EP0649911A1 - Reflection device in the mouth of a lance for applying bonded minerals and process for using said lance - Google Patents

Abstract

Injection lance provided at its exit with a device for distributing a binder-based mineral composition, the device being characterised by the fact: - that, facing the exit of the lance, it comprises a concave cavity in the form of a crown ring whose axis is coaxial with that of the said lance; - that the said crown ring has a section along the axis of the lance which is substantially M-shaped, the said M-shaped section being made up of four legs converging in pairs at a point or connected to one another by means of a curved line. The invention also relates to a process for the sealing of components forming a casting hole by means of the lance provided with the abovementioned distributing device. <IMAGE>

Description

The invention relates to a device for orienting a mineral composition based on a binder at the outlet of an injection lance and a method using this lance for the purpose of restoring and / or in particular sealing the metallurgical installations with the internal refractory lining. prefabricated refractories which form the tap hole.

For a long time now, it has been known that the operating conditions and more particularly the high temperatures practiced in metallurgical installations for carrying out, in the molten state, the various treatments allowing the transformation of metallic ores into refined metals, are, by their aggressive nature, the cause of relatively rapid wear of the internal refractory linings of these installations.

This wear phenomenon, although general, is much more pronounced in tap holes and their close internal environment. Because, the refractory parts constituting said tap holes and the internal walls of metallurgical installations, are, in addition to the thermal effects, subjected, during emptying, to mechanical erosion effects. These effects come from the turbulence (of the vortex type in particular) which reigns within the vein of the liquid metal escaping from such installations.

Consequently, the consequences of this mechanical erosion appear not only in the evolution of the dimensional characteristics of the tap holes (the diameters increase from one end to the other, often irregularly), but also within the internal wall of the installations. metallurgical where manifest, around the mouth of the tap holes, cavities, by scour generated by turbulence. Thus, the mechanical erosion of the tap holes leads to an increase in the volume of molten metal flowing per unit of time.

In order to ensure a more regular operation of metallurgical installations and to provide a metal whose physicochemical characteristics remain equal to themselves, that is to say are not affected by the presence of refractory debris from the wear of the coatings and tap holes, or due to the increase from one pour to another of the volume of molten metal flowing per unit of time, we currently use a regular restoration of tap holes and their internal circumference.

To avoid prolonged shutdown of metallurgical installations, this restoration is generally carried out hot, after emptying, during a pause between two treatment operations.

At least two types of tap hole restoration techniques are practiced.

In a first type of known technique, the used refractory elements are eliminated from the taphole and replaced by new refractory elements. Then a mineral composition based on a binder is projected, hydraulic or not, using a long lance (of the order of 6 to 12 m in length), bent at its end. This lance, operated by an operator through the main opening of the metallurgical installation, is positioned to allow the application of the mineral composition in the empty space created between the new refractory elements, which form the taphole, and the refractory lining of the internal wall of the metallurgical installation.

This restoration requires significant physical effort for the operator who must not only maintain the lance but also control the position of his end on the internal periphery of the tap hole, this tap hole being located away from the operator by a distance substantially equivalent to the length of the lance. In addition, this stain is made painful by the fact of radiant heat emanating from the main opening of the metallurgical installation: to achieve the best restoration, the operator must be in the immediate vicinity of this opening. For example, in the particular case of a converter, the temperature prevailing inside, after draining, can vary from 700 ° C. to 1000 ° C. Consequently, this technique for restoring tap holes cannot be carried out safely or easily.

In addition, as the operator is far from the main opening for safety reasons, he does not have the possibility of precisely controlling the position of the end of the lance: thus the quality of the restoration of the hole casting is uncertain.

In a second type of known technique, after elimination of the used refractory elements from the taphole and their replacement by new refractory elements, the mineral composition based on binder, hydraulic or not, is brought into the areas to be restored by means of a ladle with a long handle (of the order of 6 to 8 m) which can contain approximately 25 kg or more of said composition. Like the previous technique, this technique poses significant safety problems for the operator: in fact, this ladle is operated manually, through the main opening of the drained metallurgical installation. But this work is made difficult not only because of the radiant heat but also the weight of the ladle.

In addition, as it takes on the order of 300 to 500 kg of the mineral composition to seal the new refractory elements forming the taphole, numerous successive operations are necessary to bring, by means of the ladle, the quantity of composition mineral to flow in the area concerned: this results in a considerable loss of time and possible faults.

Finally, as the addition of the mineral composition based on a binder, hydraulic or not, is carried out discontinuously, the use of a ladle means overdosing said composition with water to avoid too rapid setting which would be caused by the temperature. ambient. However, as a result, the mineral composition after setting has a higher porosity than usual, which is detrimental to the desired mechanical characteristics: the life of the seal is therefore reduced.

