WO2005026024A1

WO2005026024A1 - Method and device for lining a metallurgical vessel

Info

Publication number: WO2005026024A1
Application number: PCT/FI2004/000548
Authority: WO
Inventors: Aatos VÄHÄKANGAS; Kyösti Ruotanen
Original assignee: Bet-Ker Oy
Priority date: 2003-09-18
Filing date: 2004-09-20
Publication date: 2005-03-24
Also published as: ATE395283T1; DE602004013828D1; FI20031342A0; FI117279B; FI20031342A; EP1692061B1; EP1692061A1

Abstract

A method of lining a metallurgical vessel by installing a lining material into the space (9) between a form (8) and the inner wall of the vessel (7) is characterized in that a screw conveyor device (3a, 5a; 3b, 5b) is placed above the space (9), which is left upwards open, to extend along the space in the close vicinity to it, the bottom wall of the screw conveyor device is provided with one or more openings (6a, 6b) extending essentially on the whole length of it, and lining material is brought into the screw conveyor device in which it is transferred and at the same time fed through said openings on essentially the whole length of it into said space (9). The invention concerns also a corresponding device.

Description

METHOD AND DEVICE FOR LINING A METALLURGICAL VESSEL

FIELD OF THE INVENTION The invention is related to a method and device for lining a metallurgical vessel by installing a lining material between a form and the inner wall of the vessel.

BACKGROUND OF THE INVENTION Rheology and other properties of refractory masses used for lining metallurgical vessels vary widely. The rheological behavior of the materials have been described in the litterature with the following terms: plastic, pseudoplastic, dilatant, newtonian, self-flowing, self-levelling, self- compacting, thixotropic. These terms describe usually materials having a liquid as a carrier phase. In lining masses which are to be installed dry, the carrier medium for solid particles is a gas mixture, normally air. Earth-moist or semidry masses include both liquid and gas mixture as a carrier medium. The amount and properties of the used carrier medium are to large extent controlling the rheological behavior of a lining material in particle form. The rheological behavior of dry masses is affected remarkably by circumstances, too. In some known lining methods utilizing a form, a dry mass and water are mixed first to homogeneous mass, and the wet mass is transferred into the space formed with a form by means of a screw conveyor with the output at one end (US 5368459), belt conveyor, container or a hose pressurized in any suitable way. The screw or belt conveyor, container or the end of the hose is moved during the lining job for delivering mass to every place between the form and the surface to be lined. The mass is self-compacting or compacted by vibrating. These methods are suitable for installing wet flowing masses as great compactness is required for the lining. However, with these methods addition of water at the the place of use is always needed, and the methods are not suitable for installing dry or earth-moist masses. Methods suitable for installing dry masses are used for installing heat insulating coatings of intermediate vessels, especially. The dry mass may be transferred into the space between the form and the surface to be lined e.g. by means of pressurized air (FI 820412). Another method is to let the mass run or drop the mass (US 6280664) into its place by means of a big bag or a valve at the bottom of a container or one or more outlets extending from the bottom. The end of the outlet may be located at the top level of the object to be lined, and the outlet and the mass supply are moved horizontally according to need. The outlets may be extended to the bottom of the space to be lined as the lining is started whereby the outlets and the mass supply are raised as the lining is going on and the mass is flowing into the space with a short free fall (US 4534730). A dry mass may be installed also with conventional mass conveying devices, like screw or belt conveyors, whereby the mass is discharged into the space to be lined from the end of the screw conveyor or belt. This kind of solution needs normally a mechanism for moving the conveyor. All the above methods utilizing dry mass have their drawbacks, e.g. dusting of the mass during installing, great need of manpower, high costs of the installing equipment, great need of service, inferior quality of the lining structure, or restrictions as to the type and rheology of the lining material. In the modern smelting technology, it is desirable that the above drawbacks would be avoided. The installation of a lining material would be carried out quickly and simply with low manpower and energy. Also the equipment would be simple and reliable. The methods would be safe and environmentally benign, and the lining made with the methods would be of high quality. Moreover, it would be advantageous if lining materials with different rheologies and casting properties, e.g. masses for dry installation, masses to be installed as earth-moist or semidry, masses which are wet when installed, like casting masses, and also masses including carrier or liquid phase during installation, would be installed and aftertreated.

