Preparation method of corundum-mullite-silicon carbide castable containing middle-low grade bauxite-based spherical particles
By preparing low-to-medium grade bauxite-based corundum-mullite-silicon carbide castables, the problems of insufficient high-temperature strength and thermal shock resistance of traditional materials have been solved, realizing the preparation of low-cost, high-performance castables and improving resource utilization and service life.
Patent Information
- Authority / Receiving Office
- CN · China
- Patent Type
- Applications(China)
- Current Assignee / Owner
- Filing Date
- 2025-12-31
- Publication Date
- 2026-04-07
AI Technical Summary
Traditional bauxite-based refractory materials cannot meet the high-temperature strength and thermal shock resistance requirements of waste incinerators, and low- and medium-grade bauxite resources are not effectively utilized, resulting in resource waste and environmental pollution.
Using low- to medium-grade bauxite spherical particles as aggregate, combined with andalusite particles, white corundum powder, silicon carbide powder and other raw materials, and using aluminosilicate cement as binder, corundum-mullite-silicon carbide-based castables are prepared. High-performance castables are then prepared through rolling molding, drying, sintering and heat treatment processes.
It improves the high-temperature stability and thermal shock resistance of castables, reduces costs, increases the utilization rate of low- and medium-grade bauxite resources, and extends the service life of refractory materials.
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Figure CN121800519A_ABST
Abstract
Description
TECHNICAL FIELD
[0001] The application relates to the technical field of refractory materials, in particular to a preparation method of corundum-mullite-silicon carbide-based castable containing low-grade bauxite-based spherical particles. BACKGROUND
[0002] The use environment of the waste incinerator also often faces problems such as strong oxidizing atmosphere, high-temperature thermal stress and mechanical stress, and the selection of the refractory material directly affects the service life and safety of the waste incinerator. At present, the refractory material for the waste incinerator is mainly an aluminum-silicon system, among which, the aluminum-silicon system castable prepared based on traditional bauxite ore as a raw material is widely studied. With the large-scale of the waste incinerator and the increasingly deteriorating working conditions, the traditional bauxite-based refractory material cannot meet the requirements of high-temperature strength and thermal shock resistance, and is currently commonly used as a raw material to prepare bauxite-based corundum materials, corundum-mullite systems and bauxite-based oxide-non-oxide composite materials and other products.
[0003] The corundum-mullite system castable is a high-aluminum refractory material taking corundum and mullite as main crystal phases, and is widely applied to the inner lining of industrial kilns in the metallurgical, mechanical and building material industries due to the advantages of high-temperature resistance, creep resistance and good oxidation resistance. The corundum-mullite system castable is generally prepared by taking corundum and mullite particles, calcined bauxite particles, alumina fine powder, clay, bauxite fine powder and the like as main raw materials, and has high raw material cost and poor thermal shock resistance.
[0004] The bauxite resources in China are mainly difficult-to-handle diaspore ore, and the bauxite ore contains a large amount of harmful impurities such as silicon, sulfur and iron which need to be additionally treated by impurity removal process, and the lack of standardization of mining activities, which makes it difficult to effectively utilize a large amount of low-grade bauxite, and also leads to the risk of environmental pollution. At present, the bauxite used for refractory materials has become one of the relatively scarce bulk mineral resources. Based on this status, efficient and reasonable utilization of low-grade bauxite is crucial to improve the comprehensive utilization rate of bauxite resources.
[0005] In order to improve the high temperature strength and thermal shock resistance of the refractory material for waste incinerator, based on the urgent demand of high value utilization of low-grade bauxite, combined with the easy construction characteristics of castable, based on the characteristics of rich raw material resources, good wear resistance, high temperature resistance and high hardness of low-grade bauxite, the high value utilization potential of low-grade bauxite resources is fully tapped, the low-grade bauxite spherical particle is used as aggregate, the andalusite particle, white corundum powder, silicon carbide powder, alumina powder, Fe-TiCN fine powder are used as raw materials, the aluminosilicate cement is used as binder, the explosion-proof fiber and steel fiber are used as additives, the corundum-mullite-silicon carbide based castable for waste incinerator containing bauxite spherical particles with low cost and high performance is prepared, which has important significance for improving the comprehensive utilization rate of low-grade bauxite resources and reducing the consumption of refractory resources, and prolonging the service life and high temperature stability of the castable. SUMMARY
[0006] The purpose of the embodiment of the present application is to provide a method for preparing high-performance corundum-mullite-silicon carbide based castable by using low-grade bauxite, which has the advantages of simple process, low cost, high mineral resource utilization rate and low energy consumption, and provides a technical approach with clear practical value for the utilization of low-grade bauxite resources.