The invention aims to overcome the aforementioned drawbacks.

A main object of the invention is to propose a device for orienting a refractory mineral composition based on a binder, hydraulic or not, at the outlet of an injection lance making it possible to fill with ease, precision and continuously, an empty space which can be created by wear in the internal refractory lining in the vicinity of the tap holes of metallurgical installations, this device being of great technical simplicity and undeniable safety of use for the operator.

Another object of the invention is a method using said device and guaranteeing the durability of the refractory periphery of the tap hole, for example a durable sealing of the elements forming the tap holes of metallurgical installations.

• qu'il comporte en regard de la sortie de la lance un évidement concave en forme de couronne dont l'axe est coaxial à celui de ladite lance
• que ladite couronne a une section selon l'axe de la lance, sensiblement en forme de "M", ladite section en "M" étant formée de quatre jambages concourants deux à deux en un point ou reliés l'un à l'autre par l'intermédiaire d'une ligne courbe.

According to the invention, these objects are achieved by means of an injection lance provided at its outlet with a device for distributing the mineral composition based on a binder, hydraulic or not, the device being characterized by the fact:

• that it comprises, opposite the outlet of the lance, a concave recess in the form of a crown whose axis is coaxial with that of said lance
• that said crown has a section along the axis of the lance, substantially in the shape of an "M", said section in an "M" being formed of four legs which compete in pairs at a point or are connected to each other by through a curved line.

• a) si nécessaire, on élimine le pourtour usé du trou de coulée ou bien le ou les éléments réfractaires usés formant le trou de coulée et on les remplace par un ou plusieurs éléments neufs en matériau réfractaire ou non
• b) on introduit l'extrémité de la lance munie du dispositif de répartition de la composition minérale dans l'installation métallurgique en la faisant passer à travers le trou de coulée formé du ou des éléments neufs
• c) on ajuste la position de l'extrémité de la lance à l'intérieur de l'installation métallurgique, pour permettre au dispositif de répartition placé en son extrémité d'effectuer le remplissage dudit espace vide
• d) on injecte sous pression la composition minérale à l'aide de la lance, cette composition étant déviée, à la sortie de la lance, et dirigée à l'aide dudit dispositif de répartition en direction de l'espace vide qu'elle remplit complètement.

The invention also relates to a method using the lance provided with the distribution device according to the invention which allows the filling of the empty space existing between the refractory lining of the internal wall and the new element or elements forming the tap holes of the installations. metallurgical, by means of a lance supplied with a refractory mineral composition, previously wetted and kneaded, based on hydraulic binder or not, this process being characterized in that:

• a) if necessary, remove the worn periphery of the taphole or the used refractory element (s) forming the taphole and replace them with one or more new elements made of refractory material or not
• b) the end of the lance fitted with the device for distributing the mineral composition is introduced into the metallurgical installation by passing it through the taphole formed from the new element or elements
• c) the position of the end of the lance is adjusted inside the metallurgical installation, to allow the distribution device placed at its end to fill said empty space
• d) the mineral composition is injected under pressure using the lance, this composition being deflected, at the outlet of the lance, and directed using said distribution device towards the empty space which it fills completely.

Once the operations have been completed, the lance equipped with its distribution device according to the invention is removed from the metallurgical installation.

The device and method according to the invention are more particularly intended to allow the sealing of the new element or elements, of refractory material or not, constituting the new taphole by filling the empty space delimited by the external lateral wall of said elements and the refractory lining of the internal wall of the metallurgical installation.

Thanks to the invention, the mineral composition based on a binder, hydraulic or not, exiting under pressure from the lance is projected inside the recess concave in the form of a crown of the device according to the invention, then, by the shape of said recess, it is deflected and directed towards the space to be filled.

The geometrical dimensions of the distribution device according to the invention are conditioned mainly by the dimensions of the space to be filled, by the height separating the device from the empty space to be filled, by the internal diameter of the lance and by the dimensions of the tap hole.

Therefore, the length of the outer legs of the "M" section of the crown can be equal, less or even greater than that of the inner legs. Preferably, the external legs of the section substantially in "M" of the concave recess define a frustoconical volume.

Preferably also, and this to avoid fallout of the mineral composition towards the taphole, the angle a defined by one or the other of the external legs of the section substantially in "M" of the concave recess and the axis of the lance is chosen to be of the order of 15 ° or greater.

As for the internal legs of the section substantially in "M" of the concave recess in the form of a crown of the device according to the invention, they preferably define a cone of revolution.

In this way, a uniform distribution of the mineral composition leaving the device is ensured in the empty space.

