Chromium-free base brick for rh alloy ladle and method for manufacturing the same

Abstract

The application discloses an RH alloy material tank chromium-free base brick and a preparation method thereof. The RH alloy material tank chromium-free base brick is integrally cast by corundum castable and internal steel structure components. The raw material composition and weight percentage of the corundum castable are as follows: tabular corundum 55-75%, zirconium corundum 10-35%, pure calcium aluminate cement 6-12%, alpha alumina micropowder 6-12%, and water reducing agent 0.2-1%. The RH alloy material tank chromium-free base brick prepared by the method can adapt to RH chromium-free, greatly improves the toughness, strength and impact resistance of the RH furnace alloy material tank base brick, prolongs the service life of the base brick, and reduces the excavation and repair of the alloy material tank base brick and the surrounding wall bricks.

Description

TECHNICAL FIELD

[0001] The application belongs to the technical field of refractories for RH furnace, and particularly relates to a RH alloy tank chromium-free base brick and a preparation method thereof. BACKGROUND

[0002] The RH furnace is the most common furnace outside refining equipment in the steel metallurgical industry, which is composed of an immersion tube, a circulation pipe, a bottom tank, a middle tank, an upper tank, an alloy chute and a hot elbow pipe.

[0003] The magnesium-chromium brick may produce Cr 6+ which is harmful to the human body or the environment, and has been listed as a limited use refractory material.

[0004] The original material of the alloy tank base brick is a magnesium-chromium brick, which is usually assembled by at least 4 machine-pressed bricks, and the more the number of assembled bricks, the worse the impact resistance. The service life of the alloy tank base brick is generally less than 1200 furnaces under the influence of the scouring of the alloy and the impact of the high-temperature oxygen lance slag at high temperature. When the alloy tank base brick is replaced, the alloy tank brick and the wall brick below the alloy tank must also be replaced, which causes great waste. It is necessary to redesign the RH furnace alloy tank base brick. SUMMARY

[0005] To adapt to the RH chromium-free, improve the impact resistance and oxidation resistance of the RH furnace alloy tank base brick, and prolong the service life thereof, the application provides a RH alloy tank chromium-free base brick and a preparation method thereof.

[0006] To solve the above technical problems, the application realizes the technical scheme as follows:

[0007] A RH alloy tank chromium-free base brick is formed by integrally pouring corundum castable and an internal steel structure component, and the raw material composition and weight percentage of the corundum castable are as follows: tabular corundum 55-75%, zirconium corundum 10-35%, pure calcium aluminate cement 6-12%, alpha alumina micropowder 6-12%, and water reducing agent 0.2-1%.

[0008] Preferably, the mass fraction of Al2O3 in the tabular corundum is not less than 98.5%, and the particle size range of the tabular corundum is selected from 12-8 mm, 8-5 mm, 5-3 mm, 3-1 mm, 1-0.088 mm and -325 mesh.

[0009] Preferably, the zirconia corundum has an Al2O3 mass fraction of not less than 55%, a ZrO2 mass fraction of not less than 25%, and a particle size range of 3-1 mm or 1-0.088 mm. The ZrO2 particles are selected to be 3-1 mm or 1-0.088 mm, only because large particles cannot achieve the desired effect of the patent, and if particles with a size of ≤0.088 mm are used, the reflection is too fast and the long-term use effect cannot be achieved.

[0010] Preferably, the pure calcium aluminate cement has an Al2O3 mass fraction of not less than 68.5%.

[0011] Preferably, the α-alumina micropowder has an Al2O3 mass fraction of not less than 98% and a particle size of ≤4 μm.

[0012] Preferably, the water reducing agent is one or more of polyphosphates, lignin, naphthalene-based water reducing agent, melamine-based water reducing agent, or other organic or inorganic water reducing agent.

[0013] Preferably, the internal steel structure assembly includes a cross rib, a hook, and an anchor, the cross rib is embedded in the corundum castable, the hook is located above the cross rib and is fixedly connected therewith, and the anchor is symmetrically welded on the cross rib in a "V" shape.

