Magnesium spinel hot wet gunning material, preparation method and application thereof

Abstract

The present invention relates to the technical field of refractory materials, and in particular to a magnesium spinel hot wet gunning material, a preparation method and an application thereof. The magnesium spinel hot wet gunning material comprises: 45 wt%~60 wt% of magnesium spinel brick waste; 20 wt%~25 wt% of magnesia sand; 15 wt%~20 wt% of spinel; 5 wt%~10 wt% of α-alumina micropowder; 5 wt%~10 wt% of binder; 1 wt%~2 wt% of aluminum powder; 0.1 wt%~0.2 wt% of water reducer; 1 wt%~3 wt% of saturated polyaluminum chloride solution; the sum of the amounts of the components is 100%. The magnesium spinel hot wet gunning material has the advantages of good high-temperature mechanical strength, long service life and low production cost during use through the combination of various components, and is not easy to generate dust.

Description

Technical Field

[0001] The invention relates to the technical field of refractory materials, and in particular to a magnesium spinel hot wet gunning material, a preparation method and application thereof. Background Art

[0002] With the rapid development of economic construction, the demand for clean steel and ultra-low carbon steel is increasing, and the quality requirements for clean steel are also getting higher and higher. RH circulating vacuum degassing furnace is one of the important intermittent refining production equipment in clean steel smelting. It has the advantages of short processing cycle, large production capacity, good refining effect, low cost and simple operation. RH furnace also shows significant superiority in the production of ultra-low carbon steel, and is an important refining device outside the furnace in modern steel plants.

[0003] As an important part of the RH circulating vacuum degassing refining furnace, the RH immersion tube and circulation tube are responsible for the key processes of molten steel circulation, flow and mixing. They are the high-corrosion areas of the RH device, and their service life determines the overall life of the RH circulating degassing furnace. Therefore, the materials of the RH immersion tube and circulation tube must have excellent thermal shock resistance, high-temperature spalling resistance, erosion resistance and excellent high-temperature strength. Therefore, the use of RH immersion tube refractory materials directly affects the efficiency of the entire refining and degassing operation. In the actual production process, the immersion tube with uneven erosion needs to be hot-repaired to ensure the smooth progress of the molten steel refining operation.

[0004] The patent application document "An environmentally friendly magnesium carbon gunning material for RH furnaces and its preparation method" (CN201910929987.8) discloses a gunning material for RH furnace impregnated tubes. This technology uses post-burning regenerated magnesium carbon material and magnesia sand as the main raw materials, and adds high-grade alumina and magnesium oxide as the basic raw materials. The patent application document "A gunning material for RH furnaces" (CN201911029517.2) discloses a preparation method for RH furnace gunning material using corundum and native magnesia sand as the main raw materials. However, in the above two prior arts, at high temperatures, liquid phases are easily generated in the system, which reduces the strength of the gunning material at high temperatures and deteriorates the corrosion resistance. Moreover, both gunning materials are semi-dry gunning materials, which are gunned on the working surface after adding water to the gun tip. The gunning material itself is in powder form and is transported to the working surface by gas, which easily causes dust and pollutes the production environment. Summary of the invention

[0005] In view of this, the technical problem to be solved by the present invention is to provide a magnesium spinel hot wet gunning material, a preparation method and an application thereof. The magnesium spinel hot wet gunning material has the advantages of good high-temperature mechanical strength, long service life and low production cost during use, and is not easy to generate dust.

[0006] The present invention provides a magnesium spinel hot wet gunning material, comprising:

[0007] Magnesium spinel brick waste 45 wt%~60 wt%;

[0008] Magnesia 20 wt%~25 wt%;

[0009] Spinel 15 wt%~20 wt%;

[0010] α-alumina powder 5 wt%~10 wt%;

[0011] Binder 5 wt%~10 wt%;

[0012] Aluminum powder 1 wt%~2 wt%;

[0013] Water reducing agent 0.1 wt%~0.2 wt%;

[0014] Saturated polyaluminium chloride solution 1 wt%~3 wt%;

[0015] The sum of the amounts of the various components is 100%.

[0016] Preferably, the waste magnesium spinel bricks are residual bricks after being used for the lining of the RH cycle vacuum degassing furnace; in the waste magnesium alumina spinel bricks, the mass content of MgO is ≥70%, and the mass content of Al2O3 is ≥22%.

