阅读说明：本技术 一种用于aod炉的镁铬质不烧砖及制备方法 (Magnesium-chromium unburned brick for AOD furnace and preparation method thereof ) 是由 *** 张义先 尹斌 金钊 耿贺贺 于 2019-10-25 设计创作，主要内容包括：本发明涉及一种用于AOD炉的镁铬质不烧砖及制备方法,一种用于AOD炉的镁铬质不烧砖,包括以下重量份数的原料：0＜粒度≤1mm的98大结晶镁砂5-10份；0＜粒度≤1mm的低铁电熔镁铬20砂15-20份；1mm＜粒度≤3mm的低铁电熔镁铬20砂25-30份；3mm＜粒度≤5mm的低铁电熔镁铬20砂10-15份；200目细粉的低铁电熔镁铬20砂10-15份；325目细粉的低铁电熔镁铬36砂8-10份；氧化铬绿1-3份；巴基斯坦铬矿超微粉5-10份；结合剂2-4份。优点是：用低铁电熔镁铬砂为主要原料制作不烧铬镁砖,使用效果远远超过目前使用的烧成镁铬砖、镁钙砖。(The invention relates to a magnesia-chromite unburned brick for an AOD furnace and a preparation method thereof, and the magnesia-chromite unburned brick for the AOD furnace comprises the following raw materials in parts by weight: 5-10 parts of 98 large crystal magnesia with the granularity more than 0 and less than or equal to 1 mm; 15-20 parts of low-iron fused magnesia-chromia with the granularity more than 0 and less than or equal to 1 mm; 25-30 parts of low-iron fused magnesia-chromia 20 sand with the granularity being more than 1mm and less than or equal to 3 mm; 10-15 parts of low-iron fused magnesia-chromia 20 sand with the granularity being more than 3mm and less than or equal to 5 mm; 10-15 parts of low-iron fused magnesia-chrome 20 sand of 200-mesh fine powder; 8-10 parts of 325-mesh fine low-iron fused magnesia-chrome 36 sand; 1-3 parts of chromium oxide green; 5-10 parts of Pakistan chromium ore superfine powder; 2-4 parts of a binding agent. The advantages are that: the low-iron fused magnesia-chrome sand is used as a main raw material to manufacture unburned chrome-magnesia brick, and the using effect is far better than that of the currently used calcined magnesia-chrome brick and magnesia-calcium brick.)

1. The magnesium-chromium unburned brick for the AOD furnace is characterized by comprising the following raw materials in parts by weight:

5-10 parts of 98 large crystal magnesia with the granularity more than 0 and less than or equal to 1 mm;

15-20 parts of low-iron fused magnesia-chromia with the granularity more than 0 and less than or equal to 1 mm;

25-30 parts of low-iron fused magnesia-chromia 20 sand with the granularity being more than 1mm and less than or equal to 3 mm;

10-15 parts of low-iron fused magnesia-chromia 20 sand with the granularity being more than 3mm and less than or equal to 5 mm;

10-15 parts of low-iron fused magnesia-chrome 20 sand of 200-mesh fine powder;

8-10 parts of 325-mesh fine low-iron fused magnesia-chrome 36 sand;

1-3 parts of chromium oxide green;

5-10 parts of Pakistan chromium ore superfine powder;

2-4 parts of a binding agent.

2. The magnesite-chrome unburned brick for the AOD furnace according to claim 1, wherein the superfine powder size of the Bakistan chrome ore is 325 mesh.

3. The magnesite-chrome unburned brick for an AOD furnace according to claim 1, wherein the grain size of the chrome oxide green is 200 mesh.

4. The magnesite-chrome unburned brick for an AOD furnace of claim 1, wherein the binder is a phenolic resin.

5. A method of making a magnesia-chromia non-fired brick for an AOD furnace according to any one of claims 1 to 4, comprising the steps of:

1) crushing, screening and fine grinding of raw materials:

crushing the low-iron fused magnesia-chrome 20 sand in a crusher, and sieving into fine powder with the granularity of more than 0 and less than or equal to 1mm, the granularity of more than 1mm and less than or equal to 3mm, the granularity of more than 3mm and less than or equal to 5mm and 200 meshes; crushing chromium oxide green, superfine Bakistan chromium ore powder, low-iron fused magnesia-chrome 36 sand and 98 large-crystal magnesia, and screening to obtain the granularity;

2) premixing:

premixing chromium oxide green, superfine Bakistan chromium ore powder, low-iron fused magnesia-chrome 36 sand and 98 large-crystal magnesia;

3) mixing:

firstly adding 3-5mm, 1-3mm and the rest of low-iron fused magnesia-chromite 20 sand with the granularity of 0-1mm, dry-mixing for more than 3min, then adding a bonding agent, mixing for 3-5 min, adding a premix and 200-mesh low-iron fused magnesia-chromite 20 sand, mixing for 20-25 min, and then discharging;

4) and (3) mechanical pressing and forming:

molding by using a 1000-ton brick molding press, wherein the density of a molded body is more than or equal to 3.42g/cm³；

5) And (3) heat treatment:

the temperature of the drying kiln is more than or equal to 200 ℃, and the heat treatment time is more than 24 h.

