WO1992004473A1 - Scavenging port for passing gases and/or solids into a metallurgical melt, and a process for manufacturing the port - Google Patents

Abstract

The invention concerns a scavenging port for passing gases and/or solids into a metallurgical melt, as well as a process for manufacturing the port.

Description

 Flush for the passage of gases and / or

Solids in the melt of a metallurgical

Vessel and process for its manufacture

Description

The invention relates to a sink for passing gases and / or solids into the melt of a metallurgical vessel and a method for its production.

Sink blocks of the generic type have long been known. For example "Radex-Rundschau, 1986, 203" there

an overview of different types of sink and their application. A distinction is made between the following types of rinsers

- Floor washer

- Dishwasher with undirected porosity

- Dishwasher with directed porosity.

The purging stones are coated on the bottom side (around the gas supply pipe) as well as on the circumference side. A gas distribution chamber is generally formed between the bottom sheet metal section and the bottom of the sink in order to enable a gas supply that is uniform over the cross section.

For the rest, the sheet metal jacket serves primarily to prevent uncontrolled lateral gas diffusion. The gas should rather be injected completely and specifically into the molten metal.

The application of the sheet metal jacket presents considerable difficulties, in particular in the case of gas purging stones which have the shape of a truncated cone. It would be best to design the sheet metal jacket in one piece. However, this is usually only possible with difficulty, especially if the sheet metal jacket extends over the entire height of the peripheral surface and the sink itself has a truncated cone shape. Difficulties with sealing occur, in particular, in the connection area between the circumferential and bottom sheet metal jacket. As a rule, the corresponding sheet metal sections are welded together. A simple weld seam often fulfills the safety requirements Not. At higher temperatures, such as occur when the flushing stones are used in the bottom or the wall of a metallurgical vessel, the weld seams often burst and the gas supplied can escape in an uncontrolled manner. There is then a risk of the sink block breaking out overall and thus of a molten metal breakthrough.

DE-PS 25 52 474 specifies a certain type of welded connection between ¹ : hen the circumferential and bottom-side section of the -echmaπtels.

Apart from the relatively complicated assembly, the further problem remains unchanged, namely to apply a sheet metal jacket that is as seamless as possible to a frusto-conical ceramic body.

In this respect, the invention is based on the object of specifying the simplest possible measure of how sink blocks of the generic type can be securely sealed on the circumference and / or bottom side.

The invention proceeds from the consideration of replacing the reared from corresponding blanks or listed va ^"th sheet metal casing by a coating d-.ae in-situ formed on the corresponding surface portion of the plug. Thus, the coating is only on the Surface itself are formed, which has the advantage over a sheet metal jacket that no gluing or mortar between sheet metal jacket and ceramic is necessary.

In its most general embodiment, the Invention according to a flushing stone of the generic type, in which the cover consists of a non-metallic inorganic and / or of a metallic coating applied using a thermal spraying process.

The metallic coating can be applied by flame spraying or plasma spraying. The metallic coating is carried out either directly on the corresponding surface sections of the sink, optionally with the interposition of an adhesion promoter, or on a previously applied coating made of an inorganic, non-metallic material. This is preferably chemical, preferably phosphate-bound, and is processed as a viscous or liquid mass. The coating composition is, for example, brushed on or sprayed on and then dried and optionally tempered. The ceramic solid component should be as fine as possible (<500 μm, preferably <100 μm) in order to achieve the greatest possible gas tightness after drying / tempering. A phosphate-bonded mass, such as is offered under the name K 709 Cr F by Radex Deutschland AG, Urmitz (Germany), has a high gas tightness, high fire resistance (approx. 1,900 ° C.) and a good one Adhesion to the ceramic sink as well as to a possibly subsequently applied metallic coating, the latter then primarily having the task of forming a separable separating layer from adjacent refractory components, such as a perforated brick. With a flame spray or plasma spray process, a continuous metallic coating can also be applied directly to the ceramic surface of the sink.

Special measures must be taken in the area of the gas supply pipe at the bottom. If the gas feed pipe lies directly against the bottom of the purge - as shown for example in FIG. 2 of DE-PS 25 52 474 - the bottom surface running around the gas feed pipe can in the simplest case be coated using one of the methods described above. A spraying method with a metallic material is preferred, the metal preferably being the same metal from which the gas supply pipe is made, in order to achieve an in-situ connection between the gas supply pipe and the coating.

