High temperature fired magnesia zirconia slide plate brick reinforced with titanium and its production method

Abstract

The application relates to a high-temperature sintered magnesium-zirconium slide plate brick reinforced by titanium and a production method thereof, raw materials are as follows: 58-69.5% sintered magnesite, 10-15% large-crystal fused magnesite, 5-15% titanium reinforced corundum, 5-10% zirconium corundum, 0.5-1% silica ash, 2-3% metallic silicon, 1-2% metallic silicon powder, 1-2% magnesium-aluminum alloy, and 3-5% thermosetting phenolic resin binders of the total weight of the above raw materials are additionally added; the product has a porosity of 5-8%, a bulk density of 3.00-3.10 g / cm 3 , a normal-temperature compressive strength of 120-180 MPa, a normal-temperature bending strength of 15-35 MPa, a high-temperature bending strength of 15-18 MPa, and a residual bending strength retention rate (1100 DEG C water cooling for 3 times) of 62-73%. The slide plate brick contains only a small amount of resin and asphalt cracking carbon, has strong oxidation resistance, excellent thermal shock stability and erosion resistance, and is suitable for smelting of low-carbon steel, high-calcium steel, clean steel and other varieties of steel.

Description

TECHNICAL FIELD

[0001] The present application relates to a kind of high-temperature sintered magnesium-zirconium slide plate brick of titanium reinforced corundum addition and its production method, belong to functional refractory technical field. BACKGROUND

[0002] As the key component of the slide gate nozzle system, the performance and service life of the slide plate brick directly determine the quality of the slide gate nozzle system, and has a significant impact on the efficiency of continuous casting. At the same time, the slide plate brick is subjected to the erosion of high-temperature molten steel and the corrosion of molten steel during service, especially when smelting calcium-treated steel, high-manganese steel, and high-oxygen steel, the corrosion of the slide plate is more serious, and the slide plate brick has higher requirements for corrosion resistance and oxidation resistance.

[0003] Traditional slide plate bricks are usually carbon-containing refractory materials, commonly using aluminum-carbon and aluminum-zirconium-carbon, with a carbon content of about 5-10%. The traditional slide plate bricks have high carbon content during production and use, and the refractory material is lost during high-temperature service. Carbon dissolves in the molten steel, causing carbon pollution and affecting the quality of the steel. It is difficult to meet the needs of high-quality steel production such as clean steel and ultra-clean steel. At the same time, the high-temperature mechanical properties of the material are low, the carbon is poor in resistance to molten steel erosion and easy to oxidize, which affects the service life of the slide plate and directly affects the continuous casting efficiency. In addition, carbon is easy to oxidize when used at high temperatures, which destroys the material structure and affects the service life.

[0004] On the other hand, when traditional aluminum-carbon and aluminum-zirconium-carbon slide plate bricks are used to smelt high-calcium steel and high-manganese steel, the slide plate material is easy to form low-melting substances with Ca and Mn in the molten steel, causing abnormal erosion of the slide plate brick, affecting the safety factor and service life of the slide plate brick. Magnesia-carbon slide plate has superior corrosion resistance, but due to the large thermal expansion coefficient of periclase, the thermal shock stability of magnesia-carbon slide plate is poor, and the service life is relatively low. SUMMARY

[0005] In view of the shortcomings of the prior art, the present application aims to provide a high-temperature sintered magnesium-zirconium slide plate brick with titanium reinforced corundum addition and its production method.

[0006] To achieve the above-mentioned purpose, the technical solution adopted by the present application is:

[0007] A high-temperature sintered magnesium-zirconium slide plate brick with titanium reinforced corundum addition, the raw material composition is as follows in terms of weight percentage: 58-69.5% sintered magnesia, 10-15% large crystal fused magnesia, 5-15% titanium reinforced corundum, 5-10% zirconium corundum, 0.5-1% silica fume, 2-3% metallic silicon, 1-2% metallic silicon powder, 1-2% magnesium-aluminum alloy, plus 3-5% thermosetting phenolic resin binder based on the total weight of the above-mentioned raw materials.

