阅读说明：本技术 一种低碳微孔镁碳砖及其制备方法 (Low-carbon microporous magnesia carbon brick and preparation method thereof ) 是由 吴沁晔 徐娜娜 魏志鹏 于 2021-09-03 设计创作，主要内容包括：本发明涉及一种低碳微孔镁碳砖及其制备方法。其技术方案是：先以96.0～98.0wt％的镁碳砖回收料、0.9～1.7wt％的纳米炭黑、0.7～1.1wt％的乳酸镁和0.4～1.2wt％的钛酸铝为原料,外加所述原料2.2～3.4wt％的结合剂,混合均匀；再于15～20MPa条件下机压成型,在160～180℃条件下保温5～9小时,制得低碳微孔镁碳砖。其中：所述镁碳砖回收料的主要化学成分是：MgO含量≥85.0wt％,CaO含量≤1.1wt％,SiO-(2)含量≤1.5wt％,Fe-(2)O-(3)含量≤0.7wt％,IL≤3.9wt％；所述结合剂为聚甲基丙烯酸甲酯、聚碳酸酯和环氧丙烷中的一种。因此,本发明具有工艺简单、绿色环保、节省资源和成本低廉的特点；所制备的低碳微孔镁碳砖的机械强度高、导热系数低、抗热震性能好和使用寿命长。(The invention relates to a low-carbon microporous magnesia carbon brick and a preparation method thereof. The technical scheme is as follows: firstly, 96.0-98.0 wt% of magnesia carbon brick reclaimed materials, 0.9-1.7 wt% of nano carbon black, 0.7-1.1 wt% of magnesium lactate and 0.4-1.2 wt% of aluminum titanate are used as raw materials, and a bonding agent in an amount of 2.2-3.4 wt% of the raw materials is added to be uniformly mixed; and performing mechanical pressing forming under the condition of 15-20 MPa, and performing heat preservation for 5-9 hours at the temperature of 160-180 ℃ to obtain the low-carbon microporous magnesia carbon brick. Wherein: the magnesia carbon brick recycled material comprises the following main chemical components: MgO content is more than or equal to 85.0 wt%, CaO content is less than or equal to 1.1 wt%, SiO 2 Content is less than or equal to 1.5 wt%, Fe 2 O 3 The content is less than or equal to 0.7wt percent, and the IL is less than or equal to 3.9wt percent; the bonding agent is one of polymethyl methacrylate, polycarbonate and propylene oxide. Therefore, the invention has the characteristics of simple process, environmental protection, resource saving and low cost; the prepared low-carbon microporous magnesia carbon brick has high mechanical strength, low heat conductivity coefficient and heat resistanceGood shock performance and long service life.)

1. The preparation method of the low-carbon microporous magnesia carbon brick is characterized by comprising the following steps of firstly, uniformly mixing 96.0-98.0 wt% of magnesia carbon brick reclaimed materials, 0.9-1.7 wt% of nano carbon black, 0.7-1.1 wt% of magnesium lactate and 0.4-1.2 wt% of aluminum titanate as raw materials, and additionally adding 2.2-3.4 wt% of a bonding agent as the raw materials; and performing mechanical pressing forming under the condition of 15-20 MPa, and performing heat preservation for 5-9 hours at the temperature of 160-180 ℃ to obtain the low-carbon microporous magnesia carbon brick.

2. The preparation method of the low-carbon microporous magnesia carbon brick according to claim 1, wherein the recycled magnesia carbon brick material is obtained by removing an altered layer from a waste magnesia carbon brick, crushing and screening the waste magnesia carbon brick material to obtain recycled magnesia carbon brick materials with different grain size fractions: 30 to 35.0 wt% of particles having a particle diameter of less than 8mm and not less than 5mm, 19.0 to 22 wt% of particles having a particle diameter of less than 5mm and not less than 3mm, and not less than16.0-20 wt% of particles with the particle size of 3mm and more than or equal to 1mm, 8.0-10 wt% of particles with the particle size of less than 1mm and more than or equal to 0.088mm, and 18-22.0 wt% of fine powder with the particle size of less than 0.088 mm; the magnesia carbon brick recycled material comprises the following main chemical components: MgO content is more than or equal to 85.0 wt%, CaO content is less than or equal to 1.1 wt%, SiO₂Content is less than or equal to 1.5 wt%, Fe₂O₃The content is less than or equal to 0.7wt percent, and the IL is less than or equal to 3.9wt percent.

