A regenerated carbon fiber and boron nitride nanosheet coupling reinforced and toughened spinel slide and a preparation process thereof

Abstract

The present application relates to a kind of regenerative carbon fiber and boron nitride nanosheet coupling reinforced toughened magnesium spinel slide and its preparation process, using magnesium aluminate spinel, regenerative carbon fiber and boron nitride nanosheet mixture, aluminum fiber, binder as raw material, after mixing and grinding forming, 670~690 ℃ 3~6h heat preservation is fired.The magnesium spinel slide prepared by the present application has excellent mechanical strength, thermal shock resistance, alkali resistance and oxidation resistance, and is used for special steel continuous sliding frequency more than 4 times.

Description

TECHNICAL FIELD

[0001] The application relates to a recycled carbon fiber and boron nitride nanosheet coupled reinforced and toughened magnesia spinel slide plate and a preparation process thereof, and belongs to the field of high-temperature ceramics and refractory materials in the discipline of inorganic non-metallic materials. BACKGROUND

[0002] With the progress of metallurgical technology, the high carbon content of the magnesia-alumina spinel carbon slide plate leads to problems such as carbon pickup of molten steel, poor high-temperature mechanical properties compared with aluminum carbon slide plates, and the like, which limits its use in special steel smelting. Introducing smaller size carbon sources is a common method to reduce the carbon content of the slide plate, but small size carbon sources have the disadvantages of high price and easy agglomeration.

[0003] Patent CN113831111B discloses a carbon fiber added unburned aluminum carbon slide plate and a preparation method thereof, which is characterized in that the carbon fiber is etched with nitric acid and then ultrasonically immersed in silica sol to obtain silica sol coated carbon fiber which is introduced into the unburned aluminum carbon slide plate. Although the application effectively solves the dispersion problem of carbon fiber in the slide plate and improves the strength, toughness, thermal shock resistance and corrosion resistance of the slide plate, it has problems such as complex processing technology, mismatch between the price of carbon fiber raw materials and the production cost of the slide plate, and the like, which limit the large-scale industrial application of the preparation process. Patent CN108585797B discloses a self-lubricating magnesia stopper slide plate brick added with boron nitride and a preparation method thereof, which is characterized in that the raw materials and the weight percentage of the slide plate brick are as follows: 20-25% of magnesia-chromia-alumina sand with a particle size of 0-1mm, 18-20% of magnesia-chromia-alumina sand with a particle size of 1-3mm, 22-25% of magnesia-chromia-alumina sand with a particle size of 3-5mm, 12% of magnesia-zirconia sand fine powder, 4-5% of alpha-Al2O3 micro powder, 1-3% of silicon carbide fine powder, 2-5% of metallic silicon powder, 2-4% of carbon black, 4% of high-temperature reinforcing agent, 2% of Guangxi white clay, and 3-5% of boron nitride; and 3-6% of 5323 phenolic resin binder is additionally added. Although the application has good high-temperature resistance, corrosion resistance, erosion resistance and thermal shock stability, it does not consider the problems such as the fact that the high-temperature mechanical property enhancement of carbon black is not obvious, the high content of carbon black, and large-size boron nitride.

[0004] In view of the above problems, the application uses boron nitride and carbon fiber reinforced resin-based solid waste to co-grind, obtains cheap and well-dispersed carbon fiber and boron nitride nanosheet, uniformly introduces the carbon fiber and boron nitride nanosheet into the magnesia-alumina spinel slide plate, and uses the high strength, good slag corrosion resistance, high thermal conductivity and small thermal expansion coefficient of the recycled carbon fiber and boron nitride nanosheet to reduce the carbon content of the slide plate, improve the brittleness of the slide plate itself, improve the fracture strength of the slide plate, slow down the problem of thermal stress concentration of the slide plate due to sharp temperature fluctuations, meet the use requirements of special steel such as calcium-treated steel and low-carbon steel in continuous casting production, and develop a recycled carbon fiber and boron nitride nanosheet coupled reinforced and toughened magnesia spinel slide plate. SUMMARY

[0005] The application discloses a regenerated carbon fiber and boron nitride nanosheet coupled reinforced and toughened magnesium spinel alkaline slide and a preparation process thereof. Raw materials of a formula are as follows in terms of percentage by weight:

[0006] (1) 38-50% of magnesium aluminum spinel with a particle size of 3-1mm,

[0007] (2) 8-12% of magnesium aluminum spinel with a particle size of 1-0mm,

[0008] (3) 10-15% of magnesium aluminum spinel with a particle size of less than 0.074mm,

[0009] (4) 25-30% of magnesium aluminum spinel with a particle size of less than 5um,

[0010] (5) 0.5-1% of carbon fiber reinforced resin-based solid waste,

[0011] (6) h 1.5-2% of BN powder,

[0012] (7) 3-6% of aluminum fiber with a particle size of 3-10mm,

[0013] (8) 3-6% of a binder.

[0014] The binder of the raw material (8) is a phenolic resin, and is additionally added and not included in the total mass percentage of the raw materials.

[0015] Specific process steps are as follows:

[0016] (1) Preparation of regenerated carbon fiber and boron nitride nanosheet: carbon fiber reinforced resin-based solid waste is poured into a pulverizer for pulverization, and h BN powder is poured into a ball mill and ball milled at-40 DEG C for 3h, and then the pulverized and ball milled materials are mixed and co-milled for 3-5min to obtain a mixture of regenerated carbon fiber and boron nitride nanosheet;

[0017] (2) Fine powder premixing: magnesium aluminum spinel with a particle size of less than 0.074mm, magnesium aluminum spinel with a particle size of less than 5um and aluminum fiber with a particle size of 3-10mm are weighed according to proportions and put into an airflow mixer, and premixing of the fine powder is completed by relying on the impact of the compressed gas spirally rising in the equipment;

[0018] (3) Mixing: magnesium aluminum spinel with a particle size of 3-1mm and magnesium aluminum spinel with a particle size of 1-0mm are mixed, and then the mixture of regenerated carbon fiber and boron nitride nanosheet and the premixed fine powder are sequentially added, and high-speed mixing and rolling are performed for 10-15min;

[0019] (4) Discharging and compacting;

[0020] (5) Pressing forming;

[0021] (6) drying: after natural drying for 24-36h, drying at 220-260℃ for 36-48h;

[0022] (7) sintering: heat treating the dried semi-finished product at 670-690℃ for 3-6h;

[0023] (8) finishing treatment: grinding, hoop beating, non-working surface veneering, inspection and packaging of the sintered and cooled semi-finished product.

[0024] The application uses regenerated carbon fibers and boron nitride nanosheets to prepare magnesium spinel slide plates, which not only effectively reduces the carbon content in the slide plate, but also improves the mechanical properties of the slide plate. The regenerated carbon fiber is made by crushing carbon fiber reinforced resin-based solid waste, which not only has the advantages of low price and high tensile strength as a substitute for carbon source, but also solves the serious environmental problem caused by the difficulty of natural degradation of carbon fiber reinforced resin-based solid waste, realizing the recycling of solid waste materials. The boron nitride nanosheet is obtained by exfoliating h -BN at low temperature, solving the problem of easy agglomeration during the preparation of two-dimensional nanosheets. By introducing boron nitride nanosheets with good mechanical properties, small thermal expansion coefficient, high thermal conductivity and higher oxidation initiation temperature than graphite, part of the carbon source is replaced, effectively reducing the carbon content of the material while improving the strength and oxidation resistance of the material.

[0025] The application constructs a continuous regenerated carbon fiber-boron nitride nanosheet three-dimensional network in the slide plate matrix, effectively connects one-dimensional materials and two-dimensional materials, bears part of the stress load, and realizes the toughening of the slide plate by the coupling effect of the two.