[0017] Preferably, the particle size distribution of the magnesium spinel brick waste includes:

[0018] Particles smaller than 5 mm and greater than or equal to 3 mm: 15 wt%~25 wt%;

[0019] 50 wt%~65wt% of particles smaller than 3mm and greater than or equal to 1mm;

[0020] Particles smaller than 1 mm and greater than or equal to 0.088 mm: 20 wt%~25wt%;

[0021] The sum of the amounts of the various components is 100%.

[0022] Preferably, the mass content of MgO in the magnesia is ≥96%; the particle gradation of the magnesia includes:

[0023] 40 wt%~50 wt% for particles smaller than 3 mm and greater than or equal to 1 mm;

[0024] 0.088~1 mm particles 42 wt%~50 wt%;

[0025] Particles smaller than 0.088 mm 8 wt%~10 wt%;

[0026] The sum of the amounts of the various components is 100%.

[0027] Preferably, in the spinel, the mass content of Al2O3 is ≥75%, and the mass content of MgO is ≥22%;

[0028] The particle size distribution of the spinel includes:

[0029] 0.088~1 mm particles 40 wt%~60 wt%;

[0030] Particles smaller than 0.088 mm: 40 wt%~60 wt%;

[0031] The sum of the amounts of the various components is 100%.

[0032] Preferably, in the α-alumina micropowder, the mass content of Al2O3 is ≥98%; and the particle size of the α-alumina micropowder is ≤1 μm.

[0033] Preferably, the binder is aluminum sol and silica sol, the mass ratio of aluminum sol to silica sol is 2.5-3.5:1.5-2.5, such as 3:2; the solid content of Al2O3 in the aluminum sol is ≥20%; the solid content of SiO2 in the silica sol is ≥30%; the room temperature viscosity of the binder is ≤1000 mPa·s;

[0034] The mass content of Al in the aluminum powder is ≥97%; and the particle size of the aluminum powder is ≤0.075 mm.

[0035] Preferably, the water reducing agent is selected from one or more of sodium polycarboxylate, sodium polyacrylate, sodium lignin sulfonate, acetone sulfonated carbonyl pyroaldehyde and melamine.

[0036] Preferably, the saturated polyaluminium chloride solution is obtained by dissolving solid powder of polyaluminium chloride in water; the mass content of Al2O3 in the saturated polyaluminium chloride solution is ≤29.0%, the basicity is 45.0%~90.0%, and the mass content of insoluble matter is ≤0.1%.

[0037] The present invention also provides a preparation method for preparing the magnesium spinel hot wet gunning material described above, comprising the following steps:

[0038] The waste materials of magnesium spinel bricks, magnesia sand, spinel, alpha-alumina powder, binder, aluminum powder, water reducing agent and saturated polyaluminium chloride solution are mixed to obtain magnesium spinel hot wet gunning material.

[0039] The present invention also provides an application of the magnesium spinel hot wet gunning material described above or the magnesium spinel hot wet gunning material prepared by the preparation method described above in hot repair of the inner and outer lining parts of the immersion pipe and the circulating pipe of an RH circulating vacuum degassing furnace.

[0040] Preferably, the application comprises the following steps:

[0041] Water is added to the magnesium spinel hot wet gunning material, mixed evenly, and pumped to form the material by wet spraying on the outer wall, inner wall and / or inner lining of the RH furnace immersion pipe.

[0042] The present invention provides a magnesium spinel hot wet gunning material, comprising: 45 wt%~60 wt% of magnesium spinel brick waste; 20 wt%~25 wt% of magnesia sand; 15 wt%~20 wt% of spinel; 5 wt%~10 wt% of α-alumina micropowder; 5 wt%~10 wt% of binder; 1 wt%~2 wt% of aluminum powder; 0.1 wt%~0.2 wt% of water reducer; 1 wt%~3 wt% of saturated polyaluminum chloride solution; the sum of the amounts of the components is 100%. In the magnesium spinel hot wet gunning material provided by the present invention, by adding aluminum sol and silica sol, calcium aluminate cement can be avoided from being introduced into the gunning material, thereby improving the medium-temperature bonding strength and adhesion performance of the gunning material; at the same time, it can avoid the reaction of calcium aluminate cement, magnesium oxide and silica at high temperature of the gunning material to generate a liquid phase, thereby improving the high-temperature strength of the gunning material. In addition, low-cost polyaluminium chloride is added to the gunning material, which dissolves in water during the use of the gunning material, increases the adhesion of the gunning material, and makes the gunning material harden in time to avoid the rebound of the gunning material and reduce material consumption. The above-mentioned magnesium spinel hot wet gunning material has the advantages of good high-temperature mechanical strength, chemical corrosion resistance, long service life and low production cost during use through the combination of various components. DETAILED DESCRIPTION

[0043] The technical solution of the present invention will be clearly and completely described below in conjunction with the embodiments of the present invention. Obviously, the described embodiments are only part of the embodiments of the present invention, not all of the embodiments. Based on the embodiments of the present invention, all other embodiments obtained by ordinary technicians in this field without creative work are within the scope of protection of the present invention.