3. The method for preparing the low-carbon microporous magnesia carbon brick according to claim 1, wherein the nano carbon black has a particle size of less than 172 nm; the C content of the nano carbon black is more than or equal to 97.9 wt%.

4. The method for preparing the low-carbon microporous magnesia carbon brick according to claim 1, wherein the particle size of the magnesium lactate is less than 0.02 mm; 2 (C) of magnesium lactate₃H₅O₃)Mg·3(H₂O) content is more than or equal to 98.0 wt%.

5. The method of claim 1, wherein the aluminum titanate has a particle size of less than 0.05 mm; the main chemical components of the aluminum titanate are as follows: al (Al)₂O₃Content is more than or equal to 49.1 wt%, TiO₂The content is more than or equal to 47.5wt percent.

6. The method for preparing the low-carbon microporous magnesia carbon brick according to claim 1, wherein the binder is one of polymethyl methacrylate, polycarbonate and propylene oxide.

7. A low-carbon microporous magnesia carbon brick prepared by the preparation method of the low-carbon microporous magnesia carbon brick according to any one of claims 1 to 6.

Technical Field

The invention belongs to the technical field of low-carbon magnesia carbon bricks. In particular to a low-carbon microporous magnesia carbon brick and a preparation method thereof.

Background

The magnesia carbon brick is a refractory material developed in the 70 th of the 20 th century, has excellent thermal shock resistance, slag corrosion resistance and slag penetration resistance, and is widely applied to the refining continuous casting process of molten steel. With the market demand for special steel grades and the development of an external refining process, the existing magnesia carbon brick can not meet the requirements of some special smelting processes due to the problems of large amount of recarburization of molten steel, oxidation failure and the like. At the beginning of the 21 st century, how to scientifically reduce the carbon content in the magnesia carbon brick becomes a focus of attention of scientific and technical personnel at home and abroad.

It is well known that as the carbon content decreases, the slag penetration resistance, thermal shock stability, and spalling resistance of the magnesia carbon brick article are affected. Therefore, the optimization of the performance of the low-carbon magnesia carbon brick becomes a topic of intense research in recent years.

For example, the patent technology of "a magnesia carbon brick added with polycarbosilane" (CN106674528B) discloses a brick made of tabular corundum, electric melting white corundum and alpha-Al₂O₃The technical scheme is that the magnesia carbon brick is prepared by taking micro powder, clay, shale, coal gangue, coal ash and crystalline flake graphite as raw materials and taking environment-friendly asphalt, liquid thermoplastic phenolic resin, solid resin powder, solid polycarbosilane and normal hexane as curing agents through mechanical compression molding; a large amount of loose substances with a loose microstructure are introduced into the raw materials of the technology, so that the strength of the prepared magnesia carbon brick product is greatly influenced, and the high heat conductivity coefficient of the crystalline flake graphite is not beneficial to energy conservation and heat preservation at the slag line of the ladle.

For example, the patent technology of 'a low-carbon magnesia carbon brick for a ladle and a preparation method thereof' (CN107285744A) discloses a patent technology for preparing a magnesia carbon brick by using electric melting magnesia, magnesia zirconium sand and scale graphite as raw materials and phenolic resin and modified asphalt as bonding agents through mechanical compression molding, and ZrO is introduced into the technology₂The phase change toughening optimizes the thermal shock resistance of the magnesia carbon brick, but the increase of the solid phase density leads to the increase of the heat conductivity coefficient, which is not beneficial to the heat accumulation at the slag line.

For example, the patent technology of 'a magnesia carbon brick prepared by using magnesia carbon brick residual bricks and a preparation method thereof' (CN105622070B) discloses a method for preparing a magnesia carbon brick by using electric melting magnesia, magnesia carbon brick residual bricks, crystalline flake graphite and phenolic resin as raw materials.

For example, the patent technology of 'a low-carbon magnesia carbon brick with a non-oxide reinforced and toughened structure and a preparation method thereof' (CN104478455B) discloses a patent technology for preparing a magnesia carbon brick by using fused magnesia, silicon nitride and metal aluminum powder as raw materials and phenolic resin as a binding agent through mechanical compression molding, the technology optimizes the thermal shock resistance of the magnesia carbon brick by introducing non-oxide silicon nitride, but the silicon nitride is easily oxidized and loses efficacy under an oxidizing atmosphere, the service life of the prepared magnesia carbon brick product is shortened, and potential safety hazards exist.

