Al-La-Ce series rare earth composite high-heat-storage refractory clay brick and preparation method thereof

Abstract

The invention provides an Al-La-Ce series rare earth composite high heat storage refractory clay brick and a preparation method thereof, and relates to the technical field of refractory bricks, the refractory brick comprises the following raw materials by weight: 10-25 parts of 3-2mm kaolin, 12-20 parts of 2-1mm kaolin, 30-40 parts of 1-0.088 mm kaolin, 18-22 parts of less than 0.088 mm kaolin, 8-16 parts of soft clay powder, 3-5 parts of lignin combined slurry, and 1-10 parts of a rare earth functional additive; wherein the rare earth functional additive comprises a lanthanum element and a cerium element. After the clay refractory brick is modified by the rare earth additive, the prepared finished product has the advantages that the normal-temperature strength is increased, the water absorption rate is reduced, the refractoriness under load is increased, the heat storage rate is increased, and the saturated heat storage rate is increased; and the operation stability and the heat energy conversion efficiency of the hot-blast stove are improved.

Description

Technical Field

[0001] The invention belongs to the technical field of refractory bricks, and in particular relates to an Al-La-Ce series rare earth composite high heat storage clay refractory brick and a preparation method thereof. Background Art

[0002] The regenerator is the most important component of the hot blast stove. It is generally a vertically placed cylindrical structure, which is a space filled with checker bricks. The flue gas from the combustion chamber flows downward into the regenerator where the regenerator is stacked. The regenerator must have fast heat transfer and large heat storage, and the temperature level must be as high as possible. The main function of the regenerator is to withstand the pressure of the airflow and the force (structural stress and thermal stress) of the checker bricks (or refractory balls) on it, maintain the appropriate temperature environment of the regenerator, and the stability of its own structure. Due to the large temperature change from top to bottom, different materials must be used for masonry in order to ensure structural stability (the basic choice is to be consistent with the material of the checker bricks), and it must be ensured that it has a corresponding structure to release its internal stress in the upper and lower directions, that is, a labyrinth connection device that can slide between them during combustion is set.

[0003] Checker bricks are made of different materials according to their working temperatures. The temperature of the part close to the combustion chamber is high, so materials with good high temperature performance and strong anti-adhesion ability are selected, such as siliceous or low creep high alumina materials. The temperature of the part close to the cold wind is low, so materials with good low temperature performance and high strength are selected, such as clay or andalusite clay. The material in the middle part is transitional, but high temperature performance is still its main requirement, such as high alumina or andalusite high alumina. In addition, there are enough expansion gaps between checker bricks during stacking, so that each checker brick can release the volume expansion caused by the temperature increase to avoid additional thermal stress.

[0004] The main features of checker bricks are that they can store a certain amount of heat in a certain period of time, and they have low creep rate, high refractoriness, and good chemical stability. Therefore, there is a great demand for checker bricks in blast furnace hot blast furnaces. However, there are many problems with the current use of checker bricks. In recent years, some formulations and data parameters have been disclosed in literature reports, and there are some common problems, including: the shape and size of checker bricks are used to improve the heat absorption and release capacity, but the material itself is not studied; low high temperature strength and life; unstable creep rate and potential safety hazards; therefore, the overall stability and heat absorption and release efficiency are the focus that urgently needs to be improved. Summary of the invention

[0005] In view of the above-mentioned deficiencies in the prior art, the present invention provides an Al-La-Ce series rare earth composite high heat storage clay refractory brick and a preparation method thereof to solve the problems raised in the above-mentioned background technology.

[0006] In order to solve the above technical problems, the technical solution specifically adopted by the present invention is:

[0007] The first aspect of the present invention provides an Al-La-Ce series rare earth composite high heat storage clay refractory brick, comprising the following raw materials in parts by weight: 10 to 25 parts of 3-2 mm kaolin, 12 to 20 parts of 2-1 mm kaolin, 30 to 40 parts of 1-0.088 mm kaolin, 18 to 22 parts of kaolin less than 0.088 mm, 8 to 16 parts of soft clay powder, 3 to 5 parts of lignin-bound slurry, and 1 to 10 parts of rare earth functional additives; wherein the rare earth functional additives contain lanthanum and cerium.

[0008] As a further illustration of the present invention, the rare earth functional additive is a mixture of lanthanum oxide, cerium oxide, praseodymium oxide and magnesia.

[0009] As a further illustration of the present invention, the mass ratio of lanthanum oxide, cerium oxide, praseodymium oxide and magnesia in the rare earth functional additive is 2.5-4.2:1.5-2.5:0-0.5:3-5.

[0010] As a further illustration of the present invention, the lignin-bound pulp is prepared by mixing calcium lignin sulfonate powder with water, and the Baume degree of the obtained lignin-bound pulp is 1.13.

