Magnesium aluminate spinel refractory material containing trace manganese and preparation method thereof

Abstract

The invention discloses a magnesium aluminate spinel refractory material containing trace manganese and a preparation method thereof, and the magnesium aluminate spinel refractory material is prepared from the following components by weight: 84-88% of magnesia, 5-8% of magnesium aluminate spinel, 1.2-1.6% of bauxite, 1-1.4% of manganese dioxide powder, 0.3-0.8% of metal manganese powder, 0.6-1.5% of a binder, 0.4-1% of an additive, and 0.4-0.8% of a molding aid. The magnesite is at least one of sintered magnesite, light-burned magnesite and fused magnesite, the binding agent is formed by combining at least one of silica powder, clay, dextrin and water glass, and the stabilizing agent is added for mixing and stirring. According to the invention, functionality which can be directly used in high-temperature environments such as a firing zone and a transition zone of a rotary cement kiln and has ideal microstructure and performance is added, so that the magnesium aluminate spinel refractory material has the effects of efficiently constructing the magnesium aluminate spinel refractory material and improving the fire resistance; and the condition that the magnesium aluminate spinel refractory material is relatively unstable in a firing zone and a transition zone of the rotary cement kiln is prevented.

Description

Technical Field

[0001] The invention relates to the technical field of refractory materials, in particular to a magnesium-aluminum spinel refractory material containing trace manganese and a preparation method thereof. Background Art

[0002] Magnesia-alumina spinel refractory is a high-quality refractory raw material with many excellent physical and chemical properties. The following is a detailed summary and analysis of magnesia-alumina spinel refractory: 1. Definition and composition Definition: Magnesia-alumina spinel is a spinel refractory material synthesized by high-temperature calcination or melting with magnesium oxide (MgO) and aluminum oxide (Al2O3) as the main raw materials. Composition: The chemical formula of magnesia-alumina spinel is usually MgO·Al2O3, in which the MgO content is about 28.3% and the Al2O3 content is about 71.7%. 2. Physical properties Melting point and high temperature performance: The melting point of magnesia-alumina spinel is as high as 2135℃ to 2250℃, and it has extremely high high temperature resistance. Hardness and density: Mohs hardness ≥9.0, high volume density, high mineral phase content, well-developed grains, and uniform structure. Thermal stability: small thermal expansion coefficient, thermal conductivity decreases with rising temperature, and good thermal shock stability. 3. Chemical property stability: Magnesium aluminum spinel is very stable in redox atmosphere, and its chemical stability is better than FeCr2O4. Corrosion resistance: It has strong resistance to alkaline slag, and has strong resistance to erosion, corrosion and spalling.

[0003] Magnesium aluminate spinel refractory materials are needed in cement, steel, glass, ceramics and other industries. However, most of the existing magnesium aluminate spinel refractory materials on the market are relatively unstable in the firing zone and transition zone of cement rotary kiln, resulting in the magnesium aluminate spinel refractory materials having less than ideal microstructure and performance during use, affecting the normal and efficient use of magnesium aluminate spinel refractory materials.

[0004] Therefore, it is necessary to design and transform the magnesia-alumina spinel refractory material to effectively prevent the magnesia-alumina spinel refractory material from being unstable in the firing zone and transition zone of the cement rotary kiln. Summary of the invention

[0005] In order to solve the problems raised in the above-mentioned background technology, the purpose of the present invention is to provide a magnesium-aluminum spinel refractory material containing trace manganese and a preparation method thereof, which has the advantages of being directly used in high-temperature environments such as the firing zone and transition zone of a cement rotary kiln and having an ideal microstructure and performance, and solves the problem that the magnesium-aluminum spinel refractory material is relatively unstable in the firing zone and transition zone of a cement rotary kiln.

[0006] To achieve the above purpose, the present invention provides the following technical scheme: the powder is prepared from the following components in parts by weight: 84-88% magnesia sand, 5-8% magnesia-alumina spinel, 1.2-1.6% bauxite, 1-1.4% manganese dioxide powder, 0.3-0.8% metallic manganese powder, 0.6-1.5% binder, 0.4-1% additive, and 0.4-0.8% molding aid.

[0007] As a preferred embodiment of the present invention, the magnesia is at least one of sintered magnesia, light-burned magnesia and fused magnesia.

[0008] As a preferred embodiment of the present invention, the binder is composed of at least one of silicon micropowder, clay, dextrin and water glass, and a stabilizer is added and mixed.

[0009] As a preferred embodiment of the present invention, the additive is composed of a sintering aid, a dispersant, a stabilizer, etc., the sintering aid is borax, the dispersant is a silicate, and the stabilizer is a lead salt.

[0010] As a preferred embodiment of the present invention, the molding aid is one of dioctyl phthalate DOP and dibutyl phthalate DBP.

[0011] As a preferred embodiment of the present invention, the particle size of the magnesia is 0.1-3 mm, which is the standard magnesia particle size.