The value of the angle b , defined by one or other of the internal legs with the axis of the lance is largely dependent on the injection conditions, and more particularly on the flow rate of the projected refractory mineral composition, as well as geometric dimensions of the distribution device according to the invention. Preferably, the angle b is between 30 ° and 60 ° and more preferably is between 40 ° and 50 °.

Thus, the invention offers a device and a method allowing the restoration and / or the sealing of the new element or elements, in refractory material or not, forming the tap hole of metallurgical installations in a simple and reliable manner.

Similarly, thanks to the invention, the application of the mineral composition is carried out with great precision and regularity.

In addition, the operator can carry out the restoration in significantly improved safety conditions because he is much less exposed to the radiant heat of the installation. In addition, the handling operation is greatly simplified by the fact that the operator no longer has to operate a bulky and heavy device. Finally, the time required for a restoration and / or sealing operation of the new element or elements forming the taphole is considerably reduced thanks to the invention.

• La figure 1 représente, en coupe schématique longitudinale, l'extrémité avale d'une lance d'injection munie du dispositif conforme à l'invention ;
• La figure 2 montre la réalisation, au moyen du dispositif selon l'invention, d'un scellement des éléments réfractaires neufs formant le trou de coulée d'un convertisseur dont seul un détail de la paroi au voisinage du trou de coulée a été représenté.

The invention will be better understood from the following description of a preferred and non-limiting embodiment.

• FIG. 1 shows, in longitudinal schematic section, the downstream end of an injection lance provided with the device according to the invention;
• Figure 2 shows the embodiment, by means of the device according to the invention, of a sealing of the new refractory elements forming the taphole of a converter of which only a detail of the wall in the vicinity of the taphole has been shown.

According to Figure 1, the distribution device 1 according to the invention is fixed to an injection lance 2 by means of three rods 3. These rods 3 are made integral with the lance 2 by a fixing means 4, and the device 1 by a fixing means 5. These rods are distributed at 120 ° from one another around the periphery of the lance 2. In addition to the fixing function, these rods 3 also have the function of keeping the device 1 at a determined distance from lance 2, this in order to allow the passage of the deflected jet of the mineral composition towards the area to be restored.

The distribution device 1 comprises a concave recess 6 in the form of a crown whose axis is coaxial with that of the lance 2. According to the invention, the section of the recess 6 along the axis 8 of the lance 2 leads to a shape substantially in "M".

The angle defined by the leg 7 and the axis 8 of the lance 2 is determined so that the mineral composition is deflected and directed towards the space to be filled. In the device illustrated, the angle a is chosen to be close to 15 °.

Similarly, the angle b defined by the leg 9 and the axis 8 of the lance 2 is determined so that the mineral composition is deflected and directed towards the space to be filled. In the exemplified device, the angle b is chosen to be close to 45 °.

In accordance with a preferred embodiment of the invention, here exemplified, the external legs 7 define a frustoconical volume of revolution while the internal legs 9 define a cone of revolution.

In addition, the geometric dimensions of the recess 6 are determined to allow the reception and the deviation of the above composition towards the space to be filled.

The lance 2 comprises a central duct 10 which is connected to a supply of mineral composition based on binder, wet and kneaded.

On the centering flange 11 of the lance, fixed on the periphery of the body of said lance by means of three gussets 12 welded at 120 ° from one another, two insulating seals 13a and 13b are placed: these seals are made of flame-retardant material and annular in shape. As can be seen in FIG. 2, the insulating seals which come to bear on the new refractory elements 15 reconstituting the tap hole 14, prevent the mineral composition from leaking through the tap hole 14. The seal 13b, which is placed on the seal 13a, essentially has the role of facilitating the withdrawal of the lance 2 from the metallurgical installation at the end of the operation, and this despite the layer of the hardened mineral composition which can cover these seals. To do this, the seal 13b is advantageously connected to the device 1, for example, by means of a steel cable. Therefore, the lance 2 can be easily extracted from the tap hole 14 and the seal 13b can also be driven out of the installation.

The operation of the injection lance 2 according to the invention appears clearly in the light of FIG. 2. According to the invention, it suffices to spray the mineral composition based on binder on the surroundings of the tap hole, this injection simply by the taphole itself. To do this, after elimination of the used refractory elements defining the taphole 14, a ferrule 15, here made up of several superimposed cylindrical refractory pieces, is put in place and held in position thanks to a closing cover 16 which is keyed to the metal enclosure of the installation. A sealed closure of the converter is obtained by bonding the cover 16 to the metallurgical installation and the shell 15 to the cover 16 by means of a refractory grout. Through the central orifice of the ferrule 15, the lance is introduced with the device 1 suspended at a good distance by chains 17, for example at the handles of the cover 16, after identification of the best position of the lance inside the converter . The mineral composition is then injected under pressure and deflected using the device 1 to fill the space 18 located between the outer wall of the shell 15 and the refractory lining 19 of the converter.