Usually there is an intermediate space between the bottom of the sheet metal jacket and the bottom of the ceramic part of the sink, which forms a so-called gas distribution chamber.

In this case, it makes sense to design the base section in a conventional manner from a sheet metal with a connected gas supply pipe, but to extend the peripheral edge only over a relatively small section of the peripheral surface of the ceramic part of the gas purging plug

In order to allow the sink to be held securely in this pot-shaped holder, the corresponding section of the ceramic part of the sink can also be cylindrical. Are then still inside on the upstanding edge of the sheet metal base cracks arranged, the ceramic part of the sink can simply be inserted into the corresponding receptacle and, for example, be mortared there. The further outer coating (in the area of the peripheral surface) is then carried out in the manner described above, with a metallic coating preferably again here, optionally on an inorganic non-metallic coating. is provided in order to achieve a secure, gas-tight connection in the connection area to the edge of the pot-shaped base plate. This can be favored by the fact that the edge of the floor plate is guided somewhat higher than the corresponding ceramic section of the sink block, which runs from there in a conical shape, so that a kind of triangular joint is formed between the sink block and the sheet metal jacket, which, for example, when the flame is sprayed around the is filled with the metallic material, whereby a particularly secure connection between the sheet metal jacket and flame-sprayed coating is achieved. This area can also be sealed with the inorganic non-metallic mass.

This goal can alternatively also be achieved in that the rising edge of the "cup-shaped receptacle" is made higher, possibly up to shortly before or up to the end face of the sink, and is formed with vertical longitudinal slots, only the part immediately adjacent to the floor remaining unslit . The slotted part is then pressed onto the sink surface, possibly after the “slats” have been heated beforehand, and the sink is then — as described above — further coated with a metallic coating compound, ie directly over the slats and between the slats on the ceramic surface of the sink or the inorganic, non- metallic base coating. Further embodiments of the coating (cover) will be described later using the method according to the invention.

The sheet metal used in the prior art has - as stated - in particular the task of sealing the ceramic material of the sink against the outside in a gas-tight manner. The sheet metal jacket also fulfills a second function at the same time.

The flushing stone, which is usually inserted (mortared) in a perforated brick and worn out after a certain time, must then be replaced. This is done, for example, with the aid of a pull-out device, as is known from European Patent 137,961. When the flushing stone is pulled out of the perforated stone or the bottom of the metallurgical vessel, mechanical stresses on the flushing stone inevitably arise because the mortar joint located between the metal casing and the perforated stone has to be broken out.

Here, the well-known sheet metal jacket creates a mechanical lock for the ceramic part of the sink, so that the sink can be pulled out as a whole. This function of the sheet metal jacket takes over the metallic coating in a sink according to the invention, which, owing to the connection areas described above, for example to form a connected, bottom-side, pot-shaped sheet metal element, is quasi integrally formed therewith, in particular if the coating is made of the same Material like the sheet / metal section is made of. However, if a different material is used for the coating, it may be that the transition area between the cup-shaped metallic section in the area of the gas distribution chamber does not provide a sufficient mechanical connection which ensures that when the flushing stone is pulled out, it does not tear off somewhere along its height.

In this respect, the invention proposes in an advantageous embodiment to design the ceramic part of the sink with reinforcement elements. This can be done, for example, by running metallic anchors perpendicular to the direction of flow of the gas through the purging plug, which project slightly beyond the purging plug on the circumference and are connected to the corresponding sections of the metal casing in the area of the gas distribution chamber, for example by a welded seam or by mechanical means Ways. These anchors can be integrated in the manufacture of the sink. If the sink is poured, this can be achieved in a particularly simple manner by also pouring in the anchors.

Likewise, however, reinforcement elements running vertically (in the direction of the gas flow) can also be integrated in the ceramic body in an analogous manner. It is also possible to run perpendicular and parallel to the gas flow

to connect the arranged anchors to one another, for example, by arranging a corresponding metal frame in the ceramic section.