[0014] A preparation method of a chromium-free base brick for an RH alloy ladle, comprising the following steps:

[0015] 1) Preparing a pouring mold according to the requirements of the drawing of the base brick for the RH alloy ladle;

[0016] 2) Welding the internal steel structure assembly according to the size of the pouring mold;

[0017] 3) Welding a castable protective steel plate on the lower part of the base brick and closely adhering to the pouring mold;

[0018] 4) Loading the internal steel structure assembly and the castable partition into the pouring mold, and pouring and constructing according to the raw material composition of the base brick for the RH alloy ladle;

[0019] 5) Demolding after at least 24 hours of curing, and dividing the base brick for the RH alloy ladle into two blocks at the position of the castable partition;

[0020] 6) Placing the demolded base brick for the RH alloy ladle into an electric baking cover, and baking at low temperature for 12-48 hours;

[0021] 7) Placing the base brick for the RH alloy ladle after low-temperature baking into a drying kiln and baking for 24-48 hours;

[0022] 8) Taking the dried base brick for the RH alloy ladle out of the drying kiln after natural cooling in the drying kiln for at least 24 hours, and packaging after complete cooling to obtain the finished product.

[0023] Preferably, the baking temperature of the electric baking cover is ≤80℃, and the maximum baking temperature of the drying kiln is 350℃. The electric baking cover is a cylindrical cover with a diameter of 2m and a height of 1m, which is internally provided with resistance wires, temperature measuring thermocouples and heat insulation materials.

[0024] Preferably, the thickness of the castable protective steel plate is 5-10mm.

[0025] Compared with the prior art, the present application has the following beneficial effects:

[0026] (1) The present application adds part of zirconia corundum in the RH alloy ladle seat brick corundum castable, and the ZrO2 in the corundum castable can greatly improve the fracture toughness and strength of the corundum castable.

[0027] (2) The present application adds 6-12% of pure calcium aluminate cement in the RH alloy ladle seat brick castable, which can greatly improve the strength of the corundum castable, and with the increase of the amount of pure calcium aluminate cement, the penetration of alkaline slag is more obvious, which can improve the slag hanging effect of the corundum castable and achieve the effect of protecting the corundum castable.

[0028] (3) The present application uses the castable prefabricated part forming mode, reduces the RH alloy ladle seat brick assembly brick from at least 4 pieces to 2 pieces, and improves the integrity of the seat brick.

[0029] (4) The transverse ribs and anchor pieces are pre-embedded in the cast prefabricated part, which greatly improves the toughness of the RH alloy ladle seat brick and can effectively prevent the fracture of the RH alloy ladle seat brick castable.

[0030] (5) The present application locally welds a 5-10mm thick castable protective steel plate at the lower opening of the RH alloy ladle seat brick castable, which can effectively alleviate the impact damage of the seat brick castable during alloy feeding.

[0031] (6) The present application can greatly improve the service life of the RH alloy ladle seat brick, and can also reduce the amount of excavation and repair of the RH alloy ladle seat brick and the surrounding wall bricks.

[0032] (7) The present application does not contain "chromium" element, and will not cause harm to the environment or human body. BRIEF DESCRIPTION OF DRAWINGS

[0033] Figure 1 It is a left view of the RH alloy ladle chromium-free seat brick cast mold shown in the present application;

[0034] Figure 2 It is a plan view of the RH alloy ladle chromium-free seat brick cast mold shown in the present application;

[0035] Figure 3 It is a plan view of the internal steel structure of the RH alloy ladle chromium-free seat brick cast shown in the present application;

[0036] Figure 4 The figure is a front view of the internal steel structure of the RH alloy material tank chromium-free base brick pouring material shown in the present application.

[0037] Marked in the figure: 1, pouring material partition; 2, cross rib; 3, hook; 4, anchor; 5, pouring material protective steel plate; 6, pouring mold. DETAILED DESCRIPTION

[0038] In order for those skilled in the art to better understand the technical solutions of the present application, the preferred embodiments of the present application are described below in combination with specific examples, but it should not be understood as limiting the present patent, but only as an example.

[0039] The test methods or test methods described in the following examples are all conventional methods unless otherwise specified; the reagents and materials are obtained from conventional commercial channels or prepared by conventional methods unless otherwise specified.