Once these operations have been completed, the system (lance 2 equipped with device 1) is removed. Only the insulation means (13a and 13b), which provided the seal to avoid the fallout of the mineral composition, can remain partly in place, without being recovered, thanks to the aforementioned system.

Thanks to the invention, the restoration of the taphole is carried out under much more advantageous conditions, although there is a high temperature in the metallurgical installation. In addition, the restoration is much more precise and allows the use of a mineral composition based on hydraulic binder formulated to achieve high levels of resistance when hot.

The present invention is of course not limited to the embodiment presented in the figures and also relates to the various alternative embodiments.

• le mode de fixation du dispositif de répartition à la lance : ce dispositif peut être rendu amovible et remplacé par un autre quand il est fixé à la lance par un moyen de fixation permettant son démontage. Pour ce faire, un moyen de fixation peut être constitué, par exemple, d'un pas de vis ménagé sur la lance et d'un raccord droit adapté à ce pas, les tiges 3 reliant le dispositif de répartition à la lance étant dans ce cas soudées sur le raccord.
• la nature des éléments neufs délimitant le trou de coulée : ces éléments sont généralement choisis en matériau réfractaire. Cependant ils peuvent aussi être constitués par un tube métallique, virole ou manchon, que l'on peut introduire soit à l'intérieur des éléments usés formant l'ancien trou de coulée ou à l'intérieur du trou résultant de l'élimination du pourtour usé du trou de coulée. Dans ce cas, le tube métallique, virole ou manchon, fait office de moule perdu dès lors qu'il est exposé à des températures supérieures à la température de fusion du métal.

As an example of a variant, there may be mentioned:

• the method of fixing the distribution device to the lance: this device can be made removable and replaced by another when it is fixed to the lance by a fixing means allowing its disassembly. To do this, a fixing means may consist, for example, of a screw thread formed on the lance and of a straight connector adapted to this pitch, the rods 3 connecting the distribution device to the lance being in this cases welded on the fitting.
• the nature of the new elements delimiting the taphole: these elements are generally chosen from refractory material. However they can also be constituted by a metal tube, ferrule or sleeve, which can be introduced either inside the worn elements forming the old tap hole or inside the hole resulting from the elimination of the periphery worn out of the tap hole. In this case, the metal tube, ferrule or sleeve, acts as a lost mold as soon as it is exposed to temperatures above the melting temperature of the metal.

Also, the application of the lance and of the process according to the invention is not limited to the sealing of the refractory elements acting as a tap hole but also extends to the repair of the refractory lining located in the vicinity of the hole. of casting. Likewise, the application of the invention is not limited to the metallurgical field but also extends to civil engineering and to any other field where it will be necessary to deviate a mineral composition.

Claims (6)

Injection lance provided at its outlet with a device for distributing a mineral composition based on a binder, the device being characterized by the fact: - It comprises, opposite the outlet of the lance, a concave recess in the form of a crown, the axis of which is coaxial with that of said lance; - That said crown has a section along the axis of the lance, substantially in the shape of an "M", said section in "M" being formed of four legs which work in pairs at one point or are connected to each other through a curved line. Lance according to claim 1, characterized in that the external legs (7) of the substantially "M" section of the concave recess (6) in the shape of a crown define a frustoconical volume. Lance according to claim 2, characterized in that the angle a made by the external leg (7) with the axis (8) of the lance (2) is chosen to be of the order of 15 ° or greater. Lance according to one of claims 1 to 3, characterized in that the internal legs (9) of the substantially "M" section of the concave recess (6) in the form of a crown define a cone of revolution. Lance according to claim 4, characterized in that the angle b formed by the internal leg (9) with the axis (8) of the lance (2) is between 30 ° and 60 °, and preferably still between 40 ° and 50 °. Method using the injection lance equipped with the distribution device according to one of claims 1 to 5, allowing the filling of the empty space existing on the refractory lining of metallurgical installations, in the vicinity of a tap hole, by means of said lance supplied with a mineral composition based on a binder, hydraulic or not, previously wetted and kneaded, this process being characterized in that: a) if necessary, eliminate the worn elements forming the taphole and replace them with new elements; b) the end of the lance fitted with the device for distributing the mineral composition based on binder is introduced into the metallurgical installation by passing it through the tap hole; c) the position of the end of the lance is adjusted inside the metallurgical installation, to allow said distribution device placed at its end to fill said empty space; d) the mineral composition based on binder is injected under pressure, using the lance, this composition, at the outlet of the lance, being deflected using said distribution device in the direction of the empty space which 'it completely fills.

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