Refractory castable for hazardous waste incinerator and preparation method of refractory castable

Abstract

The invention relates to a refractory castable for a hazardous waste incinerator and a preparation method of the refractory castable. The preparation method of the refractory castable for the hazardous waste incinerator comprises the following steps: mixing silicon carbide, mullite, corundum fine sand, a binding agent, a defoaming agent, aluminum oxide micro powder, silicon micro powder and calcium oxide to obtain a mixture, and introducing carbon dioxide gas carrying silicon dioxide powder into the mixture, and after the oxygen silicon dioxide powder is completely introduced, standing to obtain slurry, pouring the slurry into a mold for natural air drying, and then sintering at a high temperature to obtain the composite material. According to the refractory castable for the hazardous waste incinerator, carbon dioxide is used for replacing air, then calcium hydroxide generated after calcium oxide is dissolved in water is used for absorbing carbon dioxide in the mixture, air holes generated due to the fact that air exists in the castable in the preparation process of the refractory castable for the hazardous waste incinerator can be reduced, and the situation that HCl invades into the castable to corrode the castable is avoided.

Description

Technical Field

[0001] The invention belongs to the technical field of refractory materials, and particularly relates to a refractory castable for a hazardous waste incinerator and a preparation method thereof. Background Art

[0002] High-temperature incineration is an important method for treating hazardous waste. The industrial hazardous waste treated by hazardous waste incinerators mainly contains some chemical materials such as S, Cl, P, halogen materials, fluorides, inorganic salts, etc. During the high-temperature incineration process, industrial hazardous waste will produce HCl. Hazardous waste incinerators are generally prepared by refractory brick masonry or castable casting. The brick joints of hazardous waste incinerators prepared by refractory brick casting are easily damaged by penetration and erosion. Hazardous waste incinerators prepared by castable casting will have pores. The presence of pores will allow HCl to penetrate, thereby causing the lining of the hazardous waste incinerator to be damaged. Summary of the invention

[0003] The first object of the present invention is to provide a refractory castable for a hazardous waste incinerator to solve the technical problem that pores are easily formed in the existing refractory castables after casting, thereby causing HCl to penetrate through the pores and damage the lining of the hazardous waste incinerator.

[0004] The second object of the present invention is to provide a method for preparing refractory castables for hazardous waste incinerators.

[0005] In order to achieve the above purpose, the technical solution adopted by the present invention is:

[0006] A method for preparing a refractory castable for a hazardous waste incinerator comprises the following steps: mixing silicon carbide, mullite, corundum fine sand, a binder, a defoamer, alumina micropowder, silicon micropowder and calcium oxide to obtain a mixture, introducing carbon dioxide gas carrying silicon dioxide powder into the mixture, and standing the mixture to obtain a slurry after the introduction of the silicon dioxide powder, pouring the slurry into a mold, air-drying it naturally, and then sintering it at high temperature to obtain the mixture.

[0007] Furthermore, the mass ratio of the silicon dioxide powder to the calcium oxide is 1:0.1 to 0.15.

[0008] Furthermore, the high temperature sintering temperature is 1000-1200° C., and the high temperature sintering time is 10-12 hours.

[0009] Furthermore, the carbon dioxide gas carrying the silicon dioxide powder is introduced into the mixture while it is being stirred.

[0010] Furthermore, the binder is sodium silicate, and the defoamer is an organosilicon defoamer.

[0011] Furthermore, the silicon carbide is 5-15 parts by mass, the mullite is 5-15 parts by mass, the corundum fine sand is 50-70 parts by mass, the binder is 3-8 parts by mass, the defoamer is 2-3 parts by mass, the water is 30-40 parts by mass, the alumina powder is 5-6 parts by mass, the silicon powder is 5-6 parts by mass, and the calcium oxide is 1-3 parts by mass.

