Environment-friendly and energy-saving corundum crucible for medium-frequency electric furnace and preparation method of corundum crucible

Abstract

The invention discloses an environment-friendly and energy-saving corundum crucible for a medium-frequency electric furnace. The corundum crucible comprises the following raw materials: 65-70% of fused corundum powder; 5-7% of fused magnesia powder; 12-17% of fused magnesium aluminate spinel powder; 6-8% of alumina micro powder; and 3-7% of pure calcium aluminate cement. The invention further discloses a preparation method. A scientific and reasonable grain composition mode is adopted, fused corundum, fused magnesia and fused magnesium aluminate spinel are combined, a proper amount of efficient composite dispersing agent is added, the high temperature resistance, high strength, good high-temperature volume stability, erosion resistance and thermal shock resistance of the material are guaranteed, the use performance of the material is effectively improved, and the service life of the material is prolonged. The prepared product does not contain harmful elements such as carbon and chromium, and has no pollution to human bodies and the environment; the crucible furnace lining prefabrication mode is adopted, only replacement is needed on site, and the operation efficiency is high; and high-temperature pretreatment is not needed, and the product can be directly put into use only through on-site low-temperature baking, so that the purposes of energy conservation and emission reduction are achieved.

Description

Technical Field

[0001] The invention belongs to the technical field of crucible linings and preparation thereof, and in particular relates to an environmentally friendly and energy-saving corundum crucible for a medium-frequency electric furnace and a preparation method thereof. Background Art

[0002] With the continuous development and progress of the steel industry, people's technical requirements for the smelting of special steels are increasing day by day. Especially in the current environment of rapid development of the steel smelting industry, high-quality steel smelting companies not only require refractory materials to have a longer service life, but also require refractory furnace linings to be environmentally friendly and energy-saving.

[0003] As one of the important equipment for steel smelting, medium frequency electric furnace determines the quality of steel smelting. In the production process, the refractory lining is not only required to have good anti-scouring, anti-slag erosion, high temperature volume stability, fire resistance, thermal shock stability and other characteristics, but also requires the refractory lining to be energy-saving and environmentally friendly.

[0004] Therefore, the present invention develops an environmentally friendly and energy-saving corundum crucible for medium-frequency electric furnaces and a preparation method thereof, which has the characteristics of environmental protection and energy saving, strong anti-scouring ability, good high-temperature volume stability, good thermal shock stability and excellent resistance to slag erosion, thereby improving the service life of refractory materials for medium-frequency electric furnaces for steelmaking. Summary of the invention

[0005] The purpose of the present invention is to provide an environmentally friendly and energy-saving corundum crucible for a medium-frequency electric furnace, and providing a preparation method thereof is the second purpose of the present invention.

[0006] In order to achieve the above-mentioned invention object, the present invention adopts the following technical solutions:

[0007] An environmentally friendly and energy-saving corundum crucible for a medium-frequency electric furnace, the raw materials of which are composed of 65-70% fused corundum powder, 5-7% fused magnesia powder, 12-17% fused magnesia-alumina spinel powder, 6-8% alumina powder, and 3-7% pure calcium aluminate cement by weight percentage.

[0008] The sum of the weight percentages of the above raw materials is 100%.

[0009] Preferably, the raw material composition is as follows, by weight percentage: 67% fused corundum, 6% fused magnesia, 15% fused magnesia-alumina spinel, 7% alumina powder, and 5% pure calcium aluminate cement.

[0010] Preferably, the particle size of fused corundum is 6mm-325 mesh; the particle size of fused magnesia is 1mm-0.074mm; the particle size of fused magnesia-alumina spinel is 1mm-0.074mm; the particle size of alumina micropowder is ≤2μ; and the particle size of pure calcium aluminate cement is ≤0.045mm.

[0011] Preferably, a high-efficiency composite dispersant is also required to be added during the preparation of the corundum crucible, and the added amount is 0.12-0.3% of the total weight of the above raw materials.

[0012] Further preferably, the high-efficiency composite dispersant is a mixture of FS-10 and FDN-3000, wherein FS-10 is added in an amount of 0.1 to 0.2% of the total amount, and FDN-3000 is added in an amount of 0.02 to 0.1% of the total amount.

[0013] More preferably, the amount of the high-efficiency composite dispersant added is 0.2-0.25% of the total weight of the above raw materials, wherein the amount of FS-10 added is 0.12-0.15%.

