CN112897994A

CN112897994A - Preparation method of corundum spinel complex phase material

Info

Publication number: CN112897994A
Application number: CN201911130753.3A
Authority: CN
Inventors: 何健; 吕戌生; 张嘉良; 张家勤
Original assignee: Jiangsu Jingxin New Material Co ltd
Current assignee: Jiangsu Jingxin New Material Co ltd
Priority date: 2019-11-19
Filing date: 2019-11-19
Publication date: 2021-06-04

Abstract

The invention relates to a preparation method of a corundum spinel complex phase material. The main chemical components (wt) of the complex phase material are as follows: al2O3 is more than 97 percent, MgO is less than 3 percent, and the main phases are corundum phase and spinel phase, the invention takes industrial alumina, alpha-alumina, aluminum hydroxide, brucite, light-burned magnesium, heavy-burned magnesium and the like as raw materials, adds magnesium chloride as a burning promoter or a bonding agent, grinds and processes by a continuous or intermittent ball mill to prepare uniformly mixed powder, forms by forming processes such as balling or green pressing and the like, then dries in a drying tower, finally rapidly sinters in a shaft kiln or other high-temperature equipment at 1800-0 ℃, and then obtains the corundum-spinel complex phase material by processes such as crushing, grading, deironing, packaging and the like. The invention obtains the multiphase material with excellent performances of corundum and spinel, has good stability in high-temperature atmosphere and strong alkali and slag corrosion resistance.

Description

Preparation method of corundum spinel complex phase material

Technical Field

The invention belongs to the technical field of refractory materials for high-temperature industries such as ferrous metallurgy, cement, glass and the like, and particularly relates to a preparation method of a corundum spinel complex-phase material.

Background

The corundum-spinel castable is widely applied to large-scale ladle working linings, ladle brick holders, air bricks, electric furnace roof prefabricated parts and the like, and has the characteristics of high temperature resistance, high thermal state strength, good slag resistance and the like. At present, researches on corundum-spinel castable mainly focus on optimization of matrix composition, such as addition amount and particle size distribution of spinel powder and alumina micropowder, and research reports on aggregate materials are less. In the system, spinel is intensively distributed on a substrate part and plays a role in improving slag resistance and thermal shock stability, and aggregate is usually sintered corundum or fused corundum; from the microstructure, the components and the properties of the matrix and the aggregate are mutually isolated, and the inconsistency of the high-temperature properties of the two materials can influence the service life of the refractory material product in the high-temperature use process.

The corundum spinel complex phase material is a refractory material aggregate obtained through in-situ reaction, corundum phase and spinel phase are solid-dissolved to form the corundum-spinel complex phase material, the defects of brittleness, insufficient slag resistance and the like of a single corundum phase can be overcome, the corundum intergranular spinel can prevent corundum crystals from growing too fast, and the composite material has the excellent performances of both corundum and spinel. When the corundum-spinel complex phase material aggregate is used for preparing corundum-spinel series refractory products, the corundum-spinel complex phase material aggregate and the spinel-containing matrix have good similarity in chemical composition and physical properties, and particularly in high-temperature service performance, the overall service performance of the refractory products is improved due to the characteristics of matching of thermal expansion coefficients, improvement of interface bonding strength and the like.

Disclosure of Invention

The invention provides a corundum-spinel complex phase material and a preparation method thereof, which enable corundum and spinel phases to form a solid solution, realize the real complex phase material, have the advantages of high purity, strong erosion resistance, good thermal shock stability and the like, are suitable for preparing high-efficiency, energy-saving and long-life high-temperature industrial kiln liners, and are more suitable for ladle liners, sliding plates, air bricks and continuous casting three major pieces as basic raw materials.

In order to realize the task, the technical scheme adopted by the invention is as follows: taking one or more of 70-100% of industrial alumina, 0-30% of aluminum hydroxide and 0-30% of alpha-alumina as an aluminum source; one or more of 0-4% brucite, 0-3% light-burned magnesium, 0-3% heavy-burned magnesium and 0-3% magnesite are used as magnesium sources; adding 0-1% of magnesium chloride as a burning promoter; the corundum-spinel composite material is prepared by uniformly mixing and grinding the materials by a ball mill into mixed powder, forming the mixed powder by processes such as balling or compacting, taking magnesium chloride aqueous solution with the concentration of 0-10% as a binding agent during forming, drying a blank, quickly firing the dried blank in a vertical kiln or a rotary kiln at the high temperature of 1800-1950 ℃, and crushing a cooked ball blank, wherein the main chemical components of the corundum-spinel composite material are Al2O3 & gt 97%, and MgO is less than 3%.

The method comprises the steps of premixing a plurality of raw materials, then feeding the raw materials into a ball mill, controlling the fineness and the particle size distribution of mixed powder ground by the ball mill, and being beneficial to realizing the improvement of the density of a green body, wherein D50 of the mixed powder is between 2 and 10 mu m, and the residue of a 325-mesh sieve is less than 20 percent.

A horizontal or disc type ball forming mill adopting a semi-dry process is selected for ball blank forming, water or a magnesium chloride aqueous solution with the concentration of 0-10% is used as a binding agent, the size of a ball blank is controlled to be 20-30mm, the water content is 10-25%, and compared with wet grinding (the moisture of a blank body is 40-80%) and drying, the energy consumption is greatly reduced, and meanwhile, the ball blank is more compact due to the adoption of powder with multimodal particle size distribution, so that the growth and development of a multiphase material crystal are facilitated.

And drying the green body in a drying tower, then, quickly firing the green body in a shaft kiln at 1800-1950 ℃, forming hot-pressing sintering due to the gravity applied by the upper material to the lower material, facilitating the quick firing of aluminum oxide and magnesium oxide to form a spinel phase, and crushing a fired ball blank to obtain the corundum-spinel complex phase material.