[0044] The present invention provides a magnesium spinel hot wet gunning material, comprising:

[0045] Magnesium spinel brick waste 45 wt%~60 wt%;

[0046] Magnesia 20 wt%~25 wt%;

[0047] Spinel 15 wt%~20 wt%;

[0048] α-alumina powder 5 wt%~10 wt%;

[0049] Binder 5 wt%~10 wt%;

[0050] Aluminum powder 1 wt%~2 wt%;

[0051] Water reducing agent 0.1 wt%~0.2 wt%;

[0052] Saturated polyaluminium chloride solution 1 wt%~3 wt%;

[0053] The sum of the amounts of the various components is 100%.

[0054] The waste magnesia spinel bricks are the residual bricks after the lining of the RH cycle vacuum degassing furnace is used; specifically, the waste magnesia alumina spinel bricks and / or the waste magnesia chrome spinel bricks after use. In the waste magnesia alumina spinel bricks, the mass content of MgO is ≥70%, such as 75%; the mass content of Al2O3 is ≥22%, such as 23%.

[0055] The particle size distribution of the magnesium spinel brick waste material includes:

[0056] Particles smaller than 5 mm and greater than or equal to 3 mm: 15 wt%~25 wt%;

[0057] 50 wt%~65wt% of particles smaller than 3mm and greater than or equal to 1mm;

[0058] Particles smaller than 1 mm and greater than or equal to 0.088 mm: 20 wt%~25wt%;

[0059] The sum of the amounts of the various components is 100%.

[0060] In certain embodiments of the present invention, the content of magnesium spinel brick waste in the magnesium spinel hot wet gunning material is 48 wt%, 45 wt%, or 50 wt%.

[0061] The mass content of MgO in the magnesia is ≥ 96%, such as 98%. The particle size distribution of the magnesia includes:

[0062] 40 wt%~50 wt% for particles smaller than 3 mm and greater than or equal to 1 mm;

[0063] 0.088~1 mm particles 42 wt%~50 wt%;

[0064] Particles smaller than 0.088 mm 8 wt%~10 wt%;

[0065] The sum of the amounts of the various components is 100%.

[0066] In certain embodiments of the present invention, the content of magnesia in the magnesium spinel hot wet gunning material is 22wt% and 20wt%.

[0067] In the spinel, the mass content of Al2O3 is ≥75%, such as 76%; the mass content of MgO is ≥22%, such as 22%.

[0068] The particle size distribution of the spinel includes:

[0069] 0.088~1 mm particles 40 wt%~60 wt%;

[0070] Particles smaller than 0.088 mm: 40 wt%~60 wt%;

[0071] The sum of the amounts of the various components is 100%.

[0072] In certain embodiments of the present invention, the content of spinel in the magnesium spinel hot wet gunning material is 15 wt%.

[0073] The mass content of Al2O3 in the α-alumina micropowder is ≥98%, such as 99%; and the particle size of the α-alumina micropowder is ≤1 μm.

[0074] In certain embodiments of the present invention, the content of α-alumina powder in the magnesium spinel hot wet gunning material is 5 wt % or 10 wt %.

[0075] The binder is aluminum sol and silica sol, and the mass ratio of aluminum sol to silica sol is 2.5~3.5:1.5~2.5, such as 3:2. The solid content (mass content) of Al2O3 in the aluminum sol is ≥20%, such as 25%. The aluminum sol is aluminum oxide sol or nano aluminum oxide sol. The solid content (mass content) of SiO2 in the silica sol is ≥30%, such as 32%. The silica sol is nano silica sol or alkaline silica sol. The room temperature viscosity of the binder is ≤1000 mPa·s, such as 800 mPa·s.

[0076] In certain embodiments of the present invention, the content of the binder in the magnesium spinel hot wet gunning material is 5wt%.

