A refractory castable and its preparation method

Abstract

The present invention relates to the technical field of refractories, and specifically relates to a refractory castable and a preparation method thereof. By mass percentage, the composition of the refractory castable is as follows: 50% - 80% of aggregate with a particle size of 0.075 - 3 mm, 0 - 40% of aggregate with a particle size < 0.075 mm, 0 - 20% of powder with a particle size < 0.075 mm, 0.1% - 20% of binder; additionally, a water reducing agent accounting for 0.1% - 10% of the total weight of the above raw materials and 5% - 10% of water are added; the binder is potassium-based aluminosilicate geopolymer or / and cesium-based aluminosilicate geopolymer. The refractory castable of the present invention has good erosion resistance to the precursor of new energy cathode materials, excellent high-temperature mechanical properties and thermal shock stability, greatly improves the service life of the lower part of the refractory, and can also effectively avoid the pollution of new energy cathode materials during the calcination process. The prepared new energy cathode materials have high quality and good performance.

Description

Technical Field

[0001] The present invention belongs to the technical field of refractory materials, and particularly relates to a refractory castable and a preparation method thereof. Background Art

[0002] At present, the main way to prepare the precursor of the positive electrode material of new energy batteries industrially is to place the precursor of the positive electrode material of new energy batteries in a refractory crucible and calcine it at a high temperature of 600-1100 °C. Currently, the refractory crucibles for calcining the positive electrode materials of new energy batteries are prepared from refractory components such as mullite, cordierite, magnesium aluminate spinel, and forsterite. First, they are mechanically pressed and then calcined at a high temperature. The use of mechanical pressing to prepare refractory crucible products has low construction efficiency, high labor intensity, high energy consumption, pollution, and material consumption, and the applicability of the crucible products is low. Moreover, during the calcination of the positive electrode material of new energy batteries, the alkali metal oxides (such as Li2O, Na2O, etc.) formed by the decomposition of the precursor of the new energy positive electrode material under high temperature conditions will react with the refractory components (such as mullite, cordierite, magnesium aluminate spinel, forsterite, etc.) in the refractory crucible to form silicate, aluminate, and / or aluminosilicate interfacial reaction products such as Li2SiO4, LiAlSiO4, LiAlSi2O6, and LiAlO2 accompanied by a large volume expansion, resulting in the erosion of the refractory crucible and even the peeling of the interfacial reaction layer. This will not only affect the service life of the crucible but also pollute the obtained new energy positive electrode material and reduce the yield rate of the positive electrode material. Summary of the Invention

[0003] Aiming at the problems and deficiencies in the prior art, the present invention provides a refractory castable and a preparation method thereof.

[0004] To achieve the purpose of the invention, the technical solutions adopted by the present invention are as follows:

[0005] In the first aspect, the present invention provides the application of geopolymers in the preparation of refractory castables, and the geopolymers are potassium-based aluminosilicate geopolymers or / and cesium-based aluminosilicate geopolymers.

[0006] According to the above application, preferably, the geopolymer is used as a binder for the refractory castable.

[0007] According to the above application, preferably, the refractory castable is a refractory castable for calcining the positive electrode material of the battery; more preferably, the refractory castable is used to prepare a refractory crucible for calcining the positive electrode material of the battery.

[0008] According to the above application, preferably, the battery is a new energy battery. More preferably, the new energy battery is a lithium battery or a sodium battery.

[0009] According to the above applications, preferably, the positive electrode material includes lithium cobaltate, lithium nickel cobalt manganate, lithium nickel cobalt aluminate, lithium iron phosphate, layered transition metal oxides, Prussian blue analogs, Prussian white analogs, and polyanion compounds. More preferably, the positive electrode material of the lithium battery includes lithium cobaltate, lithium nickel cobalt manganate, lithium nickel cobalt aluminate, and lithium iron phosphate; the positive electrode material of the sodium battery includes layered transition metal oxides, Prussian blue analogs, Prussian white analogs, and polyanion compounds.

[0010] In the present invention, the potassium-based aluminosilicate geopolymer is prepared according to the preparation method reported in the literature "Peigang He, Dechang Jia, Meirong Wang, Yu Zhou, Improvement of high-temperature mechanical properties of heat-treated C f / geopolymer composites by Sol-SiO2 impregnation, Journal of the European Ceramic Society 30(2010)3053–3061". The cesium-based aluminosilicate geopolymer is prepared according to the preparation method reported in the literature "Peigang He, Dechang Jia, Meirong Wang, Yu Zhou, Effect of cesium substitution on the thermal evolution and ceramics formation of potassium-based geopolymer, Ceramics International 36(2010)2395–2400".

[0011] In the second aspect, the present invention provides a refractory castable. By mass percentage, the composition of the refractory castable is as follows: 50% - 80% of aggregate with a particle size of 0.075 - 3 mm, 0 - 40% of aggregate with a particle size < 0.075 mm, 0 - 20% of powder with a particle size < 0.075 mm, 0.1% - 20% of binder; additionally, 0.1% - 10% of water reducer and 5% - 10% of water based on the total weight of the above raw materials are added; the binder is a potassium-based aluminosilicate geopolymer or / and a cesium-based aluminosilicate geopolymer.

[0012] According to the above refractory castable, preferably, the aggregate is at least one of mullite, andalusite, kyanite, sillimanite, burned clays, coal gangue, and magnesium aluminate spinel. More preferably, the aggregate is mullite.

[0013] According to the refractory castable described above, preferably, the powder is at least one of mullite, andalusite, cyanite, sillimanite, pyrophyllite, coal gangue, potassium feldspar, potassium carbonate, potassium hydroxide, silica fume, and magnesium aluminate spinel. More preferably, the powder is mullite.