Disclosure of Invention

The invention aims to overcome the defects of the prior art and provides a preparation method of a low-carbon microporous magnesia carbon brick, which has the advantages of simple process, environmental protection, resource saving and low cost; the prepared low-carbon microporous magnesia carbon brick has the advantages of high mechanical strength, low heat conductivity coefficient, good thermal shock resistance, excellent stability and long service life.

In order to achieve the purpose, the technical scheme adopted by the invention is as follows: firstly, 96.0-98.0 wt% of magnesia carbon brick reclaimed materials, 0.9-1.7 wt% of nano carbon black, 0.7-1.1 wt% of magnesium lactate and 0.4-1.2 wt% of aluminum titanate are used as raw materials, and a bonding agent in an amount of 2.2-3.4 wt% of the raw materials is added to be uniformly mixed; and performing mechanical pressing forming under the condition of 15-20 MPa, and performing heat preservation for 5-9 hours at the temperature of 160-180 ℃ to obtain the low-carbon microporous magnesia carbon brick.

The magnesia carbon brick recycled material is obtained by removing an altered layer, crushing and screening the waste magnesia carbon bricks and has different grain size grades: 30-35.0 wt% of particles with the particle size of less than 8mm and not less than 5mm, 19.0-22 wt% of particles with the particle size of less than 5mm and not more than 3mm, 16.0-20 wt% of particles with the particle size of less than 3mm and not less than 1mm, 8.0-10 wt% of particles with the particle size of less than 1mm and not more than 0.088mm, and 18-22.0 wt% of fine powder with the particle size of less than 0.088 mm; the magnesia carbon brick recycled material comprises the following main chemical components: MgO content is more than or equal to 85.0 wt%, CaO content is less than or equal to 1.1 wt%, SiO₂Content is less than or equal to 1.5 wt%, Fe₂O₃The content is less than or equal to 0.7wt percent, and the IL is less than or equal to 3.9wt percent.

The particle size of the nano carbon black is less than 172 nm; the C content of the nano carbon black is more than or equal to 97.9 wt%.

The particle diameter of the magnesium lactate is less than0.02 mm; 2 (C) of magnesium lactate₃H₅O₃)Mg·3(H₂O) content is more than or equal to 98.0 wt%.

The grain diameter of the aluminum titanate is less than 0.05 mm; the main chemical components of the aluminum titanate are as follows: al (Al)₂O₃Content is more than or equal to 49.1 wt%, TiO₂The content is more than or equal to 47.5wt percent.

The bonding agent is one of polymethyl methacrylate, polycarbonate and propylene oxide.

Due to the adoption of the technical scheme, compared with the prior art, the invention has the following positive effects:

1. the carbon microporous magnesia carbon brick with excellent performance is prepared by taking the recycled magnesia carbon brick as a main raw material, nano carbon black as a carbon source, magnesium lactate and aluminum titanate as ceramic matrix reinforcing agents, adding a bonding agent, performing mechanical compression molding, and preserving heat at 160-180 ℃, and has the advantages of simple process and energy conservation. The method can optimize the performance and prolong the service life of the low-carbon microporous magnesia carbon brick while realizing the ultra-low carbon content in the low-carbon microporous magnesia carbon brick. The utilization rate of the magnesia carbon brick recycled material of the low-carbon microporous magnesia carbon brick prepared by the invention is more than or equal to 96 percent, the resource is saved, the environment is protected, and the cost is low.

2. The magnesium lactate adopted by the invention is decomposed to generate CO in a high-temperature use environment₂CO in the matrix structure₂The atmosphere can avoid the added nano carbon black from oxidation failure; the periclase generated by decomposing the magnesium lactate has a microporous structure, and the thermal shock resistance of the low-carbon microporous magnesia carbon brick can be further improved while the heat-insulating property is optimized.

3. The aluminum titanate used in the present invention has advantages of low thermal expansion and high mechanical strength, but is easily decomposed at 1350 ℃. The MgO obtained by dehydroxylation of the periclase added in the invention in the high-temperature use process can effectively inhibit the decomposition of aluminum titanate and optimize the stability of the low-carbon microporous magnesia carbon brick in the high-temperature use process.

The low-carbon microporous magnesia carbon brick prepared by the invention is detected as follows: the compressive strength is 35.5-42.0 MPa; the apparent porosity is 3.3-4.4%; the thermal conductivity coefficient is 3.22-3.55W/(m.K), and the performance is superior to that of similar products.