[0012] Furthermore, the particle size of the alumina micropowder is 1-1.2 μm, the Al2O3 content is ≥98.5%, and the total content of Fe and Si is ≤0.05; the particle size of the silicon micropowder is 1.2-1.5 μm, and the SiO2 content is ≥92%; the particle size of the silicon carbide is 0.5-0.8 μm; the particle size of the corundum fine sand is 0.1-1 mm; and the particle size of the mullite is 0.1-1 mm.

[0013] A refractory castable for a hazardous waste incinerator is prepared by using the above-mentioned method for preparing the refractory castable for a hazardous waste incinerator.

[0014] Beneficial effects of the present invention:

[0015] The present invention uses carbon dioxide to replace air, and then uses calcium hydroxide generated by dissolving calcium oxide in water to absorb carbon dioxide in the mixture, so as to reduce pores generated in the refractory castable for the hazardous waste incinerator of the present invention due to the presence of air in the castable during the preparation process, and prevent HCl from invading the castable and then corroding the castable.

[0016] The present invention uses carbon dioxide gas to bring silicon dioxide powder into a mixture, calcium oxide generates calcium hydroxide after meeting water, and calcium hydroxide absorbs carbon dioxide in the mixture to generate calcium carbonate. Silicon dioxide forms a silicon dioxide layer on the surface of the calcium carbonate, and the silicon dioxide layer can effectively improve the fire resistance and HCl resistance of the calcium carbonate. BRIEF DESCRIPTION OF THE DRAWINGS

[0017] Figure 1 This is a physical picture of the casting obtained by the refractory castable for the hazardous waste incinerator in Example 1 after one month of use;

[0018] Figure 2 This is a physical picture of the casting obtained by the refractory castable for the hazardous waste incinerator in Comparative Example 1 after one month of use;

[0019] Figure 3 This is a physical picture of the casting obtained by the refractory castable for the hazardous waste incinerator in Comparative Example 2 after one month of use. DETAILED DESCRIPTION

[0020] The present invention will be further described below in conjunction with the embodiments of the present invention and the accompanying drawings.

[0021] Example 1

[0022] The preparation method of the refractory castable for the hazardous waste incinerator of Example 1 comprises the following steps: 5kg of silicon carbide, 5.5kg of mullite, 53kg of corundum fine sand, 4kg of sodium silicate, 2kg of polydimethylsiloxane, 5kg of alumina powder, 5kg of silicon powder, 30kg of water, and 1.3kg of calcium oxide are mixed to obtain a mixture, and carbon dioxide gas carrying silicon dioxide powder is introduced into the mixture under stirring, and after the silicon dioxide powder is introduced, it is allowed to stand for 2 hours to obtain a slurry, and the slurry is poured into a mold and naturally air-dried, and then sintered at 1000°C for 11 hours. The silicon dioxide powder is 0.13kg. The particle size of the alumina powder is 1-1.2μm, the Al2O3 content is ≥98.5%, and the total content of Fe and Si is ≤0.05. The particle size of the silicon powder is 1.2-1.5μm, and the SiO2 content is ≥92%. The particle size of silicon carbide is 0.5-0.8 μm; the particle size of corundum fine sand is 0.1-1 mm; and the particle size of mullite is 0.1-1 mm.

[0023] Example 2

[0024] The preparation method of the refractory castable for the hazardous waste incinerator of Example 2 comprises the following steps: 13g of silicon carbide, 15g of mullite, 60g of corundum fine sand, 7.3g of sodium silicate, 3g of polydimethylsiloxane, 6g of alumina powder, 6g of silicon powder, 38g of water, and 3g of calcium oxide are mixed to obtain a mixture, and carbon dioxide gas carrying silicon dioxide powder is introduced into the mixture under stirring, and after the silicon dioxide powder is introduced, it is allowed to stand for 1h to obtain a slurry, and the slurry is poured into a mold and naturally air-dried, and then sintered at 1200°C for 10h. The silicon dioxide powder is 0.4g. The particle size of the alumina powder is 1-1.2μm, the Al2O3 content is ≥98.5%, and the total content of Fe and Si is ≤0.05. The particle size of the silicon powder is 1.2-1.5μm, and the SiO2 content is ≥92%. The particle size of silicon carbide is 0.5-0.8 μm; the particle size of corundum fine sand is 0.1-1 mm; and the particle size of mullite is 0.1-1 mm.