[0014] According to the refractory castable described above, preferably, by mass percentage, the composition of the refractory castable is as follows: 50% of mullite with a particle size of 0.075 - 3 mm, 35% of mullite with a particle size < 0.075 mm, and 15% of binder; additionally, 0.2% of water reducing agent and 6% of water based on the total weight of the above raw materials are added; the binder is potassium-based aluminosilicate geopolymer or / and cesium-based aluminosilicate geopolymer.

[0015] According to the refractory castable described above, preferably, the water reducing agent is polycarboxylate water reducing agent, naphthalene-based water reducing agent or sodium hexametaphosphate.

[0016] According to the refractory castable described above, preferably, the binder is potassium-based aluminosilicate geopolymer.

[0017] In the third aspect, the present invention provides an application of the refractory castable described in the second aspect above in preparing a refractory container for calcining a battery cathode material.

[0018] According to the above application, preferably, the battery is a new energy battery. More preferably, the new energy battery is a lithium battery or a sodium battery.

[0019] According to the above application, preferably, the cathode material includes lithium cobaltate, lithium nickel cobalt manganate, lithium nickel cobalt aluminate, lithium iron phosphate, layered transition metal oxide, Prussian blue analogue, Prussian white analogue, and polyanion compound. More preferably, the cathode material of the lithium battery includes lithium cobaltate, lithium nickel cobalt manganate, lithium nickel cobalt aluminate, and lithium iron phosphate; the cathode material of the sodium battery includes layered transition metal oxide, Prussian blue analogue, Prussian white analogue, and polyanion compound.

[0020] According to the above application, preferably, the refractory container is a refractory crucible.

[0021] In the fourth aspect, the present invention provides a preparation method of the refractory castable described in the second aspect above, including the following steps:

[0022] (1) Mix the aggregate, powder, binder, and water reducing agent evenly to obtain a mixed material.

[0023] (2) Add water to the mixed material prepared in step (1), and stir and mix evenly to obtain a wet-mixed castable.

[0024] (3) The wet-mixed castable prepared in step (2) is calcined at 1000°C to 1300°C for 1h to 6h after casting, curing, and drying to obtain a refractory castable product.

[0025] In a fifth aspect, the present invention provides a refractory crucible, which is prepared from the refractory castable described in the second aspect above.

[0026] According to the above refractory crucible, preferably, the refractory crucible is a refractory crucible for calcining the positive electrode material of a battery.

[0027] According to the above refractory crucible, preferably, the battery is a new energy battery. More preferably, the new energy battery is a lithium battery or a sodium battery.

[0028] According to the above refractory crucible, preferably, the positive electrode material includes lithium cobaltate, lithium nickel cobalt manganate, lithium nickel cobalt aluminate, lithium iron phosphate, layered transition metal oxides, Prussian blue analogs, Prussian white analogs, and polyanion compounds. More preferably, the positive electrode material of the lithium battery includes lithium cobaltate, lithium nickel cobalt manganate, lithium nickel cobalt aluminate, and lithium iron phosphate; the positive electrode material of the sodium battery includes layered transition metal oxides, Prussian blue analogs, Prussian white analogs, and polyanion compounds.

[0029] The preparation method of the above weather-resistant crucible is as follows: Mix the aggregate, powder, binder, and water reducer evenly to obtain a mixture; add water to the mixture and stir evenly to obtain a wet-mixed castable; the wet-mixed castable is calcined at 1000°C to 1300°C for 1h to 6h after casting, curing, and drying to obtain a refractory crucible.

[0030] Compared with the prior art, the positive and beneficial effects obtained by the present invention are as follows:

[0031] (1) Potassium-based aluminosilicate geopolymer and / or cesium-based aluminosilicate geopolymer are cementitious phase K / Cs{-(SiO2)z-AlO2}n·wH2O materials with a three-dimensional network structure. When the potassium-based aluminosilicate geopolymer and / or cesium-based aluminosilicate geopolymer are used as binders for preparing refractory castables in the present invention, the potassium-based aluminosilicate geopolymer and cesium-based aluminosilicate geopolymer can uniformly adhere to the surface of refractory raw material particles, playing the role of wrapping the refractory raw material particles, and can avoid the contact between the refractory raw materials and the alkali metal oxide formed by the decomposition of the precursor of the new energy battery cathode material (such as Ni5Co2Mn3(OH)2 / Li2CO3; Ni8Co1Mn1(OH)2 / LiOH; Na2CO3 / MnO2) under high-temperature calcination, avoid the interfacial reaction between the alkali metal oxide and the refractory raw materials, and reduce the erosion of the refractory by the precursor of the new energy cathode material during the calcination process; moreover, the potassium-based aluminosilicate geopolymer wrapped on the surface of the refractory raw material particles can form KAlSiO4 phase or KAlSi2O6 phase with high melting point during the calcination process of the refractory material, and the cesium-based aluminosilicate geopolymer can form CsAlSiO4 phase or CsAlSi2O6 phase with high melting point during the calcination process of the refractory material. These high-melting-point phases can greatly improve the erosion resistance, high-temperature mechanical properties and thermal shock stability of the refractory castable against the precursor of the new energy battery cathode material, greatly improve the service life of the lower part of the refractory material, and at the same time can effectively avoid the pollution of the new energy cathode material during the calcination process. The prepared new energy cathode material has high quality and good performance.