[0011] The second aspect of the present invention provides a method for preparing the Al-La-Ce rare earth composite high heat storage clay refractory brick described in any one of the above, comprising the following steps:

[0012] S1. Ingredients: Weigh kaolin, soft clay powder and rare earth functional additive raw materials respectively according to any of the weight ratios described above;

[0013] S2, obtaining lignin-bound slurry by a water-soluble method;

[0014] S3, raw material mixing: kaolin, soft clay powder, lignin binding slurry and rare earth functional additives are stirred and mixed to obtain a semi-dry mixture;

[0015] S4, pressing and molding: placing the semi-dry mixture obtained in step S3 in a brick press mold and pressing and molding to obtain a semi-finished refractory brick;

[0016] S5, firing: drying, high-temperature sintering and cooling the semi-finished refractory bricks to obtain finished rare earth composite high heat storage clay refractory bricks.

[0017] As a further illustration of the present invention, step S2 specifically comprises: stirring calcium lignin sulfonate powder in 45° C. water to obtain a lignin-bound slurry having a Baume degree of 1.13.

[0018] As a further illustration of the present invention, the raw material mixing process of step S3 specifically includes:

[0019] S301: Premixing: Use a three-dimensional premixer to premix kaolin with a particle size less than 0.088 mm, soft clay powder and rare earth functional additive powder for 15-20 minutes;

[0020] S302: Mixing: Pour the prepared 3-2 mm kaolin, 2-1 mm kaolin and 1-0.088 mm kaolin into a wet mill and stir for 3-4 min, add the lignin combined slurry obtained in step S2 and mix for another 2-3 min, then add the premixed powder and stir for 5-8 min. The total mixing time is 8-15 min to finally obtain a semi-dry mixture.

[0021] As a further illustration of the present invention, the preparation process of the rare earth functional additive powder comprises:

[0022] Lanthanum oxide, cerium oxide, praseodymium oxide and magnesia are mixed in a mass ratio of 2.5-4.2:1.5-2.5:0-0.5:3-5, and the obtained mixture is ground by a ball mill wet grinding process for 8 hours to prepare a mixed material with a particle size D50<3 μm;

[0023] The obtained mixture is dried at a temperature of 110°C for 24 hours and then pressed into balls by a ball press at 10-20MPa;

[0024] The balled mixed material is fired at a maximum firing temperature of 1650°C and a holding time of 6 hours;

[0025] The sintered mixed ball material is crushed into fine powder by a ball mill dry grinding process, and the particle size is controlled at D50<5μm to obtain rare earth functional additive powder.

[0026] As a further explanation of the present invention, step S4 is specifically as follows: the semi-dry mixture obtained in step S3 is weighed and poured into a brick press mold, and is flattened with a tool, and is pressed and formed using a 630-ton spiral brick press. The pressure per unit area of ​​the material is controlled at 125 to 145 MPa to obtain a semi-finished refractory brick.

[0027] As a further illustration of the present invention, step S5 specifically comprises: drying the obtained semi-finished refractory brick at a temperature of 80° C. to 130° C. for 24 h to 36 h to obtain a semi-finished brick blank, and controlling the moisture content after drying to be ≤1%;

[0028] The semi-finished bricks are placed in a tunnel kiln, fired in a high temperature oxidizing atmosphere at 1330°C to 1350°C for 5h to 8h, cooled along with the cooling section of the tunnel kiln, and taken out to obtain rare earth composite high heat storage clay refractory bricks.

[0029] Compared with the prior art, the present invention has the following technical effects:

[0030] 1. The main raw material aggregate is kaolin, which is widely distributed and easy to obtain.

[0031] 2. The firing temperature is low during the preparation process, saving energy.

[0032] The rare earth composite high heat storage clay refractory brick provided by the present invention has a firing temperature range of 1330° C. to 1350° C. The rare earth functional additive has a certain fluxing and firing effect, which reduces energy consumption and is beneficial to improving the physical indicators of the clay checker brick. The firing temperature is about 30° C. lower than that of ordinary clay checker bricks, which reduces the firing energy consumption in disguise.

[0033] 3. The rare earth composite high heat storage clay refractory bricks prepared by the present invention have high heat storage capacity and high heat storage rate, while broadening the application field of light rare earth products such as lanthanum, cerium and praseodymium, and providing a new market channel for checker bricks for blast furnace hot blast stoves. BRIEF DESCRIPTION OF THE DRAWINGS

[0034] Figure 1 The present invention provides a flow chart of a method for preparing an Al-La-Ce series rare earth composite high heat storage clay refractory brick. DETAILED DESCRIPTION

[0035] The following will be combined with the drawings in the embodiments of the present invention to clearly and completely describe the technical solutions in 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.

[0036] Rare earth atoms have a compact electron layer structure, high electric charge, variable valence, large radius, strong polarization force, and active chemical properties. The inner 4f electrons of rare earth elements are shielded by the outer 5s and 5p electrons, which has a localization effect. The outermost electrons that determine the properties of the element are arranged in 4f and 5d to form a conduction band. The localization and incomplete filling of 4f electrons give rare earths unique optical, magnetic, and oxygen storage and release properties. 3+ Partially replace Al 3+ etc. enter the crystal, and the binding force with the surrounding ions is enhanced, which promotes the enhancement of the stability of the organizational structure. The rare earth composite high heat storage clay brick provided by the present invention evenly disperses the high emissivity material inside the refractory material or matrix, thereby improving the heat storage efficiency of the clay brick. The energy-saving mechanism of the present invention is to evenly distribute the high emissivity fine powder material inside the refractory brick, and the contacted heat is covered from point to line and then to surface, which improves the absorption rate and emissivity of the refractory brick to infrared radiation, promotes the full utilization of heat, saves heat energy, and improves the thermal efficiency of the kiln.