[0026] Compared with the prior art, the technical characteristics of the regenerated carbon fiber and boron nitride nanosheet coupling enhanced and toughened magnesium spinel alkaline slide plate of the application are:

[0027] (1) Using boron nitride nanosheets to replace part of the carbon source effectively reduces the carbon content of the slide plate while ensuring that the comprehensive performance of the slide plate does not decrease. (2) A regenerated carbon fiber-boron nitride nanosheet three-dimensional network is constructed in the slide plate matrix, and the coupling effect of the two realizes the toughening of the slide plate. (3) The oxidation initiation temperature of boron nitride nanosheet is higher than that of graphite and other carbon sources, and replacing part of the carbon source can effectively improve the oxidation resistance of the slide plate. DETAILED DESCRIPTION Example 1

[0028] According to the following formula (weight and particle size content) as follows:

[0029] (1) 38% of magnesium aluminum spinel with particle size of 3-1mm,

[0030] (2) 10% of magnesium aluminum spinel with particle size of 1-0mm,

[0031] (3) Magnesium aluminate spinel 13% with particle size ≤0.074 mm,

[0032] (4) Magnesium aluminate spinel 30% with particle size ≤5 μm,

[0033] (5) Carbon fiber reinforced resin-based solid waste 0.5%,

[0034] (6) h -BN powder 1.5%,

[0035] (7) Aluminum fiber 6% with particle size 3-10 mm,

[0036] (8) Externally added, binder phenolic resin 6%, not included in the total mass percentage of raw materials.

[0037] Specifically includes the following process steps:

[0038] (1) Preparation of regenerated carbon fiber and boron nitride nanosheet: pour the carbon fiber reinforced resin-based solid waste into a pulverizer for pulverization, pour the h-BN powder into a ball mill for ball milling at -40°C for 3 h, and then mix and co-mill the pulverized and ball milled materials for 3 min to obtain a mixture of regenerated carbon fiber and boron nitride nanosheet;

[0039] (2) Fine powder premixing: weigh the magnesium aluminate spinel with particle size ≤0.074 mm, the magnesium aluminate spinel with particle size ≤5 μm, and the aluminum fiber with particle size 3-10 mm according to the proportion, and put the above fine powder into an air flow mixer to complete the premixing of the fine powder by relying on the impact of the compressed gas spirally rising in the equipment;

[0040] (3) Mixing: mix the magnesium aluminate spinel with particle size 3-1 mm and the magnesium aluminate spinel with particle size 1-0 mm, and then sequentially add the mixture of regenerated carbon fiber and boron nitride nanosheet and the premixed fine powder, and mix and roll at high speed for 15 min;

[0041] (4) Discharging and compacting;

[0042] (5) Pressing forming;

[0043] (6) Drying: natural drying for 36 h, and then drying at 220°C for 48 h;

[0044] (7) Sintering: heat treatment of the dried semi-finished product at 690°C for 6 h;

[0045] (8) Finishing treatment: grinding, hoop punching, non-working face veneering, inspection, and packaging of the sintered and cooled semi-finished product.

[0046] The volume density of Example 1 is 3.03 g / cm 3The apparent porosity is 7.8%, the normal temperature pressure strength reaches 90 MPa, the high temperature bending strength (1400 DEG C x 0.5h) is 12 MPa, the 1100 DEG C water cooling rapid cooling cycle times is greater than 6 times, the air oxidation area ratio (1500 DEG C x 24h) is 15.3%, the average service life in the 120 ton ladle special steel continuous casting of a special steel factory is 4 times, the used slide plate has micro cracks, no through cracks and no peeling.

[0047] Example 2

[0048] According to the following formula (weight and particle size content) as follows:

[0049] (1) 50% of magnesium aluminate spinel with particle size of 3-1mm,

[0050] (2) 8% of magnesium aluminate spinel with particle size of 1-0mm,

[0051] (3) 10% of magnesium aluminate spinel with particle size of less than 0.074mm,

[0052] (4) 25% of magnesium aluminate spinel with particle size of less than 5um,

[0053] (5) 1% of carbon fiber reinforced resin-based solid waste,

[0054] (6) h -2% of BN powder,

[0055] (7) 4% of 3-10mm aluminum fiber,

[0056] (8) 3% of additional binder phenolic resin, which is not included in the total mass percentage of raw materials.