[0032] (2) Compared with the castables with calcium aluminate cement, hydrated mullite or magnesia-silica composite powder as binders, the wet-mixed castables prepared with sodium-based aluminosilicate geopolymer, potassium-based aluminosilicate geopolymer or cesium-based aluminosilicate geopolymer as binders in the present invention can be constructed, cured and demolded within 24 hours, with high construction efficiency; compared with the existing method of first mechanically pressing and then high-temperature calcining to prepare refractory saggers, the construction is convenient, the labor intensity is low, the energy consumption is low, the pollution is small, and the applicability is high; moreover, the wet-mixed castables prepared in the present invention have a flexural strength of 5.3 - 7.8 MPa and a compressive strength of 11.1 - 15.9 MPa at room temperature after curing and demolding, with high demolding strength; moreover, after calcination at 1000 - 1300 °C, the strength is high, the flexural strength can reach 11.2 - 23.4 MP, the compressive strength can reach 21.4 - 44.1 MPa, and the thermal shock stability is good (the residual strength retention rate after 3 times of air cooling is 70% - 80%). Description of the Drawings

[0033] Figure 1 Photograph of the refractory material sample of the sagger prepared in Example 1 of the present invention;

[0034] Figure 2Backscattered electron micrograph of the sagger refractory material specimen prepared in Example 1 of the present invention. Detailed implementation manners

[0035] The present invention will be further described in detail below through specific embodiments, but the scope of the present invention is not limited.

[0036] For the experimental methods without specific conditions indicated in the following examples, conventional techniques in the technical field of the present invention are used, or the conditions recommended by the manufacturer are followed; for the reagents or instruments without the manufacturer indicated, they are all conventional products that can be obtained through commercial purchase.

[0037] In order to enable those skilled in the art to more clearly understand the technical solution of the present invention, the technical solution of the present invention will be described in detail below in combination with specific embodiments.

[0038] Example 1:

[0039] A refractory castable, by mass percentage, the composition of the refractory castable is: 50% of mullite with a particle size of 0.075 - 3 mm, 35% of mullite with a particle size < 0.075 mm, 15% of binder, and additionally 0.2% of water reducer and 6% of water based on the total weight of the above raw materials. Among them, the binder is a potassium-based aluminosilicate geopolymer, and the water reducer is a naphthalene-based water reducer (FS10).

[0040] A refractory sagger, which is prepared from the above refractory castable.

[0041] The specific preparation method of the above refractory sagger is as follows:

[0042] (1) Mix mullite with a particle size of 0.075 - 3 mm, mullite with a particle size < 0.075 mm, binder, and water reducer, and stir evenly to obtain a mixed material;

[0043] (2) Add water to the mixed material prepared in step (1), and stir and mix evenly to obtain a wet-mixed castable;

[0044] (3) The wet-mixed castable is cast, cured, dried at 110°C, and then calcined at 1300°C for 3 h to obtain a refractory sagger.

[0045] Figure 1 Photo of the sagger refractory material specimen prepared in Example 1 of the present invention. From Figure 1 It can be seen that after the sagger refractory material specimen bonded with potassium-based aluminosilicate geopolymer is calcined at 1300°C, it becomes a dense refractory material with a complete structure, and no melting phenomenon occurs, because KAlSi2O6 has a melting temperature higher than 1600°C.

[0046] Figure 2This is the backscattered electron micrograph of the sagger refractory material sample prepared in Example 1 of the present invention. From Figure 2 It can be seen that after calcination at 1300 °C, potassium-based aluminosilicate geopolymers generate KAlSi2O6 at high temperatures, forming a strong bond between particles in the material.

[0047] Example 2:

[0048] A refractory castable, by mass percentage, the composition of the refractory castable is: 50% of coal gangue with a particle size of 0.075 - 3 mm, 35% of coal gangue with a particle size < 0.075 mm, 15% of binder, and additionally 0.2% of water reducer and 8% of water based on the total weight of the above raw materials. Among them, the binder is a potassium-based aluminosilicate geopolymer, and the water reducer is sodium hexametaphosphate.

[0049] A refractory sagger, which is prepared from the above refractory castable.

[0050] The specific preparation method of the above refractory sagger is as follows:

[0051] (1) Mix coal gangue with a particle size of 0.075 - 3 mm, coal gangue with a particle size < 0.075 mm, binder, and water reducer, and stir evenly to obtain a mixture.

[0052] (2) Add water to the mixture prepared in step (1), and stir and mix evenly to obtain a wet-mixed castable.

[0053] (3) After the wet-mixed castable is cast, cured, dried at 110 °C, and calcined at 1100 °C for 3 h, a refractory sagger is obtained.

[0054] Example 3:

[0055] A refractory castable, by mass percentage, the composition of the refractory castable is: 80% of mullite with a particle size of 0.075 - 3 mm, 12.8% of mullite with a particle size < 0.075 mm, 0.2% of mullite with a particle size < 0.075 mm, 7% of binder, and additionally 1.7% of water reducer and 8% of water based on the total weight of the above raw materials. Among them, the binder is a potassium-based aluminosilicate geopolymer, and the water reducer is a naphthalene-based water reducer (FS20).

[0056] A refractory sagger, which is prepared from the above refractory castable.

[0057] The specific preparation method of the above refractory sagger is as follows:

[0058] (1) Mix mullite with a particle size of 0.075 - 3 mm, mullite with a particle size < 0.075 mm, binder, and water reducer, and stir evenly to obtain a mixture.

[0059] (2) Add water to the mixture prepared in step (1), and stir and mix evenly to obtain a wet-mixed casting material;

[0060] (3) After the wet-mixed casting material is cast, cured, and dried at 110 °C, it is calcined at 1100 °C for 3 h to obtain a refractory crucible.