[0008] The high-temperature sintered magnesium-zirconium slide plate brick with titanium reinforced corundum has the following components: TiO2: 15-18%, Al2O3: 70-75%, MgO≤5%, CaO≤1%, Fe2O3+SiO2≤2%, and the particle size is ≤0.074 mm.

[0009] The high-temperature sintered magnesium-zirconium slide plate brick with titanium reinforced corundum has the following components: TiO2: 15-18%, Al2O3: 70-75%, MgO≤5%, CaO≤1%, Fe2O3+SiO2≤2%, and the particle size is ≤0.074 mm.

[0010] The high-temperature sintered magnesium-zirconium slide plate brick with titanium reinforced corundum has the following components: TiO2: 15-18%, Al2O3: 70-75%, MgO≤5%, CaO≤1%, Fe2O3+SiO2≤2%, and the particle size is ≤0.074 mm.

[0011] The high-temperature sintered magnesium-zirconium slide plate brick with titanium reinforced corundum has the following components: TiO2: 15-18%, Al2O3: 70-75%, MgO≤5%, CaO≤1%, Fe2O3+SiO2≤2%, and the particle size is ≤0.074 mm.

[0012] The high-temperature sintered magnesium-zirconium slide plate brick with titanium reinforced corundum has the following components: TiO2: 15-18%, Al2O3: 70-75%, MgO≤5%, CaO≤1%, Fe2O3+SiO2≤2%, and the particle size is ≤0.074 mm.

[0013] The high-temperature sintered magnesium-zirconium slide plate brick with titanium reinforced corundum has the following components: TiO2: 15-18%, Al2O3: 70-75%, MgO≤5%, CaO≤1%, Fe2O3+SiO2≤2%, and the particle size is ≤0.074 mm.

[0014] The high-temperature sintered magnesium-zirconium slide plate brick with titanium reinforced corundum has the following components: TiO2: 15-18%, Al2O3: 70-75%, MgO≤5%, CaO≤1%, Fe2O3+SiO2≤2%, and the particle size is ≤0.074 mm.

[0015] The high-temperature sintered magnesium-zirconium slide plate brick with titanium reinforced corundum has the following components: TiO2: 15-18%, Al2O3: 70-75%, MgO≤5%, CaO≤1%, Fe2O3+SiO2≤2%, and the particle size is ≤0.074 mm.

[0016] The high-temperature sintered magnesium-zirconium slide plate brick with titanium reinforced corundum has the following components: TiO2: 15-18%, Al2O3: 70-75%, MgO≤5%, CaO≤1%, Fe2O3+SiO2≤2%, and the particle size is ≤0.074 mm.

[0017] (1) Weigh the raw materials according to the proportion and prepare them for use.

[0018] (2) Add the raw materials with a particle size ≤0.5mm to the cone mixer in the order of lightest to heaviest, mix for 20-30 minutes to obtain premixed powder;

[0019] (3) Add the particles larger than 0.5 mm in the raw materials to the roller mill and stir for 3-5 minutes. Add the thermosetting phenolic resin and stir for 5-8 minutes. After all the particles are wetted, add the premixed powder and continue mixing for 20-30 minutes to obtain the mud.

[0020] (4) After the temperature of the clay material is reduced to below 30°C, it is pressed and molded to obtain the blank of the sliding plate brick;

[0021] (5) After the billet is naturally dried for 24 hours, it is put into a dryer for drying. The heating rate is 10-15℃ / h, the drying temperature is 160-180℃, and the temperature is kept for 8-10 hours after the temperature reaches the drying temperature.

[0022] (6) The dried green body is fired in a nitrogen atmosphere at a temperature of 1100-1300℃ and a holding time of 6-10h.

[0023] (7) After firing, the product is impregnated with asphalt and annealed at 500℃-800℃; after impregnation with oil, it is processed by adding hoops, grinding and coating to make the target product.

[0024] Beneficial effects of this invention:

[0025] This invention improves the thermal shock stability of magnesia-zirconium slab slide blocks by modifying magnesia-carbon slab slide blocks and using non-oxide reinforcement and phase transformation microcrack toughening technology. At the same time, it eliminates the introduction of direct carbon sources and reduces the carbon content of slab slide blocks, thus developing high-performance magnesia-zirconium slab slide blocks.

