory material. If the method comprises a covering step, the method may comprise covering the hardened surface area 5 of the surface 4 of the cooling element 1 in the covering step at least partly with refractory material 6 so that the hardened surface area 5 of the surface 4 of the cooling element 1 remains at least partly uncovered by any refractory material 6.

If the method comprises a covering step, the surface 4 of the cooling element 1, which is hardened in the hardening step, may be a surface 4 of a supporting part 7 of the cooling element 1 that is configured for supporting refractory material 6 such as bricks of refractory material 6 at the cooling element 1.

If the method comprises a covering step, the surface 4 of the cooling element 1, which is hardened in the hardening step, may be a surface 4 a supporting part 7 of the cooling element 1, which supporting part 7 is supported at a base element 8 of the cooling element 1 and which supporting part 7 is configured for supporting refractory material 6 such as bricks of refractory material 6 at the cooling element 1.

The hardening step of the method may comprise by hardening in the hardening step a surface 4 at an edge area, such as a lower edge area, of the cooling element 1.

The method may comprise providing in the providing step a cooling element 1 that is provided with at least one cooling fluid channel 9 for circulating cooling fluid in the cooling element 1. The method may comprise hardening in the hardening step the surface 4 of a part of the cooling element 1 that is made of at least one of steel or copper alloy.

Next the cooling element 1 and some preferred embodiments and variants of the cooling element 1 will be described in greater detail.

The cooling element 1 has a surface 4 that is to be arranged turned towards the inner space 2 of the metallurgical furnace 3.

The surface 4 of the cooling element 1 that is to be arranged turned towards the inner space 2 of the metallurgical furnace 3 has at least partly been hardened by any one of air hammering, shot blasting, shot peening, pearl blasting, and laser peening to provide the surface 4 of the cooling element 1 with a hardened surface area 5.

The hardened surface area 5 of the surface 4 of the cooling element 1 may be at least partly covered by refractory material 6.

The hardened surface area 5 of the surface 4 of the cooling element 1 may be partly covered by refractory material 6 so that by the hardened surface area 5 of the surface 4 of the cooling element 1 being at least partly uncovered by any refractory material 6.

In the surface 4 of the cooling element 1 is at least partly covered by refractory material 6 such as bricks of refractory material 6, the hardened surface area 5 of the surface 4 of the cooling element 1 may be a supporting part 7 of the cooling element 1 configured for supporting refractory material 6 such as bricks of refractory material 6.

In the surface 4 of the cooling element 1 is at least partly covered by refractory material 6 such as bricks of refractory material 6, the hardened surface area 5 of the surface 4 of the cooling element 1 may be a supporting part 7 of the cooling element 1, which supporting part 7 is supported at a base element 8 of the cooling element 1 and which supporting part 7 is configured for supporting refractory material 6 such as bricks of refractory material 6.

The hardened surface area 5 of the surface 4 of the cooling element 1 may be provided at an edge area, such as a lower edge area, of the cooling element 1.

The cooling element 1 may be provided with at least one cooling fluid channel for circulating cooling fluid in the cooling element 1.

The part of the cooling element 1 having said surface 4 having said hardened surface area 5 may be made of at least one of steel or copper alloy.

Next the metallurgical furnace 3 and some preferred embodiments and variants of the metallurgical furnace 3 will be described in greater detail.

The surface 4 of at least one of the cooling elements 1, which surface 4 is turned towards the inner space 2 of the metallurgical furnace 3, has at least partly been hardened by any of air hammering, shot blasting, shot peening, pearl blasting, and laser peening to provide said surface 4 of said at least one cooling element 1 with a hardened surface area 5.

The hardened surface area 5 of said surface 4 of said at least one cooling element 1 may be at least partly covered by refractory material 6. The hardened surface area 5 of said surface 4 of at least one cooling element 1 may be partly covered by refractory material 6 so that the hardened surface area 5 of said surface 4 is at least partly uncovered by any refractory material 6.

In the surface 4 of the cooling element 1 is at least partly covered by refractory material 6 such as bricks of refractory material 6, the hardened surface area 5 of the surface 4 of the cooling element 1 may be a supporting part 7 of the cooling element 1 configured for supporting refractory material 6 such as bricks of refractory material 6.

In the surface 4 of the cooling element 1 is at least partly covered by refractory material 6 such as bricks of refractory material 6, the hardened surface area 5 of the surface 4 of the cooling element 1 may be a supporting part 7 of the cooling element 1, which supporting part 7 is supported at a base element 8 of the cooling element 1 and which supporting part 7 is configured for supporting refractory material 6 such as bricks of refractory material 6.

The hardened surface area 5 of the surface 4 of the cooling element 1 may be provided at an edge area, such as a lower edge area, of the cooling element 1.

The cooling element 1 may be provided with at least one cooling fluid channel for circulating cooling fluid in the cooling element 1.

The part of the cooling element 1 having said surface 4 having said hardened surface area 5 may be made of at least one of steel or copper alloy.

The cooling elements 1 may be releasable arranged in the metallurgical furnace 3.

Example

A preliminary high-temperature erosion test was conducted with copper sample (Cu- HCP) having an air-hammered surface (Cu treated in the Graph) and with a corresponding copper sample without an air-hammered surface (Cu conventional in the Graph) at a test temperature on 200°C. The abrasive used for the erosion was silica sand and the velocity was 30 m/s. The test proved that the erosion resistance of copper could be improved by surface modification, in this case with air-hammering. The surface hardness of the copper sample having the air-hammered surface was about double (125 HVl) the surface hardness of the copper sample without an air-hammered surface (60 HVl). The test showed that the copper sample having the air-hammered surface had a reduction of 25 % in the erosion wear rate compared to the copper sample without an air-hammered surface.

Cu conventional Cu treated

Graph: Erosion rate at 200°C

It is apparent to a person skilled in the art that as technology advanced, the basic idea of the invention can be implemented in various ways. The invention and its embodiments are therefore not restricted to the above examples, but they may vary within the scope of the claims.