[0040] All raw materials in the embodiments of the present application are market known, commercially available chemical raw materials unless otherwise specified.

[0041] Example 1

[0042] The present application is realized by the following technical solutions:

[0043] The RH alloy material tank chromium-free base brick provided by the present application is composed of corundum-based pouring material and internal steel structure components. Among them, the internal steel structure components include cross rib 2, hook 3 and anchor 4, the cross rib 2 is embedded in the corundum-based pouring material, the hook 3 is located above the cross rib 2 and is fixedly connected with it; the anchor 4 is "V" type, symmetrically welded on the cross rib 2. The diameter of the cross rib 2 is 10 mm, the diameter of the anchor 4 is 6 mm, and the diameter of the hook 3 is 20 mm.

[0044] The present application provides a kind of RH alloy material tank chromium-free base brick pouring corundum-based pouring material, and its composition and weight percentage are as follows:

[0045] Tabular corundum, particle size 12-8mm, 15%;

[0046] Tabular corundum, particle size 8-5mm, 12%;

[0047] Tabular corundum, particle size 5-3mm, 12%;

[0048] Tabular corundum, particle size 3-1mm, 12%;

[0049] Tabular corundum, particle size 1-0.088mm, 8%;

[0050] Tabular corundum, -325 mesh, 16%;

[0051] Zirconia corundum, 3-1 mm, 5%;

[0052] Zirconia corundum, 1-0.088 mm, 8%;

[0053] Pure calcium aluminate cement, 6%;

[0054] Alpha alumina fines, 5.8%;

[0055] Sodium tripolyphosphate, 0.2%.

[0056] The application also provides a preparation method of a chromium-free base brick of an RH alloy ladle, comprising the following steps:

[0057] 1) preparing a pouring mold 6 according to the requirements of a drawing of the base brick of the RH alloy ladle, as shown in Figure 1 and 2 ;

[0058] 2) welding internal steel structure components including cross ribs, anchorages and hooks according to the size of the pouring mold, as shown in Figure 3 and 4 ;

[0059] 3) welding a 5mm-thick castable protective steel plate 5 at the lower part of the base brick close to the pouring mold, as shown in Figure 3 ;

[0060] 4) loading the internal steel structure components and the castable partition plate 1 into the pouring mold, and pouring and constructing according to the raw material composition of the base brick of the RH furnace alloy ladle;

[0061] 5) demolding after at least 24 hours of curing, and dividing the base brick of the RH furnace alloy ladle into two blocks at the position of the castable partition plate 1;

[0062] 6) placing the demolded base brick of the RH furnace alloy ladle into an electric baking cover, and baking at 70℃ for 12 hours;

[0063] 7) placing the low-temperature baked base brick of the RH furnace alloy ladle into a drying kiln, and baking for 48 hours at a maximum temperature of 350℃;

[0064] 8) taking out the dried base brick of the RH furnace alloy ladle from the drying kiln after natural cooling for at least 24 hours, and packaging after complete cooling to obtain the finished product.

[0065] Example 2

[0066] The application is realized by the following technical scheme:

[0067] The application provides a chromium-free seat brick of an RH alloy ladle, which is composed of corundum castable and an internal steel structure component.

[0068] The application provides a chromium-free seat brick of an RH alloy ladle, which is composed of corundum castable and an internal steel structure component.

[0069] The application provides a chromium-free seat brick of an RH alloy ladle, which is composed of corundum castable and an internal steel structure component.

[0070] Tabular corundum, particle size 8-5mm, 10%;

[0071] Tabular corundum, particle size 5-3mm, 10%;

[0072] Tabular corundum, -325 mesh, 12%;

[0073] Zircon corundum, particle size 3-1mm, 15%;

[0074] Zircon corundum, particle size 1-0.088mm, 20%;

[0075] Pure calcium aluminate cement, 8%;

[0076] Alpha alumina micro powder, 9.8%;

[0077] Calcium lignosulfonate, 0.2%.