[0007] To achieve the above purpose, the embodiment of the present application provides a method for preparing corundum-mullite-silicon carbide castable by using low-grade bauxite, which comprises the following steps:
[0008] The present application provides a method for preparing corundum-mullite-silicon carbide castable by using low-grade bauxite, which is characterized by using calcined bauxite natural particles and low-grade bauxite based spherical particles, the total amount of large, medium and small particle aggregates is 5-8 mm (20%), 3-5 mm (15%), 1-3 mm (15%) and 0-1 mm (10%), andalusite particles are 0-1 mm (10%), white corundum fine powder is 325 mesh (8%), alumina powder is D50=2.5 μm (10%), silicon carbide powder is 200 mesh (5%), Fe-TiCN powder is 2%, calcium aluminate cement is 5%, dispersant is 1%, explosion-proof fiber is 0.1%, and steel fiber is 0.1%.
[0009] The application provides a preparation method of corundum-mullite-silicon carbide castable prepared from low-grade bauxite, and the method is characterized by the following steps: firstly, low-grade bauxite is used as raw material to prepare spherical particles by rolling forming granulation, and then the bauxite spherical particles are prepared by drying and sintering at 1600 DEG C for 3 hours; secondly, the bauxite spherical particles and andalusite particles with different particle sizes are used as aggregates, and aluminate cement is used as a binder; thirdly, the aggregates and the binder are mixed according to a certain proportion, and then the mixture is uniformly dry-mixed and wet-mixed by using a cement mixer, and then the mixture is poured into a standard mold; fourthly, the mixture is taken out after 24 hours of room temperature curing, and then the mixture is dried in a drying oven at 110 DEG C for 24 hours; and finally, the dried sample is placed in a box-type resistance furnace for heat treatment, the heating mechanism is to heat the sample to not more than 300 DEG C at a set rate and keep the temperature for 6 hours, and then the corundum-mullite-silicon carbide castable containing low-grade bauxite spherical particles is obtained after cooling. 3 The related performance is as follows: the bulk density is 2.47 g / cm BRIEF DESCRIPTION OF DRAWINGS
[0010] Figure 1 The sample appearance graph of the corundum-mullite-silicon carbide castable prepared from low-grade bauxite is provided for the embodiment 1 of the application.
[0011] Figure 2 The micro-morphology graph of the corundum-mullite-silicon carbide castable prepared from low-grade bauxite is provided for the embodiment 2 of the application. DETAILED DESCRIPTION
[0012] The following examples are used to illustrate the application, but are not used to limit the scope of the application.
[0013] Embodiment 1
[0014] The low-grade bauxite raw material is dried and poured into a rolling granulator, and a ball blank is prepared by spraying water and rolling powder. Then, the ball blank is dried in an electric heating constant temperature air drying oven at 110°C for 24 hours, and the dried ball blank is placed in a corundum crucible and sintered in a muffle furnace at 1600°C for 6 hours to prepare a spherical particle. The bauxite particles with different particle sizes of 5-8 mm (20%), 3-5 mm (15%), 1-3 mm (15%) and 0-1 mm (10%), 0-1 mm andalusite particles (10%) as aggregate, 325 mesh white corundum powder (8%), D50 = 2.5 μm alumina powder (10%), 200 mesh silicon carbide powder (5%), Fe-TiCN powder (2%), calcium aluminate cement (5%) as fine powder, dispersing agent (1%), explosion-proof fiber (0.1%) and steel fiber (0.1%) as raw materials, are mixed uniformly according to a certain proportion, and then poured into a standard mold after dry mixing and wet mixing uniformly using a cement mixer. After demolding, the sample is cured at room temperature for 24 hours, and then dried in a drying oven at 110°C for 24 hours. The dried sample is placed in a box-type resistance furnace for heat treatment, and the heating mechanism is as follows: the system is set to heat to 260°C at a certain rate and keep for 6 hours, and then cooled to obtain the sample. The main performance indicators of the product are as follows: the bulk density of the sample is 2.23-2.34 g / cm 3 , the bending strength is 16.19-18.23 MPa, and the compressive strength is 52.41-76.85 MPa.