[0026] (1) The high-temperature sintered magnesium zirconium low-carbon sliding plate brick of the present invention contains only a small amount of resin and pitch cracking carbon, has strong oxidation resistance, excellent thermal shock stability and erosion resistance, and is suitable for smelting of various steels such as low-carbon steel, high-calcium steel and clean steel.

[0027] (2) The granular aggregate in this invention is sintered magnesia, which can improve the thermal shock stability and erosion resistance of the slide block. The main crystalline phase of sintered magnesia is periclase grains with relatively small grain size, usually 30-50μm. The crystal size is uniform, the texture is pure, the material has multiple grain boundaries and microporous structures, few intercrystalline silicate phases, and crystals are mostly directly bonded. There are many closed pores in the crystals and between the crystals. The pore size is uniform, and the pore diameter is mostly below 5μm. It has good thermal shock resistance and slag erosion resistance.

[0028] (3) The large crystalline fused magnesia in the present application is introduced in the form of particles less than 0.5 mm and fine powder, which can significantly improve the corrosion resistance of the slide plate brick. Since the large crystalline fused magnesia has complete grain development, relatively large grain size, and low silicate phase content, the direct bonding degree of periclase is high, and the corrosion resistance is superior. The fine powder of the large crystalline fused magnesia is used together with high-purity brine magnesia aggregate to improve the thermal shock stability of the slide plate brick while improving the corrosion resistance of the slide plate brick.

[0029] (4) In the present application, titanium reinforced corundum raw material is introduced, and a high-temperature sintering heat treatment process is adopted. During the high-temperature heat treatment process, Ti2O3 in the titanium reinforced corundum, MgO in the magnesia, and ZrO2 in the zirconia corundum react to form a non-oxide solid solution reinforcing phase Mg 0.25 Zr 0.38 Ti 0.38 O 1.75 , which can improve the thermal shock stability of the slide plate brick (see Figure 1 );

[0030] (5) In the present application, silica fume is introduced. At high temperatures, the amorphous SiO2 in the silica fume, the aluminum-magnesium alloy, the Al2O3 in the titanium reinforced corundum, and the MgO in the magnesia form MgO-Al2O3-SiO2 system non-oxide reinforcing phases such as MgAl2O4 and Mg2SiO4, thereby improving the performance of the slide plate brick.

[0031] (6) In the present application, magnesium-aluminum alloy and metal silicon of different particle sizes and metal silicon powder are used as metal raw materials. By utilizing the differences in reactivity and melting point, the magnesium-aluminum alloy and the metal silicon undergo a temperature-based gradient reaction during the high-temperature sintering and use of the product, generating non-oxide reinforcing phases such as SiC and MgAl2O4, thereby continuously improving the performance of the slide plate brick.

[0032] (7) Zirconia corundum raw material is introduced into the magnesia system. By utilizing the micro-crack toughening characteristics generated by the phase transition of zirconia, the thermal shock stability of the slide plate brick is improved, and by utilizing the excellent chemical stability of zirconia, the corrosion resistance of the slide plate brick is improved.

[0033] (8) The slide plate brick of the present application has the advantages of high strength, good thermal shock stability, strong adaptability to steel grades, long service life, and the like, by using a reasonable raw material ratio and an optimized heat treatment process.

[0034] The performance indicators of the product measured by the test are as follows: apparent porosity 5-8%, bulk density 3.00-3.10 g / cm 3 , cold crushing strength 120-180 MPa, cold modulus of rupture 15-35 MPa, high-temperature modulus of rupture 15-18 MPa, and residual modulus of rupture retention rate (1100°C water cooling for 3 times) 62-73%.

[0035] The product of the application meets the performance index requirements of HBMLT-80 grade (immersion) in the YB / T 5049-2019 "Slip Plate Brick" industry standard: apparent porosity is less than or equal to 10%, volume density is greater than or equal to 2.80 g / cm 3 , normal temperature compressive strength is greater than or equal to 90 MPa, and has significant advantages. BRIEF DESCRIPTION OF DRAWINGS

[0036] Figure 1 XRD diffraction pattern of the product of the application. DETAILED DESCRIPTION

[0037] The specific embodiments of the application are further described in detail below in combination with examples.

