Method for preparing ceramsite by using waste incineration fly ash as ingredient

Abstract

The invention provides a method for preparing ceramsite by using waste incineration fly ash as an ingredient and adding blast furnace slag and chemical sludge. The method comprises the following steps: firstly, uniformly mixing fly ash with crushed blast furnace slag and chemical sludge according to a certain proportion to obtain a mixture; the mixture is sequentially subjected to drying, mixed ball milling, high-pressure dry forming, sintering and cooling, and the ceramsite is obtained.

Description

Technical Field

[0001] The invention relates to the technical field of solid waste resource utilization, and in particular to a method for preparing ceramsite by using fly ash from garbage incineration as ingredients. Background Art

[0002] Incineration of domestic waste is a common way of waste disposal, but a certain amount of fly ash will be produced during the incineration process. Fly ash contains harmful substances such as heavy metals and dioxins. If not properly disposed, it will cause serious pollution to the environment. In addition, fly ash also contains a certain amount of aluminum oxide, silicon oxide and other substances. Studies have shown that fly ash can be rendered harmless through high temperature, and silicon and aluminum elements can be used for resource utilization; blast furnace slag is a solid waste formed by gangue in ore, ash in fuel and non-volatile components in solvent (usually limestone) during the blast furnace ironmaking process. The main components of blast furnace slag are oxides such as CaO, SiO2, Al2O3 and MgO. Blast furnace slag and waste incineration fly ash are both typical aluminosilicate materials; the flocculated chemical sludge produced by industrial sewage treatment plants contains very high levels of elements such as iron and aluminum; how to use waste incineration fly ash as an ingredient to prepare expanded clay, and at the same time use other industrial wastes (such as blast furnace slag and chemical sludge) to prepare expanded clay, so as to realize the comprehensive utilization of waste resources, is an urgent problem to be solved in the environmental protection industry. Summary of the invention

[0003] The purpose of the present invention is to provide a method for preparing ceramsite by using fly ash from garbage incineration as ingredients and adding blast furnace slag and chemical sludge. The present invention firstly mixes fly ash with crushed blast furnace slag and chemical sludge in a certain proportion to obtain a mixture; the mixture is successively dried, mixed ball milled, high pressure dry molding, sintered, and cooled to obtain ceramsite.

[0004] The technical process of the present invention realizes the resource utilization of several solid wastes by coordinating and matching several solid wastes and sintering them into expanded clay under certain conditions. The present invention can simultaneously process waste incineration fly ash, blast furnace slag and chemical sludge, which is of great significance for alleviating environmental pollution, realizes the resource utilization of waste treatment, and prepares high-value-added expanded clay, which has broad market application prospects and high economic and social environmental benefits.

[0005] The present invention provides a method for preparing ceramsite by using fly ash from garbage incineration, blast furnace slag and chemical sludge, comprising the following steps: (1) crushing the blast furnace slag; (2) homogenously mixing the crushed blast furnace slag prepared in step (1) with fly ash and chemical sludge to obtain a mixed material; (3) drying the mixed material prepared in step (2); (4) ball milling the dried material obtained in step (3); (5) adding a binder to the ball milled material prepared in step (4) and subjecting it to high pressure dry molding; and (6) sintering the material prepared in step (5) and cooling it to obtain ceramsite.

[0006] The present invention provides a method for preparing ceramsite by using fly ash from garbage incineration, blast furnace slag and chemical sludge, comprising the following steps: (1) crushing the blast furnace slag; (2) homogenously mixing the crushed blast furnace slag prepared in step (1) with fly ash and chemical sludge to obtain a mixed material; (3) drying the mixed material prepared in step (2); (4) ball milling the dried material obtained in step (3); (5) adding a binder to the ball milled material prepared in step (4) and subjecting it to high pressure dry molding; and (6) sintering the material prepared in step (5) and cooling it to obtain ceramsite.

[0007] In an embodiment of the present invention, in step (1), the blast furnace slag comes from steel smelting, and the main components of the blast furnace slag are 30-50% CaO, 20-40% SiO2, 10-30% Al2O3, 3-15% MgO, 0.1-3% TiO2, 0.1-3% Na2O, 0.1-3% Fe2O3, 0.1-3% K2O and 0.1-3% MnO.

[0008] In the embodiment of the present invention, in step (2), the fly ash produced by the incineration of garbage mainly consists of 1.56-12.43% Al2O3, 19.37-39.90% CaO, 0.85-5.02% Fe2O3, 5.13-15.24% K2O, 0.67-2.19% MgO, 2.45-9.17% Na2O, 4.48-24.84% SiO2, 7.03-14.30% SO3, 0.1-0.33% Cr2O3, 0.09-0.51% CuO, 0.25-1.36% PbO, and 0.96-3.11% ZnO. Chemical sludge mainly contains silicon, aluminum, iron, and calcium compounds.

