Method for preparing ceramsite from gasification slag and ceramsite prepared thereby

Abstract

The application provides a method for preparing ceramsite from gasification slag, and raw materials for preparing the ceramsite include the following components in parts by weight: 31-60 parts of a first component, 39-68 parts of a second component, 1-20 parts of a third component, and 0.1-1 parts of a fourth component; the first component is gasification slag with a moisture content of 50-70 wt%, and a dry basis carbon content of 35-45 wt%; the second component is fly ash and / or engineering slag, and in the second component, the total content of Al2O3 and SiO2 is greater than or equal to 60 wt%, and the content of Al2O3 is less than or equal to 25 wt%; the third component is bentonite and / or kaolin; and the fourth component is a plasticizer. The gasification slag with a higher moisture content and a specific dry basis carbon content is used in cooperation with fly ash and / or engineering slag, bentonite and / or kaolin, and a plasticizer to prepare ceramsite, and the prepared ceramsite has stable bulk density, high strength, and low water absorption.

Description

Technical Field

[0001] This invention relates to the field of coal chemical solid waste utilization and lightweight aggregates, and particularly to a method for preparing ceramsite from gasification slag and the resulting ceramsite. Background Technology

[0002] Industrial waste mainly includes coal-based solid waste and mineral waste. In some areas with concentrated coal mines and power plants, large amounts of solid waste accumulate and are landfilled every year. The large accumulation of gasification slag, fly ash, and coal gangue causes serious environmental pollution.

[0003] Gasification slag has a dense, glossy appearance and is generally grayish-black. It is a solid residue formed from inorganic minerals and residual carbonaceous particles during the coal gasification reaction, including coarse and fine slag. With the large-scale promotion of coal gasification technology, a large amount of gasification slag has been generated, exceeding hundreds of millions of tons annually. The annual emissions of gasification slag are also increasing daily, making its large-scale disposal and resource utilization urgent.

[0004] my country's annual consumption of expanded clay aggregate exceeds 20 million cubic meters, indicating a huge market potential for producing expanded clay aggregate from industrial solid waste. Currently, the main type of expanded clay aggregate produced from industrial solid waste in my country is sludge-based, with other types including coal gangue, steel slag, and tailings such as red mud. However, sludge-based expanded clay aggregate has a lower density and strength. While coal gangue and steel slag expanded clay aggregate can achieve higher strength, their bulk density is also higher. Red mud expanded clay aggregate is generally calcined at temperatures above 1100℃. For example, Pei Huifang et al. prepared porous expanded clay aggregate using coal gangue and urban sludge, and investigated the effects of different ratios and firing regimes on the aggregate's properties. The results showed that when m(coal gangue):m(urban sludge) = 80%:20%–50%:50%, the firing temperature was 1120℃, and the holding time was 60 min, the density of the resulting porous expanded clay aggregate was 1030–1200 kg / m³. 3 The water absorption rate is between 23% and 35%. Meanwhile, the preparation of ceramsite from industrial solid waste is mostly done using dry granulation; there is currently no research on directly preparing ceramsite from the gasification wet slag discharged from coal gasification scrubbing towers. Furthermore, ceramsite prepared from solid waste generally has low strength, high water absorption, and high energy consumption. Therefore, the lightweight aggregate construction field urgently needs ceramsite with stable bulk density, high strength, and low water absorption. Summary of the Invention

[0005] The purpose of this invention is to provide a method for preparing ceramsite using gasification slag with high moisture content and a specific dry basis carbon content as raw material. The resulting ceramsite exhibits stable bulk density, low water absorption, and high cylinder compressive strength. This invention utilizes the wet raw slag (i.e., gasification slag) from a coal-to-syngas scrubbing tower, and uses the washing water therein as the molding water for the ceramsite, turning wastewater into a valuable resource and effectively conserving water resources.

[0006] To achieve the above objectives, the present invention adopts the following technical solution:

[0007] The first aspect of the present invention provides a method for preparing ceramsite from gasification slag. The raw materials for preparing ceramsite comprise the following components by weight: a first component of 31-60 parts, a second component of 39-68 parts, a third component of 1-20 parts, and a fourth component of 0.1-1 parts; the first component is gasification slag with a moisture content of 50-70 wt% and a dry basis carbon content of 35-45 wt%; the second component is fly ash and / or engineering slag, wherein the total content of Al2O3 and SiO2 in the second component is ≥60 wt%, and the content of Al2O3 is ≤25 wt%; the third component is bentonite and / or kaolin; and the fourth component is a plasticizer.

[0008] This invention uses gasification slag with high moisture content and specific dry basis carbon content as the first component, and mixes it with the second, third and fourth components to prepare ceramsite. No external water is required, and the resulting ceramsite has stable bulk density, high strength and low water absorption.

