阅读说明：本技术 以草酰乙酸为络合剂的无铬镁耐火捣打料及其制备方法 (Chromium-free magnesium refractory ramming mass with oxaloacetic acid as complexing agent and preparation method thereof ) 是由 尹斌 张义先 王新杰 王振宇 于 2019-10-23 设计创作，主要内容包括：本发明涉及耐火材料技术领域,尤其涉及一种以草酰乙酸为络合剂的无铬镁耐火捣打料及其制备方法。包括以下重量份的原料：高纯度镁砂颗粒15～45份；无水硫酸镁5～15份；刚玉细粉5～10份；络合剂和缓冲剂2～6份；粘合剂和分散剂3～8份；共磨粉5～10份；捣打料不含铬,避免了对人体和环境的危害；草酰乙酸使得产生的水分得到了极好的吸收,增强了捣打料的抗水化性,优化了可塑时间；高温下的无水硫酸镁进一步提升了抗水化性,同时使得主料电熔镁砂含量进一步提高,提升捣打料的抗烧结性和体积稳定性。(The invention relates to the technical field of refractory materials, in particular to a chromium-free magnesium refractory ramming mass taking oxaloacetic acid as a complexing agent and a preparation method thereof. The feed comprises the following raw materials in parts by weight: 15-45 parts of high-purity magnesia particles; 5-15 parts of anhydrous magnesium sulfate; 5-10 parts of corundum fine powder; 2-6 parts of a complexing agent and a buffer; 3-8 parts of a binder and a dispersant; 5-10 parts of co-ground powder; the ramming material does not contain chromium, so that the damage to human bodies and the environment is avoided; the oxaloacetic acid ensures that the generated moisture is well absorbed, the hydration resistance of the ramming mass is enhanced, and the plasticity time is optimized; the hydration resistance of the anhydrous magnesium sulfate at high temperature is further improved, the content of the main material fused magnesia is further improved, and the sintering resistance and the volume stability of the ramming mass are improved.)

1. A chromium-free magnesium refractory ramming mass taking oxaloacetic acid as a complexing agent is characterized by comprising the following raw materials in parts by weight:

2. the chrome-free magnesium refractory ramming mass taking oxaloacetic acid as a complexing agent according to claim 1, wherein sintered or electrofused MgO is adopted as the high-purity magnesite grains, and comprises MgO with three grain sizes of 6-3 mm, 3-1 mm and <1mm, and the molar ratio of the MgO to the MgO is 6:2: 1.

3. The chrome-free magnesium refractory ramming mass taking oxaloacetate as a complexing agent according to claim 1, wherein the particle size of the anhydrous magnesium sulfate is less than or equal to 0.04 mm.

4. The chrome-free magnesium refractory ramming mass taking oxaloacetic acid as a complexing agent according to claim 1, wherein the granularity of the corundum fine powder is less than or equal to 0.06mm, and Al of the corundum fine powder₂O₃≥90％。

5. The chrome-free magnesium refractory ramming mass taking oxaloacetate as a complexing agent according to claim 1, wherein the complexing agent and the buffering agent are mainly oxaloacetate, and the particle size is less than or equal to 0.06 mm.

6. The chrome-free magnesium refractory ramming mass taking oxaloacetic acid as a complexing agent according to claim 1, wherein the binding agent and the dispersing agent are mainly calcium lignosulphonate, and the particle size fraction is more than or equal to 800.

7. The chromium-free magnesium refractory ramming mass taking oxaloacetic acid as a complexing agent according to claim 1, wherein the co-ground powder is one or a mixture of more of silica fume, aluminum powder, fluorite powder and sodium metasilicate with the grain size of more than or equal to 800, and the grain size is less than 0.07 mm.

