JPS58110624A - Permeable refractory element for introducing agitating fluid into molten metal bath - Google Patents

Abstract

1. A permeable refractory element for introducing a stirring fluid into a molten liquid metal bath held in a metallurgical vessel, such as an oxygen-blown (through the top) steelworks converter, element to be inserted for walling and, usually, for lining at the bottom of said vessel and comprising an unobstructed face for the stirring-fluid outlet, and characterized in that it comprises at least two electroconductive bodies (16, 6), arranged according to the thickness of the element and insulated from one another, one of their ends being flush with the outlet face (8) for the stirring fluid, the other end being connected to electric-supply source (17) so as to make up two live terminals, of opposite polarities, of an open electric circuit, said circuit including at least one audible-indicating means (18), showing whether the circuit is "open or closed".

Description

DETAILED DESCRIPTION OF THE INVENTION The present invention relates to the refining of metals, particularly steel. More specifically,
The present invention relates to a permeable refractory element embedded in the furnace wall or bottom of a metallurgical vessel for introducing a stirring fluid, usually an inert gas, into a bath of molten metal within the vessel.

Fluid agitation in metal refining is particularly applied in oxygen top-blown steel converters, and this technology is being deployed worldwide under the name of the “LBH” (Lanceu Stirring-Equilibrium) process. As the name suggests, this method aims to balance the metal and slag, and has the advantages of both the conventional top-blowing refining method and the bottom-blowing refining method.

As a rule, the permeable refractory elements used consist of a permeable body of refractory material (magnesia, dolomite, etc.) placed within a thin-walled metal enclosure, with dimensions similar to the conventional refractory bricks replaced by the element as a whole. , is the shape. The enclosure leaves the blowing surface free within the plane formed by the surface of the refractory lining material covering the inside of the refining vessel, and the bottom of the enclosure covering the opposite surface is equipped with an inlet pipe for stirring fluid. .

A number of proposals have been made to provide refractory sections with sufficient selective permeability to ensure a flow rate of stirring fluid while sufficiently preventing molten metal from entering in the opposite direction.

Furthermore, permeable elements, like all refractories, are subject to wear due to contact with molten metal;11 conventional refractory linings have been largely successful in controlling the rate of wear. Additionally, it is useful to know when and for how long the molten metal contacts the refractory material.

The present invention aims to provide an indication of the presence of molten metal at the blowing surface of a permeable refractory element.

Another object of the invention is to measure the degree of wear of the elements (thus knowing the wear of the entire refractory lining), so that when the residual thickness reaches the minimum thickness within the permissible range, It is possible to make arrangements for repairing the bottom of the hearth.

The present invention aims to provide a permeable refractory element for introducing a stirring fluid into a molten metal bath.

The element of the present invention has a free exit surface for the agitated fluid and further includes at least two electrical conductors arranged according to the thickness of the element and electrically insulated from each other, one of the electrical conductors One end is adjoinable to the outlet surface of the agitated fluid and the other end is connected to a power source to constitute the terminals of the opposing electrodes of the open electrical circuit, which circuit is connected to the "open" or "close" state of the circuit. It is equipped with a means of correspondence to indicate the status.

That is, the present invention provides a permeable refractory element with a system for detecting the presence of molten metal by utilizing the conductive properties of the molten metal.

When the molten metal contacts the blowing surfaces, the electrical terminals located on the same three sides are connected, closing an electrical circuit and allowing current to be detected.

In one aspect of the invention, the terminal is a metallic rod-shaped body that longitudinally traverses the refractory material portion of the element.

According to another aspect of the invention, the refractory element is left in a metal enclosure leaving the blown surface free, the enclosure forming one of the electrical terminals.

According to yet another aspect of the invention, at least one of the electrical terminals comprises a plurality of metal bodies, such as rods, disposed longitudinally within the refractory portion of the element, the ends of which are blown during initial use. Starting from the grooved surface, they are located at different levels depending on the thickness of the element.

Therefore, as the refractory material wears down, each end of the metal body becomes exposed, and the progress of the wear can thus be detected.

Other features and advantages of the invention will become apparent from the following description of the exemplary embodiments, which refers to the accompanying drawings.

The transparent refractory element 1 shown in FIG. 1 is in a state before use,
It is approximately in the shape of a truncated pyramid with a rectangular base to replace the conventional bottom brick of a converter. Figures 1a, 2 and 3 respectively show the elements buried in the hearth bottom, where 2 is the outer metal shell, 3 is the so-called "reinforcement" refractory layer, and 4 is the "refractory" material (brick). shows a wear layer.

As shown in FIG. 1, the element 1 is essentially formed from a permeable body 5 of refractory material provided within a metal enclosure 6 by joint material 7 forming a lateral gas-tight layer.