[0009] In an embodiment of the present invention, in step (2), the mass ratio of fly ash to crushed blast furnace slag and chemical sludge is 5:4:1 to 4:5:1.

[0010] In an embodiment of the present invention, in step (3), the mixed material obtained in step (2) is dried and the moisture content is controlled to be below 3%.

[0011] In an embodiment of the present invention, in step (4), the dried material obtained in step (3) is ball-milled. During the ball-milling process, the ball-milling time is 0.5 to 3 hours, the ball-milling speed is 300 to 600 rpm, the ball-to-material ratio is 4:1 to 6:1, and the powder particle size obtained by grinding is 50 to 300 meshes. The surface activation of the material and the increase of uniformity can be achieved by grinding, which is beneficial to the high-temperature phase change reaction.

[0012] In an embodiment of the present invention, in step (5), the ball-milled material obtained in step (4) is added with a binder for high-pressure dry molding, and the binder is one or more of polyvinyl alcohol and water, waste mineral oil, epoxy resin, and sodium silicate. The mass of the binder is 10% to 20% of the mass of the mixed material, and the volume ratio of polyvinyl alcohol to water is 1:10 to 3:20.

[0013] In an embodiment of the present invention, in step (5), the high pressure molding pressure is 5 to 20 MPa, and the die casting time is 3 to 5 min.

[0014] In an embodiment of the present invention, in step (6), the ceramsite blank obtained in step (5) is sintered at a temperature of 1200 to 1350°C and a sintering time of 0.5 to 2h; during the sintering process, the heating rate is controlled within the range of 10 to 12°C / min below 1000°C, and after reaching 1000°C, the heating rate is controlled within the range of 3 to 6°C / min, and the sintering cooling rate is controlled within the range of 10 to 20°C / min.

[0015] The prepared ceramsite is tested by the relevant standard method, and its water absorption is 10-40%, the porosity is 40-50%, the cylinder pressure strength is 3-9 Mpa, and the bulk density is 400-800 kg / m 3 , meeting the requirements of expanded clay products. BRIEF DESCRIPTION OF THE DRAWINGS

[0016] Figure 1 The present invention is a process flow chart of a method for preparing ceramsite by using fly ash from waste incineration as an ingredient. DETAILED DESCRIPTION

[0017] Example 1 Step 1: Take 50kg of fly ash from an incineration plant, 40kg of blast furnace slag from a smelter, and 10kg of chemical sludge from a sewage plant; Step 2: crush 40kg of blast furnace slag, mix with 50kg of fly ash and 10kg of chemical sludge, and stir evenly; Step 3: Dry the mixed material prepared in the second step, and the moisture content is detected to be 2.5%; Step 4: ball mill the dried material obtained in the third step. During the ball milling process, the ball milling time is 1 hour, the ball milling speed is 500 rpm, the ball-to-material ratio is 4:1, and the powder particle size obtained by grinding is 100 mesh; Step 5: Add 1L of polyvinyl alcohol and 10L of water to the ball-milled material prepared in step 4, mix well, and form by high-pressure dry method. The hydraulic pressure is 15MPa, and the die-casting time is 4min; Step 6: Sinter the ceramsite blank formed by die casting in the fifth step. During the sintering process, the heating rate is controlled at 10-12°C / min below 1000°C. After reaching 1000°C, the heating rate is 3-6°C / min. The sintering temperature is 1200°C. After stable sintering at 1200°C for 1h, the cooling rate is 10-20°C / min to obtain the final ceramsite. The prepared ceramsite was tested using relevant standard methods, and its water absorption was 20%, porosity was 45%, cylinder pressure strength was 8 Mpa, and bulk density was 500 kg / m 3 , meeting the requirements of expanded clay products.

[0018] Example 2 Step 1: Take 40kg of fly ash from an incineration plant, 50kg of blast furnace slag from a smelter, and 10kg of chemical sludge from a sewage plant; Step 2: crush 50kg of blast furnace slag, mix with 40kg of fly ash and 10kg of chemical sludge, and stir evenly; Step 3: Dry the mixed material prepared in the second step, and the moisture content is detected to be 2%; Step 4: ball mill the dried material obtained in the third step. During the ball milling process, the ball milling time is 0.5h, the ball milling speed is 500rpm, the ball-to-material ratio is 4:1, and the powder particle size obtained by grinding is 50 mesh; Step 5: Add 10kg of sodium silicate to the ball-milled material prepared in step 4 and mix well, and then form by high-pressure dry method. The hydraulic pressure is 15MPa, and the die-casting time is 5min; Step 6: Sinter the ceramsite blank formed by die casting in the fifth step. During the sintering process, the heating rate is controlled at 10-12°C / min below 1000°C. After reaching 1000°C, the heating rate is 3-6°C / min. The sintering temperature is 1250°C. After stable sintering at 1250°C for 1h, the cooling rate is 10-20°C / min to obtain the final ceramsite. The prepared ceramsite was tested using relevant standard methods, and its water absorption was 25%, porosity was 44%, cylinder pressure strength was 8 Mpa, and bulk density was 650 kg / m 3 , meeting the requirements of expanded clay products.