[0014] The present invention further discloses a method for preparing an environmentally friendly and energy-saving corundum crucible for a medium-frequency electric furnace. When making the crucible, firstly, fused corundum powder, fused magnesia powder, fused magnesia-aluminum spinel powder, alumina powder, and pure calcium aluminate cement are mixed, and then a high-efficiency composite dispersant is added and mixed, and then room temperature water is added while stirring to mix, and then the crucible is formed, cured, demolded, and low-temperature baked.

[0015] Preferably, the high-efficiency composite dispersant is a mixture of FS-10 and FDN-3000, wherein FS-10 is added in an amount of 0.1 to 0.2% of the total amount, and FDN-3000 is added in an amount of 0.02 to 0.1% of the total amount.

[0016] Preferably, the temperature of the room temperature water is 20-30°C, and the amount of room temperature water added is 4.2-4.8%.

[0017] More preferably, the temperature used for low-temperature baking is 200° C. to 250° C., and the baking time is 72 hours.

[0018] In the present invention, the functions of each raw material are:

[0019] 1. The fused corundum, fused magnesia and fused magnesium-aluminum spinel of the present invention are main raw materials for corundum crucibles, wherein the fused corundum is high-purity aluminum oxide that has been fused at high temperature, and the aluminum oxide content can reach 99.5%, the melting point is 2050°C, and it has good refractoriness, acid and alkali corrosion resistance and good high-temperature volume stability; the fused magnesia is magnesium oxide that has been fused at high temperature, and the magnesium oxide content can reach 98%, the melting point is 2800°C, and it has good refractoriness and strong resistance to alkaline corrosion; magnesium oxide reacts with aluminum oxide at high temperature to generate magnesium-aluminum spinel, which can improve the thermal shock stability of the material; the fused magnesium-aluminum spinel is a magnesium-aluminum composite oxide that has been fused at high temperature, has a regular octahedral structure, a melting point of 2350°C, has good corrosion resistance, can strengthen the matrix structure, and improve the high-temperature strength of the material. The present invention combines the above three raw materials according to a certain gradation, effectively ensuring the high temperature resistance, high strength, good high temperature volume stability, corrosion resistance and thermal shock stability of the material, and realizing the optimization and improvement of the comprehensive performance of the material. However, if any two of the raw materials are selected, it is difficult to achieve the optimization and improvement of the comprehensive performance of the material.

[0020] 2. Alumina powder and pure calcium aluminate cement are binders of the present invention, and their functions in the present invention are:

[0021] Alumina powder reacts with water to generate aluminum hydroxide gel, which has good polymerization effect and improves the bonding strength of the material; pure calcium aluminate cement reacts with water to generate calcium hydroxide and calcium aluminate gel, which has good hydration effect and improves the bonding strength of the material.

[0022] 3. The high-efficiency composite dispersant of the present invention is a mixture of FS-10 and FDN-3000, both of which are high molecular polymers with good dispersibility, can increase the molecular distance between materials, and effectively improve the performance of the product. The present invention combines the two in a certain proportion. Experiments show that the water consumption of the castable can be effectively reduced while significantly improving the density and strength of the material.

[0023] Compared with the prior art, the present invention can achieve the following technical effects:

[0024] Compared with the existing corundum dry ramming material for medium frequency electric furnace, the environmentally friendly and energy-saving corundum crucible for medium frequency electric furnace prepared by the present invention has the following advantages: first, the product of the present invention does not contain harmful elements such as carbon and chromium, and is pollution-free to human body and environment; second, the present invention adopts the method of prefabricating the crucible lining, which only needs to be replaced on site, and the operation efficiency is high; third, the corundum crucible product of the present invention does not need to be pretreated at high temperature, and can be directly put into use after low-temperature baking on site, thereby achieving the purpose of energy saving and emission reduction; fourth, the present invention adopts a scientific and reasonable particle grading method, optimizes the matrix combination, and adds an appropriate amount of high-efficiency composite dispersant to effectively improve the use performance of the material; fifth, the present invention adopts fused corundum, fused magnesia, and fused magnesium-aluminum spinel, which ensures the high temperature resistance, high strength, good high-temperature volume stability, corrosion resistance and thermal shock stability of the material. DETAILED DESCRIPTION

[0025] The following examples are given to illustrate the specific embodiments of the present invention in more detail, but the present invention is certainly not limited to these embodiments.