[0012] As preferred embodiments of the present invention, the step A) is material preparation; the step B) is grinding; the step C) is stirring and mixing; the step D) is molding; the step E) is drying; the step F) is sintering; and the step G) is polishing and packaging.

[0013] As the preferred embodiment of the present invention, the following steps are included:

[0014] 1) Step A) Magnesium sand, magnesium aluminum spinel, bauxite, manganese dioxide powder, metallic manganese powder, binder, additives, and molding aids are weighed and added into a grinding machine;

[0015] 2) Step B) putting a plurality of materials into a grinder for grinding to separate them into fine particles, thereby achieving an efficient mixing effect;

[0016] 3) Step C) starting a mixer to stir and mix the various materials so that they are evenly mixed together;

[0017] 4) Step D) forming the mixed powder after stirring into a desired shape by hand or machine. During the forming process, attention should be paid to the shape and thickness of the blank to avoid excessive thickness or defects;

[0018] 5) Step E) After the green body is formed, it is placed in a dryer for drying to avoid the green body having high moisture content and cracking;

[0019] 6) Step F) placing the formed green body into a kiln for firing. The firing temperature and time should be set according to the characteristics of the green body to ensure the fire resistance and wear resistance of the green body. After firing, the green body should have sufficient strength and fire resistance stability;

[0020] 7) Step G) The fired green body is processed with a grinder to remove raised parts of the green body, and then the green body is packaged in sequence with a packaging machine for packaging.

[0021] Compared with the prior art, the present invention has the following beneficial effects:

[0022] 1. The present invention increases the functionality of being directly used in high-temperature environments such as cement rotary kiln firing zone and transition zone and having ideal microstructure and performance, so that it has the effect of efficiently structuring and improving the refractory performance of magnesia-alumina spinel refractory materials, and preventing the magnesia-alumina spinel refractory materials from being relatively unstable in cement rotary kiln firing zone and transition zone. DETAILED DESCRIPTION

[0023] The following will be combined with 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.

[0024] The invention provides a magnesium-aluminum spinel refractory material containing trace manganese and a preparation method thereof. The refractory material is prepared from the following components in parts by weight: 84-88% of magnesia sand, 5-8% of magnesium-aluminum spinel, 1.2-1.6% of bauxite, 1-1.4% of manganese dioxide powder, 0.3-0.8% of metal manganese powder, 0.6-1.5% of binder, 0.4-1% of additive and 0.4-0.8% of forming aid.

[0025] The present invention is further configured such that the magnesia is at least one of sintered magnesia, light-burned magnesia and fused magnesia.

[0026] The present invention is further configured such that the binder is composed of at least one of silicon micropowder, clay, dextrin and water glass, and a stabilizer is added and mixed.

[0027] The present invention is further configured that the additive is composed of a sintering aid, a dispersant, a stabilizer, etc., the sintering aid is borax, the dispersant is silicate, and the stabilizer is lead salt.

[0028] The present invention is further configured such that the molding aid is one of dioctyl phthalate DOP and dibutyl phthalate DBP.

[0029] The present invention is further configured such that the particle size of the magnesia is 0.1 to 3 mm, which is the standard magnesia particle size.

[0030] The present invention is further configured as follows: step A) material preparation; step B) grinding; step C) stirring and mixing; step D) molding; step E) drying; step F) sintering; and step G) grinding and packaging.

[0031] The present invention is further configured to include the following steps:

[0032] 1) Step A) Magnesium sand, magnesium aluminum spinel, bauxite, manganese dioxide powder, metallic manganese powder, binder, additives, and molding aids are weighed and added into a grinding machine;

[0033] 2) Step B) putting a plurality of materials into a grinder for grinding to separate them into fine particles, thereby achieving an efficient mixing effect;

[0034] 3) Step C) starting a mixer to stir and mix the various materials so that they are evenly mixed together;

[0035] 4) Step D) forming the mixed powder after stirring into a desired shape by hand or machine. During the forming process, attention should be paid to the shape and thickness of the blank to avoid excessive thickness or defects;

[0036] 5) Step E) After the green body is formed, it is placed in a dryer for drying to avoid the green body having high moisture content and cracking;

[0037] 6) Step F) placing the formed green body into a kiln for firing. The firing temperature and time should be set according to the characteristics of the green body to ensure the fire resistance and wear resistance of the green body. After firing, the green body should have sufficient strength and fire resistance stability;

[0038] 7) Step G) The fired green body is processed with a grinder to remove raised parts of the green body, and then the green body is packaged in sequence with a packaging machine for packaging.