Therefore, the invention has the characteristics of simple process, environmental protection, energy conservation, resource saving and low cost; the prepared low-carbon microporous magnesia carbon brick has the advantages of high mechanical strength, low heat conductivity coefficient, good thermal shock resistance, excellent stability and long service life.

Detailed Description

The invention is further described with reference to specific embodiments, which do not limit the scope of the invention.

A low-carbon microporous magnesia carbon brick and a preparation method thereof. Firstly, 96.0-98.0 wt% of magnesia carbon brick reclaimed materials, 0.9-1.7 wt% of nano carbon black, 0.7-1.1 wt% of magnesium lactate and 0.4-1.2 wt% of aluminum titanate are used as raw materials, and a bonding agent in an amount of 2.2-3.4 wt% of the raw materials is added to be uniformly mixed; and performing mechanical pressing forming under the condition of 15-20 MPa, and performing heat preservation for 5-9 hours at the temperature of 160-180 ℃ to obtain the low-carbon microporous magnesia carbon brick.

The bonding agent is one of polymethyl methacrylate, polycarbonate and propylene oxide.

In this embodiment:

the magnesia carbon brick recycled material is obtained by removing an altered layer, crushing and screening the waste magnesia carbon bricks and has different grain size grades: 30-35.0 wt% of particles with the particle size of less than 8mm and not less than 5mm, 19.0-22 wt% of particles with the particle size of less than 5mm and not more than 3mm, 16.0-20 wt% of particles with the particle size of less than 3mm and not less than 1mm, 8.0-10 wt% of particles with the particle size of less than 1mm and not more than 0.088mm, and 18-22.0 wt% of fine powder with the particle size of less than 0.088 mm; the magnesia carbon brick recycled material comprises the following main chemical components: MgO content is more than or equal to 85.0 wt%, CaO content is less than or equal to 1.1 wt%, SiO₂Content is less than or equal to 1.5 wt%, Fe₂O₃The content is less than or equal to 0.7wt percent, and the IL is less than or equal to 3.9wt percent.

The particle size of the nano carbon black is less than 172 nm; the C content of the nano carbon black is more than or equal to 97.9 wt%.

The particle size of the magnesium lactate is less than 0.02 mm; 2 (C) of magnesium lactate₃H₅O₃)Mg·3(H₂O) content is more than or equal to 98.0 wt%.

The grain diameter of the aluminum titanate is less than 0.05 mm; the main chemical components of the aluminum titanate are as follows: al (Al)₂O₃Content is more than or equal to 49.1 wt%, TiO₂The content is more than or equal to 47.5wt percent.

The detailed description is omitted in the embodiments.

Example 1

A low-carbon microporous magnesia carbon brick and a preparation method thereof. Firstly, 96.0 wt% of magnesia carbon brick reclaimed material, 1.7 wt% of nano carbon black, 1.1 wt% of magnesium lactate and 1.2 wt% of aluminum titanate are taken as raw materials, and a bonding agent accounting for 2.2 wt% of the raw materials is added to be uniformly mixed; and then performing mechanical pressing forming under the condition of 15MPa, and preserving heat for 5 hours at the temperature of 160 ℃ to obtain the low-carbon microporous magnesia carbon brick.

The binding agent is polymethyl methacrylate.

The low-carbon microporous magnesia carbon brick prepared by the embodiment is detected as follows: compressive strength 42.2 MPa; apparent porosity is 3.3%; the thermal conductivity is 3.55W/(mK).

Example 2

A low-carbon microporous magnesia carbon brick and a preparation method thereof. Firstly, 96.5 wt% of magnesia carbon brick reclaimed material, 1.5 wt% of nano carbon black, 1.0 wt% of magnesium lactate and 1.0 wt% of aluminum titanate are used as raw materials, a bonding agent accounting for 2.5 wt% of the raw materials is added, and the raw materials are uniformly mixed; and then performing mechanical pressing forming under the condition of 17MPa, and preserving heat for 6 hours at the temperature of 170 ℃ to obtain the low-carbon microporous magnesia carbon brick.

The binder is polycarbonate.

The low-carbon microporous magnesia carbon brick prepared by the embodiment is detected as follows: compressive strength 40.5 MPa; apparent porosity is 3.5%; the thermal conductivity was 3.46W/(mK).