[0077] In the aluminum powder, the mass content of Al is ≥97%, such as 98%; and the particle size of the aluminum powder is ≤0.075 mm.

[0078] In certain embodiments of the present invention, the content of aluminum powder in the magnesium spinel hot wet gunning material is 2wt%.

[0079] The water reducing agent is selected from one or more of sodium polycarboxylate, sodium polyacrylate, sodium lignin sulfonate, acetone sulfonated carbonyl pyroaldehyde and melamine. In certain embodiments of the present invention, the water reducing agent is selected from sodium polycarboxylate and sodium lignin sulfonate in a mass ratio of 3:2. In certain embodiments of the present invention, the water reducing agent is selected from sodium polyacrylate and sodium polycarboxylate in a mass ratio of 2:3.

[0080] In certain embodiments of the present invention, the content of the water reducer in the magnesium spinel hot wet gunning material is 0.2 wt % or 0.1 wt %.

[0081] The saturated polyaluminium chloride solution is obtained by dissolving the solid powder of polyaluminium chloride in water. The mass content of Al2O3 in the saturated polyaluminium chloride solution is ≤29.0%, the basicity is 45.0% to 90.0%, and the mass content of insoluble matter is ≤0.1%. Specifically, the mass content of Al2O3 in the saturated polyaluminium chloride solution is 25.0%, the basicity is 90%, and the mass content of insoluble matter is 0.1%.

[0082] In certain embodiments of the present invention, the content of saturated polyaluminium chloride solution in the magnesium spinel hot wet gunning material is 2.8 wt % or 2.9 wt %.

[0083] The present invention also provides a preparation method for preparing the magnesium spinel hot wet gunning material described above, comprising the following steps:

[0084] The waste materials of magnesium spinel bricks, magnesia sand, spinel, alpha-alumina powder, binder, aluminum powder, water reducing agent and saturated polyaluminium chloride solution are mixed to obtain magnesium spinel hot wet gunning material.

[0085] Specifically, they include:

[0086] The waste materials of magnesium spinel brick, magnesia sand, spinel, α-alumina powder, binder and aluminum powder are firstly mixed, and then mixed with a water reducer and a saturated polyaluminum chloride solution to obtain a magnesium spinel hot wet gunning material.

[0087] The mixing is stirring mixing, which is carried out in a mixer.

[0088] The present invention also provides an application of the magnesium spinel hot wet gunning material described above or the magnesium spinel hot wet gunning material prepared by the preparation method described above in hot repair of the inner and outer lining parts of the immersion pipe and the circulation pipe of the RH circulation vacuum degassing furnace. That is, the application in hot repair of the outer wall, inner wall and circulation pipe of the immersion pipe of the RH furnace.

[0089] Furthermore, the application comprises the following steps:

[0090] Water is added to the magnesium spinel hot wet gunning material, mixed evenly, and pumped to form the material by wet spraying on the outer wall, inner wall and / or inner lining of the RH furnace immersion pipe.

[0091] The water accounts for 1% to 3% of the mass of the magnesium spinel hot wet gunning material, such as 2%.

[0092] After the spraying molding, no curing and baking is required. The curing and baking means that the curing time is more than 6 hours, the baking time is more than 10 hours, and the material contains a large amount of free water and bound water.

[0093] After the spraying molding, sintering is further performed. The sintering temperature is 1500-1650° C., such as 1550° C. or 1600° C., and the sintering time is 5-10 min, such as 7 min.

[0094] In the magnesium spinel hot wet gunning material provided by the present invention, by adding aluminum sol and silica sol, calcium aluminate cement can be avoided from being introduced into the gunning material, thereby improving the medium-temperature bonding strength and adhesion performance of the gunning material; at the same time, it can avoid the reaction of calcium aluminate cement, magnesium oxide and silicon dioxide to form a liquid phase under high temperature of the gunning material, thereby improving the high-temperature strength of the gunning material. In addition, inexpensive polyaluminum chloride is added to the gunning material, which is dissolved in water during the use of the gunning material, thereby increasing the adhesion of the gunning material and allowing the gunning material to harden in time to avoid rebound of the gunning material and reduce material consumption. The above-mentioned magnesium spinel hot wet gunning material has the advantages of good high-temperature mechanical strength, chemical corrosion resistance, long service life and low production cost during use through the coordination of various components.