[0019] Example 3 Step 1: Take 45kg of fly ash from an incineration plant, 45kg of blast furnace slag from a smelter, and 10kg of chemical sludge from a sewage plant; Step 2: crush 45kg of blast furnace slag, mix with 45kg of fly ash and 10kg of chemical sludge, and stir evenly; Step 3: Dry the mixed material prepared in the second step, and the moisture content is detected to be 2.2%; Step 4: ball mill the dried material obtained in the third step. During the ball milling process, the ball milling time is 1 hour, the ball milling speed is 600 rpm, the ball-to-material ratio is 5:1, and the powder particle size obtained by grinding is 100 mesh; Step 5: Add 12L of waste oil to the ball-milled material prepared in step 4 and mix well, and then form it by high-pressure dry method. The hydraulic pressure is 15MPa, and the die-casting time is 4min; Step 6: Sinter the ceramsite blank formed by die casting in the fifth step. During the sintering process, the heating rate is controlled at 10-12°C / min below 1000°C. After reaching 1000°C, the heating rate is 3-6°C / min. The sintering temperature is 1350°C. After stable sintering at 1350°C for 1h, the cooling rate is 10-20°C / min to obtain the final ceramsite. The prepared ceramsite was tested using relevant standard methods, and its water absorption rate was 10%, the porosity was 45%, the cylinder pressure strength was 8Mpa, and the bulk density was 550 kg / m 3 , meeting the requirements of expanded clay products.

Claims

1. The present invention discloses a method for preparing ceramsite using fly ash from garbage incineration as an ingredient, characterized in that: The method comprises the following steps: (1) crushing blast furnace slag; (2) homogenously mixing the crushed blast furnace slag prepared in step (1) with fly ash and chemical sludge to obtain a mixed material; (3) drying the mixed material prepared in step (2); (4) ball milling the dried material obtained in step (3); (5) adding a binder to the ball milled material prepared in step (4) and performing high pressure dry molding; and (6) sintering the material prepared in step (5) and cooling it to obtain ceramsite.

2. The method for preparing ceramsite using fly ash from garbage incineration as an ingredient according to claim 1, characterized in that: In one embodiment of the present invention, in step (2), the mass ratio of fly ash to crushed blast furnace slag and chemical sludge is 5:4:1 to 4:5:

1.

3. The method for preparing ceramsite using fly ash from garbage incineration as an ingredient according to claim 1, characterized in that: In step (3), the mixed material obtained in step (2) is dried and the moisture content is controlled to be below 3%.

4. The method for preparing ceramsite using fly ash from garbage incineration as an ingredient according to claim 1, characterized in that: In step (4), the dried material obtained in step (3) is ball-milled. During the ball-milling process, the ball-milling time is 0.5 to 3 hours, the ball-milling speed is 300 to 600 rpm, the ball-to-material ratio is 4:1 to 6:1, and the powder particle size obtained by grinding is 50 to 300 meshes. The surface activation of the material and the increase of uniformity can be achieved by grinding, which is beneficial to the high-temperature phase change reaction.

5. The method for preparing ceramsite using fly ash from garbage incineration as an ingredient according to claim 1, characterized in that: In step (5), the ball-milled material obtained in step (4) is added with a binder for high-pressure dry molding, wherein the binder is one or more of polyvinyl alcohol and water, waste mineral oil, epoxy resin, and sodium silicate. The mass of the binder is 10% to 20% of the mass of the mixed material, and the volume ratio of polyvinyl alcohol to water is 1:10 to 3:

20.

6. The method for preparing ceramsite using fly ash from garbage incineration as an ingredient according to claim 1, characterized in that: In step (5), the high pressure molding pressure is 5 to 20 MPa, and the die casting time is 3 to 5 minutes.

7. The method for preparing ceramsite using fly ash from garbage incineration as an ingredient according to claim 1, characterized in that: In step (6), the ceramsite blank obtained in step (5) is sintered at a temperature of 1200 to 1350° C. and a sintering time of 0.5 to 2 h. During the sintering process, the heating rate is controlled within a range of 10 to 12° C. / min below 1000° C., and after reaching 1000° C., the heating rate is controlled within a range of 3 to 6° C. / min, and the sintering cooling rate is controlled within a range of 10 to 20° C. / min.

8. The method for preparing ceramsite using fly ash from garbage incineration as an ingredient according to claim 1, characterized in that: The prepared ceramsite is tested by the relevant standard method, and its water absorption is 10-40%, the porosity is 40-50%, the cylinder pressure strength is 3-9Mpa, and the bulk density is 400-800kg / m 3 , meet the requirements of expanded clay products.

9. A method for preparing ceramsite using fly ash from garbage incineration as an ingredient, characterized in that: Obtained by the preparation method described in claims 1-8.

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