Preparation process of hydration-resistant synthetic magnesia-calcium sand

Abstract

The invention relates to the technical field of refractory materials, in particular to a preparation process of hydration-resistant synthetic magnesia-calcium sand. Comprising the following steps: 1) grinding dolomite and magnesite into fine powder with the granularity of 200 meshes; (2) adding the workmanship dolomite fine powder and the magnesite fine powder in the step (1) into a high-speed mixing mill, adding cerium oxide and iron oxide red powder, and fully mixing; 3) adding water accounting for 22-38% of the total weight of the mixed material, and mixing for 45-60 minutes to obtain uniform wet powder without dry powder; (4) pressing the uniform wet powder into wet green bricks by using a brick press; (5) putting the wet green bricks into a drying kiln, drying for 24-30 hours at the drying temperature of 50-80 DEG C, and sintering in a high-temperature sintering device; the firing temperature is 1600 to 1700 DEG C; and 6) crushing the sintered green brick to finally obtain the magnesia-calcium sand. The magnesia-calcium sand prepared by the invention has good hydration resistance and high-temperature usability.

Description

Technical Field

[0001] The present invention relates to the technical field of refractory materials, and particularly to a preparation process of anti-hydration synthetic magnesia-calcia sand. Background Art

[0002] Magnesia-calcia sand is mainly applied in the field of refractory materials, especially for manufacturing high-performance refractory bricks and other refractory products. These refractory products are widely used in high-temperature industrial fields such as iron and steel smelting, non-ferrous metal smelting, glass manufacturing, and cement production.

[0003] However, due to the presence of free CaO in magnesia-calcia sand, it is extremely easy to hydrate, which is also the bottleneck restricting the popular application of magnesia-calcia sand refractory materials.

[0004] Currently, the commonly used method is to add SiO2, Al2O3, and TiO2 oxides, so that the free CaO reacts with the additives at high temperature to form low-melting-point phases, promote the sintering of magnesia-calcia sand materials, improve their sintering performance, reduce the pores in the materials, and thus improve their anti-hydration performance. However, the addition of SiO2, Al2O3, and TiO2 oxides reduces the high-temperature strength and corrosion resistance of magnesia-calcia sand materials to a certain extent.

[0005] Therefore, it is necessary to develop a preparation process of synthetic magnesia-calcia sand that can ensure the anti-hydration performance without reducing the high-temperature service performance of magnesia-calcia sand. Summary of the Invention

[0006] To overcome the defects of the prior art, the technical problem solved by the present invention is to provide a preparation process of anti-hydration synthetic magnesia-calcia sand, and the magnesia-calcia sand prepared by the present invention has good anti-hydration performance and high-temperature service performance.

[0007] To achieve the above purpose, the present invention adopts the following technical solutions:

[0008] A preparation process of anti-hydration synthetic magnesia-calcia sand includes the following steps:

[0009] 1) Grinding dolomite and magnesite into fine powders with a particle size of 200 meshes;

[0010] 2) Adding the dolomite fine powder and magnesite fine powder obtained in step 1) into a high-speed mixer, and adding cerium oxide and iron oxide red powder externally, and fully mixing;

[0011] 3) Adding 22-38% of the total weight of the mixed materials of water, and mixing for 45-60 min to obtain a uniform wet powder without dry powder;

[0012] 4) Using a brick press to press the uniform wet powder into a wet brick blank;

[0013] 5) Feed the wet brick blanks into a drying kiln, with a drying temperature of 50 - 80 °C for 24 - 30 h, and then send them to a high-temperature sintering device for sintering; the sintering temperature is 1600 - 1700 °C;

[0014] 6) Crush the sintered brick blanks to finally obtain magnesia-calcia sand.

[0015] In the dolomite, SiO2 < 0.7%, Al2O3 < 0.1%, CaO ≥ 30%, and MgO ≥ 22%.

[0016] In the magnesite, SiO2 < 0.8%, Al2O3 < 0.1%, CaO < 1.2%, and MgO ≥ 46%.

[0017] In the iron oxide red, SiO2 < 1% and Fe2O3 > 92%.

[0018] The particle size of the iron oxide red is 325 mesh.

[0019] The particle size of the cerium oxide is 325 mesh.

[0020] Compared with the prior art, the beneficial effects of the present invention are as follows:

[0021] The present invention uses dolomite and magnesite as raw materials, and adds iron oxide red and cerium oxide to prepare magnesia-calcia sand. Since iron oxide can react with MgO to form compounds such as MgFe2O4, it can serve as the core for grain growth during the sintering process, promoting the sintering of the material. Moreover, iron oxide red can increase the density and mechanical strength of the material, while reducing the sintering temperature and sintering time, thereby improving the high-temperature performance of magnesia-calcia sand. Adding cerium oxide improves the microstructure of magnesia-calcia sand, thereby enhancing the anti-hydration property of magnesia-calcia sand, and cerium oxide reacts with oxygen under high-temperature conditions to form a dense oxide film, thereby improving the oxidation resistance of magnesia-calcia sand. Specific Embodiments

[0022] The following further describes the specific embodiments of the present invention:

[0023] The present invention provides a preparation process for anti-hydration synthetic magnesia-calcia sand, including the following steps:

[0024] 1) Grind dolomite and magnesite into fine powders, both with a particle size of 200 mesh;

[0025] 2) Add the dolomite fine powder and magnesite fine powder obtained in step 1) into a high-speed mixer, and externally add cerium oxide and iron oxide red powder, and mix thoroughly;

[0026] 3) Then add 30% of the total weight of the mixed materials of water and mix for 50 min to obtain a uniform wet powder without dry powder;

[0027] 4) Use a brick press to press the evenly moistened powder into moist brick blanks;

[0028] 5) Feed the moist brick blanks into a drying kiln, dry at a temperature of 55 °C for 28 h, and then send them to a high-temperature sintering device for sintering; the sintering temperature is 1650 °C;

[0029] 6) Crush the sintered brick blanks to finally obtain magnesia-calcia sand.