[0095] The above-mentioned magnesium spinel hot wet gunning material can be used for targeted gunning maintenance on the red hot surface of the RH furnace immersion pipe and circulation pipe repeatedly during each production interval of the RH furnace, so that the RH furnace immersion pipe and circulation pipe refractory materials can be fully and routinely maintained to extend their service life. At the same time, it can also repair the partially damaged immersion pipe and circulation pipe, or increase the thickness of a key area, eliminating the existing hidden dangers and possible production accidents of piercing and sucking slag.

[0096] In the present invention, aluminum sol and silica sol compound liquid are added to the magnesium spinel brick waste in the mixer to form a pseudoplastic fluid, which is then pumped to the spray gun tip by a double-bar piston pump, and a saturated solution of polyaluminum chloride is uniformly mixed according to a proportion at the gun tip, and repair application is performed when the RH furnace immersion pipe and the circulation pipe are in a red hot state.

[0097] The present invention adds powder and particles into liquid in advance and mixes them in a mixer to form particle slurry, and then uses a double-cylinder piston pump to pressure-transport it to a gun head, and then uses a certain gas to add kinetic energy to the particle slurry to make it fly onto the working surface. No dust is generated during construction, thus solving the problem of dust pollution.

[0098] The present invention has no particular limitation on the sources of the raw materials used above, and they can be generally commercially available.

[0099] In order to further illustrate the present invention, the magnesium spinel hot wet gunning material, its preparation method and application provided by the present invention are described in detail below in combination with embodiments, but they should not be understood as limiting the scope of protection of the present invention.

[0100] Example 1

[0101] A magnesium spinel hot wet gunning material, whose raw materials include: 48wt% of magnesium spinel brick waste, 22wt% of magnesia sand, 15wt% of spinel, 5wt% of alpha-alumina micropowder, 5wt% of binder, 2wt% of metal aluminum powder, 0.2wt% of water reducer, and 2.8wt% of polyaluminum chloride saturated solution.

[0102] The waste magnesium spinel bricks are the residual bricks after the lining of the RH cycle vacuum degassing furnace is used; in the waste magnesium alumina spinel bricks, the mass content of MgO is 75%, and the mass content of Al2O3 is 23%; the particle gradation of the waste magnesium spinel bricks includes:

[0103] 20 wt% of particles smaller than 5 mm and greater than or equal to 3 mm;

[0104] 55 wt% for particles smaller than 3 mm and greater than or equal to 1 mm;

[0105] 25 wt% of particles smaller than 1 mm and greater than or equal to 0.088 mm.

[0106] The mass content of MgO in the magnesia is 98%; the particle size distribution of the magnesia includes:

[0107] 45 wt% for particles smaller than 3 mm and greater than or equal to 1 mm;

[0108] 0.088~1 mm particles 46 wt%;

[0109] 9 wt% of particles smaller than 0.088 mm.

[0110] In spinel, the mass content of Al2O3 is 76%, and the mass content of MgO is 22%;

[0111] The particle size distribution of the spinel includes:

[0112] 0.088~1 mm particles 50 wt%;

[0113] 50 wt% of particles smaller than 0.088 mm.

[0114] The mass content of Al2O3 in the α-alumina micropowder is 99%, and the particle size of the α-alumina micropowder is ≤1 μm.

[0115] The binder is aluminum sol and silica sol, and the mass ratio of aluminum sol to silica sol is 3:2; the aluminum sol is nano alumina sol, and the solid content of Al2O3 in the aluminum sol is 25%; the silica sol is nano silica sol, and the solid content of SiO2 in the silica sol is 32%; the room temperature viscosity of the binder is 800 mPa·s.

[0116] The mass content of Al in the aluminum powder is 98%; the particle size of the aluminum powder is ≤0.075 mm.

[0117] The water reducing agent is selected from sodium polycarboxylate and sodium lignin sulfonate, with a mass ratio of 3:2.

[0118] The saturated polyaluminium chloride solution is obtained by dissolving the solid powder of polyaluminium chloride in water. The mass content of Al2O3 in the saturated polyaluminium chloride solution is 25.0%, the basicity is 90%, and the mass content of insoluble matter is 0.1%.

[0119] The method for preparing the magnesium spinel hot wet gunning material comprises the following steps:

[0120] The waste materials of magnesium spinel brick, magnesia sand, spinel, α-alumina powder, binder and aluminum powder are firstly mixed, and then stirred and mixed with a water reducer and a saturated polyaluminum chloride solution to obtain a magnesium spinel hot wet gunning material.