The reinforcing elements running in the direction of the gas flow can protrude upwards at the free end of the flushing stone, that is, where the gas exits into the molten metal, and can be connected to one another, for example in the form of a bracket, so that at the same time one that projects above the flushing stone Element is formed with which the scavenging stone can be gripped particularly favorably, for example when inserted into a perforated stone or vessel bottom.

Such mounting brackets are known from the prior art (for example DE-PS 35 20 783), but they are formed there in an extension of the circumferential sheet metal jacket.

The rinsing stone according to the invention thus has all the advantages of sheet metal-coated rinsing stones, but is much easier to manufacture, as will be described below. In particular, there is no complicated deformation of a metal sheet to cover the mostly frustoconical circumferential surface of the sink.

The method for applying a dense protective layer to predetermined surface sections of a sink for introducing gases and / or solids into a metallurgical melting vessel can be different realize alternative embodiments:

- In the first case, only an inorganic, non-metallic (ceramic) coating composition is applied, for example brushed on or sprayed on, and then dried or tempered. Alternatively or cumulatively, too

- A metallic coating material is applied in a viscous form to the corresponding surface sections, which is subsequently converted to a molten or at least partially molten state under the influence of temperature and then cooled to form a gas-tight protective layer.

In a further embodiment, the coating material is first transferred to a molten or at least partially molten state, then sprayed onto the surface sections by means of a carrier gas and then cooled to form a gas-tight protective layer.

The coating (s) can be applied to both an unfired and a fired ceramic body. The coefficient of thermal expansion of the coatings should be less than the coefficient of thermal expansion of the ceramic material of the sink in order to avoid tensile stresses in the coating. According to the alternative method mentioned, the coating material is sprayed onto the surface in the molten or at least partially molten state. The coating material can be introduced as a fine powder, which should preferably have a grain size of less than 100 μm. This can be melted particularly easily and intimately. The finer the material, the more homogeneous it can be subsequently distributed in the carrier gas.

For example, ethine, propane or hydrogen can be used as fuel gases. However, it is also possible to melt the coating material, for example in an acetylene flame, and then to use the resulting exhaust gases as carrier gas.

However, inert gases such as argon or the like can also be used as the carrier gas.

The coating materials used in this process are preferably metals or metal alloys, for example based on Al / Ni. A suitable metallic spray compound is available from Metco Vertrieb Ges.m.b.H. , A-Salzburg, offered under the Metco 405 NS label. Powders based on other nickel and aluminum alloys are also suitable.

The metallic coating material is preferably the same from which the above-mentioned, preformed metallic section for the gas distribution chamber is formed at the lower end of the gas purging plug. This leaves a homogeneous, material connection between the preformed metallic part and the outer coating is achieved when spraying. The invention also provides for the rinsing stone to first be coated on the circumferential side and / or the bottom side in accordance with one of the possibilities described and the preformed, metallic sections to be applied to the already coated rinsing stone. After assembly, it can be coated again completely or in sections.

The metallic coating material can be applied by flame spraying, but also by plasma spraying. The spraying process should be continued until a protective layer thickness is reached which ensures safe gas impermeability. As a rule, a thickness of 0.2 to 0.5 mm is sufficient for the protective layer, but the protective layer can also be thicker without further notice. The sink can also be assembled in several passes with correspondingly thinner coating layers.

It is not a problem if the temperature of the combustion flame or the carrier gas is higher than the sintering temperature of the ceramic base body, because it has been found that the ceramic body or the previously applied ceramic intermediate layer is exposed to a flame spray or plasma spray process heat the surface only to a relatively small extent (to approx. 300 to 600 degrees Celsius). Since the ceramic body has a certain surface roughness, the process measures mentioned lead to an intimate bond between the coating material and the ceramic base material. This is important with regard to mechanical stabilization of the sink.

It goes without saying that the further features according to the invention, for example arrangement of reinforcement in the sink, can also be realized in the same way in the flame or plasma spraying process.

The invention is illustrated below with reference to various

Execution examples explained in more detail, which are only examples and in no way limit the inventive concept.

Otherwise, further features of the invention result from the features of the subclaims and the others

Registration documents.