[0039] Example 1

[0040] The invention is prepared from the following components in parts by weight: 84% magnesia sand, 6% magnesia aluminum spinel, 1.4% bauxite, 1.2% manganese dioxide powder, 0.5% metal manganese powder, 0.9% binder, 1% additive, and 0.6% molding aid. Magnesia sand, magnesia aluminum spinel, bauxite, manganese dioxide powder, metal manganese powder, binder, additive, and molding aid are weighed and added to the inside of a grinder respectively. A variety of materials are put into the inside of the grinder for grinding. The grinder grinds the materials for 5 minutes to separate them into fine particles, which has the effect of efficient mixing. A mixer is started to stir and mix the various materials. The mixer is 2000 revolutions / h for stirring. Stir for 8 minutes to mix them evenly, and then mold the mixed powder into the required shape by hand or machine. During the molding process, attention should be paid to the shape and thickness of the blank to avoid excessive thickness or defects. After the blank is formed, it is placed in a dryer for drying. The dryer temperature is set to 130°C and dried for 50 hours to avoid high moisture content and cracking of the blank. The formed blank is placed in a kiln for firing at a temperature of 1800°C and a time of 6 hours to ensure the refractory and wear-resistant properties of the blank. After firing, the blank should have sufficient strength and refractory stability.

[0041] Example 2

[0042] The invention is prepared from the following components in parts by weight: 86% magnesia sand, 5% magnesia aluminum spinel, 1.3% bauxite, 1.1% manganese dioxide powder, 0.8% metal manganese powder, 1.3% binder, 0.6% additive, and 0.4% molding aid. Magnesia sand, magnesia aluminum spinel, bauxite, manganese dioxide powder, metal manganese powder, binder, additive, and molding aid are weighed and added to the inside of a grinder respectively. A variety of materials are put into the inside of the grinder for grinding. The grinder grinds the materials for 5 minutes to separate them into fine particles, which has the effect of efficient mixing. A mixer is started to stir and mix the various materials. The mixer is 1800 revolutions / h. Stir for 9 minutes to mix them evenly, and then mold the mixed powder into the desired shape by hand or machine. During the molding process, attention should be paid to the shape and thickness of the blank to avoid excessive thickness or defects. After the blank is molded, it is placed in a dryer for drying. The dryer temperature is set to 140°C and dried for 50 hours to avoid cracking due to high moisture content. The molded blank is placed in a kiln for firing at a temperature of 1700°C and a time of 8 hours to ensure the refractory and wear-resistant properties of the blank. After firing, the blank should have sufficient strength and refractory stability.

[0043] 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.

[0044] 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. A magnesium-aluminum spinel refractory material containing trace manganese, characterized in that: The invention is prepared from the following components in parts by weight: 84-88% of magnesia sand, 5-8% of magnesia-alumina spinel, 1.2-1.6% of bauxite, 1-1.4% of manganese dioxide powder, 0.3-0.8% of metal manganese powder, 0.6-1.5% of binder, 0.4-1% of additive and 0.4-0.8% of forming aid.

2. The magnesium-aluminum spinel refractory material containing trace amounts of manganese according to claim 1, characterized in that: The magnesia is at least one of sintered magnesia, light-burned magnesia and fused magnesia.

3. The magnesium-aluminum spinel refractory material containing trace amounts of manganese according to claim 1, characterized in that: The binder is composed of at least one of silicon micropowder, clay, dextrin and water glass, and a stabilizer is added and mixed.

4. The magnesium-aluminum spinel refractory material containing trace amounts of manganese according to claim 1, characterized in that: The additives are composed of a sintering aid, a dispersant, a stabilizer, etc. The sintering aid is borax, the dispersant is silicate, and the stabilizer is lead salt.

5. The magnesium-aluminum spinel refractory material containing trace amounts of manganese according to claim 1, characterized in that: The molding aid is one of dioctyl phthalate DOP and dibutyl phthalate DBP.

6. The magnesium-aluminum spinel refractory material containing trace amounts of manganese according to claim 2, characterized in that: The particle size of the magnesia is 0.1-3 mm, which is the standard magnesia particle size.

7. The method for preparing a magnesium-aluminum spinel refractory material containing trace manganese according to claim 1, characterized in that: The steps include: A) material preparation; B) grinding; C) stirring and mixing; D) molding; E) drying; F) sintering; and G) polishing and packaging.

8. The method for preparing a magnesium-aluminum spinel refractory material containing trace manganese according to claim 7, characterized in that: The method comprises the following steps: 1) Step A) Magnesium sand, magnesium aluminum spinel, bauxite, manganese dioxide powder, metallic manganese powder, binder, additives, and molding aids are weighed and added into a grinding machine; 2) Step B) putting a plurality of materials into a grinder for grinding to separate them into fine particles, thereby achieving an efficient mixing effect; 3) Step C) starting a mixer to stir and mix the various materials so that they are evenly mixed together; 4) Step D) forming the mixed powder after stirring into a desired shape by hand or machine. During the forming process, attention should be paid to the shape and thickness of the blank to avoid excessive thickness or defects; 5) Step E) After the green body is formed, it is placed in a dryer for drying to avoid the green body having high moisture content and cracking; 6) Step F) placing the formed green body into a kiln for firing. The firing temperature and time should be set according to the characteristics of the green body to ensure the fire resistance and wear resistance of the green body. After firing, the green body should have sufficient strength and fire resistance stability; 7) Step G) The fired green body is processed with a grinder to remove raised parts of the green body, and then the green body is packaged in sequence with a packaging machine for packaging.