[0121] Application of magnesium spinel hot wet gunning material:

[0122] Add 2% water by weight to the above-mentioned magnesium spinel hot wet gunning material, mix evenly, pump and wet spray to the inner lining of the outer wall of the RH furnace immersion tube, without curing and baking (the curing and baking refers to the curing time of more than 6 hours, the baking time of more than 10 hours, and the material contains a large amount of free water and bound water), start steel production after sintering at 1550℃ for 7 minutes, observe the material peeling and use, and can be used for 35 furnaces; take the gunning sample and bake it at 110℃ for 30 hours for testing, and the volume density is 2.9 g / cm 3 The room temperature compressive strength is 82.3 Mpa; the room temperature flexural strength is 8.62 MPa; the high temperature flexural strength of 1400℃×0.5h is 10 MPa; the apparent porosity is 10.3%.

[0123] Example 2

[0124] The difference from Example 1 is:

[0125] The raw materials of the magnesium spinel hot wet gunning material include: 45 wt% of magnesium spinel brick waste, 20 wt% of magnesia sand, 15 wt% of spinel, 10 wt% of α-alumina powder, 5 wt% of binder, 2 wt% of metal aluminum powder, 0.2 wt% of water reducer, and 2.8 wt% of polyaluminum chloride saturated solution.

[0126] The water reducing agent is acetone sulfonated carbonyl pyroaldehyde.

[0127] Application of magnesium spinel hot wet gunning material:

[0128] Add 2% water by weight to the above-mentioned magnesium spinel hot wet gunning material, mix well, pump and wet spray to the inner lining of the outer wall of the RH furnace immersion tube, without curing and baking (the curing and baking refers to the curing time of more than 6 hours, the baking time of more than 10 hours, and the material contains a large amount of free water and bound water), and start steel production after sintering at 1600℃ for 7 minutes. Observe the material peeling and use, and it can be used for 36 furnaces; take the gunning sample and bake it at 110℃ for 30 hours for testing, and the volume density is 3.11 g / cm 3 The room temperature compressive strength is 100.8 MPa; the room temperature flexural strength is 9.05 MPa; the high temperature flexural strength of 1400℃×0.5h is 10.5 MPa; the apparent porosity is 8.36%.

[0129] Example 3

[0130] The difference from Example 1 is:

[0131] The raw materials of the magnesium spinel hot wet gunning material include: 50 wt% of magnesium spinel brick waste, 20 wt% of magnesia sand, 15 wt% of spinel, 5 wt% of α-alumina powder, 5 wt% of binder, 2 wt% of metal aluminum powder, 0.1 wt% of water reducer, and 2.9 wt% of polyaluminum chloride saturated solution.

[0132] The water reducing agent is sodium polyacrylate and sodium polycarboxylate, with a mass ratio of 2:3.

[0133] Application of magnesium spinel hot wet gunning material:

[0134] Add 2% water by weight to the above-mentioned magnesium spinel hot wet gunning material, mix evenly, pump and wet spray to form on the inner lining of the outer wall of the RH furnace immersion tube, without curing and baking (the curing and baking refers to the curing time of more than 6 hours, the baking time of more than 10 hours, and the material contains a large amount of free water and bound water), and start steel production after sintering at 1600℃ for 7 minutes. Observe the material peeling and use, and it can be used for 37 furnaces; take the gunning sample and bake it at 110℃ for 30 hours for testing, and the volume density is 3.01 g / cm 3 The room temperature compressive strength is 98.6 MPa; the room temperature flexural strength is 9.65 MPa; the high temperature flexural strength of 1400℃×0.5h is 10.2 MPa; the apparent porosity is 9.08%.

[0135] Comparative Example 1

[0136] The difference from Example 1 is:

[0137] The binder is aluminum sol (nano alumina sol); the solid content of Al2O3 in the aluminum sol is 23%; and the room temperature viscosity of the binder is 1000 mPa·s.

[0138] The remaining materials and steps are the same as those in Example 1.

[0139] Application of magnesium spinel hot wet gunning material:

[0140] Add 2% water by weight to the above-mentioned magnesium spinel hot wet gunning material, mix well, pump and wet spray to the inner lining of the outer wall of the RH furnace immersion tube, no curing and baking is required (the curing and baking refers to a curing time of more than 6 hours, a baking time of more than 10 hours, and the material contains a large amount of free water and bound water), and start steel production after sintering at 1550℃ for 7 minutes. Observe the material peeling and use, and it can be used for 25 furnaces; take the gunning sample and bake it at 110℃ for 30 hours for testing, and the volume density is 2.8g / cm 3 The room temperature compressive strength is 75.2Mpa; the room temperature flexural strength is 5.13Mpa; the high temperature flexural strength of 1400℃×0.5h is 9.6Mpa; the apparent porosity is 15.6%.