[0057] Specifically includes the following process steps:

[0058] (1) Preparation of regenerated carbon fiber and boron nitride nanosheet: pour the carbon fiber reinforced resin-based solid waste into a pulverizer for crushing, pour the h-BN powder into a ball mill and ball mill at -40 DEG C for 3h, then mix and co-mill the pulverized and ball milled materials for 5min to obtain a mixture of regenerated carbon fiber and boron nitride nanosheet;

[0059] (2) Fine powder premixing: weigh the magnesium aluminate spinel with particle size of less than 0.074mm, the magnesium aluminate spinel with particle size of less than 5um and the 3-10mm aluminum fiber according to the proportion, and put the above fine powder into an air flow mixer to complete the premixing of the fine powder by relying on the impact of the compressed gas rising spirally in the equipment;

[0060] (3) Mixing: mix the magnesium aluminate spinel with particle size of 3-1mm and the magnesium aluminate spinel with particle size of 1-0mm, then sequentially add the mixture of regenerated carbon fiber and boron nitride nanosheet and the premixed fine powder, and high-speed mix and roll for 10min;

[0061] (4) Discharging and material blocking;

[0062] (5) Press forming;

[0063] (6) Drying: after natural drying for 24h, drying at 260℃ for 36h;

[0064] (7) Sintering: heat treatment of the dried semi-finished product at 670℃ for 3h;

[0065] (8) Finishing treatment: grinding, hoop punching, non-working surface facing, inspection, and packaging of the sintered and cooled semi-finished product.

[0066] The volume density of the example 2 is 3.06g / cm 3 , the apparent porosity is 8.3%, the cold crushing strength reaches 97MPa, the hot modulus of rupture (1400℃×0.5h) is 14MPa, the water-cooling quenching cycle times at 1100℃ is greater than 6, the oxidation area ratio in air (1500℃×24h) is 20.3%, the average service life in a 120-ton ladle special steel continuous casting of a certain special steel factory is 4 times, the used slide plate has micro-cracks, no through cracks, and no peeling.

[0067] Example 3

[0068] According to the following formula (weight and particle size content) as follows:

[0069] (1) 40% of magnesium aluminate spinel with particle size of 3~1mm,

[0070] (2) 12% of magnesium aluminate spinel with particle size of 1~0mm,

[0071] (3) 15% of magnesium aluminate spinel with particle size of ≤0.074mm,

[0072] (4) 26% of magnesium aluminate spinel with particle size of ≤5μm,

[0073] (5) 0.75% of carbon fiber reinforced resin-based solid waste,

[0074] (6) h -1.75% of BN powder,

[0075] (7) 4.5% of aluminum fiber with particle size of 3~10mm,

[0076] (8) Additional, 4.5% of binder phenolic resin, which is not included in the total mass percentage of raw materials.

[0077] Specifically includes the following process steps:

[0078] (1) Preparation of recycled carbon fiber and boron nitride nanosheet: pour the carbon fiber reinforced resin-based solid waste into a pulverizer for crushing, pour the h-BN powder into a ball mill for ball milling at -40°C for 3h, and then mix and co-mill the crushed and ball milled materials for 4min to obtain a mixture of recycled carbon fiber and boron nitride nanosheet;

[0079] (2) Fine powder premixing: weigh the magnesium aluminate spinel with a particle size of ≤0.074mm, the magnesium aluminate spinel with a particle size of ≤5μm, and the aluminum fiber with a particle size of 3~10mm according to the proportion, and put the above fine powder into an air flow mixer to complete the premixing of the fine powder by relying on the impact of the compressed gas spirally rising in the equipment;

[0080] (3) Mixing: mix the magnesium aluminate spinel with a particle size of 3~1mm and the magnesium aluminate spinel with a particle size of 1~0mm, and then sequentially add the mixture of recycled carbon fiber and boron nitride nanosheet and the premixed fine powder, and mix and roll at high speed for 13min;

[0081] (4) Discharging and compacting;

[0082] (5) Pressing forming;

[0083] (6) Drying: after natural drying for 30h, dry at 240°C for 42h;

[0084] (7) Sintering: heat treat the dried semi-finished product at 680°C for 5h;

[0085] (8) Finishing treatment: grind, hoop, non-working face veneer, inspect, and package the sintered and cooled semi-finished product.

[0086] The volume density of Example 1 is 3.04g / cm 3 , the apparent porosity is 7.3%, the cold crushing strength reaches 96MPa, the high temperature bending strength (1400℃×0.5h) is 14MPa, the water cooling quenching cycle times at 1100℃ is greater than 6 times, the oxidation area ratio in air (1500℃×24h) is 13.7%, and the average service life in the use of a 120-ton ladle special steel continuous casting in a certain special steel plant is 4 times, the used slide plate has micro cracks, no through cracks, and no peeling.