[0025] Example 3

[0026] The preparation method of the refractory castable for the hazardous waste incinerator of Example 3 comprises the following steps: 10 kg of silicon carbide, 8 kg of mullite, 70 kg of corundum fine sand, 4.8 kg of sodium silicate, 2 kg of polydimethylsiloxane, 5.4 kg of alumina powder, 6 kg of silicon powder, 39 kg of water, and 2.2 kg of calcium oxide are mixed to obtain a mixture, and carbon dioxide gas carrying silicon dioxide powder is introduced into the mixture under stirring, and after the silicon dioxide powder is introduced, it is allowed to stand for 1.5 hours to obtain a slurry, and the slurry is poured into a mold and naturally air-dried, and then sintered at 1100°C for 12 hours. The silicon dioxide powder is 0.3 kg. The particle size of the alumina powder is 1 to 1.2 μm, the Al2O3 content is ≥98.5%, and the total content of Fe and Si is ≤0.05. The particle size of the silicon powder is 1.2 to 1.5 μm, and the SiO2 content is ≥92%. The particle size of silicon carbide is 0.5-0.8 μm; the particle size of corundum fine sand is 0.1-1 mm; and the particle size of mullite is 0.1-1 mm.

[0027] Comparative Example 1

[0028] The preparation method of the refractory castable for the hazardous waste incinerator of comparative example 1 comprises the following steps: 5kg of silicon carbide, 5.5kg of mullite, 53kg of corundum fine sand, 4kg of sodium silicate, 2kg of polydimethylsiloxane, 5kg of alumina powder, 5kg of silicon powder, 30kg of water, and 1.3kg of calcium oxide are mixed to obtain a mixture, carbon dioxide gas is introduced into the mixture, and the mixture is allowed to stand for 2 hours to obtain a slurry, and the slurry is poured into a mold and naturally air-dried, and then sintered at 1000°C for 11 hours. The particle size of the alumina powder is 1-1.2μm, the Al2O3 content is ≥98.5%, and the total content of Fe and Si is ≤0.05. The particle size of the silicon powder is 1.2-1.5μm, and the SiO2 content is ≥92%. The particle size of silicon carbide is 0.5-0.8 μm; the particle size of corundum fine sand is 0.1-1 mm; and the particle size of mullite is 0.1-1 mm.

[0029] Comparative Example 2

[0030] The preparation method of the refractory castable for the hazardous waste incinerator of Comparative Example 2 comprises the following steps:

[0031] 5 kg of silicon carbide, 5.5 kg of mullite, 53 kg of corundum fine sand, 30 kg of water, 4 kg of sodium silicate, 2 kg of polydimethylsiloxane, 5 kg of alumina powder, 5 kg of silicon powder, and 1.3 kg of calcium oxide are mixed to obtain a mixture, which is poured into a mold and naturally air-dried, and then sintered at 1000° C. for 11 hours.

[0032] Test Example 1

[0033] According to the porosity test method specified in YB / T5200-1993, the porosity of the refractory castable for hazardous waste incinerator of Example 1 was tested. The porosity of the refractory castable for hazardous waste incinerator of Example 1 was 6%.

[0034] Test Example 2

[0035] The HCl resistance of the refractory castables for hazardous waste incinerators of Example 1 and Comparative Examples 1-2 was tested. The pictures of the castables obtained in Example 1 and Comparative Examples 1-2 after one month of use are as follows: Figure 1-3 As shown, from Figure 1 It can be seen that the casting obtained in Example 1 is less corroded, while the castings obtained in Comparative Examples 1 and 2 are more deeply corroded.