[0038] Example 1

[0039] A high-temperature fired magnesium-zirconium slip plate brick with titanium reinforced corundum, the raw material composition is: 69.5% sintered magnesia, 15% large crystal fused magnesia, 5% titanium reinforced corundum, 5% zirconium corundum, 0.5% silica fume, 3% metallic silicon, 1% metallic silicon powder, 1% magnesium-aluminum alloy, plus 3% thermosetting phenolic resin binder of the total weight of the above raw materials.

[0040] Sintered magnesia: prepared by calcining high-purity magnesium hydroxide extracted from brine, MgO content is greater than or equal to 98.5%, including two kinds of 1mm < particle size 1 ≤ 3mm, 0.5mm < particle size 2 ≤ 1mm, different particle size weight ratio: particle size 1: particle size 2 = 35:34.5.

[0041] Large crystal fused magnesia: MgO content is greater than or equal to 98%, CaO / SiO2 content ratio is greater than 1.5, particle size is less than or equal to 0.044mm.

[0042] Titanium reinforced corundum: a molten slag waste during titanium-iron metallurgical smelting, prepared by 2000-2300 DEG C electric melting and impurity removal, particle size is less than or equal to 0.074mm, main components: TiO2: 15-18%, Al2O3: 70-75%, MgO ≤ 5%, CaO ≤ 1%, Fe2O3+SiO2 ≤ 2%.

[0043] Zirconium corundum: fine powder, particle size is less than or equal to 0.044mm, main components: ZrO2: 23-27%, Al2O3: 71-75%, SiO2 ≤ 0.5%, Fe2O3 ≤ 0.5%, Na2O ≤ 0.3%.

[0044] Silica fume: smoke dust collected and treated by a collection device during the high-temperature smelting of industrial silicon and silicon-iron by industrial electric furnaces, SiO2 content in silica fume is greater than or equal to 93%, average particle size is greater than 0.1um and less than or equal to 0.15um.

[0045] Metallic silicon powder: Si content ≥ 98%, particle size ≤ 0.044 mm.

[0046] Metallic silicon powder: Si content ≥ 98%, particle size ≤ 0.044 mm.

[0047] Magnesium-aluminum alloy: particle size ≤ 0.074 mm, magnesium-aluminum content ratio: Al:Mg = 1:1.

[0048] Phenolic resin: model PF5323.

[0049] The production method of the magnesium-zirconium slide plate brick comprises the following steps:

[0050] (1) The raw materials are weighed according to the proportion and prepared for use;

[0051] (2) First, the materials ≤ 0.5 mm in the raw materials are added to the conical mixer in the order of light first and heavy last, mixed for 20-30 min, and the premixed powder is obtained;

[0052] (3) Then, the granular materials greater than 0.5 mm in the raw materials are added to the wet grinder and stirred for 3-5 min, and then an appropriate amount of thermosetting phenolic resin is added and stirred for 5-8 min, and then the premixed powder is added after the granular materials are completely wetted, and the mixture is continuously mixed for 20-30 min, and the mud is obtained;

[0053] (4) After the temperature of the mud is reduced to below 30℃, the mud is pressed and formed to obtain the slide plate brick blank;

[0054] (5) After the blank is naturally dried for 24 h, it is dried in a dryer, the heating rate is 10-15℃ / h, the drying temperature is 160-180℃, and after the drying temperature reaches the target temperature, the temperature is kept for 8-10 h;

[0055] (6) The dried product is fired in a nitrogen atmosphere in a nitriding furnace, the firing temperature is 1300℃, and the holding time is 6 h;

[0056] (7) The fired product is treated by impregnating asphalt and annealing at 800℃, and after the oil-impregnated product is subjected to the processes of hoop adding, grinding and coating, the target product is obtained.

[0057] The product of the embodiment is subjected to XRD diffraction analysis of the phase composition of the product, as shown in Figure 1 .