8. The preparation method of the chromium-free magnesium refractory ramming mass taking oxaloacetic acid as the complexing agent, which is disclosed by claim 1, is characterized by comprising the following steps:

1) crushing the high-purity fused magnesia, and then screening to obtain three high-purity fused magnesia particles with the particle sizes of 6-3 mm, 3-1 mm and less than 1 mm;

2) preheating the granules before mixing, wherein the temperature is 120-150 ℃ and the time is 4-6 hours;

3) after magnesia particles with different granularities are respectively measured according to the proportion requirement, 15-45 parts of high-purity magnesia particles are added into a high-speed mixing roll according to the mol ratio of 6:2:1, 5-10 parts of corundum fine powder, 5-10 parts of cofired powder, 2-6 parts of complexing agent and buffer agent in sequence to be mixed for 40-60 minutes at a low speed to prepare a mixed material;

4) adding 3-8 parts of adhesive and dispersant and 5-15 parts of anhydrous magnesium sulfate into the mixed materials in the high-speed mixing roll, and mixing for 60-90 minutes at a high speed to fully mix the mixed materials;

5) and heating the mixed materials to 150-200 ℃ for 2-4 hours, so that the mixed materials are fully fused to obtain the ramming mass.

Technical Field

The invention relates to the technical field of refractory materials, in particular to a chromium-free magnesium refractory ramming mass taking oxaloacetic acid as a complexing agent and a preparation method thereof.

Background

The magnesium-calcium refractory material is a basic refractory material, is used as a lining material of a steel-making converter in the early 60 s of the last century, and makes a contribution to the development of the steel-making industry of the converter in China. At present, it has been largely applied to refining facilities of high grade steel grades such as stainless steel and clean steel, and developed at a faster speed.

However, the defects of the magnesium-calcium refractory material are obvious, and the use effect is influenced because the magnesium-calcium refractory material contains free calcium oxide and is easy to generate hydration reaction. Therefore, the water contact is avoided to the utmost extent in the production, storage and transportation and use processes. At present, anhydrous bonding agents are adopted in the production process of the magnesium-calcium refractory bricks, and sealed packaging is adopted in the storage and transportation process, so that the hydration problems of production, storage and transportation are solved. However, in the use process, as the refractory bricks of the stainless steel refining equipment are built, some structures are complex and gaps are narrow, and the refractory bricks must be manually filled by workers by using unshaped refractory materials. Therefore, the refractory ramming material can be produced at the same time.

Meanwhile, most of the refractory ramming materials are Cr for having good using effect₂O₃High component content and serious environmental pollution.

Disclosure of Invention

The invention provides a chromium-free magnesium refractory ramming mass taking oxaloacetic acid as a complexing agent and a preparation method thereof, the sintering performance, the volume stability, the erosion resistance, the scouring resistance and the thermal shock stability of the chromium-free magnesium refractory ramming mass can be well adapted to severe environments such as turbulent scouring and erosion of vacuum, high temperature and high speed molten steel in a furnace, the performance is obviously improved, and the pollution of chromium to the environment is avoided.

The technical scheme of the invention is realized as follows:

a chromium-free magnesium refractory ramming mass taking oxaloacetic acid as a complexing agent comprises the following raw materials in parts by weight:

the high-purity magnesite grains are sintered or fused MgO, and the sintered or fused MgO comprises MgO with the grain sizes of 6-3 mm, 3-1 mm and less than 1mm, and the molar ratio of the MgO to the MgO is 6:2: 1.

The particle size of the anhydrous magnesium sulfate is less than or equal to 0.04 mm.

The grain size of the corundum fine powder is less than or equal to 0.06mm, and Al of the corundum fine powder₂O₃≥90％。

The complexing agent and the buffering agent are mainly oxaloacetic acid, and the granularity is less than or equal to 0.06 mm.

The adhesive and the dispersant are mainly calcium lignosulphonate, and the particle size is more than or equal to 800.

The co-milled powder is one or a mixture of more of silica fume (the grain size is more than or equal to 800), aluminum powder, fluorite powder and sodium metasilicate, and the grain size is less than 0.07 mm.