[0087] Comparative Example 1

[0088] The following formula (weight and particle size content) is as follows:

[0089] (1) 40% of the magnesium aluminate spinel with a particle size of 3~1mm,

[0090] (2) 12% of the magnesium aluminate spinel with a particle size of 1~0mm,

[0091] (3) 15% of the magnesium aluminate spinel with a particle size of ≤0.074mm,

[0092] (4) Magnesium aluminate spinel with particle size of 5 pm or less 26.75%,

[0093] (5) h BN powder 1.75%,

[0094] (6) Aluminum fiber with a length of 3-10 mm 4.5%,

[0095] (7) Additional, binder phenolic resin 4.5%, not included in the total mass percentage of raw materials.

[0096] Specifically includes the following process steps:

[0097] (1) Preparation of boron nitride nanosheets: h-BN powder is poured into a ball mill and ball milled at -40°C for 3 h to obtain boron nitride nanosheets;

[0098] (2) Fine powder premixing: Magnesium aluminate spinel with a particle size of 0.074 mm or less, magnesium aluminate spinel with a particle size of 5 pm or less, and aluminum fiber with a length of 3-10 mm are weighed according to the proportion, and the above fine powders are put into an air flow mixer to complete the premixing of the fine powders by relying on the impact of the compressed gas spirally rising in the equipment;

[0099] (3) Mixing: Magnesium aluminate spinel with a particle size of 3-1 mm and magnesium aluminate spinel with a particle size of 1-0 mm are mixed, and then boron nitride nanosheets and premixed fine powders are added in turn and mixed at high speed for 13 min;

[0100] (4) Discharging and compacting;

[0101] (5) Pressing;

[0102] (6) Drying: After natural drying for 30 h, drying at 240°C for 42 h;

[0103] (7) Firing: The dried semi-finished product is heat treated at 680°C for 5 h;

[0104] (8) Finishing treatment: The semi-finished product after firing and cooling is ground, hooped, non-working face veneered, inspected, and packaged.

[0105] The volume density of Comparative Example 1 is 3.04 g / cm 3 , the apparent porosity is 9.0%, the cold crushing strength reaches 76 MPa, the hot modulus of rupture (1400°C x 0.5h) is 9 MPa, the number of water cooling and quenching cycles at 1100°C is 5 times, and the oxidation area ratio in air (1500°C x 24h) is 12.6%. Compared with Example 3, the formula does not use carbon fiber reinforced resin-based solid waste, and the recycled carbon fiber is not introduced into the slide, the strength is significantly reduced, and the thermal shock resistance is also slightly decreased. If applied to calcium treatment steel continuous casting production, the number of continuous slides must be reduced. Therefore, it is very necessary to add 0.5-1% of carbon fiber reinforced resin-based solid waste.

[0106] Comparative Example 2

[0107] According to the following formula (weight and particle size content) as follows:

[0108] (1) Magnesium aluminate spinel with particle size of 3-1 mm 50%,

[0109] (2) Magnesium aluminate spinel with particle size of 1-0 mm 8%,

[0110] (3) Magnesium aluminate spinel with particle size of ≤0.074 mm 10%,

[0111] (4) Magnesium aluminate spinel with particle size of ≤5 μm 27%,

[0112] (5) Carbon fiber reinforced resin-based solid waste 1%,

[0113] (6) Aluminum fiber with particle size of 3-10 mm 4%,

[0114] (7) Extra, binder phenolic resin 3%, not included in the total mass percentage of raw materials.