[0061] Example 4:

[0062] A refractory casting material, by mass percentage, the composition of the refractory casting material is: 67% mullite with a particle size of 0.075 - 3 mm, 17% mullite with a particle size < 0.075 mm, 11% coal gangue with a particle size < 0.075 mm, 5% binder, plus 6% water reducing agent and 5% water based on the total weight of the above raw materials. Among them, the binder is a potassium-based aluminosilicate geopolymer, and the water reducing agent is a naphthalene-based water reducing agent (FS65).

[0063] A refractory crucible, the refractory crucible is prepared from the above refractory casting material.

[0064] The specific preparation method of the above refractory crucible is:

[0065] (1) Mix mullite with a particle size of 0.075 - 3 mm, mullite with a particle size < 0.075 mm, coal gangue with a particle size < 0.075 mm, binder, and water reducing agent, and stir evenly to obtain a mixture;

[0066] (2) Add water to the mixture prepared in step (1), and stir and mix evenly to obtain a wet-mixed casting material;

[0067] (3) After the wet-mixed casting material is cast, cured, and dried at 105 °C, it is calcined at 1300 °C for 1 h to obtain a refractory crucible.

[0068] Example 5:

[0069] A refractory casting material, by mass percentage, the composition of the refractory casting material is: 70% mullite with a particle size of 0.075 - 3 mm, 1% mullite with a particle size < 0.075 mm, 20% coal gangue with a particle size < 0.075 mm, 9% binder, plus 0.1% water reducing agent and 10% water based on the total weight of the above raw materials. Among them, the binder is a potassium-based aluminosilicate geopolymer, and the water reducing agent is a polycarboxylate water reducing agent.

[0070] A refractory crucible, the refractory crucible is prepared from the above refractory casting material.

[0071] The specific preparation method of the above refractory crucible is:

[0072] (1) Mix mullite with a particle size of 0.075 - 3 mm, mullite with a particle size < 0.075 mm, coal gangue with a particle size < 0.075 mm, a binder, and a water reducer, and stir evenly to obtain a mixture.

[0073] (2) Add water to the mixture prepared in step (1), and stir and mix evenly to obtain a wet-mixed casting material.

[0074] (3) After the wet-mixed casting material is cast, cured at room temperature, and dried at 105°C, it is calcined at 1200°C for 4 h to obtain a refractory crucible.

[0075] Example 6:

[0076] A refractory casting material, by mass percentage, the composition of the refractory casting material is: 75% of mullite with a particle size of 0.075 - 3 mm, 5% of mullite with a particle size < 0.075 mm, 10% of coal gangue with a particle size < 0.075 mm, 10% of binder, plus 10% of water reducer and 10% of water based on the total weight of the above raw materials. Among them, the binder is a potassium-based aluminosilicate geopolymer, and the water reducer is a naphthalene-based water reducer (FS60).

[0077] A refractory crucible, which is prepared from the above refractory casting material.

[0078] The specific preparation method of the above refractory crucible is as follows:

[0079] (1) Mix mullite with a particle size of 0.075 - 3 mm, mullite with a particle size < 0.075 mm, coal gangue with a particle size < 0.075 mm, a binder, and a water reducer, and stir evenly to obtain a mixture.

[0080] (2) Add water to the mixture prepared in step (1), and stir and mix evenly to obtain a wet-mixed casting material.

[0081] (3) After the wet-mixed casting material is cast, cured at room temperature, and dried at 105°C, it is calcined at 1100°C for 6 h to obtain a refractory crucible.

[0082] Example 7:

[0083] A refractory casting material, by mass percentage, the composition of the refractory casting material is: 65% of coal gangue with a particle size of 0.075 - 3 mm, 25% of coal gangue with a particle size < 0.075 mm, 1% of potassium feldspar with a particle size < 0.075 mm, 9% of binder, plus 8% of water reducer and 6.5% of water based on the total weight of the above raw materials. Among them, the binder is a potassium-based aluminosilicate geopolymer, and the water reducer is a naphthalene-based water reducer (FS60).

[0084] A refractory crucible, which is prepared from the above refractory casting material.

[0085] The specific preparation method of the above refractory sagger is as follows:

[0086] (1) Mix gangue with a particle size of 0.075 - 3 mm, gangue with a particle size < 0.075 mm, potassium feldspar with a particle size < 0.075 mm, a binder, and a water reducing agent, and stir evenly to obtain a mixture;

[0087] (2) Add water to the mixture prepared in step (1), and stir and mix evenly to obtain a wet-mixed casting material;

[0088] (3) After the wet-mixed casting material is cast, cured at room temperature, and dried at 105 °C, it is calcined at 1100 °C for 3 h to obtain the refractory sagger.

[0089] Example 8:

[0090] A refractory casting material, by mass percentage, the composition of the refractory casting material is: 60% mullite with a particle size of 0.075 - 3 mm, 20% mullite with a particle size < 0.075 mm, 19.9% gangue with a particle size < 0.075 mm, 0.1% binder, and additionally 2% water reducing agent and 6% water based on the total weight of the above raw materials. Among them, the binder is a potassium-based aluminosilicate geopolymer, and the water reducing agent is a naphthalene-based water reducing agent (FS60).

[0091] A refractory sagger, which is prepared from the above refractory casting material.

[0092] The specific preparation method of the above refractory sagger is as follows:

[0093] (1) Mix mullite with a particle size of 0.075 - 3 mm, mullite with a particle size < 0.075 mm, gangue with a particle size < 0.075 mm, a binder, and a water reducing agent, and stir evenly to obtain a mixture;

[0094] (2) Add water to the mixture prepared in step (1), and stir and mix evenly to obtain a wet-mixed casting material;

[0095] (3) After the wet-mixed casting material is cast, cured at room temperature, and dried at 110 °C, it is calcined at 1100 °C for 3 h to obtain the refractory sagger.