A preparation method of a chromium-free magnesium refractory ramming mass taking oxaloacetic acid as a complexing agent specifically comprises the following steps:

(1) crushing the high-purity fused magnesia, and then screening to obtain three high-purity fused magnesia particles with the particle sizes of 6-3 mm, 3-1 mm and less than 1 mm;

(2) preheating the granules before mixing, wherein the temperature is 120-150 ℃ and the time is 4-6 hours;

(3) after magnesia particles with different granularities are respectively measured according to the proportion requirement, 15-45 parts of high-purity magnesia particles are added into a high-speed mixing roll according to the mol ratio of 6:2:1, 5-10 parts of corundum fine powder, 5-10 parts of cofired powder, 2-6 parts of complexing agent and buffer agent in sequence to be mixed for 40-60 minutes at a low speed to prepare a mixed material;

(4) adding 3-8 parts of adhesive and dispersant and 5-15 parts of anhydrous magnesium sulfate into the mixed materials in the high-speed mixing roll, and mixing for 60-90 minutes at a high speed to fully mix the mixed materials;

(5) heating the mixed materials at the temperature of 150 ℃ and 200 ℃ for 2-4 hours to fully fuse the mixed materials to obtain the ramming material;

compared with the prior art, the invention has the beneficial effects that:

the ramming material does not contain chromium, so that the damage to human bodies and the environment is avoided; the oxaloacetic acid ensures that the generated moisture is well absorbed, the hydration resistance of the ramming mass is enhanced, and the plasticity time is optimized; the hydration resistance of the anhydrous magnesium sulfate at high temperature is further improved, the content of the main material fused magnesia is further improved, and the sintering resistance and the volume stability of the ramming mass are improved.

Detailed Description

The following further illustrates embodiments of the invention, but is not intended to limit the scope thereof:

a chromium-free magnesium refractory ramming mass taking oxaloacetic acid as a complexing agent comprises the following raw materials in parts by weight:

the high-purity magnesite grains are sintered or fused MgO, and the sintered or fused MgO comprises MgO with the grain sizes of 6-3 mm, 3-1 mm and less than 1mm, and the molar ratio of the MgO to the MgO is 6:2: 1.

The particle size of the anhydrous magnesium sulfate is less than or equal to 0.04 mm.

The grain size of the corundum fine powder is less than or equal to 0.06mm, and Al of the corundum fine powder₂O₃≥90％。

The complexing agent and the buffering agent are mainly oxaloacetic acid, and the granularity is less than or equal to 0.06 mm.

The particle size fraction of the adhesive and the dispersant is more than or equal to 800.

The co-milled powder is one or a mixture of more of silica fume (the grain size is more than or equal to 800), aluminum powder, fluorite powder and sodium metasilicate, and the grain size is less than 0.07 mm.

A preparation method of a chromium-free magnesium refractory ramming mass taking oxaloacetic acid as a complexing agent specifically comprises the following steps:

(1) crushing the high-purity fused magnesia, and then screening to obtain three high-purity fused magnesia particles with the particle sizes of 6-3 mm, 3-l mm and less than l mm;

(2) preheating the granules before mixing, wherein the temperature is 120-150 ℃ and the time is 4-6 hours;

(3) after magnesia particles with different granularities are respectively measured according to the proportion requirement, 15-45 parts of high-purity magnesia particles are added into a high-speed mixing roll according to the mol ratio of 6:2:1, 5-10 parts of corundum fine powder, 5-10 parts of cofired powder, 2-6 parts of complexing agent and buffer agent in sequence to be mixed for 40-60 minutes at a low speed to prepare a mixed material;

(4) adding 3-8 parts of adhesive and dispersant and 5-15 parts of anhydrous magnesium sulfate into the mixed materials in the high-speed mixing roll, and mixing for 60-90 minutes at a high speed to fully mix the mixed materials;

(5) heating the mixed materials at the temperature of 150 ℃ and 200 ℃ for 2-4 hours to fully fuse the mixed materials to obtain the ramming material;