[0037] In addition, the rare earth functional additive prepared by the present invention has the effects of lowering the firing temperature, improving the density of the finished product, increasing the load softening temperature, the heat storage rate and the unit heat storage capacity. Therefore, after the clay refractory bricks are modified by the rare earth additives in the present invention, the room temperature strength of the prepared finished product is increased, the water absorption rate is reduced, the load softening temperature is increased, the heat storage rate is increased, and the saturated heat storage rate is increased; the stability of the hot blast furnace operation and the thermal energy conversion efficiency are improved.

[0038] like Figure 1 As shown, the present invention provides an Al-La-Ce series rare earth composite high heat storage clay refractory brick, which includes the following raw materials in parts by weight: 10 to 25 parts of 3-2mm kaolin, 12 to 20 parts of 2-1mm kaolin, 30 to 40 parts of 1-0.088mm kaolin, 18 to 22 parts of kaolin less than 0.088mm, 8 to 16 parts of soft clay powder, 3 to 5 parts of lignin combined slurry, and 1 to 10 parts of rare earth functional additives; wherein the rare earth functional additives contain lanthanum and cerium.

[0039] Specifically, the rare earth functional additive is a mixture of lanthanum oxide, cerium oxide, praseodymium oxide and magnesia, and the mass ratio of lanthanum oxide, cerium oxide, praseodymium oxide and magnesia in the rare earth functional additive is 2.5-4.2:1.5-2.5:0-0.5:3-5. The lignin-bound slurry is prepared by mixing calcium lignin sulfonate powder with water, and the Baume degree of the obtained lignin-bound slurry is 1.13.

[0040] The preparation method of the above-mentioned Al-La-Ce series rare earth composite high heat storage clay refractory brick comprises the following steps:

[0041] S1. Ingredients: According to the above weight ratio, kaolin, soft clay powder and rare earth functional additive raw materials are weighed respectively.

[0042] S2. Obtain lignin-bound slurry through a water-soluble method.

[0043] Step S2 specifically comprises: stirring the calcium lignin sulfonate powder in 45° C. water to obtain a lignin-bound slurry having a Baume degree of 1.13.

[0044] S3. Raw material mixing: kaolin, soft clay powder, lignin binding slurry and rare earth functional additives are stirred and mixed to obtain a semi-dry mixture.

[0045] Specifically, the raw material mixing process in step S3 includes:

[0046] S301: Premixing: Use a three-dimensional premixer to premix kaolin with a particle size less than 0.088 mm, soft clay powder and rare earth functional additive powder for 15-20 minutes;

[0047] S302: Mixing: Pour the prepared 3-2 mm kaolin, 2-1 mm kaolin and 1-0.088 mm kaolin into a wet mill and stir for 3-4 min, add the lignin combined slurry obtained in step S2 and mix for another 2-3 min, then add the premixed powder and stir for 5-8 min. The total mixing time is 8-15 min to finally obtain a semi-dry mixture.

[0048] Furthermore, the preparation process of the rare earth functional additive powder includes:

[0049] Lanthanum oxide, cerium oxide, praseodymium oxide and magnesia are mixed in a mass ratio of 2.5-4.2:1.5-2.5:0-0.5:3-5, and the obtained mixture is ground by a ball mill wet grinding process for 8 hours to prepare a mixed material with a particle size D50<3 μm;

[0050] The obtained mixture is dried at a temperature of 110°C for 24 hours and then pressed into balls by a ball press at 10-20MPa;

[0051] The balled mixed material is fired at a maximum firing temperature of 1650°C and a holding time of 6 hours;

[0052] The sintered mixed ball material is crushed into fine powder by a ball mill dry grinding process, and the particle size is controlled at D50<5μm to obtain rare earth functional additive powder.

[0053] S4, pressing and molding: placing the semi-dry mixture obtained in step S3 in a brick press mold and pressing and molding to obtain a semi-finished refractory brick;

[0054] Step S4 is specifically as follows: weigh the semi-dry mixture obtained in step S3 and pour it into the mold of a brick press, flatten it with a tool, and use a 630-ton screw brick press to press and shape it. The pressure per unit area of ​​the material is controlled at 125-145 MPa to obtain a semi-finished refractory brick.

[0055] S5, firing: drying, high-temperature sintering and cooling the semi-finished refractory bricks to obtain finished rare earth composite high heat storage clay refractory bricks.

[0056] Step S5 specifically comprises: drying the semi-finished refractory brick at 80°C to 130°C for 24h to 36h to obtain a semi-finished brick blank, and controlling the moisture content after drying to be ≤1%;

[0057] The semi-finished bricks are placed in a tunnel kiln, fired in a high temperature oxidizing atmosphere at 1330°C to 1350°C for 5h to 8h, cooled along with the cooling section of the tunnel kiln, and taken out to obtain rare earth composite high heat storage clay refractory bricks.