The drawing shows, each in a highly schematic

Presentation :

Figure 1: A section through a truncated cone-shaped gas purging plug according to the invention in a first embodiment with a ceramic and metallic coating. Figure 2: A section through a frustoconical gas purging plug according to the invention according to a second embodiment. FIG. 3: A section through a cylindrical gas purging plug according to the invention. Figure 4: A section through a further embodiment of a frustoconical gas purging plug.

In the figures, the same and equivalent components are shown with the same reference numerals. Figure 1 shows a gas purging plug 10, the frustoconical ceramic body 12 is formed with undirected porosity.

Thereafter, the ceramic body 12 has a flat bottom 14, a frustoconical peripheral surface 16 and an upper, flat end face 18 facing the molten metal.

The bottom 14 is covered by a steel sheet 20, into which a gas feed pipe 22 opens from below. At the upper end of the gas supply pipe 22 there is a pot-shaped recess 24 within the ceramic body 12, which serves to distribute the gas supplied via the gas supply pipe 22 evenly on all sides in the ceramic body 12 so that it passes through the pores in Direction towards the end face 18 and over the end face 18 into the molten metal.

The steel sheet 20 on the bottom is screwed to the bottom 14 of the ceramic body 12 and additionally connected to the ceramic body 12 via a plurality of screw connections 26. For this purpose, metal sleeves are mortared in the base 14 in the ceramic body 12, the sleeves 28 being open in the direction of the steel sheet 20 and otherwise having an internal thread. Screws 30, which are guided through corresponding openings 32 in the steel sheet 20, engage in the internal thread, the screw heads resting against the steel sheet 20 from below in the anchoring position. The screw connections 26 are only shown schematically and can of course extend into the ceramic body 12 over a greater height, so that at the same time they perform an arming function.

In addition, additional reinforcement anchors 25 are arranged in the ceramic body 12, which extend and extend vertically, that is to say in the direction of the gas flow. extend from the end face 18 through the ceramic body 12 and through corresponding openings in the steel sheet 20 and are firmly locked on the outside (ie below the steel sheet 20).

The peripheral surface 16 of the ceramic body 12 is coated with a phosphate-bonded ceramic mass 34 'and thereon with a metallic spray layer 34' '.

In this way, the ceramic body 12 is sealed gas-tight on the floor side by the steel sheet 20 and on the circumference by the coatings 34 ', 34' '. Only the end face 18 is free of any coating, so that the gas can flow freely into the molten metal.

The coatings 34 ', 34''were applied as described below: a ceramic slip with monoaluminum phosphate as a binder is sprayed onto the peripheral surface 16 using a spray gun. This process can be mechanized by placing the ceramic body 12 - previously assembled with the steel sheet 20 - on a turntable, and the spray gun, possibly with the aid of a robot, is moved up and down, so that a full surface coating is formed due to the rotating with the help of the rotary plate ceramic body. The layer thickness is approx. 3 mm at the end.

The gas purging plug 10 with the applied coating 34 'is then dried and tempered at about 220 ° C.

The metallic coating 34 ″ is then sprayed on. The spraying process is explained below using the further exemplary embodiments.

The gas purging plug 10 according to FIG. 2 has a somewhat modified geometric shape compared to the gas purging plug 10 according to FIG. 1. The difference is that the lower section 12a of the ceramic body 12 is not frustoconical, but cylindrical.

With this design, it is possible to provide a prefabricated, pot-shaped sheet metal jacket 36 on the bottom side. The sheet metal jacket 36 has a flat bottom 36a at a distance from the bottom 14 of the ceramic body 12, into which a gas supply pipe 22 opens.

The upstanding edge region 36b extends beyond the bottom 14 of the ceramic body 12 and surrounds the lower section 12a of the ceramic body 12 in a form-fitting manner. For a better connection, the edge area 36b and the lower section 12a are mortared together.

As can be seen from the figure, the edge region 36b protrudes a little further beyond the cylindrical section 12a of the ceramic body 12, so that a circumferential joint with an approximately triangular cross-section is in comparison with the adjoining, frustoconical section 12b of the ceramic body 12 13 is formed. The peripheral surface 16 of the ceramic body 12 is coated here with a metallic material which was applied by the flame spraying process.