[0036] Experimental Example 3

[0037] The compressive strength and flexural strength of the refractory castables for hazardous waste incinerators of Example 1 and Comparative Examples 1-2 at room temperature and after high temperature firing were measured by the method specified in GB / T5072-2008. The acid resistance of the refractory castables for hazardous waste incinerators of Example 1 and Comparative Examples 1-2 was tested by the method specified in GBT 17601. The results are shown in Table 1.

[0038] Table 1 Compressive strength, flexural strength and acid resistance of refractory castables for hazardous waste incinerators of Example 1 and Comparative Examples 1-2

[0039]

[0040] As can be seen from Table 1, the acid resistance rate, compressive strength and flexural strength of the refractory castable for hazardous waste incinerator of Example 1 are relatively excellent, and the refractory castable for hazardous waste incinerator of Comparative Example 1 has a low acid resistance rate due to the corrosion of calcium carbonate by HCl, and the refractory castable for hazardous waste incinerator of Comparative Example 2 has pores, and HCl will penetrate into the pores to corrode the castable, thereby reducing the acid resistance rate of the refractory castable for hazardous waste incinerator of Comparative Example 2. The refractory castable for hazardous waste incinerator of Example 1 has an extremely low porosity. Compared with Comparative Examples 1 and 2, the flexural strength and compressive strength of the refractory castable for hazardous waste incinerator of Example 1 at room temperature and after high temperature burning are relatively excellent.

Claims

1. A method for preparing a refractory castable for a hazardous waste incinerator, characterized in that: The following steps are involved: Silicon carbide, mullite, corundum fine sand, binder, defoamer, alumina powder, silicon powder and calcium oxide are mixed to obtain a mixture, carbon dioxide gas carrying silicon dioxide powder is introduced into the mixture, and after the silicon dioxide powder is introduced, the mixture is allowed to stand to obtain a slurry, and the slurry is poured into a mold and naturally air-dried, and then sintered at a high temperature to obtain the mixture.

2. The method for preparing a refractory castable for a hazardous waste incinerator according to claim 1, characterized in that: The mass ratio of the silicon dioxide powder to the calcium oxide is 1:0.1 to 0.

15.

3. The method for preparing a refractory castable for a hazardous waste incinerator according to claim 1, characterized in that: The standing time is 1 to 2 hours, the high temperature sintering temperature is 1000 to 1200° C., and the high temperature sintering time is 10 to 12 hours.

4. The method for preparing a refractory castable for a hazardous waste incinerator according to claim 1, characterized in that: The carbon dioxide gas carrying silicon dioxide powder is introduced into the mixed material while being stirred.

5. The method for preparing a refractory castable for a hazardous waste incinerator according to claim 1, characterized in that: The binder is sodium silicate, and the defoamer is an organosilicon defoamer.

6. The method for preparing a refractory castable for a hazardous waste incinerator according to claim 1, characterized in that: The silicon carbide is 5 to 15 parts by mass, the mullite is 5 to 15 parts by mass, the corundum fine sand is 50 to 70 parts by mass, the binder is 3 to 8 parts by mass, the defoamer is 2 to 3 parts by mass, the water is 30 to 40 parts by mass, the alumina powder is 5 to 6 parts by mass, the silicon powder is 5 to 6 parts by mass, and the calcium oxide is 1 to 3 parts by mass.

7. The method for preparing a refractory castable for a hazardous waste incinerator according to claim 6, characterized in that: The particle size of the alumina micropowder is 1-1.2 μm, the Al2O3 content is ≥98.5%, and the total content of Fe and Si is ≤0.05; the particle size of the silicon micropowder is 1.2-1.5 μm, and the SiO2 content is ≥92%; the particle size of the silicon carbide is 0.5-0.8 μm; the particle size of the corundum fine sand is 0.1-1 mm; and the particle size of the mullite is 0.1-1 mm.

8. A refractory castable for a hazardous waste incinerator, characterized in that: The refractory castable material is prepared by the preparation method of the refractory castable material for hazardous waste incinerator according to any one of claims 1 to 7.

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