[0141] Comparative Example 2

[0142] The difference from Example 1 is:

[0143] The binder is silica sol (nano silica sol); the solid content of SiO2 in the silica sol is 35%; and the room temperature viscosity of the binder is 1200 mPa·s.

[0144] The remaining materials and steps are the same as those in Example 1.

[0145] Application of magnesium spinel hot wet gunning material:

[0146] Add 2% water by weight to the above-mentioned magnesium spinel hot wet gunning material, mix evenly, pump and wet spray to form on the inner lining of the outer wall of the RH furnace immersion tube, without curing and baking (the curing and baking refers to the curing time of more than 6 hours, the baking time of more than 10 hours, and the material contains a large amount of free water and bound water), start steel production after sintering at 1550℃ for 7 minutes, observe the material peeling and use, and can be used for 23 furnaces; take the gunning sample and bake it at 110℃ for 30 hours for testing, and the volume density is 2.7g / cm 3 The room temperature compressive strength is 70.6Mpa; the room temperature flexural strength is 6.12Mpa; the high temperature flexural strength of 1400℃×0.5h is 8.3Mpa; the apparent porosity is 14.3%.

[0147] Comparative Example 3

[0148] The difference from Example 1 is:

[0149] The binder is zirconium oxide sol; the room temperature viscosity of the binder is 1200 mPa·s.

[0150] The remaining materials and steps are the same as those in Example 1.

[0151] Application of magnesium spinel hot wet gunning material:

[0152] Add 2% water by weight to the above-mentioned magnesium spinel hot wet gunning material, mix evenly, pump and wet spray to form on the lining of the outer wall of the RH furnace immersion tube, without curing and baking (the curing and baking refers to the curing time of more than 6 hours, the baking time of more than 10 hours, and the material contains a large amount of free water and bound water), start steel production after sintering at 1550℃ for 7 minutes, observe the material peeling and use, and can be used for 28 furnaces; take the gunning sample and bake it at 110℃ for 30 hours for testing, and the volume density is 2.94g / cm 3 The room temperature compressive strength is 79.5Mpa; the room temperature flexural strength is 7.68Mpa; the high temperature flexural strength of 1400℃×0.5h is 10.2Mpa; the apparent porosity is 17.6%.

[0153] Comparative Example 4

[0154] The difference from Example 1 is:

[0155] The saturated solution of polyaluminium chloride was replaced by pure calcium aluminate cement.

[0156] The remaining materials and steps are the same as those in Example 1.

[0157] Application of magnesium spinel hot wet gunning material:

[0158] Add 2% water by weight to the above-mentioned magnesium spinel hot wet gunning material, mix evenly, pump wet spraying to the inner lining of the outer wall of the RH furnace immersion tube, no curing and baking is required (the curing and baking refers to a curing time of more than 6 hours, a baking time of more than 10 hours, and the material contains a large amount of free water and bound water), and start steel production after sintering at 1550℃ for 7 minutes. Observe the material peeling and use, and it can be used for 20 furnaces; take the gunning sample and bake it at 110℃ for 30 hours for testing, and the volume density is 2.86g / cm 3 The room temperature compressive strength is 78.5Mpa; the room temperature flexural strength is 8.96Mpa; the high temperature flexural strength of 1400℃×0.5h is 6.31Mpa; the apparent porosity is 16.6%.

[0159] It can be seen from the test results that the magnesium spinel hot wet gunning material has the characteristics of good high temperature mechanical strength, excellent volume stability, long service life and low production cost during use. In addition, the magnesium spinel hot wet gunning material provided by the present invention is resistant to chemical corrosion during use.

[0160] The above description of the disclosed embodiments enables one skilled in the art to implement or use the present invention. Various modifications to these embodiments will be apparent to one skilled in the art, and the general principles defined herein may be implemented in other embodiments without departing from the spirit or scope of the present invention. Therefore, the present invention will not be limited to the embodiments shown herein, but rather to the widest scope consistent with the principles and novel features disclosed herein.