The metallic material is the same material from which the sheet metal jacket 36 is made. The material is first melted in an acetylene flame and then sprayed onto the peripheral surface 16 via the resulting exhaust gas (carrier gas). By spraying the molten material onto the ceramic body 12 having the ambient temperature, the coating material hardens directly on the peripheral surface 16 and thus forms a closed metallic coating 34 between the end face 18 and the upper end portion of the edge region 36b. At the same time, the above-mentioned triangular joint is filled with the coating material, so that a homogeneous, material connection between sheet metal jacket 36 and coating 34 is formed.

Alternatively, it can also be done in such a way that the protruding part of the edge region 36b is pressed flat on the inside onto the peripheral surface of the ceramic body 12, so that the sprayed-on coating then immediately follows because a triangular joint is no longer formed. The sprayed-on coating can also be sprayed on easily beyond the connection area of the sheet metal jacket 36. This additionally seals the connection.

In order not to injure the ceramic body 12 when the protruding section of the sheet metal jacket 36 is pressed on, an elastic material, for example a fiber mat, can be inserted between the two parts. This can also be in the area between floor 36a and floor 14 are provided, the fiber mat then having corresponding recesses in order to achieve a continuous gas flow. The fiber mat also acts as a spacer here.

To the same extent as in the exemplary embodiment according to FIG. 1, the sink 10 is here also sealed gas-tight on all sides with the exception of the end face 18.

In contrast to the exemplary embodiment according to FIG. 1, the sink block shown in FIG. 2 is one with directed porosity, with a plurality of channels 38 running vertically between the bottom 14 and the end face 18.

The gas supplied via the gas feed pipe 22 first flows into the gas distribution chamber 40 formed between the bottom 36a of the sheet metal jacket 36 and the bottom 14 of the ceramic body 12 and from there through the channels 38 via the end face 18 into the metal melt (not shown).

The gas purging plug 10 shown in FIG. 2 differs from a metal-coated purging plug only in that the circumferential coating 34 is not formed by a sheet metal casing, but by a coating applied in situ using the flame spraying process. However, it has the same characteristics as a sheet-metal gas purging plug.

In this respect, there is also the possibility of pulling out and replacing the gas purging plug from an associated perforated brick using a known pull-out device if necessary. This also applies to the exemplary embodiment according to FIG. 1. As an additional security measure for the mechanical stabilization of the gas purging plug 10, additional reinforcement elements are arranged here - purely by way of example.

These consist of two intersecting metal strips 42, which run diagonally through the ceramic body 12 and are firmly connected to the corresponding sections of the edge region 36. This connection can be mechanical; However, it is also possible to weld the metal strips 42 to the edge region 36b. It is advantageous to design the edge region 36b with corresponding openings through which the metal strips 42 protrude and to attach the mechanical anchoring or welded connection on the outside. Two further metal strips 44 extend vertically upward from one of the metal strips 42 in the direction of the end face 18. The metal strips 44 are also connected to the metal strips 42 via weld seams and extend beyond the end face 18, where they are then angled at a distance from the end face 18 trained and connected. In this way, a mounting bracket 46 for inserting the gas purging plug 10 into a perforated brick (not shown) is formed.

The reinforcing elements 42, 44 have the further advantage that they mechanically stabilize the gas purging plug 10 overall, so that tearing off along the height of the gas purging plug is avoided when the purging plug 10 is pulled out by means of a pull-out device.

Finally, FIG. 3 shows a further embodiment of a gas purging plug 10 according to the invention, whose ceramic body 12 has a cylindrical shape.

Analogously to the exemplary embodiment according to FIG. 2, the lower section 12a of the ceramic body 12 is connected to a sheet metal jacket 36, the geometric shape of which essentially corresponds to that according to FIG. 2. A modification exists insofar as the upper end section of the rim region 36b is bent inwards, which enables the sheet metal jacket 36 to be directly anchored in the ceramic body 12. To put on the sheet metal jacket 36 and to insert the bent sections into a corresponding circumferential groove 12c, the sheet metal jacket 36 can be widened somewhat. This can be achieved particularly easily by inductively heating the sheet metal jacket 36 because it is then easier to deform. After cooling, the sheet metal jacket 36 lies absolutely firmly on the circumferential surface of the lower section 12a and, as shown, is securely fixed in the groove 12c over the upper cranked edge. Of course, a mortar can also be provided in this case between sheet metal jacket 36 and ceramic body 12.