This metal enclosure 6 has a small open bottom (upper edge in the figure) so as to leave the blowing surface 8 of the refractory part free;
Furthermore, its large bottom part 9 is provided with a tube section 10 that connects to an inlet tube 11 for stirring fluid from a fluid source (not shown).

Possible stirring fluids include inert gases such as nitrogen and argon.

The large bottom part 9 of the enclosure is located at some distance from the refractory part 5, between which a gas distribution chamber 12 is formed.

In this embodiment, the permeability of the refractory part 5 is achieved by combining plates 13 of conventional compact refractory material (for example magnesium cement). These plates 13 are stacked with longitudinal spacers 14 interposed between them. The spacer 14 has an extremely small size (metal wire) and forms a blowing gap 15 with a width of more than ten times between the plates 13. For clarity of illustration, this width is exaggerated in the figures. Gap 15
connects the distribution chamber 12 and the blowing surface 8, and its narrow width prevents the intrusion of molten metal.

The structure of the permeable refractory part 5 is not a subject of the invention, and the above description is merely to facilitate understanding of the invention. For a more detailed understanding of this part, reference is made to French Patent Publication No. 2,475.529.

According to the invention, the refractory part 1 is penetrated by a metal rod 16 whose end lies in the same plane as the blowing surface 8 .

Enveloping body 6 and rod-shaped body 16 whose edges are located in the same plane as surface 8
are preferably made of steel and constitute opposite polarity terminals of the open electrical circuit. This circuit consists of a power supply means 17 (for example a battery), an audio signal device 18, a flexible tube 11 provided in a tube 11 whose ends are respectively welded to the lower end of the rod 10 and to the tube 10 of the enclosure 6. The two lines 19.19'
It consists of

With such an arrangement, the molten metal contacts the surface 8 and at the same time makes an electrical connection between the bar 16 and the enclosure 6, thus closing the circuit and energizing the signal device 18.

Noise current that interferes with detection can be solved by electrically insulating the enclosure 6 from the bar 16. This insulation is naturally achieved by the refractory part itself. However, better insulation can be obtained by choosing a plate 13 of non-carbon-based refractory material. At the same time, the joint material 7 is also preferably insulating.

As shown in the figure, it is also possible to arrange the rod-shaped body 16 in a housing portion having slightly larger dimensions. This receptacle can be realized by creating opposing slots in two adjacent plates 13.Then, filling the gap with a non-conductive, joint material provides electrical insulation and at the same time a rod-like structure within the transparent element. Fixation of j6 can be achieved.

As a means of further ensuring insulation, an insulating joint 20 is arranged between the enclosure 6 and the metal shell 2 of the converter.

The embodiment shown in FIG. 2 differs from the above-described embodiment in that a second metal bar 21 within the refractory section 5 is used instead of the enclosure 6 as the electrical terminal.

This embodiment is the case when the blowing element 1 is formed without a metal enclosure.

Similarly, this embodiment is such that the enclosure 6 only partially surrounds the sides of the refractory part 5, i.e. the upper edge of the enclosure covers the blowing surface 8.
It is also effective when the design is set back from the position of

The embodiment shown in FIG. 3 detects the presence of molten metal on the blowing surface 8 while tracking the progress of wear of the element 1 and the surrounding refractory material 4 due to the action of the molten metal.

As shown, this embodiment is characterized in that the terminals for the detection current are constituted by a plurality of metal rods 22, 23, 24, 25 arranged within the refractory part 5. The other terminals are constituted by a metal enclosure 6 as shown. The rods 22, 23, 24, 25 have different lengths and their upper ends are in different positions depending on the thickness of the refractory part 5.

One of the rods, e.g. 22, is in the same plane as the blowing surface 8 during fabrication and is therefore similar to the embodiment described above, in the blowing gap 15.
can be placed in

The other rod-shaped body is buried in a blind hole formed in the fireproof part 5, and its lower end protrudes slightly to enable electrical connection to the power supply 17. These connections are made in parallel between the rods, and indicators 26, 26', 26", 26"' (eg lamps) indicate the presence of current on the basic circuit of each rod.

With the arrangement as described above, the presence of molten metal on the blowing surface 8 can be detected, and the wear stage of the element during use can be known by the exposure of the rod.

The present invention is extremely easy to implement and there are no particular problems in its implementation. The required power supply voltage is extremely low.
It may be on the order of several volts, and may be an alternating current voltage or a direct current voltage. The flexible wire for electrical connection between the terminal and the power source 17 is preferably placed within the gas introduction tube 11, since it is maintained at a constant temperature by the gas flow.

The present invention is not limited to the above-described embodiments (
, various embodiments are possible within the scope of the claims.

Further, the metal rods 16, 21, 22, etc. can be replaced with other materials as long as they have conductivity. For example, graphite may be used, and the shape may be rod-like, linear, plate-like, tubular, or other.