Example 3

A low-carbon microporous magnesia carbon brick and a preparation method thereof. Firstly, 97.0 wt% of magnesia carbon brick reclaimed material, 1.3 wt% of nano carbon black, 0.9 wt% of magnesium lactate and 0.8 wt% of aluminum titanate are used as raw materials, a bonding agent of 2.8 wt% of the raw materials is added, and the raw materials are uniformly mixed; and then performing mechanical pressing forming under the condition of 18MPa, and preserving heat for 7 hours at the temperature of 180 ℃ to obtain the low-carbon microporous magnesia carbon brick.

The bonding agent is propylene oxide.

The low-carbon microporous magnesia carbon brick prepared by the embodiment is detected as follows: compressive strength 39.9 MPa; apparent porosity 4.0%; the thermal conductivity was 3.39W/(mK).

Example 4

A low-carbon microporous magnesia carbon brick and a preparation method thereof. Firstly, 97.5 wt% of magnesia carbon brick reclaimed material, 1.1 wt% of nano carbon black, 0.8 wt% of magnesium lactate and 0.6 wt% of aluminum titanate are used as raw materials, and a bonding agent accounting for 3.4 wt% of the raw materials is added to be uniformly mixed; and then performing mechanical pressing forming under the condition of 19MPa, and preserving heat for 8 hours at the temperature of 170 ℃ to obtain the low-carbon microporous magnesia carbon brick.

The binding agent is polymethyl methacrylate.

The low-carbon microporous magnesia carbon brick prepared by the embodiment is detected as follows: compressive strength 38.5 MPa; apparent porosity 4.1%; the thermal conductivity was 3.27W/(mK).

Example 5

A low-carbon microporous magnesia carbon brick and a preparation method thereof. Firstly, 98.0 wt% of magnesia carbon brick reclaimed material, 0.9 wt% of nano carbon black, 0.7 wt% of magnesium lactate and 0.4 wt% of aluminum titanate are used as raw materials, and a bonding agent accounting for 3.0 wt% of the raw materials is added to be uniformly mixed; and then performing mechanical pressing forming under the condition of 20MPa, and preserving heat for 9 hours at the temperature of 180 ℃ to obtain the low-carbon microporous magnesia carbon brick.

The bonding agent is propylene oxide.

The low-carbon microporous magnesia carbon brick prepared by the embodiment is detected as follows: compressive strength 35.5 MPa; apparent porosity 4.4%; the thermal conductivity is 3.22W/(mK).

Compared with the prior art, the specific implementation mode has the following positive effects:

1. according to the specific embodiment, the carbon microporous magnesia carbon brick with excellent performance is prepared by taking the magnesia carbon brick reclaimed material as a main raw material, taking nano carbon black as a carbon source, taking magnesium lactate and aluminum titanate as ceramic matrix reinforcing agents, adding a bonding agent, carrying out mechanical compression molding, and carrying out heat preservation at 160-180 ℃, and is simple in process and energy-saving. The method can optimize the performance and prolong the service life of the low-carbon microporous magnesia carbon brick while realizing the ultra-low carbon content in the low-carbon microporous magnesia carbon brick. The utilization rate of the magnesia carbon brick recycled material of the low-carbon microporous magnesia carbon brick prepared by the specific embodiment is more than or equal to 96 percent, and the low-carbon microporous magnesia carbon brick saves resources, is green and environment-friendly and has low cost.

2. The present embodiment adoptsThe used magnesium lactate is decomposed to generate CO under the high-temperature use environment₂CO in the matrix structure₂The atmosphere can avoid the added nano carbon black from oxidation failure; the periclase generated by decomposing the magnesium lactate has a microporous structure, and the thermal shock resistance of the low-carbon microporous magnesia carbon brick can be further improved while the heat-insulating property is optimized.

3. The aluminum titanate used in the present embodiment has advantages such as low thermal expansion and high mechanical strength, but is easily decomposed at 1350 ℃. MgO obtained by dehydroxylation of periclase added in the specific embodiment in the high-temperature use process can effectively inhibit the decomposition of aluminum titanate and optimize the stability of the low-carbon microporous magnesia carbon brick in the high-temperature use process.

The low-carbon microporous magnesia carbon brick prepared by the specific embodiment is detected as follows: the compressive strength is 35.5-42.0 MPa; the apparent porosity is 3.3-4.4%; the thermal conductivity coefficient is 3.22-3.55W/(m.K), and the performance is superior to that of similar products.

Therefore, the specific implementation mode has the characteristics of simple process, environmental protection, energy conservation, resource saving and low cost; the prepared low-carbon microporous magnesia carbon brick has the advantages of high mechanical strength, low heat conductivity coefficient, good thermal shock resistance, excellent stability and long service life.