The coating 34 was applied here by plasma spraying. This process is done in an electrical

Arc produces a partially ionized gas in which the metallic coating material is melted. The coating material is then again over a carrier gas, such as an inert gas

Argon can be sprayed onto the peripheral surface 16. The high temperatures in the plasma, which can be up to 40,000 degrees Celsius depending on the plasma gas and electrode arrangement, expand the possibilities, since practically all high-melting materials can be melted without ultimately leading to a significantly elevated temperature on the peripheral surface 16 , since the sprayed-on material cools down very quickly and hardens to form a closed coating. The properties of the thermally sprayed coating 34 depend on the flame or plasma temperature, the particle size, the spraying distance and the temperature of the workpiece surface.

In any case, a continuous metallic coating is achieved in the circumferential and bottom area of the gas purging plug 10, which is provided in the lower section by the sheet metal, jacket 36 and otherwise by the coating 34.

The above description of the invention with reference to the exemplary embodiments shown in the figures is not restricted to these exemplary embodiments. Rather, the individual features can be combined with one another as desired and can be combined with one another in relation to the sink block according to the invention and the method for its production.

For example, the reinforcement strips can be omitted in the exemplary embodiments according to FIGS. 1, 2; Likewise, in the exemplary embodiment according to FIG. 3, metal strips 42, 44, as shown in FIG ceramic body 12 are integrated. The metal strips (reinforcement elements) are preferably inserted directly into the ceramic body 12 during the manufacture thereof, that is to say the ceramic material is poured around the reinforcement elements or the metal strips are inserted into the ceramic matrix material and pressed together with it.

As shown above, the coating 34 can be applied in a fully automatic process, irrespective of whether the coating consists of a ceramic mass or a metallic material.

FIG. 4 shows a further embodiment of the sink block according to the invention, the method proposed for its production also being described in more detail below.

A first essential difference compared to the embodiments described above is that the peripheral surface 16 of the sink 10 was provided with a metallic coating 34 before the further assembly with the metallic components described below using the flame spraying method. The coating 34 covers the entire circumferential surface between the upper end face 18 and the lower bottom surface 14. The method for applying the coating has been described above.

The flushing plug according to FIG. 4, like the flushing plug according to FIG. 2, has a cylindrical shape in its lower section 12a, which is adjoined at the top by a conically tapering, frustoconical section A prefabricated metal sleeve 44, which is firmly connected to the coating 34 by means of a refractory putty 46, lies on the cylindrical section 12a and a partial region of the frustoconical section of the sink block and is flush with the bottom surface 14 at the bottom. The sleeve 44 was previously placed on the corresponding surface sections from above via the end face 18. The putty 46 ensures that the sleeve 44 is fixed absolutely securely on the sink or its coating 34.

A sheet metal jacket 36 similar to that according to FIG. 2 was then pushed on from below over the lower sink end 12a. The sheet metal jacket 36 differs from that according to FIG. 2 in that the edge region 36b has a lower height and in its free edge region is welded at 45 on the circumferential side to the cylindrical portion of the sleeve 44.

However, the height of the edge region 36 ^' .st is dimensioned such that a gas distribution chamber 40 is in turn formed between the bottom surface 1- + of the sink 10 and the bottom 36a of the sheet metal jacket 36. The distance between the floor 36a and the floor surface 14 can be adjusted using known spacers (not shown). Such spacers can, for example, be fastened to the bottom 36a as metal parts or can be designed in the form of fiber strips or a fiber mat with corresponding openings for the passage of the treatment gas.

The sink in Figure 4 is circumferentially through the coating 34 or the sleeve 44 gas-tight. The bottom area is completely sealed by the sheet metal 36. At the same time, a high mechanical stability of the device as a whole is achieved via the conical section of the sleeve 44 and the sheet metal jacket 36 welded to it, which is particularly important for the removal of the flushing device - after wear - from the bottom of a metallurgical melting vessel, as in the introduction to the description shown.

If desired, the sink according to FIG. 4 can also subsequently be provided with a (further) metallic coating, which is then preferably formed in the connection area of the sleeve 44 and the coating 34 in order to additionally seal this area.