SUMMARY OF THE INVENTION With the method and device of the invention, the above mentioned drawbacks may be removed to large extent and the desirable advantages also considered above achieved. To achieve these objects and advantages, the method according to the invention for lining a metallurgical vessel by installing a lining material into the space between a form and the inner wall of the vessel is characterized in that which is defined in claim 1. Various embodiments of the method are defined in claims 2 to 4. To achieve these objects and advantages, the device according to the invention for lining a metallurgical vessel by installing a lining material into the space between a form and the inner wall of the vessel is characterized in that which is defined in claim 5. Various embodiments of the device are defined in claims 6 to 12. The solution of the invention is very suitable for installation of dry lining masses, for example. As the properties and operation of the screw conveyor device and the openings at the bottom of it may be varied in many ways, the solution may be applied widely for installing different kind of materials.

BRIEF DESCRIPTION OF THE DRAWINGS The invention and some embodiments thereof are described in further detail in the following with reference to the accompanying drawings, in which: Figs. 1 to 3 present an embodiment of the device of the invention in plant, side and front views, respectively, Figs 2 and 3 being partly in section along lines 13-11 and TJJ-IIT of Fig. 1; Fig. 4 is a schematic sectional view presenting the device of the invention and its operation in further detail; Figs. 5 to 8 present schematically in bottom view some alternative realizations of an active feeding device included in the device of the invention; Fig. 9 presents schematically in side view a still further alternative realization of an active feeding device included in the device of the invention; and Fig. 10 presents schematically in plant view a still further embodiment of the device of the invention.

DETAILED DESCRIPTION OF THE INVENTION Before starting a lining work, a form 8 is installed in a vessel 7 whereby a space 9 remains between the form and the inner wall of the vessel to be lined. The lining work advancing, the space 9 is filled with refractory material M. The vessel to be lined comprises typically a jacket 7 and a background lining 13 (Fig. 4). The device of Figs. 1 to 4 includes a frame Ion which the device is supported above the vessel 7 provided with the form 8 so that screw conveyor devices 3a, 3b, 3c and 3d extend above the upwards open space 9 along it and in the close vicinity to it. The screw conveyor devices 3a and 3b and, respectively, 3c and 3d extend at the both sides of the vessel 7 on essentially the whole length of it. At the bottom of the screw conveyor devices there are, respectively, openings 6a, 6b, 6c and 6d extending essentially on the whole length of it. Guide plates 12a, 12c etc., respectively, have been attached at the sides of the openings for conducting material M better into the space 9 and for reducing dusting. A hopper 2 comprises four parts 2a, 2b, 2c and 2d for conducting the material through corresponding outlets 4a, 4b, 4c and 4d into the corresponding screws 3a, 3b, 3c and 3d. The outlets are provided with valves 11a, lib etc., respectively. The screws 5a, 5b, 5c and 5d of the screw conveyor devices are driven by electric motors 10a, 10b, 10c and lOd, respectively. Fig. 2 demonstrates the operation of the method and the device. The aim is that material is fed into the space 9 evenly on the whole length of the screws. If the structure of the downwards open screw conveyor device is longitudinally essentially homogeneous, the lining structure, as the device is operated, begins to be made up from that end of the screw conveyor at which the mass is brought into the screw conveyor. The filling of the space to be lined under the screw conveyor is starting from one end of the device and is advancing towards the other end. Then, some segregation may be produced in the lining structure which may weaken the strength of the lining. Therefore, it may be necessary to adjust the transfer speed of the material in the screw casing in the longitudinal direction as is indicated by arrows SI, S2 and S3 in Fig. 5, in the example of which the opening 6 at the bottom of the screw conveying device is even in width. A bigger transfer speed at the beginning of the screw conveyor device causes that more material is transferred to the other end of the device and discharged there which makes the feeding of the material into the space to be filled more even along the length of the device. The discharging speed of the material may be made uniform or it may be adjusted on the whole length of the screw conveyor device also e.g. so that the opening 6' at the bottom of the screw conveyor device is widening from the beginning to the end of the device (Fig. 6). The same may be made so that there are several openings 6j, 6k, 61, 6m and 6n and that the length and/or width of them is increasing from the beginning to the end of the device (Fig. 7). A solution is to use a netting 14 in the opening 6 the mesh size of which is at the beginning of the device 3 smaller than at the end (Fig. 8). Fig. 9 describes schematically a solution in which at the bottom of or under the screw conveyor device there is a mechanism 15 in connection with the opening 6, e.g. an angle iron or a trough extending longitudinally along the device by means of which discharging speed of the material may be adjusted at any place in the longitudinal direction of the device. The material may be fed into the screw conveyor device in a conventional way through an inlet or opening (11a, 1 lb and 1 lc in Figs. 2 to 4 and 11 in Figs. 9 and 10) at one end of the device. The screw may be a normal spiral screw, and for adjusting the transfer speed the pitch of the screw may vary. According to the need, the properties of the screw may be varied widely also otherwise. The term "screw conveyor device" means here generally a device in which material may be transferred longitudinally in a tube or similar device by means of a screw-like organ. The screw conveyor device may be a conventional screw conveyor meant for transferring materal brought into one end of the conveyor into the other end and discharging it there. However, as is described above, the screw conveyor device which is the basic device in the present solution, may vary in many ways so that the material transfer efficiency and speed and also transfer direction vary along the length of the device. Material may of course be brought into the screw conveyor device at several places along the length of the device or e.g. at the middle, and the screw may be accomplished so that it transfers material in different directions at different places. The method and device of the invention may include also other special features making a lining work easier or faster and features improving working hygiene. For example, there may be a limit switch in the device by means of which the screw is stopped automatically as the space to be lined is filled. Fig. 10 presents a further example of the device of the invention. E.g. an intermediate vessel has often a rectangular form in plan. The screw conveyor device 3 is placed above the top opening of the space 9 to be filled at the longer side of the vessel 7. So that also the shorter end side of the vessel would be filled as well as possible, the structure of the screw conveyor device is added with extensions 3m and 3n at the end sides of the vessel, respectively, whereby the space to be lined is filled also at the ends of the vessel. As presented in the examples of Figs. 1 to 4, 2 to 4 screw conveyor devices and a mass storage hopper may form a unit the components of which may be fixed together. The unit may be movable or installed steadily and also automatically controlled for reducing need of manpower. Refractory material which is to be portioned out into the object may include gas mixture as a carrier medium already in a storage hopper whereby different kinds of refractory materials, like dry masses, casting masses or semidry masses may be installed by the method and device of the invention. If casting masses including liquid phase as a carrier medium or semiwet masses are to be installed, the input end of the device of the invention may be provided with an inlet for portioning liquid phase into the mass. Then, the need of mixing liquid phase into the essentially dry mass coming from the storage hopper into the screw conveyor device is taken into account in the realization of the structure of the screw. The solution of the invention may be used also with intermediate vessels for making background linings and insulating coatings. The invention may vary within the scope of the accompanying claims.

