JP2006104507A - Gas-blowing plug - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To provide a gas-blowing plug which reduces the intrusion of a solution thereinto such as a molten metal when blowing an inert gas for the purpose of stirring the metallic solution, and consequently increases the useful life. <P>SOLUTION: The gas-blowing plug 1 is formed of: a central layer 3 formed into an approximately truncated-cone shape; a layer 5 formed into the truncated cone shape on the outside of the central layer so as to surround the central layer; and a layer 7 formed into the truncated cone shape on the outside of the layer 5 so as to surround the layer 5. The central layer and the outside layer 5 are porous layers. The layer 7 is a non-porous layer for supporting the layers 3 and 5, and for passing a gas upward. Thus, the plug has a gas-blowing layer formed of a plurality of the concentric layers. <P>COPYRIGHT: (C)2006,JPO&NCIPI

Description

  The present invention relates to a gas injection plug for injecting gas into a solution of metal or the like for refining the solution. Specifically, the present invention relates to a gas blowing plug provided with a plurality of gas blowing layers.

  In order to stir the metal solution, a gas such as an inert gas is blown into the solution. For example, a gas blowing plug 51 having a cross-sectional shape as shown in FIG. 4 is provided at the bottom of the molten metal container, and gas is blown into the solution inside the molten metal container through the gas supply pipe 57.

  Incidentally, the conventional gas blowing plug as shown in FIG. 4 has a refractory having a substantially constant porosity at the center, but has the following problems. That is, with respect to the porous plug 53 provided in the gas blowing plug 51, the gas discharge amount differs between the portion corresponding to the central portion side and the portion corresponding to the outer portion, and the discharge amount increases on the central portion side. In some cases, the discharge amount was reduced.

  That is, on the central portion side of the porous plug 53, the normal gas passes intensively near the center, the gas bubbles are united and become larger, the rising speed of the gas bubbles is increased, and becomes random. That is, bubbles of an appropriate size are maximized, and if the bubbles are too large or too small, the flying speed in the liquid is slow. However, outside the porous plug 53, the porosity is usually low and the gas flow rate is low. For this reason, there is a tendency that the range of expansion of bubbles into the solution is narrowed.

  As a result, the stirring ability of the solution was lowered and the blowing time was extended. Therefore, it was necessary to increase the gas flow rate and make it uniform. Therefore, in order to solve the above problem, the present invention is to provide a method for uniformly discharging the gas discharged from the surface of the gas blowing plug over the entire upper surface of the plug and blowing in as much gas as possible.

  A first aspect of the invention is a plug composed of a substantially frustoconical breathable refractory, wherein the gas blowing layer of the plug is formed of a plurality of concentric layers. It is a plug for gas blowing.

  According to a second aspect of the present invention, there is provided a gas blowing plug, wherein the concentric gas blowing layer is composed of a layer having high air permeability and a layer having low air permeability.

  According to a third aspect of the present invention, there is provided a gas blowing plug, wherein the gas blowing layer is provided such that the layer having a large air permeability is provided on the outside and the layer having a low air permeability is provided on the inside. .

  The gas blowing layer is a gas blowing plug comprising one layer having high air permeability and one layer having low air permeability.

  In the gas blowing layer, when the diameter of the layer having a small air permeability is set to 1 in a substantially central section in the longitudinal direction of the gas blowing layer, the diameter of the layer having a large air permeability is about 1.3 to 1. The gas blowing plug is provided so as to be in the range of 7.

  The gas blowing plug is characterized in that the porosity of the layer with low air permeability is 10 to 25%, and the porosity of the layer with high air permeability is 20 to 35%.

  The gas blowing layer is a fired product obtained by firing a refractory of high alumina, alumina-chromium, alumina-chromium-zirconia refractories after press molding, It is a plug.

The configuration described above has the following effects.
(1) A uniform discharge amount can be obtained over the entire surface of the plug.
(2) Eliminate bubbles.
(3) There is no coalescence of bubbles, and the effect that gas bubbles spread over the entire solution is obtained.