[0058] The following is explained in conjunction with specific embodiments:

[0059] The composition table of kaolin and soft clay used in the following examples and comparative examples is as follows:

[0060]

[0061] The following equipment information table of the examples and comparative examples is as follows:

[0062]

[0063] The GB / T31934-2015 test method was used to measure the heat storage rate and heat storage amount of the embodiments and comparative examples.

[0064] Embodiment 1:

[0065] S1. Ingredients: The ingredients are prepared according to the following raw materials in parts by weight: 20 parts of 3-2 mm kaolin, 17 parts of 2-1 mm kaolin, 32 parts of 1-0.088 mm kaolin, 18 parts of kaolin less than 0.088 mm, 13 parts of soft clay, 4.5 parts of lignin-bound slurry, and 5 parts of rare earth functional additives.

[0066] S2. The calcium lignin sulfonate powder was stirred in 45° C. water by a water dissolution method to obtain a lignin-bound slurry (degree Baume 1.13° Bé).

[0067] S3. Preparation of rare earth functional additive powder: lanthanum oxide, cerium oxide, praseodymium oxide and magnesia are mixed in a mass ratio of 4.2:2.3:0.5:3, and the obtained ingredients are ground by a ball mill wet grinding process for 8 hours to prepare a mixture with a particle size D50<3μm; the obtained mixture is dried at a temperature of 110°C for 24 hours, and then pressed into balls by a ball press under 10MPa; the balled mixture is fired at a maximum firing temperature of 1650°C and a heat preservation time of 6 hours; the fired mixed ball material is crushed into fine powder by a ball mill dry grinding process, and the particle size is controlled to be D50<5μm, so as to obtain rare earth functional additive powder.

[0068] S4. Premixing: Use a three-dimensional premixer to premix kaolin less than 0.088 mm, soft clay powder and rare earth functional additive powder for 15 minutes.

[0069] S5, mixing: pour the prepared 3-2 mm kaolin, 2-1 mm kaolin and 1-0.088 mm kaolin into a wet mill and stir for 3 min, add the lignin combined slurry obtained in step S2 and mix for another 2 min, then add the premixed powder and stir for 5 min, the total mixing time is 8 min.

[0070] S6. Compression molding: Weigh the mixed semi-dry material, pour it into the brick press mold and flatten it with a tool, use a 630-ton screw brick press to press and mold it, and control the pressure per unit area of ​​the material at 125MPa to obtain a semi-finished product.

[0071] S7, drying: the semi-finished product is dried at 80°C for 36 hours to obtain a semi-finished brick, and the moisture content after drying is controlled to be ≤1%.

[0072] S8, firing: firing the semi-finished bricks in a high temperature oxidizing atmosphere at 1330°C for 6 hours.

[0073] S9. Finished product: The fired refractory bricks are taken out as the furnace temperature naturally cools down to room temperature to obtain rare earth composite high heat storage clay refractory bricks.

[0074] The performance test of the rare earth composite high heat storage clay refractory brick obtained in Example 1 is as follows:

[0075] The heat storage rate is 269.67 J / min, and the saturated heat storage is 1613.69 J / g. Compared with the specific comparative example 1 of ordinary clay bricks, the heat storage rate is increased by 24.6%, and the saturated heat storage is increased by 16.7%; the volume density is 2.41 g / cm 3 , 0.2MPa load softening temperature T0.6 / ℃ is 1469℃, room temperature compressive strength is 61.2Mpa, and water absorption rate is 7.9%.

[0076] Embodiment 2:

[0077] S1. Ingredients: The ingredients are prepared according to the following raw materials in parts by weight: 22 parts of 3-2 mm kaolin, 15 parts of 2-1 mm kaolin, 30 parts of 1-0.088 mm kaolin, 20 parts of kaolin less than 0.088 mm, 13 parts of soft clay, 4 parts of lignin-bound slurry, and 4 parts of rare earth functional additives.

[0078] S2. The calcium lignin sulfonate powder was stirred in 45° C. water by a water dissolution method to obtain a lignin-bound slurry (degree Baume 1.13° Bé).

[0079] S3. Preparation of rare earth functional additive powder: lanthanum oxide, cerium oxide, praseodymium oxide and magnesia are mixed in a mass ratio of 3.6:2.4:0.5:3.5, and the obtained ingredients are ground by a ball mill wet grinding process for 8 hours to prepare a mixture with a particle size D50<3μm; the obtained mixture is dried at a temperature of 110°C for 24 hours, and then pressed into balls by a ball press under 13MPa; the balled mixture is fired at a maximum firing temperature of 1650°C and a heat preservation time of 6 hours; the fired mixed ball material is crushed into fine powder by a ball mill dry grinding process, and the particle size is controlled to be D50<5μm, so as to obtain rare earth functional additive powder.

[0080] S4. Premixing: Use a three-dimensional premixer to premix kaolin less than 0.088 mm, soft clay powder and rare earth functional additive powder for 18 minutes.

[0081] S5, mixing: pour the prepared 3-2 mm kaolin, 2-1 mm kaolin and 1-0.088 mm kaolin into a wet mill and stir for 3 min, add the lignin combined slurry obtained in step S2 and mix for another 2 min, then add the premixed powder and stir for 6 min, the total mixing time is 10 min.