Of course, also in the embodiments, for example according to FIGS. 2 and 3, it is possible to coat the peripheral surface 16 of the ceramic body 12 one or more times before further assembly in order to achieve absolute gas impermeability in this area.

All embodiments have the advantage that the predominant and in particular the molten metal facing the upper peripheral portion of the ceramic body 12 is provided with a coating that can be formed from heat and scaling resistant metallic qualities, so that the scaling effects observed in known sheet metal jackets and burn-off losses can be safely avoided here. Since only the upper section of the sink facing the molten metal is thermally and metallurgically loaded during use, inferior metal qualities are simultaneously used for the metal parts connected to the bottom. However, in order to achieve a material connection as far as possible, according to an advantageous embodiment of the invention, the coating material should be the same as that of the connected metal parts, or at least both should come from the same group of materials.

In the embodiment according to FIG. 1, it is sufficient to make the metallic coating 34 ″ relatively thin because the gas diffusion barrier is already formed by the ceramic intermediate layer 34 ′. The main purpose of the metal coating here is to connect an intimate connection to neighboring components, such as a perforated brick, or the mortar inserted between the gas flushing brick and the perforated brick, in order to make it easier to remove the flushing plug when changing. The ceramic coating composition preferably consists of a high-alumina material, the solid particles of which are as fine as possible. But it can also be used in gel form.