Technical Field

The invention relates to a magnesia-chromite unburned brick for an AOD furnace and a preparation method thereof.

Background

The AOD furnace is generally used as an ultrahigh-temperature metallurgical furnace for smelting special steel, and requires that a refractory material has high-temperature resistance, erosion resistance and anti-stripping performance and a long service life, the minimum working temperature of the AOD furnace refractory material is more than 1500 ℃, and the instantaneous temperature can reach 1750 ℃ or even 1800 ℃, so that the AOD furnace refractory material is required to have high-temperature resistance, erosion resistance and stripping resistance and a long service life. In particular to smelting special steel, such as: food grade steel, special stainless steel, steel for military industry and ships have higher requirements on refractory materials.

Disclosure of Invention

In order to overcome the defects of the prior art, the invention aims to provide the magnesia-chromite unburned brick for the AOD furnace and the preparation method thereof, which improve the heat rate of the AOD furnace, replace the fired magnesia-chromite brick and magnesia-calcia brick, prolong the service life and reduce the production cost.

In order to achieve the purpose, the invention is realized by the following technical scheme:

the magnesia-chrome unburned brick for the AOD furnace comprises the following raw materials in parts by weight:

5-10 parts of 98 large crystal magnesia with the granularity more than 0 and less than or equal to 1 mm;

15-20 parts of low-iron fused magnesia-chromia with the granularity more than 0 and less than or equal to 1 mm;

25-30 parts of low-iron fused magnesia-chromia 20 sand with the granularity being more than 1mm and less than or equal to 3 mm;

10-15 parts of low-iron fused magnesia-chromia 20 sand with the granularity being more than 3mm and less than or equal to 5 mm;

10-15 parts of low-iron fused magnesia-chrome 20 sand of 200-mesh fine powder;

8-10 parts of 325-mesh fine low-iron fused magnesia-chrome 36 sand;

1-3 parts of chromium oxide green;

5-10 parts of Pakistan chromium ore superfine powder;

2-4 parts of a binding agent.

The granularity of the superfine Bakistan chromium ore powder is 325 meshes.

The granularity of the chromium oxide green is 200 meshes.

The binder is a phenolic resin.

A preparation method of a magnesia-chromite unburned brick for an AOD furnace comprises the following steps:

1) crushing, screening and fine grinding of raw materials:

crushing the low-iron fused magnesia-chrome 20 sand in a crusher, and sieving into fine powder with the granularity of more than 0 and less than or equal to 1mm, the granularity of more than 1mm and less than or equal to 3mm, the granularity of more than 3mm and less than or equal to 5mm and 200 meshes; crushing chromium oxide green, superfine Bakistan chromium ore powder, low-iron fused magnesia-chrome 36 sand and 98 large-crystal magnesia, and screening to obtain the granularity;

2) premixing:

premixing chromium oxide green, superfine Bakistan chromium ore powder, low-iron fused magnesia-chrome 36 sand and 98 large-crystal magnesia;

3) mixing:

firstly adding 3-5mm, 1-3mm and the rest of low-iron fused magnesia-chromite 20 sand with the granularity of 0-1mm, dry-mixing for more than 3min, then adding a bonding agent, mixing for 3-5 min, adding a premix and 200-mesh low-iron fused magnesia-chromite 20 sand, mixing for 20-25 min, and then discharging;

4) and (3) mechanical pressing and forming:

molding by using a 1000-ton brick molding press, wherein the density of a molded body is more than or equal to 3.42g/cm³；

5) And (3) heat treatment:

the temperature of the drying kiln is more than or equal to 200 ℃, and the heat treatment time is more than 24 h.