[0082] S6. Compression molding: Weigh the mixed semi-dry material, pour it into the brick press mold and flatten it with a tool, use a 630-ton screw brick press to press and mold it, and control the pressure per unit area of ​​the material at 135MPa to obtain a semi-finished product.

[0083] S7, drying: the semi-finished product is dried at 100°C for 30 hours to obtain a semi-finished brick, and the moisture content after drying is controlled to be ≤1%.

[0084] S8, firing: firing the semi-finished bricks in a high temperature oxidizing atmosphere at 1340°C for 6 hours.

[0085] S9. Finished product: The fired refractory bricks are taken out as the furnace temperature naturally cools down to room temperature to obtain rare earth composite high heat storage clay refractory bricks.

[0086] The performance test of the rare earth composite high heat storage clay refractory brick obtained in Example 2 is as follows:

[0087] The heat storage rate is 246.76 J / min, and the saturated heat storage is 1557.59 J / g. Compared with the specific comparative example 1 of ordinary clay brick, the heat storage rate is increased by 17.6%, and the saturated heat storage is increased by 13.7%; the volume density is 2.39 g / cm 3 , 0.2MPa load softening temperature T0.6 / ℃ is 1452℃, room temperature compressive strength is 51.9Mpa, and water absorption is 9.11%.

[0088] Embodiment 3:

[0089] S1. Ingredients: The ingredients are prepared according to the following raw materials in parts by weight: 18 parts of 3-2 mm kaolin, 17 parts of 2-1 mm kaolin, 32 parts of 1-0.088 mm kaolin, 20 parts of kaolin less than 0.088 mm, 13 parts of soft clay, 5 parts of lignin-bound slurry, and 7 parts of rare earth functional additives.

[0090] S2. The calcium lignin sulfonate powder was stirred in 45° C. water by a water dissolution method to obtain a lignin-bound slurry (degree Baume 1.13° Bé).

[0091] S3. Preparation of rare earth functional additive powder: lanthanum oxide, cerium oxide, praseodymium oxide and magnesia are mixed in a mass ratio of 2.5:2.5:0.5:4.5, and the obtained ingredients are ground by a ball mill wet grinding process for 8 hours to prepare a mixture with a particle size D50<3μm; the obtained mixture is dried at a temperature of 110°C for 24 hours, and then pressed into balls by a ball press under 20MPa; the balled mixture is fired at a maximum firing temperature of 1650°C and a heat preservation time of 6 hours; the fired mixed ball material is crushed into fine powder by a ball mill dry grinding process, and the particle size is controlled to be D50<5μm, so as to obtain rare earth functional additive powder.

[0092] S4. Premixing: Use a three-dimensional premixer to premix kaolin less than 0.088 mm, soft clay powder and rare earth functional additive powder for 20 minutes.

[0093] S5, mixing: pour the prepared 3-2 mm kaolin, 2-1 mm kaolin and 1-0.088 mm kaolin into a wet mill and stir for 4 min, add the lignin combined slurry obtained in step S2 and mix for another 3 min, then add the premixed powder and stir for 8 min, the total mixing time is 15 min.

[0094] S6. Compression molding: Weigh the mixed semi-dry material, pour it into the brick press mold and flatten it with a tool, use a 630-ton screw brick press to press and mold it, and control the pressure per unit area of ​​the material at 145MPa to obtain a semi-finished product.

[0095] S7, drying: the semi-finished product is dried at 130°C for 24 hours to obtain a semi-finished brick, and the moisture content after drying is controlled to be ≤1%.

[0096] S8, firing: firing the semi-finished bricks in a high temperature oxidizing atmosphere at 1350°C for 6 hours.

[0097] S9. Finished product: The fired refractory bricks are taken out as the furnace temperature naturally cools down to room temperature to obtain rare earth composite high heat storage clay refractory bricks.

[0098] The performance test of the rare earth composite high heat storage clay refractory brick obtained in Example 3 is as follows:

[0099] The heat storage rate is 246.16 J / min, and the saturated heat storage is 1529.24 J / g. Compared with the specific comparative example 1 of ordinary clay brick, the heat storage rate is increased by 17.4%, and the saturated heat storage is increased by 12.1%; the volume density is 2.44 g / cm 3 , 0.2MPa load softening temperature T0.6 / ℃ is 1440℃, room temperature compressive strength is 53.2Mpa, and water absorption rate is 9.05%.

[0100] Embodiment 4:

[0101] S1. Ingredients: The ingredients are prepared according to the following raw materials in parts by weight: 17 parts of 3-2 mm kaolin, 20 parts of 2-1 mm kaolin, 30 parts of 1-0.088 mm kaolin, 20 parts of kaolin less than 0.088 mm, 13 parts of soft clay, 4 parts of lignin-bound slurry, and 3 parts of rare earth functional additives.

[0102] S2. The calcium lignin sulfonate powder was stirred in 45° C. water by a water dissolution method to obtain a lignin-bound slurry (degree Baume 1.13° Bé).