[0096] Example 9:

[0097] A refractory casting material, by mass percentage, the composition of the refractory casting material is: 55% mullite with a particle size of 0.075 - 3 mm, 27% mullite with a particle size < 0.075 mm, 15% gangue with a particle size < 0.075 mm, 3% binder, and additionally 1% water reducing agent and 6% water based on the total weight of the above raw materials. Among them, the binder is a potassium-based aluminosilicate geopolymer, and the water reducing agent is a naphthalene-based water reducing agent (FS60).

[0098] A refractory sagger, which is prepared from the above refractory castable.

[0099] The specific preparation method of the above refractory sagger is as follows:

[0100] (1) Mix mullite with a particle size of 0.075 - 3 mm, mullite with a particle size < 0.075 mm, coal gangue with a particle size < 0.075 mm, a binder, and a water reducing agent, and stir evenly to obtain a mixed material;

[0101] (2) Add water to the mixed material prepared in step (1), and stir and mix evenly to obtain a wet-mixed castable;

[0102] (3) After the wet-mixed castable is cast, cured at room temperature, dried at 110°C, and calcined at 1100°C for 3 h, a refractory sagger is obtained.

[0103] Example 10:

[0104] A refractory castable, by mass percentage, the composition of the refractory castable is: 70% of mullite with a particle size of 0.075 - 3 mm, 20% of coal gangue with a particle size < 0.075 mm, 10% of a binder, plus 3% of a water reducing agent and 6% of water based on the total weight of the above raw materials. Among them, the binder is a potassium-based aluminosilicate geopolymer, and the water reducing agent is a polycarboxylate water reducing agent.

[0105] A refractory sagger, which is prepared from the above refractory castable.

[0106] The specific preparation method of the above refractory sagger is as follows:

[0107] (1) Mix mullite with a particle size of 0.075 - 3 mm, coal gangue with a particle size < 0.075 mm, a binder, and a water reducing agent, and stir evenly to obtain a mixed material;

[0108] (2) Add water to the mixed material prepared in step (1), and stir and mix evenly to obtain a wet-mixed castable;

[0109] (3) After the wet-mixed castable is cast, cured at room temperature, dried at 110°C, and calcined at 1100°C for 3 h, a refractory sagger is obtained.

[0110] Example 11:

[0111] A refractory castable, by mass percentage, the composition of the refractory castable is: 55% of mullite with a particle size of 0.075 - 3 mm, 40% of mullite with a particle size < 0.075 mm, 5% of a binder, plus 1% of a water reducing agent and 5% of water based on the total weight of the above raw materials. Among them, the binder is a potassium-based aluminosilicate geopolymer, and the water reducing agent is a naphthalene-based water reducing agent (FS60).

[0112] A refractory sagger, which is prepared from the above refractory castable.

[0113] The specific preparation method of the above refractory sagger is as follows:

[0114] (1) Mix mullite with a particle size of 0.075 - 3 mm, mullite with a particle size < 0.075 mm, a binder, and a water reducer, and stir evenly to obtain a mixed material.

[0115] (2) Add water to the mixed material prepared in step (1), and stir and mix evenly to obtain a wet-mixed castable.

[0116] (3) After the wet-mixed castable is cast, cured at room temperature, dried at 110°C, and calcined at 1100°C for 3 h, a refractory sagger is obtained.

[0117] Example 12:

[0118] A refractory castable, calculated by mass percentage, the composition of the refractory castable is: 50% of magnesium aluminate spinel with a particle size of 0.075 - 3 mm, 35% of magnesium aluminate spinel with a particle size < 0.075 mm, 10% of pyrophyllite with a particle size < 0.075 mm, 5% of binder, and additionally 0.2% of water reducer and 5.4% of water based on the total weight of the above raw materials. Among them, the binder is a potassium-based aluminosilicate geopolymer, and the water reducer is a naphthalene-based water reducer (FS60).

[0119] A refractory sagger, which is prepared from the above refractory castable.

[0120] The specific preparation method of the above refractory sagger is as follows:

[0121] (1) Mix magnesium aluminate spinel with a particle size of 0.075 - 3 mm, magnesium aluminate spinel with a particle size < 0.075 mm, pyrophyllite with a particle size < 0.075 mm, a binder, and a water reducer, and stir evenly to obtain a mixed material.

[0122] (2) Add water to the mixed material prepared in step (1), and stir and mix evenly to obtain a wet-mixed castable.

[0123] (3) After the wet-mixed castable is cast, cured at room temperature, dried at 110°C, and calcined at 1100°C for 3 h, a refractory sagger is obtained.

[0124] Example 13:

[0125] A refractory castable, by mass percentage, the composition of the refractory castable is as follows: 50% of andalusite with a particle size of 0.075 - 3 mm, 35% of andalusite with a particle size < 0.075 mm, 10% of andalusite with a particle size < 0.075 mm, 15% of binder, and additionally 0.2% of water reducing agent and 6% of water based on the total weight of the above raw materials. Among them, the binder is a potassium-based aluminosilicate geopolymer, and the water reducing agent is a naphthalene-based water reducing agent (FS60).

[0126] A refractory crucible, which is prepared from the above refractory castable.

[0127] The specific preparation method of the above refractory crucible is as follows:

[0128] (1) Mix andalusite with a particle size of 0.075 - 3 mm, andalusite with a particle size < 0.075 mm, binder and water reducing agent, and stir evenly to obtain a mixture;

[0129] (2) Add water to the mixture prepared in step (1), and stir and mix evenly to obtain a wet-mixed castable;

[0130] (3) After the wet-mixed castable is cast, cured at room temperature, dried at 110°C, and calcined at 1100°C for 3 h, a refractory crucible is obtained.