[0115] Specifically includes the following process steps:

[0116] (1) Preparation of regenerated carbon fiber: pour the carbon fiber reinforced resin-based solid waste into a pulverizer for crushing to obtain regenerated carbon fiber;

[0117] (2) Fine powder premixing: weigh the magnesium aluminate spinel with particle size of ≤0.074 mm, the magnesium aluminate spinel with particle size of ≤5 μm, and the aluminum fiber with particle size of 3-10 mm according to the proportion, and put the above fine powder into an air flow mixer to complete the premixing of the fine powder by relying on the impact of the compressed gas spirally rising in the equipment;

[0118] (3) Mixing: mix the magnesium aluminate spinel with particle size of 3-1 mm and the magnesium aluminate spinel with particle size of 1-0 mm, and then add the regenerated carbon fiber and the premixed fine powder in turn, and mix and roll at high speed for 10 min;

[0119] (4) Discharge and packing;

[0120] (5) Pressing forming;

[0121] (6) Drying: after natural drying for 24 h, dry at 260℃ for 36 h;

[0122] (7) Sintering: heat treat the dried semi-finished product at 670℃ for 3 h;

[0123] (8) Finishing treatment: grind, hoop, non-working face veneer, inspect, and package the sintered and cooled semi-finished product.

[0124] The bulk density of Example 2 is 3.05 g / cm 3, the apparent porosity is 9.8%, the cold crushing strength reaches 79 MPa, the hot modulus of rupture (1400℃×0.5h) is 7 MPa, the number of water cooling and air cooling cycles at 1100℃ is 4, and the oxidation area ratio (1500℃×24h) in air is 32.5%. Compared with Example 2, the BN powder is not used in the formula, the high-temperature modulus of rupture is significantly reduced, the thermal shock resistance is reduced, and the oxidation resistance is reduced. If applied to calcium-treated steel continuous casting production, the damage risk is increased. Therefore, it is very necessary to add 1.5~2% h BN powder. h BN powder is very necessary.

[0125] The raw material specifications, formulas and test performances of the slide plates prepared in the above examples and comparative examples are as follows Table 1:

[0126] Table 1 Raw material specifications, formulas and test performances of slide plates

[0127]

Claims

1. A recycled carbon fiber and boron nitride nanoplatelet coupled reinforced and toughened magnesia spinel skateboard, the characteristic technology of which is The formula is as follows in percentage by weight: (1) 38-50% of magnesium aluminate spinel with particle size of 3-1mm, (2) 8-12% of magnesium aluminate spinel with particle size of 1-0mm, (3) 10-15% of magnesium aluminate spinel with particle size of ≤0.074mm, (4) 25-30% of magnesium aluminate spinel with particle size of ≤5μm, (5) 0.5-1% of carbon fiber reinforced resin-based solid waste material, (6) h - BN powder 1.5-2%, (7) 3-6% of aluminum fiber with particle size of 3-10mm, (8) 3-6% of binder, which is not included in the total mass percentage of raw materials.

2. The recycled carbon fiber and boron nitride nanoplatelet coupled reinforced and toughened magnesia spinel skateboard of claim 1, wherein: The binder (8) is phenolic resin.

3. A preparation process of the regenerated carbon fiber and boron nitride nanosheet coupled enhanced and toughened magnesium spinel skateboard according to any one of claims 1-2, comprising the following process steps: (1) Preparation of recycled carbon fiber and boron nitride nanosheet: pour the carbon fiber reinforced resin-based solid waste into a pulverizer for crushing, and then h pour the BN powder into a ball mill and ball mill for 3 h at -40°C, and then mix the crushed and ball milled materials for 3-5 min, to obtain a mixture of recycled carbon fiber and boron nitride nanosheet; (2) Fine powder premixing: magnesium aluminate spinel with particle size of ≤0.074mm, magnesium aluminate spinel with particle size of ≤5μm, and aluminum fiber with particle size of 3-10mm are weighed in proportion, and the above fine powders are put into an air flow mixer, and premixing of the fine powders is completed by relying on the impact of the compressed gas spirally rising in the equipment; (3) Mixing: magnesium aluminate spinel with particle size of 3-1mm and magnesium aluminate spinel with particle size of 1-0mm are mixed, and then the mixed material of regenerated carbon fiber and boron nitride nanosheet and the premixed fine powder are sequentially added, and high-speed mixing and rolling are performed for 10-15min; (4) Discharging and compacting; (5) Pressing forming; (6) Drying: after natural drying for 24-36h, drying at 220-260℃ for 36-48h is further performed; (7) Sintering: the dried semi-finished product is heat treated at 670-690℃ for 3-6h; (8) Finishing treatment: the semi-finished product after sintering and cooling is subjected to grinding, hoop beating, non-working face veneering, inspection, and packaging.

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