[0103] S3. Preparation of rare earth functional additive powder: lanthanum oxide, cerium oxide, praseodymium oxide and magnesia are mixed in a mass ratio of 3.5:1.5:0:5, and the obtained ingredients are ground by a ball mill wet grinding process for 8 hours to prepare a mixture with a particle size D50<3μm; the obtained mixture is dried at a temperature of 110°C for 24 hours, and then pressed into balls by a ball press under 20MPa; the balled mixture is fired at a maximum firing temperature of 1650°C and a heat preservation time of 6 hours; the fired mixed ball material is crushed into fine powder by a ball mill dry grinding process, and the particle size is controlled to be D50<5μm, so as to obtain rare earth functional additive powder.

[0104] S4. Premixing: Use a three-dimensional premixer to premix kaolin less than 0.088 mm, soft clay powder and rare earth functional additive powder for 20 minutes.

[0105] S5, mixing: pour the prepared 3-2 mm kaolin, 2-1 mm kaolin and 1-0.088 mm kaolin into a wet mill and stir for 4 min, add the lignin combined slurry obtained in step S2 and mix for another 3 min, then add the premixed powder and stir for 8 min, the total mixing time is 15 min.

[0106] S6. Compression molding: Weigh the mixed semi-dry material, pour it into the brick press mold and flatten it with a tool, use a 630-ton screw brick press to press and mold it, and control the pressure per unit area of ​​the material at 145MPa to obtain a semi-finished product.

[0107] S7, drying: the semi-finished product is dried at 130°C for 24 hours to obtain a semi-finished brick, and the moisture content after drying is controlled to be ≤1%.

[0108] S8, firing: firing the semi-finished bricks in a high temperature oxidizing atmosphere at 1350°C for 6 hours.

[0109] S9. Finished product: The fired refractory bricks are taken out as the furnace temperature naturally cools down to room temperature to obtain rare earth composite high heat storage clay refractory bricks.

[0110] The performance test of the rare earth composite high heat storage clay refractory brick obtained in Example 4 is as follows:

[0111] The heat storage rate is 249.48 J / min, and the saturated heat storage is 1559.4 J / g. Compared with the ordinary clay brick comparative example 1, the heat storage rate is increased by 18.5%, and the saturated heat storage is increased by 13.8%; the volume density is 2.46 g / cm 3 , 0.2MPa load softening temperature T0.6 / ℃ is 1458℃, room temperature compressive strength is 62.5Mpa, and water absorption is 8.54%.

[0112] Comparative Example 1:

[0113] S1. Ingredients: The ingredients are prepared according to the following raw materials in parts by weight: 18 parts of 3-2 mm kaolin, 17 parts of 2-1 mm kaolin, 32 parts of 1-0.088 mm kaolin, 20 parts of kaolin less than 0.088 mm, 13 parts of soft clay, and 5 parts of lignin-bound slurry.

[0114] S2. The calcium lignin sulfonate powder was stirred in 45° C. water by a water dissolution method to obtain a lignin-bound slurry (degree Baume 1.13° Bé).

[0115] S3. Premixing: Use a three-dimensional premixer to premix kaolin and soft clay powders with a particle size less than 0.088 mm. The premixing time is 20 minutes.

[0116] S4, mixing: pour the prepared 3-2 mm kaolin, 2-1 mm kaolin and 1-0.088 mm kaolin into a wet mill and stir for 4 min, add the lignin combined slurry obtained in step S2 and mix for another 3 min, then add the premixed powder and stir for 8 min, the total mixing time is 15 min.

[0117] S5. Compression molding: Weigh the mixed semi-dry material, pour it into the brick press mold and flatten it with a tool, use a 630-ton screw brick press to press and mold it, and control the pressure per unit area of ​​the material at 145MPa to obtain a semi-finished product.

[0118] S6. Drying: The semi-finished product is dried at 130°C for 24 hours to obtain a semi-finished brick, and the moisture content after drying is controlled to be ≤1%.

[0119] S7, firing: the semi-finished bricks are fired in a high temperature oxidizing atmosphere at 1350°C for 6 hours.

[0120] S8. Finished product: The fired refractory bricks are taken out as the furnace temperature naturally cools down to room temperature to obtain ordinary clay refractory bricks.

[0121] The performance test of the ordinary clay refractory brick obtained in Comparative Example 1 is as follows:

[0122] The heat storage rate is 203.33 J / min, the saturated heat storage is 1344.2 J / g, and the volume density is 1.98 g / cm 3 , 0.2MPa load softening temperature T0.6 / ℃ is 1447℃, room temperature compressive strength is 39.5Mpa, and water absorption rate is 11.73%.

[0123] Comparative Example 2:

[0124] S1. Ingredients: The ingredients are prepared according to the following raw materials in parts by weight: 18 parts of 3-2 mm kaolin, 17 parts of 2-1 mm kaolin, 32 parts of 1-0.088 mm kaolin, 20 parts of kaolin less than 0.088 mm, 13 parts of soft clay, 5 parts of lignin-bound slurry, and 7 parts of lanthanum oxide powder.

[0125] S2. The calcium lignin sulfonate powder was stirred in 45° C. water by a water dissolution method to obtain a lignin-bound slurry (degree Baume 1.13° Bé).

[0126] S3. Premixing: Use a three-dimensional premixer to premix kaolin less than 0.088 mm, soft clay powder and lanthanum oxide powder for 20 minutes.