[0131] Example 14:

[0132] A refractory castable, by mass percentage, the composition of the refractory castable is as follows: 55% of sillimanite with a particle size of 0.075 - 3 mm, 40% of sillimanite with a particle size < 0.075 mm, 15% of binder, and additionally 1% of water reducing agent and 6% of water based on the total weight of the above raw materials. Among them, the binder is a potassium-based aluminosilicate geopolymer, and the water reducing agent is a naphthalene-based water reducing agent (FS60).

[0133] A refractory crucible, which is prepared from the above refractory castable.

[0134] The specific preparation method of the above refractory crucible is as follows:

[0135] (1) Mix sillimanite with a particle size of 0.075 - 3 mm, sillimanite with a particle size < 0.075 mm, binder and water reducing agent, and stir evenly to obtain a mixture;

[0136] (2) Add water to the mixture prepared in step (1), and stir and mix evenly to obtain a wet-mixed castable;

[0137] (3) After the wet-mixed castable is cast, cured at room temperature, dried at 110°C, and calcined at 1100°C for 3 h, a refractory crucible is obtained.

[0138] Example 15:

[0139] A refractory castable, by mass percentage, the composition of the refractory castable is: 70% of pyrophyllite with a particle size of 0.075 - 3 mm, 20% of pyrophyllite with a particle size < 0.075 mm, 10% of binder, plus 3% of water reducing agent and 5% of water based on the total weight of the above raw materials. Among them, the binder is a potassium-based aluminosilicate geopolymer, and the water reducing agent is a naphthalene-based water reducing agent (FS60).

[0140] A refractory sagger, which is prepared from the above refractory castable.

[0141] The specific preparation method of the above refractory sagger is as follows:

[0142] (1) Mix pyrophyllite with a particle size of 0.075 - 3 mm, pyrophyllite with a particle size < 0.075 mm, binder and water reducing agent, and stir evenly to obtain a mixture;

[0143] (2) Add water to the mixture prepared in step (1), and stir and mix evenly to obtain a wet-mixed castable;

[0144] (3) After the wet-mixed castable is cast, cured at room temperature, dried at 110°C, and calcined at 1100°C for 3 h, a refractory sagger is obtained.

[0145] Example 16:

[0146] A refractory castable, by mass percentage, the composition of the refractory castable is: 50% of alumina with a particle size of 0.075 - 3 mm, 35% of alumina with a particle size < 0.075 mm, 5% of potassium feldspar fine powder with a particle size < 0.075 mm, 5% of silica fume with a particle size < 0.075 mm, 15% of binder, plus 0.2% of water reducing agent and 6% of water based on the total weight of the above raw materials. Among them, the binder is a potassium-based aluminosilicate geopolymer, and the water reducing agent is a naphthalene-based water reducing agent (FS60).

[0147] A refractory sagger, which is prepared from the above refractory castable.

[0148] The specific preparation method of the above refractory sagger is as follows:

[0149] (1) Mix alumina with a particle size of 0.075 - 3 mm, alumina with a particle size < 0.075 mm, potassium feldspar with a particle size < 0.075 mm, silica fume with a particle size < 0.075 mm, binder and water reducing agent, and stir evenly to obtain a mixture;

[0150] (2) Add water to the mixture prepared in step (1), and stir and mix evenly to obtain a wet-mixed castable;

[0151] (3) After the wet-mixed castable is cast, cured at room temperature, and dried at 110°C, it is calcined at 1100°C for 3 h to obtain a refractory crucible.

[0152] Performance test of the refractory crucible prepared by the present invention:

[0153] The refractory crucibles prepared in Examples 1 to 16 of the present invention were subjected to performance tests. At the same time, for comparison with the present invention, Comparative Examples 1 to 4 were also carried out in the present invention, and four comparative crucibles were prepared respectively. The specific contents of Comparative Examples 1 to 4 are as follows:

[0154] Comparative Example 1:

[0155] The content of Comparative Example 1 was basically the same as that of Example 1, and the difference was that: the binder used in the refractory castable formula was calcium aluminate cement.

[0156] Comparative Example 2:

[0157] The content of Comparative Example 2 was basically the same as that of Example 1, and the difference was that: the binder used in the refractory castable formula was a magnesia-silica binder; the preparation method of the magnesia-silica binder was: mixing magnesia fine powder (magnesium oxide content ≥ 96%) and microsilica powder (silicon dioxide content ≥ 96%) evenly according to a mass ratio of 28:2, and stirring and mixing evenly to obtain the magnesia-silica binder.

[0158] Comparative Example 3:

[0159] The content of Comparative Example 3 was basically the same as that of Example 1, and the difference was that: the binder used in the refractory castable formula was hydrated alumina (ρ-Al2O3).

[0160] Comparative Example 4:

[0161] A refractory crucible, the preparation method thereof is: mixing 50 wt% of mullite with a particle size of 0.075 - 3 mm, 35 wt% of mullite with a particle size < 0.075 mm, and 15 wt% of KAlSi2O6 precursor evenly, adding 5 wt% of yellow dextrin and 5 wt% of water as binders based on the total weight of the above raw materials, mixing evenly, pressing and forming under 100 MPa directionally, then holding at 900°C for 6 h, and then holding at 1300°C for 3 h.

[0162] 1. High-temperature interfacial reaction analysis

[0163] The refractory crucibles prepared in Example 1, Comparative Examples 1 to 4 were respectively used to hold the precursor of the new energy battery cathode material (Ni5Co2Mn3(OH)2 / Li2CO3), and calcined at 800 - 1100°C to analyze the interfacial reaction between the refractory crucible and the new energy cathode material precursor during the high-temperature calcination process.