Claims

1. Method of lining a metallurgical vessel by installing a lining material into the space (9) between a form and the inner wall of the vessel, characterised in that: a screw conveyor device (3, 3a, 3b, 3c, 3d) is placed above the space (9), which is left upwards open, to extend along the space in the close vicinity to it; the bottom wall of the screw conveyor device is provided with one or more openings (6, 6a, 6b, 6c, 6d, 6', 6j, 6k, 61, 6m, 6n) extending essentially on the whole length of it; and lining material is brought into the screw conveyor device in which it is transferred and at the same time fed through said openings on essentially the whole length of it into said space (9).

2. Method according to claim 1, characterised in that the feeding into said space is adjusted for making it even in the longitudinal direction of the conveyor device (3, 3a, 3b, 3c, 3d).

3. Method according to claim 2, characterised in that the feeding is adjusted by changing the dimensions of said one or more openings (6', 6j, 6k, 61, 6m, 6n) in relation to the longitudinal position of the opening.

4. Method according to claim 2, characterised in that the feeding is adjusted by changing the transfer efficiency (SI, S2, S3) of the screw conveyor device (3) in relation to the longitudinal position.

5. Device for lining a metallurgical vessel by installing a lining material into the space between a form and the inner wall of the vessel, characterised in that the device comprises above the space (9), which is left upwards open, in the close vicinity to it a screw conveyor device (3, 3a, 3b, 3c, 3d) extending along the space, the bottom wall of the screw conveyor device being provided with one or more openings (6, 6a, 6b, 6c, 6d, 6', 6j, 6k, 61, 6m, 6n) extending essentially on the whole length of the bottom wall, for bringing lining material into the screw conveyor device and transferring and at the same time feeding the material through said openings on essentially the whole length of the device into said space (9).

6. Device according to claim 5, characterised in that the opening (6) is even in width.

7. Device according to claim 5, characterised in that the opening (&) is widening when going away from the input position of the material.

8. Device according to claim 5, characterised in that the bottom wall includes several openings in succession (6j, 6k, 61, 6m, 6n) the openings widening and/or lengthening when going away from the input position of the material.

9. Device according to claim 5, characterised in that the opening (6) is provided with a netting (14) the mesh of which is widening when going away from the input position of the material.

10. Device according to claim 5, characterised in that the opening (6) is provided with a device (15) extending in the longitudinal direction of the screw conveyor device (3) for adjusting the discharging speed of the material.

11. Device according to claim 5, characterised in that the screw conveyor device (5) includes a spiral screw.