[0015] Example 2
[0016] The low-grade bauxite raw material is dried and poured into a rolling granulator, and a ball blank is prepared by spraying water and rolling powder. Then, the ball blank is dried in an electric heating constant temperature air drying oven at 110°C for 24 hours, and the dried ball blank is placed in a corundum crucible and sintered in a muffle furnace at 1600°C for 6 hours to prepare a spherical particle. The bauxite particles with different particle sizes of 5-8 mm (20%), 3-5 mm (15%), 1-3 mm (15%) and 0-1 mm (10%), 0-1 mm andalusite particles (10%) as aggregate, 325 mesh white corundum powder (8%), D50=2.5 μm alumina powder (10%), 200 mesh silicon carbide powder (5%), Fe-TiCN powder (2%), calcium aluminate cement (5%) as fine powder, dispersing agent (1%), explosion-proof fiber (0.1%) and steel fiber (0.1%) as raw materials, are mixed uniformly according to a certain proportion, and then poured into a standard mold after dry mixing and wet mixing uniformly using a cement mixer. After demolding, the sample is cured at room temperature for 24 hours, and then dried in a drying oven at 110°C for 24 hours. The dried sample is placed in a box-type resistance furnace for heat treatment, and the temperature rising mechanism is as follows: the system is set to rise to 280°C at a certain rate and kept for 6 hours, and then cooled to obtain the sample. The main performance indexes of the product are as follows: the bulk density of the sample is 2.33-2.47 g / cm 3 , the bending strength is 20.07-25.51 MPa, and the compressive strength is 73.72-79.06 MPa.
[0017] Although the present application has been described in detail above with general description and specific embodiments, some modifications or improvements can be made on the basis of the present application, which is obvious to those skilled in the art. Therefore, these modifications or improvements made on the basis of not deviating from the spirit of the present application, all belong to the scope of the present application.
Claims
1. A method for using corundum-mullite-silicon carbide-based castables containing medium- and low-grade bauxite spherical particles, characterized in that: High-performance non-fired refractory materials are prepared by casting molding using medium- and low-grade bauxite spherical particles as aggregate, and andalusite particles, white corundum powder, silicon carbide powder, alumina micro powder, and Fe-TiCN fine powder as raw materials, aluminosilicate cement as binder, and explosion-proof fiber and steel fiber as additives.
2. The method for preparing corundum-mullite-silicon carbide-based castables containing medium- and low-grade bauxite spherical particles according to claim 1, characterized in that: The total aggregates of calcined bauxite natural particles and sintered low-grade bauxite spherical particles were 5-8 mm (20%), 3-5 mm (15%), 1-3 mm (15%), and 0-1 mesh (10%), respectively. Andalusite particles were 0-1 mm (10%), white corundum fine powder was 325 mesh (8%), alumina micro powder with D50=2.5 μm (10%), silicon carbide powder was 200 mesh (5%), Fe-TiCN powder was 2%, calcium aluminate cement was 5%, dispersant (added) was 1%, explosion-proof fiber (added) was 0.1%, and steel fiber (added) was 0.1%.
3. The method for preparing corundum-mullite-silicon carbide-based castables containing medium- and low-grade bauxite spherical particles according to claim 2, characterized in that: First, spherical particles are prepared using a rolling granulation machine based on low- to medium-grade bauxite. Then, the raw materials are weighed and mixed, and a cement mortar mixer is used to stir the raw materials evenly. The slurry is poured into a standard mold and placed on a vibrating table for vibration molding. After curing at room temperature for 24 hours, the precast blocks are demolded and placed in a forced-air drying oven for drying. Then, the dried precast blocks are placed in a muffle furnace for heat treatment at a temperature not exceeding 300 °C for 6 hours. After cooling, the non-fired corundum-mullite-silicon carbide refractory castable containing bauxite-based spherical particles of the present invention is obtained.
4. The method for preparing corundum-mullite-silicon carbide-based castables containing medium- and low-grade bauxite spherical particles according to claim 3, characterized in that... Casting method of corundum-mullite-silicon carbide based castable: First, after premixing, the premixed raw materials are poured into a cement mortar mixer and dry-mixed for 120 seconds. Then, about 6wt% water is added within 30 seconds. After wet mixing for 240 seconds, the slurry is poured into a standard mold of 40 mm*40 mm*160 mm and placed on a vibrating table for vibration molding. After curing at room temperature for 24 hours, the precast blocks are demolded and placed in a forced-air drying oven at 110℃*24 hours for drying.
5. The method for preparing corundum-mullite-silicon carbide-based castables containing medium- and low-grade bauxite spherical particles according to claim 4, characterized in that... Preparation of medium- and low-grade bauxite spherical particles: After drying the medium- and low-grade bauxite raw material, it was poured into a rolling granulator and prepared into spherical blanks by spraying water and rolling to coat them with powder. Then, the spherical blanks were dried in an electric heating constant temperature forced air drying oven at 110℃*24 h. The dried spherical blanks were placed in a corundum sagger and sintered in a muffle furnace at 1600℃*6 h to prepare spherical particles.