[0164] In Example 1 of the present invention, the aggregate of the refractory sagger castable is mullite, and the binder is a potassium-based aluminosilicate geopolymer. The potassium-based aluminosilicate geopolymer can evenly adhere to the surface of mullite particles, playing a role in wrapping the mullite particles, and can avoid the contact between the mullite raw material and the alkali metal oxide formed by the decomposition of the precursor of the new energy cathode material (Ni5Co2Mn3(OH)2 / Li2CO3) under high-temperature calcination, prevent the interfacial reaction between the alkali metal oxide and mullite, and reduce the erosion of the refractory by the precursor of the new energy cathode material during the calcination process; moreover, the potassium-based aluminosilicate geopolymer wrapped on the surface of mullite particles can form a KAlSiO4 phase or a KAlSi2O6 phase with a high melting point during the calcination process of the refractory (when a strontium-based aluminosilicate geopolymer is used as the binder, the strontium-based aluminosilicate geopolymer wrapped on the surface of mullite particles can form a CsAlSiO4 phase or a CsAlSi2O6 phase with a high melting point during the calcination process of the refractory). These high-melting-point phases can greatly improve the erosion resistance, high-temperature mechanical properties and thermal shock stability of the refractory castable, greatly improve the service life of the lower body of the refractory, and can also effectively avoid the pollution of the new energy cathode material during the calcination process. The prepared new energy battery cathode material has high quality and excellent performance.

[0165] In Comparative Example 1, the aggregate of the refractory crucible castable is mullite (3Al2O3·2SiO2), and the binder is calcium aluminate cement binder. During the high-temperature calcination process, mullite will undergo an interfacial reaction with the alkali metal oxide Li2O formed by the decomposition of the lithium battery cathode material, generating LiAlO2, Li2SiO3, and LiAlSiO4. In Comparative Example 2, the aggregate of the refractory crucible castable is mullite, and the binder is a magnesium oxide-silicon oxide composite binder. During the high-temperature calcination process, not only will mullite undergo an interfacial reaction with the alkali metal oxide Li2O formed by the decomposition of the lithium battery cathode material, generating LiAlO2, Li2SiO3, and LiAlSiO4, but the silicon oxide in the binder will also undergo an interfacial reaction with the alkali metal oxide Li2O formed by the decomposition of the lithium battery cathode material, generating LiSiO3. In Comparative Example 3, the aggregate of the refractory crucible castable is mullite, and the binder is hydrated alumina (ρ-Al2O3). During the high-temperature calcination process, not only will mullite undergo an interfacial reaction with the alkali metal oxide Li2O formed by the decomposition of the lithium battery cathode material, generating LiAlO2, Li2SiO3, and LiAlSiO4, but the Al2O3 in the binder will also undergo an interfacial reaction with the alkali metal oxide Li2O formed by the decomposition of the lithium battery cathode material, generating LiAlO2 and Li5AlO4. In Comparative Example 4, the aggregate of the refractory crucible castable is mullite, the powder is a KAlSi2O6 precursor, the binder is yellow dextrin and water, and it is prepared by a hydraulic pressing method. During the high-temperature calcination process, mullite will undergo an interfacial reaction with the alkali metal oxide Li2O formed by the decomposition of the lithium battery cathode material, generating LiAlO2, Li2SiO3, and LiAlSiO4.

[0166] From the above analysis, it can be seen that the refractory crucible prepared by using potassium-based aluminosilicate geopolymer or cesium-based aluminosilicate geopolymer as the binder can effectively avoid the contact between the mullite raw material and the alkali metal oxides formed by the decomposition of the new energy cathode material precursor (Ni5Co2Mn3(OH)2 / Li2CO3; Ni8Co1Mn1(OH)2 / LiOH; Na2CO3 / MnO2) under high-temperature calcination, avoid the interfacial reaction between the alkali metal oxides and mullite, reduce the erosion of the new energy cathode material precursor on the refractory material during the calcination process, and improve the service life of the refractory crucible.

[0167] 2. Detection of the mechanical properties and the resistance to erosion by the new energy battery cathode material of the refractory crucible:

[0168] The flexural strength (CMOR) and compressive strength (CCS) of refractory materials after firing at 1500 °C were detected according to GB / T 3001-2007 and GB / T 5702-2008 respectively, and the bulk density (BD) and apparent porosity (AP) of refractory materials were detected according to GB / T 2997-2000. The residual strength retention rate of the specimens after three air-coolings was detected.

[0169] The test method for the erosion resistance performance of the new energy battery cathode material is as follows: 20 g of the precursor of the lithium battery cathode material (Ni5Co2Mn3(OH)2 / Li2CO3 = 7:3) was loaded into the prepared sagger, heated at 1100 °C and maintained for 20 h, and then the obtained lithium battery cathode material was poured out, counted as 1 time; this process was repeated 10 times. After the experiment, it was cut along the central cross-section of the sagger, and the cross-sectional area ratio was measured to evaluate the erosion rate of the refractory material against the cathode material. Among them, in Examples 1-16 and Comparative Examples 1-3, refractory saggers were prepared using a casting mold, and in Comparative Example 4, a refractory sagger was pressed under a pressure of 100 MPa using a hydraulic press; the outer diameter of the sagger was 40 mm, the wall thickness was 7 mm, and the depth was 40 mm.

[0170] The specific test results are shown in Table 1.