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

the invention uses low-iron fused magnesia-chrome sand as the main raw material to manufacture the unburned chrome-magnesia brick, and the using effect is far better than that of the sintered magnesia-chrome brick and the magnesia-calcium brick used at present. The low-iron fused magnesia-chrome 20 sand, the low-iron fused magnesia-chrome 36 sand superfine powder, the chromium oxide green and the pakistan chromium ore superfine powder are selected, the phenolic resin is adopted as a binding agent, the chromium content is increased, and the magnesia-chrome spinel is generated by sintering in the production and use processes, so that the product has better performances of erosion resistance, peeling resistance, high temperature resistance and the like; the main material is low-iron fused magnesia-chrome sand with high cost performance, so that Fe in the raw material can be reduced₂O₃The content of (A) reduces the generation of low-temperature soluble substances in the secondary sintering process, increases the high-temperature performance, and prolongs the service life. The chromium oxide green plays a role in increasing the chromium content and playing a role in corrosion resistance in unburned bricks. The Pakistan chromium ore adopts superfine powder to optimize secondary sintering in the using process.

Detailed Description

The present invention is described in detail below, but it should be noted that the practice of the present invention is not limited to the following embodiments.

The magnesia-chrome unburned brick for the AOD furnace comprises the following raw materials in parts by weight:

5-10 parts of 98 large crystal magnesia with the granularity more than 0 and less than or equal to 1 mm;

15-20 parts of low-iron fused magnesia-chromia with the granularity more than 0 and less than or equal to 1 mm;

25-30 parts of low-iron fused magnesia-chromia 20 sand with the granularity being more than 1mm and less than or equal to 3 mm;

10-15 parts of low-iron fused magnesia-chromia 20 sand with the granularity being more than 3mm and less than or equal to 5 mm;

10-15 parts of low-iron fused magnesia-chrome 20 sand of 200-mesh fine powder;

8-10 parts of 325-mesh fine low-iron fused magnesia-chrome 36 sand;

1-3 parts of 200-mesh chromium oxide green fine powder;

5-10 parts of 325-mesh superfine powder of Pakistan chromium ore;

2-4 parts of a binding agent, wherein the binding agent is phenolic resin.

A preparation method of a magnesia-chromite unburned brick for an AOD furnace comprises the following steps:

1) crushing, screening and fine grinding of raw materials:

crushing the low-iron fused magnesia-chrome 20 sand in a crusher, and sieving into fine powder with the granularity of more than 0 and less than or equal to 1mm, the granularity of more than 1mm and less than or equal to 3mm, the granularity of more than 3mm and less than or equal to 5mm and 200 meshes; crushing chromium oxide green, superfine Bakistan chromium ore powder, low-iron fused magnesia-chrome 36 sand and 98 large-crystal magnesia, and screening to obtain the granularity;

2) premixing:

premixing chromium oxide green, superfine Bakistan chromium ore powder, low-iron fused magnesia-chrome 36 sand and 98 large-crystal magnesia;

3) mixing:

firstly adding 3-5mm, 1-3mm and the rest of low-iron fused magnesia-chromite 20 sand with the granularity of 0-1mm, dry-mixing for more than 3min, then adding a bonding agent, mixing for 3-5 min, adding a premix and 200-mesh low-iron fused magnesia-chromite 20 sand, mixing for 20-25 min, and then discharging;

4) and (3) mechanical pressing and forming:

molding by using a 1000-ton brick molding press, wherein the density of a molded body is more than or equal to 3.42g/cm³；

5) And (3) heat treatment:

the temperature of the drying kiln is more than or equal to 200 ℃, and the heat treatment time is more than 24 h.

The physical and chemical indexes of the obtained magnesia-chromite unburned bricks are shown in the table 1:

table 1: physical and chemical indexes of finished brick

The invention uses low-iron fused magnesia-chrome 20 sand as main raw material to make unburned chrome-magnesia brick. The using effect of the brick far exceeds that of the prior sintered magnesia-chrome brick and magnesia-calcium brick. The method selects low-iron fused magnesia-chrome 20 sand, low-iron fused magnesia-chrome 36 sand superfine powder, chromium oxide green and Pakistan chromium ore superfine powder (325 meshes), adopts phenolic resin as a binding agent, and develops a non-fired chrome-magnesia product for an AOD furnace. The low-iron fused magnesia-chrome 36 sand superfine powder and the Pakistan chromium ore superfine powder (325 meshes) aim to sinter to generate magnesia-chrome spinel in the production and use processes, so that the product has better performances of erosion resistance, peeling resistance, high temperature resistance and the like; the main material is low-iron fused magnesia-chromia 20 sand with high cost performance, and the main purpose is to reduce Fe in the raw material₂O₃The content of the (B) reduces the generation of low-temperature soluble substances in the secondary sintering process, increases the high-temperature performance and prolongs the service life.