[0127] S4, mixing: pour the prepared 3-2 mm kaolin, 2-1 mm kaolin and 1-0.088 mm kaolin into a wet mill and stir for 4 min, add the lignin combined slurry obtained in step S2 and mix for another 3 min, then add the premixed powder and stir for 8 min, the total mixing time is 15 min.

[0128] S5. Compression molding: Weigh the mixed semi-dry material, pour it into the brick press mold and flatten it with a tool, use a 630-ton screw brick press to press and mold it, and control the pressure per unit area of ​​the material at 145MPa to obtain a semi-finished product.

[0129] S6. Drying: The semi-finished product is dried at 130°C for 24 hours to obtain a semi-finished brick, and the moisture content after drying is controlled to be ≤1%.

[0130] S7, firing: the semi-finished bricks are fired in a high temperature oxidizing atmosphere at 1350°C for 6 hours.

[0131] S8. Finished product: The fired refractory bricks are taken out as the furnace temperature naturally cools down to room temperature to obtain rare earth composite clay refractory bricks.

[0132] The performance test of the rare earth composite clay refractory brick obtained in Comparative Example 2 is as follows:

[0133] The heat storage rate is 214.48 J / min, and the saturated heat storage capacity is 1387.2 J / g. Compared with comparative example 1, the heat storage rate is increased by 5.2%, and the saturated heat storage capacity is increased by 3.1%; the volume density is 2.13 g / cm 3 , 0.2MPa load softening temperature T0.6 / ℃ is 1435℃, room temperature compressive strength is 41.2Mpa, and water absorption is 9.12%.

[0134] Comparative Example 3:

[0135] S1. Ingredients: The ingredients are prepared according to the following raw materials in parts by weight: 18 parts of 3-2 mm kaolin, 17 parts of 2-1 mm kaolin, 32 parts of 1-0.088 mm kaolin, 20 parts of kaolin less than 0.088 mm, 13 parts of soft clay, 5 parts of lignin-bound slurry, and 7 parts of cerium oxide powder.

[0136] S2. The calcium lignin sulfonate powder was stirred in 45° C. water by a water dissolution method to obtain a lignin-bound slurry (degree Baume 1.13° Bé).

[0137] S3. Premixing: Use a three-dimensional premixer to premix kaolin with a particle size less than 0.088 mm, soft clay powder and cerium oxide powder for 20 minutes.

[0138] S4, mixing: pour the prepared 3-2 mm kaolin, 2-1 mm kaolin and 1-0.088 mm kaolin into a wet mill and stir for 4 min, add the lignin combined slurry obtained in step S2 and mix for another 3 min, then add the premixed powder and stir for 8 min, the total mixing time is 15 min.

[0139] S5. Compression molding: Weigh the mixed semi-dry material, pour it into the brick press mold and flatten it with a tool, use a 630-ton screw brick press to press and mold it, and control the pressure per unit area of ​​the material at 145MPa to obtain a semi-finished product.

[0140] S6. Drying: The semi-finished product is dried at 130°C for 24 hours to obtain a semi-finished brick, and the moisture content after drying is controlled to be ≤1%.

[0141] S7, firing: the semi-finished bricks are fired in a high temperature oxidizing atmosphere at 1350°C for 6 hours.

[0142] S8. Finished product: The fired refractory bricks are taken out as the furnace temperature naturally cools down to room temperature to obtain rare earth composite clay refractory bricks.

[0143] The performance test of the rare earth composite clay refractory brick obtained in Comparative Example 3 is as follows:

[0144] The heat storage rate is 226.93 J / min, and the saturated heat storage capacity is 1451.62 / g. Compared with comparative example 1, the heat storage rate is increased by 10.5%, and the saturated heat storage capacity is increased by 7.4%; the volume density is 2.19 g / cm 3 , 0.2MPa load softening temperature T0.6 / ℃ is 1430℃, compressive strength is 44.9Mpa, and water absorption is 9.03%.

[0145] By comparing the performance test results of the composite clay refractory bricks obtained in Example 3 with those in Comparative Examples 2 and 3, it can be seen that the heat storage rate and the saturated heat storage capacity are significantly reduced, the heat storage rate is reduced from 17.4% to 5.2% and 10.5%, the saturated heat storage capacity is reduced from 12.1% to 3.1% and 7.4%, the room temperature compressive strength is reduced from 53.2MPa to 41.2MPa and 44.9MPa, and the 0.2MPa load softening temperature T0.6 / ℃ is reduced by 10-20℃.

[0146] It should be noted that, in this article, relational terms such as first and second, etc. are only used to distinguish one entity or operation from another entity or operation, and do not necessarily require or imply any such actual relationship or order between these entities or operations. Moreover, the terms "include", "comprise" or any other variants thereof are intended to cover non-exclusive inclusion, so that a process, method, article or device including a series of elements includes not only those elements, but also other elements not explicitly listed, or also includes elements inherent to such process, method, article or device.

[0147] Although embodiments of the present invention have been shown and described, it will be appreciated by those skilled in the art that various changes, modifications, substitutions and variations may be made to the embodiments without departing from the principles and spirit of the present invention, and that the scope of the present invention is defined by the appended claims and their equivalents.