[0058] As can be seen from Figure 1 : (1) The aluminum-magnesium alloy phase is not detected in the fired product, the magnesium-aluminum alloy has a low reaction temperature during firing, and the reaction is complete, a small amount of residual metal Si is detected, and the metal silicon of different particle sizes is partially reacted, and the remaining metal silicon will continuously react during the use of the product, thereby improving the use performance of the product; (2) After the product of the present application is fired at high temperature, MgAl2O4, Mg2SiO4, SiC and Mg0.25 Zr 0.38 Ti 0.38 O 1.75 New non-oxide reinforcing phase such as solid solution can significantly improve the performance of the product.

[0059] Performance index of the product: apparent porosity 5%, bulk density 3.10 g / cm 3 , cold crushing strength 120 MPa, cold modulus of rupture 15 MPa, hot modulus of rupture 15 MPa, residual modulus of rupture retention rate (1100℃ water cooling for 3 times) 62%.

[0060] Example 2

[0061] A high-temperature fired magnesium-zirconium slide plate brick reinforced by titanium corundum, according to weight percentage, the raw material composition is: 64% sintered magnesia, 12% large crystal fused magnesia, 10% titanium reinforced corundum, 8% zirconium corundum, 0.5% silica fume, 2.5% metallic silicon, 1.5% metallic silicon powder, 1.5% magnesium-aluminum alloy, plus 4% thermosetting phenolic resin binder in total weight of the above raw materials.

[0062] Sintered magnesia: MgO content ≥98.5%, including two kinds of 1mm < particle size 1 ≤3mm, 0.5mm < particle size 2 ≤1mm, different particle size weight ratio: particle size 1: particle size 2 = 35:29.

[0063] Large crystal fused magnesia: MgO content ≥98%, CaO / SiO2 content ratio >1.5, including two kinds of 0.044mm < particle size 3 ≤0.5mm, particle size 4 ≤0.044mm, different particle size weight ratio: particle size 3: particle size 4 = 5:7.

[0064] The performance requirements of other raw materials are the same as those in Example 1.

[0065] The production method of the magnesium-zirconium slide plate brick is basically the same as that in Example 1, except that:

[0066] Step (6) The dried product is fired in a nitrogen atmosphere in a nitriding furnace, the firing temperature is 1200℃, and the holding time is 8h;

[0067] Step (7) The fired product is treated by impregnating pitch and annealing at 600℃; the product after oil immersion is subjected to hoop adding, grinding, coating and other processes to become the target product.

[0068] The performance index of the obtained product: apparent porosity 6%, bulk density 3.06 g / cm 3 , cold crushing strength 145 MPa, cold modulus of rupture 26 MPa, hot modulus of rupture 16.5 MPa, residual modulus of rupture retention rate (1100℃ water cooling for 3 times) 67%.

[0069] Example 3

[0070] A high-temperature sintered magnesium-zirconium slide plate brick with titanium reinforced corundum, the raw material composition is: 58% sintered magnesia, 10% large crystal fused magnesia, 15% titanium reinforced corundum, 10% zirconium corundum, 1% silica fume, 2% metallic silicon, 2% metallic silicon powder, 2% magnesium-aluminum alloy, plus 5% thermosetting phenolic resin binder based on the total weight of the above raw materials.

[0071] Sintered magnesia: MgO content ≥98.5%, including two kinds of particle size 1mm < particle size 1 ≤3mm, 0.5mm < particle size 2 ≤1mm, different particle size weight ratio: particle size 1: particle size 2 = 35:23.

[0072] Large crystal fused magnesia: MgO content ≥98%, CaO / SiO2>1.5, including two kinds of 0.044mm < particle size 3 ≤0.5mm, particle size 4 ≤0.044mm, different particle size weight ratio: particle size 3: particle size 4 = 8:2.

[0073] The performance requirements of other raw materials are the same as in Example 1.

[0074] The production method of the magnesium-zirconium slide plate brick is basically the same as in Example 1, the difference is:

[0075] (6) The dried product is sintered in a nitrogen atmosphere in a nitriding furnace, the sintering temperature is 1100℃, and the holding time is 10h;

[0076] (7) The sintered product is treated by impregnating pitch and annealing at 500℃; the product after oil immersion is subjected to hoop adding, grinding, coating and other processes to become the target product.