Claims

1. A magnesium spinel hot wet gunning material, comprising: Magnesium spinel brick waste 45 wt%~60 wt%; Magnesia 20 wt%~25 wt%; Spinel 15 wt%~20 wt%; α-alumina powder 5 wt%~10 wt%; Binder 5 wt%~10 wt%; Aluminum powder 1 wt%~2 wt%; Water reducing agent 0.1 wt%~0.2 wt%; Saturated polyaluminium chloride solution 1 wt%~3 wt%; The sum of the amounts of the components is 100%; The binder is aluminum sol and silica sol, and the mass ratio of aluminum sol to silica sol is 2.5-3.5:1.5-2.5; the solid content of Al2O3 in the aluminum sol is ≥20%; the solid content of SiO2 in the silica sol is ≥30%.

2. The magnesium spinel hot wet gunning material according to claim 1, characterized in that: The waste magnesia spinel bricks are the residual bricks after use of the lining of the RH cycle vacuum degassing furnace; specifically, the used magnesia-alumina spinel waste bricks and / or the used magnesia-chrome spinel waste bricks; in the waste magnesia-alumina spinel bricks, the mass content of MgO is ≥70%, and the mass content of Al2O3 is ≥22%.

3. The magnesium spinel hot wet gunning material according to claim 1, characterized in that: The particle size distribution of the magnesium spinel brick waste material includes: Particles smaller than 5 mm and greater than or equal to 3 mm: 15 wt%~25 wt%; 50 wt%~65wt% of particles smaller than 3mm and greater than or equal to 1mm; Particles smaller than 1 mm and greater than or equal to 0.088 mm: 20 wt%~25wt%; The sum of the amounts of the various components is 100%.

4. The magnesium spinel hot wet gunning material according to claim 1, characterized in that: The mass content of MgO in the magnesia is ≥96%; the particle gradation of the magnesia includes: 40 wt%~50 wt% for particles smaller than 3 mm and greater than or equal to 1 mm; 0.088~1 mm particles 42 wt%~50 wt%; Particles smaller than 0.088 mm 8 wt%~10 wt%; The sum of the amounts of the various components is 100%.

5. The magnesium spinel hot wet gunning material according to claim 1, characterized in that: In the spinel, the mass content of Al2O3 is ≥75%, and the mass content of MgO is ≥22%; The particle size distribution of the spinel includes: 0.088~1 mm particles 40 wt%~60 wt%; Particles smaller than 0.088 mm: 40 wt%~60 wt%; The sum of the amounts of the various components is 100%.

6. The magnesium spinel hot wet gunning material according to claim 1, characterized in that: The mass content of Al2O3 in the α-alumina micropowder is ≥98%; and the particle size of the α-alumina micropowder is ≤1 μm.

7. The magnesium spinel hot wet gunning material according to claim 1, characterized in that: The room temperature viscosity of the binder is ≤1000 mPa·s; The mass content of Al in the aluminum powder is ≥97%; and the particle size of the aluminum powder is ≤0.075 mm.

8. The magnesium spinel hot wet gunning material according to claim 1, characterized in that: The water reducing agent is selected from one or more of sodium polycarboxylate, sodium polyacrylate, sodium lignin sulfonate, acetone sulfonated carbonyl pyroaldehyde and melamine.

9. The magnesium spinel hot wet gunning material according to claim 1, characterized in that: The saturated polyaluminium chloride solution is obtained by dissolving solid powder of polyaluminium chloride in water; the mass content of Al2O3 in the saturated polyaluminium chloride solution is ≤29.0%, the basicity is 45.0%~90.0%, and the mass content of insoluble matter is ≤0.1%.

10. A preparation method for preparing the magnesium spinel hot wet gunning material according to any one of claims 1 to 9, comprising the following steps: The waste materials of magnesium spinel bricks, magnesia sand, spinel, alpha-alumina powder, binder, aluminum powder, water reducing agent and saturated polyaluminium chloride solution are mixed to obtain magnesium spinel hot wet gunning material.

11. Use of the magnesium spinel hot wet gunning material according to any one of claims 1 to 9 or the magnesium spinel hot wet gunning material prepared by the preparation method according to claim 10 in hot repair of the inner and outer lining parts of the immersion pipe and the circulation pipe of an RH cycle vacuum degassing furnace.

12. The use according to claim 11, characterized in that: The application comprises the following steps: Water is added to the magnesium spinel hot wet gunning material, mixed evenly, and pumped to form the material by wet spraying on the outer wall, inner wall and / or inner lining of the RH furnace immersion pipe.