Claims

1. An Al-La-Ce rare earth composite high heat storage clay refractory brick, characterized in that: The invention comprises the following raw materials in parts by weight: 10 to 25 parts of 3-2 mm kaolin, 12 to 20 parts of 2-1 mm kaolin, 30 to 40 parts of 1-0.088 mm kaolin, 18 to 22 parts of kaolin less than 0.088 mm, 8 to 16 parts of soft clay powder, 3 to 5 parts of lignin-bound slurry, and 1 to 10 parts of rare earth functional additives; wherein the rare earth functional additives contain lanthanum and cerium.

2. The Al-La-Ce rare earth composite high heat storage clay refractory brick according to claim 1, characterized in that: The rare earth functional additive is a mixture of lanthanum oxide, cerium oxide, praseodymium oxide and magnesia.

3. The Al-La-Ce rare earth composite high heat storage clay refractory brick according to claim 2, characterized in that: The mass ratio of lanthanum oxide, cerium oxide, praseodymium oxide and magnesia in the rare earth functional additive is 2.5-4.2:1.5-2.5:0-0.5:3-5.

4. The Al-La-Ce rare earth composite high heat storage clay refractory brick according to claim 1, characterized in that: The lignin-bound pulp is prepared by mixing calcium lignin sulfonate powder with water, and the Baume degree of the obtained lignin-bound pulp is 1.

13.

5. A method for preparing the Al-La-Ce rare earth composite high heat storage clay refractory brick according to any one of claims 1 to 4, characterized in that: The following steps are involved: S1. Ingredients: weigh kaolin, soft clay powder and rare earth functional additive raw materials respectively according to the weight ratio described in any one of claims 1 to 4; S2, obtaining lignin-bound slurry by a water-soluble method; S3, raw material mixing: kaolin, soft clay powder, lignin binding slurry and rare earth functional additives are stirred and mixed to obtain a semi-dry mixture; S4, pressing and molding: placing the semi-dry mixture obtained in step S3 in a brick press mold and pressing and molding to obtain a semi-finished refractory brick; S5, firing: drying, high-temperature sintering and cooling the semi-finished refractory bricks to obtain finished rare earth composite high heat storage clay refractory bricks.

6. The method for preparing the Al-La-Ce series rare earth composite high heat storage clay refractory brick according to claim 5, characterized in that: Step S2 specifically comprises: stirring the calcium lignin sulfonate powder in 45° C. water to obtain a lignin-bound slurry having a Baume degree of 1.

13.

7. The method for preparing the Al-La-Ce series rare earth composite high heat storage clay refractory brick according to claim 5, characterized in that: The raw material mixing process of step S3 specifically includes: S301: Premixing: Use a three-dimensional premixer to premix kaolin with a particle size less than 0.088 mm, soft clay powder and rare earth functional additive powder for 15-20 minutes; S302: Mixing: Pour the prepared 3-2 mm kaolin, 2-1 mm kaolin and 1-0.088 mm kaolin into a wet mill and stir for 3-4 min, add the lignin combined slurry obtained in step S2 and mix for another 2-3 min, then add the premixed powder and stir for 5-8 min. The total mixing time is 8-15 min to finally obtain a semi-dry mixture.

8. The method for preparing the Al-La-Ce series rare earth composite high heat storage clay refractory brick according to claim 7, characterized in that: The preparation process of the rare earth functional additive powder comprises: Lanthanum oxide, cerium oxide, praseodymium oxide and magnesia are mixed in a mass ratio of 2.5-4.2:1.5-2.5:0-0.5:3-5, and the obtained mixture is ground by a ball mill wet grinding process for 8 hours to prepare a mixed material with a particle size D50<3 μm; The obtained mixture is dried at a temperature of 110°C for 24 hours and then pressed into balls by a ball press at 10-20MPa; The balled mixed material is fired at a maximum firing temperature of 1650°C and a holding time of 6 hours; The sintered mixed ball material is crushed into fine powder by a ball mill dry grinding process, and the particle size is controlled at D50<5μm to obtain rare earth functional additive powder.

9. The method for preparing the Al-La-Ce series rare earth composite high heat storage clay refractory brick according to claim 5, characterized in that: Step S4 is specifically as follows: The semi-dry mixture obtained in step S3 is weighed and poured into a brick press mold, and then flattened with a tool. A 630-ton screw brick press is used to press and shape the mixture. The pressure per unit area of ​​the mixture is controlled at 125-145 MPa to obtain a semi-finished refractory brick.

10. The method for preparing the Al-La-Ce series rare earth composite high heat storage clay refractory brick according to claim 5, characterized in that: Step S5 is specifically as follows: Drying the obtained semi-finished refractory brick at 80°C to 130°C for 24h to 36h to obtain a semi-finished brick blank, wherein the moisture content after drying is controlled to be ≤1%; The semi-finished bricks are placed in a tunnel kiln, fired in a high temperature oxidizing atmosphere at 1330°C to 1350°C for 5h to 8h, cooled along with the cooling section of the tunnel kiln, and taken out to obtain rare earth composite high heat storage clay refractory bricks.

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