[0077] The performance indicators of the obtained product are: apparent porosity 8%, bulk density 3.00g / cm 3 , cold crushing strength 180MPa, cold modulus of rupture 35MPa, high temperature modulus of rupture 18MPa, residual modulus of rupture retention rate (1100℃ water cooling 3 times) 73%.

[0078] The XRD diffraction patterns of the products of other examples are similar to those of Example 1.

Claims

1. A high temperature fired magnesium zirconium slide plate brick reinforced with titanium addition, characterized in that, The raw material composition is 58-69.5% sintered magnesia, 10-15% large crystal fused magnesia, 5-15% titanium reinforced corundum, 5-10% zirconium corundum, 0.5-1% silica ash, 2-3% metallic silicon, 1-2% metallic silicon powder, 1-2% magnesium-aluminum alloy, and 3-5% thermosetting phenolic resin binder based on the total weight of the above-mentioned raw materials; The Si content in the metallic silicon powder is ≥98%, and D50=1 μm; The Si content in the metallic silicon is ≥98%, and the particle size is ≤0.044 mm.

2. The high-temperature fired magnesia-zirconia slide plate brick reinforced with titanium addition according to claim 1, characterized in that, The MgO content in the sintered magnesia is ≥98.5%, including two kinds of granular materials with a particle size of 1 mm 3. The high-temperature fired magnesia-zirconia slide plate brick reinforced with titanium addition according to claim 1, characterized in that, The MgO content in the large crystal fused magnesia is ≥98%, the CaO / SiO2 content ratio is >1.5, and the particle size is: 0.044 mm 4. The high-temperature fired magnesia-zirconia slide plate brick reinforced with titanium addition according to claim 1, characterized in that, The main components of the titanium reinforced corundum are: TiO2: 15-18%, Al2O3: 70-75%, MgO≤5%, CaO≤1%, Fe2O3+SiO2≤2%, and the particle size is ≤0.074 mm.

5. The high-temperature fired magnesia-zirconia slide plate brick reinforced with titanium addition according to claim 1, characterized in that, The zirconium corundum is a fine powder with a particle size of ≤0.044 mm, and the main components are: ZrO2: 23-27%, Al2O3: 71-75%, SiO2≤0.5%, Fe2O3≤0.5%, Na2O≤0.3%.

6. The high-temperature fired magnesia-zirconia slide plate brick reinforced with titanium addition according to claim 1, characterized in that, The silica ash is the smoke dust collected and treated by a trapping device during the high-temperature smelting of industrial silicon and ferrosilicon, and the SiO2 content is ≥93%, and the average particle size is 0.1 μm 7. The high-temperature fired magnesia-zirconia slide plate brick reinforced with titanium addition according to claim 1, characterized in that, The magnesium-aluminum alloy has a particle size of ≤0.074 mm, and the magnesium-aluminum content ratio is: Al:Mg=1:

1.

8. The high-temperature fired magnesia-zirconia slide plate brick reinforced with titanium addition according to claim 1, characterized in that, The phenolic resin type is PF5323.

9. A method of producing a high-temperature fired magnesia-zirconia slide plate brick reinforced with titanium additions according to any one of claims 1 to 8, characterized in that The specific steps are: (1) weigh the raw materials according to the proportion, and prepare for use; (2) add the raw materials with a particle size of ≤0.5 mm in the raw materials to the conical mixer in the order of light first and heavy last, mix for 20-30 min, and obtain a premixed powder; (3) then add the granular materials with a particle size greater than 0.5 mm in the raw materials to the wheel mill and stir for 3-5 min, add the thermosetting phenolic resin, stir for 5-8 min, add the premixed powder after the granules are completely wetted, and continue to mix for 20-30 min to obtain a mud; (4) after the mud temperature is reduced to below 30℃, it is pressed into a green body; (5) after the green body is naturally dried for 24 h, it is dried in a dryer, the heating rate is 10-15℃ / h, the drying temperature is 160-180℃, and after the temperature reaches the drying temperature, it is kept for 8-10 h; (6) the dried green body is fired in a nitrogen atmosphere, the firing temperature is 1100-1300℃, and the holding time is 6-10 h; (7) after firing, the product is treated with impregnated pitch and annealed at 500-800℃; after oil immersion, it is subjected to hoop adding, grinding and coating processes to obtain the target product.

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