[0078] The application further provides a preparation method of the chromium-free seat brick of the RH alloy ladle, which comprises the following steps:

[0079] 1) preparing a pouring mold 6 according to the requirement of a drawing of the seat brick of the RH alloy ladle, as shown in Figure 1 and 2

[0080] 2) welding the internal steel structure component, including the cross rib, the anchor and the hook, according to the size of the pouring mold, as shown in Figure 3 and 4

[0081] 3) welding a 8mm-thick castable protective steel plate on the lower part of the seat brick and close to the pouring mold, as shown in Figure 3

[0082] 4) loading the internal steel structure component and the castable partition plate 1 into the pouring mold, and pouring and constructing according to the raw material composition of the seat brick of the RH furnace alloy ladle.

[0083] ​​​5) After the health is maintained for at least 24 hours, the RH alloy trough seat brick is demolded, and the RH alloy trough seat brick is divided into two blocks from the position of the pouring material partition plate 1;

[0084] 6) The RH furnace alloy trough seat brick after demolding is placed in an electric baking cover, and baked at 60 DEG C for 48 hours;

[0085] 7) The RH furnace alloy trough seat brick after low-temperature baking is placed in a drying kiln and baked for 24 hours, and the maximum temperature is 350 DEG C;

[0086] 8) The dried RH furnace alloy trough seat brick is taken out of the drying kiln after being naturally cooled in the drying kiln for at least 24 hours, and the finished product is obtained after complete cooling and packaging.

[0087] Example 3

[0088] The present application is realized by the following technical scheme:

[0089] The RH alloy trough chromium-free seat brick provided by the present application is composed of corundum-based castable and internal steel structure components. The internal steel structure components include a cross rib 2, a hook 3 and an anchor 4, the cross rib 2 is embedded in the corundum-based castable, the hook 3 is located above the cross rib 2 and is fixedly connected with the cross rib 2, and the anchor 4 is symmetrically welded on the cross rib 2 in a V shape. The diameter of the cross rib 2 is 10 mm, the diameter of the anchor 4 is 8 mm, and the diameter of the hook 3 is 20 mm.

[0090] The present application provides a kind of RH alloy trough chromium-free seat brick cast corundum-based castable composition and weight percentage as follows:

[0091] Tabular corundum, particle size 12-8mm, 15%;

[0092] Tabular corundum, particle size 8-5mm, 10%;

[0093] Tabular corundum, particle size 5-3mm, 10%;

[0094] Tabular corundum, particle size 3-1mm, 7%;

[0095] Tabular corundum, particle size 1-0.088mm, 10%;

[0096] Tabular corundum, -325 mesh, 6%;

[0097] Zircon corundum, particle size 3-1mm, 8%;

[0098] Zircon corundum, particle size 1-0.088mm, 10%;

[0099] Pure calcium aluminate cement, 12%;

[0100] Alpha alumina powder, 11.8%;

[0101] Water-reducing agent, 0.2%.

[0102] This invention also provides a method for preparing chromium-free seat bricks for RH alloy troughs, comprising the following steps:

[0103] 1) Prepare casting mold 6 according to the requirements of the RH alloy material trough seat brick drawing, such as... Figure 1 and 2 As shown;

[0104] 2) Weld the internal steel structure components, including cross ribs, anchors, and hooks, according to the dimensions of the casting mold, such as... Figure 3 and 4 As shown;

[0105] 3) Weld a 10mm thick protective steel plate 5 for the castable refractory to a local area under the base brick, tightly against the casting mold. Figure 3 As shown;

[0106] 4) Install the internal steel structure components and the castable partition 1 into the casting mold, and carry out the casting construction according to the raw material composition of the alloy material trough seat brick of the RH furnace;

[0107] 5) After curing for at least 24 hours, demold the RH alloy material trough seat bricks, which are divided into two pieces from the position of the casting refractory partition 1;

[0108] 6) Place the demolded RH furnace alloy material trough seat bricks into the electric baking hood and bake at 80℃ for 36 hours;

[0109] 7) Place the alloy material trough seat bricks of the RH furnace after low-temperature baking into a drying kiln and bake for 36 hours at a maximum temperature of 350℃;

[0110] After the dried RH furnace alloy material trough bricks are naturally cooled in the drying kiln for at least 24 hours, they are removed from the kiln and packaged after complete cooling to obtain the finished product.