(Embodiment 1)
FIG. 1 shows an embodiment of the present invention. FIG. 1A is a schematic cross-sectional view in the vertical direction of a gas blowing plug 1 according to the present invention. FIG.1 (b) is related with AA 'of the gas blowing plug 1 of Fig.1 (a), and is horizontal cross-sectional schematic diagram of the vertical direction center part of Fig.1 (a).

  In the present embodiment, the gas blowing layer is formed of a plurality of layers. This will be described with reference to FIG. The gas blowing plug 1 includes a center layer 3 formed in a truncated cone shape, a layer 5 formed in a truncated cone shape so as to surround the center layer 3 outside the center layer 3, and a layer 5 formed outside the layer 5. And a layer 7 formed in the shape of a truncated cone so as to surround.

  The outer layer 5 of the center layer 3 is also a porous layer provided for passing gas. The layer 7 is formed of, for example, a non-porous layer provided to support the layers 3 and 5 and to flow the gas upward. In the present embodiment, the central layer 3 is one layer, and the outer layer 5 is one layer.

  In FIG. 1A, the center layer 3 and the outer layer 5 are formed. The gas blowing plug 1 shown in FIG. 1A is formed of a central layer 3 having a low air permeability and a layer 5 having a high air permeability. For the layer 7, for example, a castable refractory having no air permeability is used.

  This will be described with reference to the cross-sectional view of FIG. The gas blowing layer is formed by the center layer 3 and the outer layer 5. Here, when the outer diameter dimension of the center layer 3 is X and the outer diameter dimension of the outer layer 5 is Y, the ratio of X and Y can be appropriately selected according to design conditions. In the present invention, it is desirable that the outermost diameter dimension X of the inner layer 3 and the outermost diameter dimension Y of the outer layer 5 be 1: 1.3 to 1.7. This is because the total gas passage amount is small when the ratio is less than 1.3 and the total gas passage amount is excessive when the ratio exceeds 1.7.

  In the present invention, in order to reduce the air permeability of the center layer 3, a small amount of intermediate particles are used when forming the center layer 3, and the porosity is reduced, for example, 15 to 25%. If it is less than 15%, the amount of ventilation cannot be secured, and if it exceeds 25%, the gas becomes excessive. The porosity can be measured according to, for example, JIS 22051.

The material is preferably a fired product obtained by press-molding a high-alumina, alumina-chromium, or alumina-chromium-zirconia refractory. The example of a component composition is shown below. However, the following compositions are illustrative and not restrictive.
High alumina material: Al ₂ O ₃ 90% or more Alumina-chromium: Al ₂ O ₃ 87%, Cr ₂ O ₃ 3%
Alumina-chromium-zirconia: Al ₂ O ₃ 82%, Cr ₂ O ₃ 3%, ZrO ₂ 5%

In order to increase the air permeability of the outer layer 5, when forming the outer layer 5, a large amount of intermediate particles are used, and the porosity is increased, for example, 20 to 35%.
When it is out of the range of 20 to 35%, the gas passage amount is too short or excessive.
The material is desirably formed by a press-molded fired product of the above-described high alumina, alumina-chromium, or alumina-chromium-zirconia refractory.

  In the first embodiment, the central layer 3 is one layer and the outer layer 5 is one layer. Of course, the gas blowing plug 1 includes a layer 3 having a high air permeability and a layer 5 having a low air permeability. A plurality of layers, for example, alternately or continuously may be provided.

  For example, the gas blowing plug may have a structure in which the lower layer is a refractory having a slit structure and the upper layer is a porous refractory as in the present invention. Further, all or part of the outer periphery of the porous plug 1 may be covered with a metal case, and various means can be taken.

  2 and 3 show the results of tests conducted to explain the present invention. FIG. 2 shows test results for explaining the present invention. In the test, a test was conducted to confirm the behavior of the gas when gas was blown into one layer of the central layer 23 and one layer of the outer layer 25.