[0026] Example 1

[0027] This embodiment discloses an environmentally friendly and energy-saving corundum crucible for a medium-frequency electric furnace, the raw material composition of which is:

[0028] Fused corundum, particle size is 6mm~325 mesh, the addition amount is 69%; 6mm~3mm accounts for 30%, 3~1mm accounts for 20%, 1~325 mesh accounts for 19%;

[0029] Fused magnesia, particle size 1mm~0.074mm, added amount 6%;

[0030] Fused magnesium aluminate spinel, particle size 1mm~0.074mm, addition amount 15%;

[0031] Alumina powder, particle size ≤2μ, added amount is 7%;

[0032] Pure calcium aluminate cement, particle size ≤ 0.045 mm, added in an amount of 3%;

[0033] High-efficiency composite dispersant, added in an amount of 0.2% (external addition) of the total weight of the above raw materials, of which FS-10 added in an amount of 0.12% and FDN-3000 added in an amount of 0.08%.

[0034] The preparation method is as follows: firstly, fused corundum powder, fused magnesia powder, fused magnesia-alumina spinel powder, alumina powder and pure calcium aluminate cement are mixed, then a high-efficiency composite dispersant is added and mixed, then normal temperature water is added while stirring for mixing, and then the mixture is subjected to molding, curing, demoulding and low temperature baking. In this embodiment, the temperature of the normal temperature water is 25°C, the amount of normal temperature water added is 4.0%; the temperature used for low temperature baking is 200°C to 250°C, and the baking time is 72 hours.

[0035] Embodiment 2:

[0036] This embodiment discloses an environmentally friendly and energy-saving corundum crucible for a medium-frequency electric furnace, the raw material composition of which is:

[0037] Fused corundum, particle size is 6mm~325 mesh, the addition amount is 69%; 6mm~3mm accounts for 30%, 3~1mm accounts for 20%, 1~325 mesh accounts for 17%;

[0038] Fused magnesia, particle size 1mm~0.074mm, added amount 6%;

[0039] Fused magnesium aluminate spinel, particle size 1mm~0.074mm, addition amount 15%;

[0040] Alumina powder, particle size ≤2μ, added amount is 7%;

[0041] Pure calcium aluminate cement, particle size ≤ 0.045 mm, added in an amount of 5%;

[0042] High-efficiency composite dispersant, added in an amount of 0.3% (external) of the total weight of the above raw materials, of which FS-10 added in an amount of 0.15% and FDN-3000 added in an amount of 0.1%.

[0043] The preparation method is as follows: firstly, fused corundum powder, fused magnesia powder, fused magnesia-alumina spinel powder, alumina powder and pure calcium aluminate cement are mixed, then a high-efficiency composite dispersant is added and mixed, then normal temperature water is added while stirring for mixing, and then the mixture is subjected to molding, curing, demoulding and low temperature baking. In this embodiment, the temperature of the normal temperature water is 25°C, the amount of normal temperature water added is 4.2%; the temperature used during low temperature baking is 200°C to 250°C, and the baking time is 72 hours.

[0044] Example 3

[0045] The environmentally friendly and energy-saving corundum crucible for medium-frequency electric furnace and the preparation method thereof of this embodiment are the same as those of Example 1, except that the amount of fused corundum added is 65%; the amount of fused magnesia added is 5%; the amount of fused magnesia-alumina spinel added is 17%; the amount of alumina powder added is 6%; and the amount of pure calcium aluminate cement added is 7%.

[0046] Example 4

[0047] The environmentally friendly and energy-saving corundum crucible for medium-frequency electric furnace and the preparation method thereof of this embodiment are the same as those of Example 1, except that the amount of fused corundum added is 70%; the amount of fused magnesia added is 7%; the amount of fused magnesia spinel added is 12%; the amount of alumina powder added is 8%; and the amount of pure calcium aluminate cement added is 3%.

[0048] Test Example 1: Performance Test

[0049] To illustrate the effect of the present invention, this experiment conducted the following test comparisons on the performance and main features of the environmentally friendly and energy-saving corundum crucibles for medium-frequency electric furnaces prepared in Examples 1 and 2 and the corundum dry ramming materials for medium-frequency electric furnaces produced by a domestic refractory enterprise. The results are shown in Tables 1 and 2:

[0050] Table 1 Performance comparison of Example 1, Example 2 and corundum dry ramming material of the present invention

[0051]

[0052] Table 2 Comparison of main characteristics of Example 1, Example 2 and corundum dry ramming material of the present invention

[0053] Main features Neutral dry ramming mass This product Production and construction efficiency Furnace time ≥ 12 hours Crucible replacement time ≤ 30min Characteristics after construction <![CDATA[Material density ≤ 2.5 g / cm 3 > <![CDATA[Material density ≥ 3.0 g / cm 3 > Energy issues Waste of manpower and financial resources Automatic replacement Harmful elements Chromium oxide ≥ 3% Chromium oxide is 0%

[0054] Test Example 2: Effects of different dispersants on the performance of the material of the present invention

[0055] To illustrate the effect of the composite dispersant of the present invention on the present invention, the present invention takes Example 1 as an example, and adds different dispersants to perform performance test comparison. The preparation methods of Comparative Examples 1-5 are the same as those of Example 1, except that the dispersants and the amount of water added are different. The specific dispersants are shown in Table 3. The test results are shown in Table 4.