Claims

P a t e n t a n s r u c h e Flushing stone for passing gases and / or solids into the melt of a metallurgical vessel, with a device (22) arranged on the bottom for supplying the gas and / or solids into the flushing stone (10) and one, the peripheral surface (16 ) at least partially gas-tight cover (34), characterized in that the cover (34) consists of a non-metallic inorganic and / or of a metallic coating applied by means of a thermal spraying process. Flushing stone according to claim 1, wherein the coating consists of a chemically / ceramically bonded mass. Flushing stone according to claim 2, wherein the coating consists of a phosphate-bonded ceramic mass. Flushing stone according to one of claims 1 to 3, in which the metallic coating applied directly to the peripheral surface (16) or to the non-metallic inorganic coating is applied by means of flame or plasma spraying. Rinsing stone according to one of claims 1 to 4, in which the metallic coating is one based on NiAl or AlTi. Flushing stone according to one of claims 1 to 5, in which the circumferential coating (34) adjoins the bottom-side device (20, 22, 36). Flushing stone according to one of claims 1 to 6, with a cylindrical portion (12a) adjacent to the device (20, 22, 36). Flushing stone according to one of claims 1 to 7, in which the device consists of a prefabricated, pot-shaped sheet metal jacket (3), the Edge (36b) the lower portion (12a) of the ceramic Grips body (12) of the gas purging plug (10) and is fixed relative to this. Gas purging plug according to Claim 8, in which the free end region of the edge (36b) of the sheet metal jacket (36) is sealed off from the coating (34). 10. Flushing stone according to claim 8 or 9, wherein the bottom (36a) of the sheet metal jacket (36) at a distance from the bottom (14) of the ceramic body (12) of the gas flushing stone (10). 11. Flushing stone according to one of claims 1 to 10, in which metallic reinforcing elements (42, 44) are arranged within the ceramic body (12). 12. Flushing stone according to claim 11, in which the reinforcement elements (42, 44) are firmly connected on the circumferential side to the edge region (36b) of the sheet metal jacket (36). 13. Flushing stone according to claim 11, in which the metallic reinforcing elements consist of a hollow body which is connected on one side to a gas connection pipe which extends through this in the direction of the bottom of the gas flushing plug and projects above the bottom and at least on the opposite side Side (directed towards the face of the sink) has cutouts. 14. Method for applying a dense protective layer to predetermined surface sections of a sink for introducing gases and / or solids into a metallurgical melting vessel, in which a non-metallic, inorganic coating material is applied to the corresponding surface sections by smearing, brushing, spraying or dipping and then dried and optionally tempered. 15. The method according to claim 14, using a chemically bound, ceramic fine-grained coating composition. 16. A method for applying a dense protective layer to predetermined surface sections of a sink for introducing gases and / or solids into a metallurgical melting vessel, in which the metallic coating material is applied in a viscous form to the corresponding surface sections, then under the influence of temperature into a molten or at least partially melted one Physical state is transferred and then cooled to form a gas-tight protective layer. 17. A method for applying a dense protective layer to predetermined surface sections of a sink for introducing gases and / or solids into a metallurgical melting vessel, in which the metallic coating material first converts to a molten or at least partially molten state, then by means of a carrier gas is sprayed onto the surface sections and then cooled to form a gas-tight protective layer. 18. The method according to claim 17 with the proviso that the coating material is introduced and melted as a fine powder. 19. The method according to claim 17 or 18 with the proviso that the powdered Beschicht.ungswerkstoff is used in a Korπfraktion smaller than 100 microns. 20. The method according to any one of claims 14 to 19 with the proviso that a coating material is used whose coefficient of thermal expansion is less than the coefficient of thermal expansion of the ceramic matrix material of the sink. 21. The method according to any one of claims 16 to 20 with the proviso that the metallic coating material is applied to a previously applied coating made of an inorganic non-metallic material. 22. The method according to any one of claims 16 to 21 with the proviso that the metallic coating material is applied to a fired sink. 23. The method according to any one of claims 14 to 22 for producing a truncated cone-shaped sink with a device arranged at the bottom for supplying the gas and / or the solids into the sink, with the following steps: a) a prefabricated, pot-shaped metal jacket with a gas connection part in the bottom is placed on the bottom section of the sink so that the free edge area of the metal jacket is at a distance from the peripheral surface of the sink, b) the free edge area of the metal jacket is then on the peripheral surface of the sink pressed on before c) at least the peripheral surface of the sink which is coated by the metal jacket is coated with the inorganic non-metallic and / or metallic coating material. 24. The method according to any one of claims 14 to 22 for producing a truncated cone-shaped sink with a device arranged on the bottom for supplying the gas and / or the solids into the sink, with the following steps: a) a prefabricated, pot-shaped metal jacket with a gas connection part in the bottom and vertical longitudinal slots π in the metal jacket, which run from the upper free edge to the bottom, is placed largely without play on the bottom portion of the sink so that the slotted edge area of the metal jacket at a distance from The surface of the sink is standing, b) the slotted edge area of the metal jacket is then pressed onto the corresponding peripheral surface of the sink, c) the peripheral surface of the sink thus covered with metal strips is then covered using a metallic coating material by means of flame spraying or plasma spraying ¬ stratified. 25. The method according to any one of claims 14 to 22 for producing a truncated cone-shaped sink block with a cylindrical section in the region of a device arranged on the bottom for supplying the gas and / or the solids to the sink block, with the following steps: a) a prefabricated metallic sleeve is placed flat on the cylindrical section and a portion of the conical section of the sink which adjoins it at the top, b) a prefabricated, pot-shaped metal jacket with a cylindrical rim is placed on the bottom section provided with the sleeve of the sink, c) the free edge area of the metal casing and the sleeve are welded together in the area of the cylindrical section of the sink, before d) at least the peripheral surface of the sink uncoated by the metal casing and / or the sleeve using an inorganic, non-metallic or a metallic coating material is coated by means of flame spraying or plasma spraying. 26. The method according to any one of claims 23 to 25, in which the free edge region of the metal jacket is heated before being placed on the sink or before being pressed onto the peripheral surface of the sink. 27. The method according to any one of claims 23 to 26, wherein the cup-shaped metal jacket is positioned relative to the sink so that a cavity remains between the bottom of the metal jacket and the bottom of the sink. 28. The method according to any one of claims 23 to 27, in which one or more spacers are arranged between the bottom of the metal jacket and the bottom of the sink. 29. The method according to claim 28, in which the spacer or spacers consist of an elastic fiber mat which has a recess in the area of the gas supply, from which a plurality of recesses extend to just before the edge of the fiber mat. 30. The method according to any one of claims 23 to 29, wherein the inner surface of the cylindrical portion of the metal shell and / or the corresponding outer surface of the sink are formed with an elastic coating. 31. The method according to any one of claims 23 to 30, wherein the outer surface of the sink and / or the corresponding inner surfaces of the sleeve or the metal jacket are coated with a heat-resistant mortar or putty prior to confectioning.