Therefore, the corundum spinel complex phase material prepared by the method has the characteristics of lower thermal expansion coefficient, high strength, good thermal shock property, slag corrosion resistance, strong scouring resistance, good permeability resistance and the like compared with alumina and magnesia, is a novel complex phase material for replacing sintered corundum in corundum-spinel castable, has simple and convenient production process, obviously saves energy and reduces consumption, accords with the national industrial policy, and is suitable for large-scale industrial production.

Detailed Description

In order to avoid repetition, the following raw materials and process parameters related to the present embodiment are uniformly described as follows, and are not repeated in the examples: the content of Al2O3 in the industrial alumina is more than 99.5 percent, and the grain diameter of the industrial alumina is less than 0.2 mm; al2O3 content of aluminum hydroxide is more than 64.5%, and particle size thereofLess than 0.1 mm; the content of Al2O3 in the alpha-alumina is more than 99.5 percent, the grain diameter is less than 0.2mm, and the alpha phase is more than 90 percent; the MgO content of brucite is more than 66%, and the grain diameter is less than 0.1 mm; the MgO content of the light-burned magnesium and the heavy-burned magnesium is more than 96 percent, and the grain diameter is less than 0.1 mm; the MgO content of the magnesite is more than 45 percent, and the grain diameter of the magnesite is less than 0.1 mm; MgCl of anhydrous magnesium chloride₂The content is more than 98 percent; MgCl of magnesium chloride hexahydrate₂The content is more than 45 percent.

Example 1

A corundum spinel complex phase material and a preparation method thereof. The corundum spinel complex phase material comprises the following raw materials in percentage by mass: 85-95% of industrial alumina, 0-10% of aluminum hydroxide and 0-5% of light-burned magnesium, and 0-1% of anhydrous magnesium chloride is added to serve as a burning promoter; uniformly mixing and finely grinding in a ball mill, carrying out air separation and classification, then balling in a horizontal ball forming mill, wherein a balling binding agent is water, the diameter of a ball blank is 20-30mm, drying in a drying tower, rapidly firing at 1800-1950 ℃ in a shaft kiln, and crushing the fired ball blank to obtain the finished product of the corundum-spinel complex phase material.

Example 2

A corundum spinel complex phase material and a preparation method thereof. The corundum spinel complex phase material comprises the following raw materials in percentage by mass: more than 95 percent of industrial alumina and 0 to 5 percent of light-burned magnesium are evenly mixed and finely ground in a ball mill, after air separation and classification, the mixture is formed into balls in a horizontal ball forming mill, the ball forming binder is 0 to 10 percent of magnesium chloride aqueous solution, the diameter of a ball blank is 20 to 30mm, the ball blank is dried in a drying tower and rapidly fired at 1800 to 1950 ℃ in a shaft kiln, and the fired ball blank is crushed to obtain the corundum-spinel complex phase material finished product.

Claims

1. A preparation method of a corundum spinel complex phase material is characterized by comprising the following steps: taking one or more of 70-100% of industrial alumina, 0-30% of aluminum hydroxide and 0-30% of alpha-alumina as an aluminum source; one or more of 0-4% brucite, 0-3% light-burned magnesium, 0-3% heavy-burned magnesium and 0-3% magnesite are used as magnesium sources; adding 0-1% of magnesium chloride as a burning promoter; uniformly mixing the raw materials by a ball mill, grinding the raw materials into mixed powder, forming the mixed powder by a forming process such as balling or compacting, taking a magnesium chloride aqueous solution with the concentration of 0-10% as a binding agent during forming, drying a blank, and rapidly sintering the dried blank in a shaft kiln or a rotary kiln at the high temperature of 1800-1950 ℃;

the main chemical components of the material are Al2O3 more than 97 percent and MgO less than 3 percent.

2. The method for preparing a corundum-spinel composite phase material according to claim 1, characterized in that the content of Al2O3 in the industrial alumina is more than 99.5%, and the grain size is less than 0.2 mm.

3. The method for preparing a corundum-spinel composite phase material according to claim 1, wherein Al2O3 content of the aluminum hydroxide is more than 64.5%, and particle size is less than 0.1 mm.

4. The method for preparing the corundum-spinel composite phase material as claimed in claim 1, wherein the alpha-alumina has an Al2O3 content of more than 99.5%, a particle size of less than 0.2mm, and an alpha phase of more than 90%.

5. The method for preparing a corundum-spinel composite phase material according to claim 1, characterized in that the brucite has an MgO content of > 66% and a particle size of < 0.1 mm.

6. The method for preparing a corundum-spinel composite phase material according to claim 1, characterized in that the content of MgO in the light-burned magnesium and the heavy-burned magnesium is more than 96%, and the grain size is less than 0.1 mm.

7. The method for preparing a corundum-spinel composite phase material according to claim 1, characterized in that the magnesite has a MgO content of more than 45% and a grain size of less than 0.1 mm.

8. The method for preparing a corundum-spinel composite phase material as claimed in claim 1, wherein said magnesium chloride is used as a binder in forming or as a sintering promoter during sintering, and the magnesium chloride is derived from MgCl₂Anhydrous magnesium chloride or MgCl with a content of > 98%₂Magnesium chloride hexahydrate with the content of more than 45 percent.

9. The method for preparing the corundum spinel complex phase material according to claim 1, characterized in that a high-temperature shaft kiln or a rotary kiln is selected to realize rapid sintering at 1800-1950 ℃, and formed spinel crystals are dissolved in corundum crystals to form the corundum spinel complex phase material.