Furthermore, the permeable blowing element is not limited to airtightly stacked fireproof plates, but may also be a small tube embedded in a refractory.
The invention is carried out by selecting one or twenty-six tubules as electrical terminals, depending on whether a conductive enclosure is used (FIG. 1) or not (FIG. 2).

Similarly, the bar or its conductive substitute does not have to be in the same plane as the element surface before use! In this case, the wear of the refractory progresses to the depth of the initial position of the end of the conductor, and the end of the conductor comes to be in the same plane as the element surface.

Furthermore, tracking of the wear of the blowing element can be achieved by means of a plurality of rods embedded at different end positions.

Furthermore, for example, by using only one rod-shaped body 16, it is possible not only to detect the position of molten metal but also to function as a consumable electrical resistor.

In this case, the decrease in the length of the rod can be tracked by continuously monitoring changes in the electrical circuit characteristics associated with changes in the length of the rod. For example, changes in the resistance of the rod-shaped body may be continuously measured by measuring the current of the detection circuit.

A rod of this type can be constructed, for example, by a large length of calibrated metal wire of precisely measured resistance, wound around a continuous spiral solenoid around a refractory core. Of course, the metal wire in this case is insulated with enamel in advance.

Furthermore, in order to detect the current of each rod-shaped body, each Φ display part 26.26°26" was provided in each branch connected in parallel.
24 may be a single device that senses the total current strength of the circuit, such as a device that converts the total current strength into an A/D converter to determine the number or rank of exposed rods. good.

Many aspects of the signal means used in the present invention are possible, and can be selected depending on the needs, simplicity, or preference of the user.

[Brief explanation of the drawing]

Figure 1a shows 1! of the present invention! ! 1b is a longitudinal section of a transparent element according to the invention, ie a cross-sectional view of the surface of FIG. 1b; FIG. Figure 1b is Figure 1aB! FIG. 3 is a plan view of the element shown in FIG. Figures 2a, 3a and 2b, 2c are cross-sectional and plan views, respectively, of two other embodiments of the invention. (Main reference numbers) 1: Permeable refractory element, 2: Hearth bottom shell, 5: Permeable refractory body, 6: Metal enclosure, 7: Joint material,
8: Blowing surface, 11: Stirring fluid introduction pipe, 12:
Distribution room, 13: Fireproof board, 16.22.23.24.
25: Conductive rod-shaped body, 17: Power supply, 18.26.26
', 26'', 26''゛: Signal device. Applicant Institut de Recherche de la Siderrouzy Française agent Patent attorney Masahiko Arai

Claims (1)

[Scope of Claims] (1) A permeable refractory element for introducing an agitated fluid into a molten metal bath in a metallurgical vessel, the element having an outlet free surface for the agitated fluid; At least two electrical conductors (16, 6) are arranged according to the thickness of the element in an electrically insulated manner. , the other end being connected to a power supply (17) to constitute the terminals of the opposite electrodes of an open electrical circuit, which circuit is capable of receiving a signal indicating the "open" or "closed" state of the circuit. A permeable refractory element as described above, characterized in that it comprises means (18). (') Refractory material, material 0 permeability 0 main part 3°j is placed in the metal enclosure (6) leaving the agitated fluid outlet surface (8), and is a conductive material that constitutes one terminal of the electric circuit described above. Transparent refractory element according to claim 1, characterized in that one of the bodies is the metal enclosure (6). (3) One terminal of the above circuit has multiple conductors (22, 23,
24, 25), and their conductor exit surfaces (8
) are located at different levels according to the thickness of the element, and when one of the conductors (22) is close to the exit surface (8) at its end, the other conductor body (24,2
5) is embedded in a refractory material, further characterized in that signal means (26) are provided for detecting the current in each electrical conductor, indicating the 5 open or closed state of the electrical circuit. The transparent refractory element according to claim 1 or 2. (4) At least one terminal is constituted by a consumable electrical resistor, and the element is capable of determining the "open" or "closed" state of the electrical circuit. Signal means are provided to indicate the residual thickness of the element by measuring a change in electrical characteristics of the electrical circuit in response to a change in length of the terminal. The transparent fireproof element according to claim 1 or 2. (5) The conductor (16, 21, 22, 23, 24, 2
5) The permeable fireproof element according to any one of the above patents, characterized in that it is a metal rod-shaped body. <<6>> At least one of the metal rod-shaped bodies is tubular,
6. A permeable refractory element according to claim 5, characterized in that a stirring fluid is blown into the bath. (9) The permeable refractory element according to any one of the above claims, wherein the metallurgical vessel is a top-blown steelmaking converter. (8) The permeable refractory element according to claim 7, wherein the element is provided on the furnace wall of the converter. (9) The element is provided on the bottom of the converter. A permeable refractory element according to claim 7, characterized in that it is provided.Q@ A permeable refractory element according to any of the above claims, wherein the conductor is made of steel.