[0171] Table 1 Test results of the mechanical properties and the erosion resistance performance of the refractory sagger prepared by the present invention against the new energy battery cathode material

[0172] As can be seen from Table 1, after calcination at 1000-1300 °C, the refractory sagger prepared by the present invention has high strength, its flexural strength can reach 11.2-23.4 MP, and its compressive strength can reach 21.4-44.1 MPa, having good mechanical properties. Moreover, the erosion rate of the lithium battery cathode material of the refractory sagger prepared by the present invention using oligomers as binders is significantly lower than that of Comparative Example 1, Comparative Example 2, and Comparative Example 3, indicating that compared with the refractory saggers prepared using calcium aluminate cement, magnesia-silica binder, and hydrated alumina as binders, the refractory sagger prepared by the present invention has stronger erosion resistance against the cathode material. In addition, the residual strength retention rate of the specimens of the refractory sagger prepared by the present invention using oligomers as binders after three air-coolings is significantly higher than that of Comparative Example 1, Comparative Example 2, Comparative Example 3, and Comparative Example 4, indicating that the refractory sagger prepared by the present invention has stronger thermal shock stability.

[0173] Moreover, after calcination at 1000-1300 °C, the flexural strength and compressive strength of the refractory sagger prepared by casting the refractory material in the present invention are higher than those of the refractory sagger prepared by the hydraulic pressing method in Comparative Document 4, indicating that the method of preparing the refractory sagger for calcining the battery cathode material by casting with refractory castable in the present invention is feasible.

[0174] 3. Detection of the demolding strength of refractory castables

[0175] The demolding strength of the green refractory crucibles prepared in Examples 1 - 16 and Comparative Examples 1 - 4 of the present invention was detected, and the specific detection results are shown in Table 2.

[0176] The detection method for the demolding strength of the green refractory crucibles in Examples 1 - 16 and Comparative Examples 1 - 3 is as follows: According to the formulation composition of the refractory castable, the aggregate, powder, binder, water reducer and admixture are mixed and stirred evenly to obtain a mixture; water is added to the mixture and stirred evenly to obtain a wet-mixed castable, and the wet-mixed castable is demolded after curing for 24 h; the strength of the green refractory crucible after demolding is detected in accordance with GB / T 3001 - 2007.

[0177] The detection method for the demolding strength of the refractory crucible in Comparative Example 4 is as follows: In Comparative Example 4, the refractory crucible was prepared by a hydraulic pressing method. The refractory material was directionally pressed and molded at 100 MPa and then demolded, and the strength of the green refractory crucible was detected.

[0178] Table 2 Detection results of the demolding strength of the refractory crucibles prepared by the present invention

[0179]

[0180] As can be seen from Table 2, for the wet-mixed castable prepared by the present invention using oligomers as binders, after curing and demolding, the room-temperature flexural strength of the green body is 5.3 - 7.8 MPa, and the compressive strength is 11.1 - 15.9 MPa, which are both higher than those of Comparative Example 2 and Comparative Example 3. This shows that compared with the refractory crucibles prepared using magnesia-silica binders and hydrated alumina as binders, the green body strength of the refractory crucibles prepared by the present invention after demolding is high. Although the room-temperature flexural strength and compressive strength of the green body of the wet-mixed castable prepared by the present invention after curing and demolding are slightly lower than those of Comparative Example 1 and Comparative Example 4, their strength already meets the construction strength requirements for the next heat treatment. This shows that the green body strength of the wet-mixed castable prepared by the present invention using geopolymers as binders is high, and moreover, construction, curing and demolding can be achieved within 24 hours, with high construction efficiency.

[0181] Finally, it should be noted that the above embodiments are only used to illustrate the technical solutions of the present invention and are not intended to limit them; although the present invention has been described in detail with reference to the foregoing embodiments, those of ordinary skill in the art should understand that they can still modify the technical solutions described in the foregoing embodiments, or perform equivalent replacements for some of the technical features; and these modifications or replacements do not cause the essence of the corresponding technical solutions to deviate from the spirit and scope of the technical solutions of the embodiments of the present invention.

Claims

1. A refractory castable product, characterized in that, By mass percentage, the composition of the refractory castable is as follows: 50% - 80% of aggregate with a particle size of 0.075 - 3 mm, 0 - 40% of aggregate with a particle size < 0.075 mm, 0 - 20% of powder with a particle size < 0.075 mm, 0.1% - 20% of binder; additionally, 0.1% - 10% of water reducing agent and 5% - 10% of water based on the total weight of the above raw materials are added; the binder is potassium-based aluminosilicate geopolymer or / and cesium-based aluminosilicate geopolymer; the aggregate is at least one of mullite, andalusite, kyanite, sillimanite, pyrophyllite, coal gangue, and magnesium aluminate spinel; the powder is at least one of mullite, andalusite, kyanite, sillimanite, pyrophyllite, coal gangue, potassium feldspar, potassium carbonate, potassium hydroxide, silica fume, and magnesium aluminate spinel; The preparation method of the refractory castable product includes the following steps: (1) Mix the aggregate, powder, binder, and water reducing agent evenly to obtain a mixed material; (2) Add water to the mixed material prepared in step (1) and stir evenly to obtain a wet-mixed castable; (3) The wet-mixed castable prepared in step (2) is subjected to casting, curing, and drying treatments, and then calcined at 1000°C - 1300°C for 1 h - 6 h to obtain the refractory castable product.

2. The application of the refractory castable product as claimed in claim 1 in the preparation of a refractory container for calcining a battery cathode material.

3. According to the application as claimed in claim 2, the battery is a new energy battery.

4. According to the application as claimed in claim 3, the new energy battery is a lithium battery or a sodium battery; the cathode material includes lithium cobaltate, lithium nickel cobalt manganate, lithium nickel cobalt aluminate, lithium iron phosphate, layered transition metal oxide, Prussian blue analog, Prussian white analog, and polyanion compound.

5. The application according to any one of claims 2-4, characterized in that, The refractory container is a refractory crucible.

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