[0030] In the dolomite, SiO2 < 0.7%, Al2O3 < 0.1%, CaO ≥ 30%, MgO ≥ 22%.

[0031] In the magnesite, SiO2 < 0.8%, Al2O3 < 0.1%, CaO < 1.2%, MgO ≥ 46%.

[0032] In the iron oxide red, SiO2 < 1%, Fe2O3 > 92%.

[0033] The particle size of the iron oxide red is 325 mesh.

[0034] The particle size of the cerium oxide is 325 mesh.

[0035] Example 2

[0036] The present invention provides a preparation process for anti-hydration synthetic magnesia-calcia sand, including the following steps:

[0037] 1) Grind dolomite and magnesite into fine powder, with a particle size of 200 mesh for both;

[0038] 2) Add the dolomite fine powder and magnesite fine powder prepared in step 1) to a high-speed mixer, and externally add cerium oxide and iron oxide red powder, and mix thoroughly;

[0039] 3) Then add 25% of the total weight of the mixed materials of water, and mix for 55 min to obtain evenly moistened powder without dry powder;

[0040] 4) Use a brick press to press the evenly moistened powder into moist brick blanks;

[0041] 5) Feed the moist brick blanks into a drying kiln, dry at a temperature of 65 °C for 24 h, and then send them to a high-temperature sintering device for sintering; the sintering temperature is 1620 °C;

[0042] 6) Crush the sintered brick blanks to finally obtain magnesia-calcia sand.

[0043] In the dolomite, SiO2 < 0.7%, Al2O3 < 0.1%, CaO ≥ 30%, MgO ≥ 22%.

[0044] In the magnesite, SiO2 < 0.8%, Al2O3 < 0.1%, CaO < 1.2%, MgO ≥ 46%.

[0045] The SiO2 in the iron oxide red is less than 1%, and the Fe2O3 is greater than 92%.

[0046] The particle size of the iron oxide red is 325 mesh.

[0047] The particle size of the cerium oxide is 325 mesh.

[0048] The preferred embodiments of the present invention have been described in detail above. However, the present invention is not limited to the specific details in the above embodiments. Within the scope of the technical concept of the present invention, various simple modifications can be made to the technical solutions of the present invention, and these simple modifications all fall within the protection scope of the present invention. In addition, it should be noted that, among the various specific technical features described in the above specific embodiments, they can be combined in any suitable manner without contradiction. To avoid unnecessary repetition, the present invention will not separately describe various possible combination methods. In addition, any combination can be made between various different embodiments of the present invention, as long as it does not violate the idea of the present invention, it should also be regarded as the content disclosed by the present invention.

Claims

1. A preparation process of anti-hydration synthetic magnesia-calcia refractory, characterized in that, It includes the following steps: 1) Grind dolomite and magnesite into fine powders with a particle size of 200 mesh; 2) Add the dolomite fine powder and magnesite fine powder obtained in step 1) into a high-speed mixer, and externally add cerium oxide and iron oxide red powder, and mix well; 3) Then add 22-38% of the total weight of the mixed materials of water, and mix for 45-60 min to obtain a uniform wet powder without dry powder; 4) Use a brick press to press the uniform wet powder into a wet brick blank; 5) Put the wet brick blank into a drying kiln, the drying temperature is 50-80 °C, dry for 24-30 h, and then send it to a high-temperature sintering device for sintering; the sintering temperature is 1600-1700 °C; 6) Crush the sintered brick blank to finally obtain magnesia-calcia sand.

2. The preparation process of a hydration-resistant synthetic magnesia-calcia refractory aggregate according to claim 1, characterized in that, In the dolomite, SiO2 < 0.7%, Al2O3 < 0.1%, CaO ≥ 30%, MgO ≥ 22%.

3. The preparation process of a hydration-resistant synthetic magnesia-calcia sand according to claim 1, characterized in that In the magnesite, SiO2 < 0.8%, Al2O3 < 0.1%, CaO < 1.2%, MgO ≥ 46%.

4. The preparation process of a hydration-resistant synthetic magnesia-calcia refractory aggregate according to claim 1, characterized in that, In the iron oxide red, SiO2 < 1%, Fe2O3 > 92%.

5. The preparation process of a hydration-resistant synthetic magnesia-calcia sand according to claim 1, characterized in that, The particle size of the iron oxide red is 325 mesh.

6. The preparation process of a hydration-resistant synthetic magnesia-calcia refractory aggregate according to claim 1, characterized in that, The particle size of the cerium oxide is 325 mesh.