[0056] Table 3 Dispersants of different comparative examples

[0057]

[0058] Table 4 Test results

[0059]

[0060] From the results in Table 4, it can be seen that the addition of the dispersant of the present invention can effectively reduce the water consumption of the castable and significantly improve the density and strength of the material.

[0061] The above embodiments are only used to illustrate the detailed methods of the present invention, but the present invention is not limited to the above detailed methods, that is, it does not mean that the present invention must rely on the above detailed methods to be implemented. Those skilled in the art should understand that any improvement of the present invention, equivalent replacement of the raw materials of the product of the present invention, addition of auxiliary components, selection of specific methods, etc., all fall within the protection scope and disclosure scope of the present invention.

Claims

1. An environmentally friendly and energy-saving corundum crucible for medium-frequency electric furnace, characterized in that: In terms of weight percentage, the raw material composition is: 65-70% fused corundum powder; 5-7% fused magnesia powder; 12-17% fused magnesia alumina spinel powder; 6-8% alumina powder; 3-7% pure calcium aluminate cement; The sum of the weight percentages of the above raw materials is 100%.

2. The environmentally friendly and energy-saving corundum crucible for medium-frequency electric furnace according to claim 1, characterized in that: The raw material composition is as follows by weight percentage: 67% fused corundum, 6% fused magnesia, 15% fused magnesia-alumina spinel, 7% alumina powder and 5% pure calcium aluminate cement.

3. The environmentally friendly and energy-saving corundum crucible for medium-frequency electric furnace according to claim 1 or 2, characterized in that: The particle size of fused corundum is 6mm~325 mesh; the particle size of fused magnesia is 1mm~0.074mm; the particle size of fused magnesia-alumina spinel is 1mm~0.074mm; the particle size of alumina micropowder is ≤2µ; the particle size of pure calcium aluminate cement is ≤0.045mm.

4. The environmentally friendly and energy-saving corundum crucible for medium-frequency electric furnace according to claim 3, characterized in that: When preparing the corundum crucible, it is also necessary to add a high-efficiency composite dispersant, and the added amount is 0.12~0.3% of the total weight of the above raw materials.

5. The environmentally friendly and energy-saving corundum crucible for medium-frequency electric furnace according to claim 4, characterized in that: The high-efficiency composite dispersant is a mixture of FS-10 and FDN-3000, wherein FS-10 is added in an amount of 0.1-0.2% of the total amount, and FDN-3000 is added in an amount of 0.02-0.1% of the total amount.

6. The environmentally friendly and energy-saving corundum crucible for medium-frequency electric furnace according to claim 5, characterized in that: The amount of high-efficiency composite dispersant added is 0.2-0.25% of the total weight of the above raw materials, of which the amount of FS-10 added is 0.12-0.15%.

7. The method for preparing an environmentally friendly and energy-saving corundum crucible for a medium-frequency electric furnace according to claim 1 or 2, characterized in that: When making a crucible, first mix fused corundum powder, fused magnesia powder, fused magnesia-alumina spinel powder, alumina powder, and pure calcium aluminate cement, then add a high-efficiency composite dispersant, and then add room temperature water while stirring to mix, and then form, cure, demould, and low-temperature bake.

8. The method for preparing an environmentally friendly and energy-saving corundum crucible for a medium-frequency electric furnace according to claim 7, characterized in that: The high-efficiency composite dispersant is a mixture of FS-10 and FDN-3000, in which FS-10 is added at 0.1~0.2% of the total amount and FDN-3000 is added at 0.02~0.1% of the total amount.

9. The method for preparing an environmentally friendly and energy-saving corundum crucible for a medium-frequency electric furnace according to claim 7, characterized in that: The temperature of room temperature water is 20-30℃, and the addition amount of room temperature water is 4.2-4.8%.

10. The method for preparing an environmentally friendly and energy-saving corundum crucible for a medium-frequency electric furnace according to claim 7, characterized in that: The temperature used for low-temperature baking is 200℃~250℃, and the baking time is 72h.

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