As shown in FIG. 2 (a), the central layer 23 is formed of a high-alumina (Al ₂ O ₃ 90%), low-breathability layer 23 with a porosity of 23%. A water model test was performed using a member having a large layer formed on the outer layer 5.

FIG. 2B shows the results obtained using the test apparatus described above. The gas flow rate is 55 l / min and the gas pressure is 0.5 kg / cm ² . That is, the following can be said with respect to FIG.
(1) Fine bubbles are uniformly discharged from the entire surface of the plug.
(2) There is no coalescence of bubbles and the bubbles spread over the entire water.

FIG. 3 shows test results for explaining a comparative example. In the test, one layer of the gas blowing layer 33 was used, and a test for confirming the behavior of the gas when the gas was blown was performed.
As shown in FIG. 3A, a layer 33 having a high alumina material and a porosity of 23% was used, and the same water test as described above was performed.

FIG. 3B shows the results obtained using the test apparatus. The gas flow rate is 50 l / min and the gas pressure is 0.5 kg / cm ² . The following can be seen from FIG.
(1) The air bubbles inside the plug are rough, the air bubbles outside are fine, and the air bubbles are uneven.
(2) Coalescence of bubbles is seen and the entire bubbles are shrunk inward.
From the above experiment, it was confirmed that the bubbles can be uniformly dispersed in the water model as shown in FIG. 2B by appropriately selecting the porosity, blowing pressure, and blowing amount of the plug.

  The above is a test result using water, but when the gas blowing plug according to the present invention was prepared and used in a 300 t molten steel pan, the present invention product has a larger flow area of molten steel than the conventional product, and the stirring efficiency is large. Was confirmed to have increased.

The gas blowing plug according to the present invention has the following effects.
(1) A uniform discharge amount can be obtained over the entire surface of the plug.
(2) The bubble size is not uneven.
(3) There is no coalescence of bubbles and a spread is obtained.
Therefore, it can be used for refining molten metals, particularly metals such as hot metal, molten steel, aluminum, and other molten copper.

It is a figure which shows one Embodiment of this invention. It is a figure explaining the test which concerns on this invention. It is a figure explaining the test which concerns on a prior art example. It is a figure which shows a prior art example.

Explanation of symbols

DESCRIPTION OF SYMBOLS 1 Gas blowing plug 3 Center layer 5 Outer layer 7 Castable refractory 23 Center layer 25 Outer 33 Conventional layer 51 Gas blowing plug 53 Porous plug 55 Castable refractory

Claims (7)

  A plug for gas injection, characterized in that the plug is made of a substantially frustoconical breathable refractory, and the gas injection layer of the plug is formed of a plurality of concentric layers.   2. The gas blowing plug according to claim 1, wherein the concentric gas blowing layer is composed of a layer having high air permeability and a layer having low air permeability.   3. The gas blowing plug according to claim 1 or 2, wherein the gas blowing layer is provided so that the layer with high air permeability is on the outside and the layer with low air permeability is on the inside.   The said gas blowing layer is comprised from 1 layer with large air permeability, and 1 layer with low air permeability, The plug for gas blowing in any one of Claims 1-3 characterized by the above-mentioned.   In the gas blowing layer, when the diameter of the layer having a small air permeability is set to 1 in a substantially central section in the longitudinal direction of the gas blowing layer, the diameter of the layer having a large air permeability is about 1.3 to 1. The gas blowing plug according to claim 4, wherein the plug is provided so as to be in a range of 7.   The gas according to any one of claims 2 to 5, wherein the porosity of the layer with low air permeability is 10 to 25%, and the porosity of the layer with high air permeability is 20 to 35%. Plug for blowing.   7. The gas injection layer according to claim 1, wherein the gas blowing layer is a fired product obtained by firing a refractory material of high alumina, alumina-chromium, or alumina-chromium-zirconia after press molding. The plug for gas injection as described in crab.

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