[0111] Table 1 shows a comparison of the performance of the chromium-free seat bricks for the RH furnace alloy feeder obtained in the above embodiments:

[0112] Table 1 Comparison of Performance of Alloy Feeder Bricks in RH Furnace

[0113] Service life, furnace Whether need to repair in the middle Example 1 1500 No Example 2 1750 No Example 3 2000 No Conventional sitting brick 1200 Yes

[0114] As can be seen from Table 1, a chromium-free base brick for the RH furnace alloy feed trough can significantly improve the service life of the RH alloy feed trough base brick and reduce the need for excavation and repair of the RH alloy feed trough base brick and surrounding wall bricks.

[0115] The above merely describes the preferred embodiments of the present application, and it should be pointed out that the above preferred embodiments should not be regarded as a limitation to the present application, and the protection scope of the present application should be defined by the scope of the claims. For those skilled in the art, several improvements and refinements can be made without departing from the spirit and scope of the present application, and these improvements and refinements should also be regarded as the protection scope of the present application.

Claims

1. A chromium-free seat brick for an RH alloy trough, characterized in that, It is integrally cast from corundum castable and internal steel structure components. The raw material composition and weight percentage of the corundum castable are as follows: 58% tabular corundum, 18% zirconium corundum, 12% pure calcium aluminate cement, 11.8% α-alumina micro powder, and 0.2% water-reducing agent. The tabular alumina contains an Al2O3 mass fraction of not less than 98.5%, and is composed of the following particle size distributions: 12-8 mm, 15%; 8-5 mm, 10%; 5-3 mm, 10%; 3-1 mm, 7%; 1-0.088 mm, 10%; -325 mesh, 6%. The zirconium alumina contains an Al2O3 mass fraction of not less than 55% and a ZrO2 mass fraction of not less than 25%, and is composed of the following particle size distributions: 3-1 mm, 8%; 1-0.088 mm, 10%. The internal steel structure components include horizontal ribs, hooks, and anchors. The horizontal ribs are embedded inside the alumina castable, and the hooks are located above and fixedly connected to the horizontal ribs. The anchors are V-shaped and symmetrically welded to the horizontal ribs. The preparation method of chromium-free seat bricks for RH alloy feed troughs includes the following steps: 1) Prepare the casting mold according to the requirements of the RH alloy material trough seat brick drawing; 2) Weld the internal steel structure components according to the dimensions of the casting mold; 3) Weld a protective steel plate for the castable refractory to a portion of the lower part of the base brick, tightly against the casting mold; 4) Install the internal steel structure components and castable partitions into the casting mold, and carry out the casting construction according to the raw material composition of the alloy material trough seat bricks of the RH furnace; 5) After curing for at least 24 hours, demold the RH alloy material trough seat bricks, which are divided into two pieces from the position of the casting refractory partition. 6) Place the demolded RH furnace alloy material trough seat bricks into the electric baking hood and bake at low temperature for 12-48 hours; 7) Place the alloy material trough seat bricks of the RH furnace after low-temperature baking into a drying kiln and bake for 24-48 hours; 8) After the dried RH furnace alloy material trough bricks are naturally cooled in the drying kiln for at least 24 hours, they are removed from the kiln and packaged after complete cooling to obtain the finished product.

2. The chromium-free seat brick for the RH alloy trough according to claim 1, characterized in that, The mass fraction of Al2O3 in the pure calcium aluminate cement is not less than 68.5%.

3. The chromium-free seat brick for the RH alloy trough according to claim 1, characterized in that, The α-alumina micro powder contains no less than 98% Al2O3 by mass and has a particle size of ≤4μm.

4. The chromium-free seat brick for the RH alloy trough according to claim 1, characterized in that, The water-reducing agent is one or more of the following: polysodium phosphate, lignin-based, naphthalene-based, melamine-based, or other organic or inorganic water-reducing agents.

5. The chromium-free seat brick for the RH alloy trough according to claim 1, characterized in that, The baking temperature of the electric baking hood is ≤80℃, and the maximum baking temperature of the drying kiln is 350℃.

6. The chromium-free seat brick for the RH alloy trough according to claim 1, characterized in that, The thickness of the castable protective steel plate is 5-10mm.

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