[0009] In this invention, the gasification slag has a high moisture content, making full use of the original moisture in the slag. No external water needs to be added during raw material preparation, reducing water pollution. Furthermore, the ceramsite produced from gasification slag with a suitable moisture content has a stable bulk density, meaning the ceramsite maintains good strength while achieving a lightweight material. Although the gasification slag in this application has a high moisture content, the moisture content cannot be too high. If the moisture content in the raw material system is too high, the system will be in a muddy state, resulting in excessively high bulk density of the ceramsite, failing to achieve the lightweight effect. If the moisture content is too low, the system will be in a loose, sandy state, unable to provide sufficient strength for the forming process to obtain raw material particles. Even if raw material balls are extruded with difficulty, the loose system will result in excessive water absorption and poor strength of the ceramsite material.

[0010] The gasification slag in this application also needs to have a specific dry basis carbon content, which refers to the carbon content in the coal gasification slag dried to constant weight at 105±5℃. The gasification slag serves as the main pore-forming agent for the ceramsite. On the one hand, the carbon in the gasification slag undergoes a reduction reaction with Fe2O3 in fly ash / engineering slag at high temperature to generate CO2. On the other hand, after the carbon particles react with O2, vacancies are created in the original carbon particle positions, forming a large number of pores within the ceramsite spheres, reducing the density of the resulting ceramsite and thus achieving lightweight material. Maintaining a specific dry basis carbon content in the gasification slag ensures stable bulk density of the resulting ceramsite, allowing it to maintain good strength while achieving a lightweight effect. Furthermore, the carbon in the gasification slag releases a large amount of heat during oxidation, reducing the external energy requirement and thus lowering the firing temperature of the ceramsite. Simultaneously, compared to external energy supply, it better ensures the uniformity and strength of the ceramsite.

[0011] In the second component of this invention, a certain total aluminum-silicon content must first be ensured, and under this premise, the amount of Al2O3 in the total aluminum-silicon content is reduced. A sufficiently high total aluminum-silicon content ensures that the amount of silicon-aluminum tetrahedral structure formed after mineral phase transformation at high temperature is sufficient, and this silicon-aluminum tetrahedral structure guarantees the strength of the ceramsite after calcination. However, the higher the Al2O3 content, the higher the calcination temperature, leading to increased energy consumption. This application needs to reduce the calcination temperature of the ceramsite, and a higher Al2O3 content will lead to a corresponding increase in the bulk density of the ceramsite, thus failing to achieve the effect of a lightweight material. Therefore, it is necessary to control the Al2O3 content to maintain a low level.

[0012] In some preferred embodiments, the gasification slag has a moisture content of 55-65 wt% and a dry basis carbon content of 38-42 wt%; preferably, the particle size D90 ≤ 30 mesh.

[0013] In some preferred embodiments, the total content of Al2O3 and SiO2 in the second component is ≥65wt%, and the content of Al2O3 is ≤23wt%.

[0014] In some preferred embodiments, the second component contains ≤8 wt% Fe2O3 and ≤12 wt% CaO.

[0015] In some preferred embodiments, the second component is manually crushed or crushed by a crusher before use to reduce its particle size D90 to below 200 μm, preferably below 150 μm; the third component is manually crushed or crushed by a crusher before use to reduce its particle size D90 to below 75 μm, thereby removing large particles and improving the bonding force, interlocking force, and internal friction between the various mixtures, resulting in the ceramsite having higher bonding force, strength, and stability.

[0016] In some preferred embodiments, the plasticizer is selected from one or more of cellulose ether, starch ether, and guar gum.

[0017] In some preferred embodiments, the preparation method includes the following steps:

[0018] (1) Mix the first component, the second component, the third component and the fourth component and stir evenly to obtain a mixture;

[0019] (2) The mixture is extruded and granulated to obtain granules;

[0020] (3) Polish the particles to obtain raw material balls;

[0021] (4) The raw material balls are calcined and cooled to obtain the ceramic granules.

[0022] The ceramsite preparation process of this invention differs from traditional methods. Traditional methods involve disc rolling molding, which requires drying the gasification slag to reduce the introduction of total moisture into the mixture. During granulation, a suitable amount of water is added to cause the water and mixture to agglomerate and achieve the desired particle size. In contrast, this invention uses direct extrusion granulation after mixing, allowing for a larger water content in the gasification slag. This fully utilizes the original moisture in the slag, eliminating the need for external water addition during raw material preparation, reducing water pollution. Furthermore, the ceramsite prepared from gasification slag with appropriate moisture content has a stable bulk density, meaning that the ceramsite maintains good strength while achieving a lightweight material.

[0023] In some preferred embodiments, the polishing speed is 600-1000 rpm / min and the polishing time is 15-30 min; the calcination temperature is 800-900℃ and the calcination time is 30-60 min.

[0024] In some preferred embodiments, the raw material pellets are dried before calcination;

[0025] Preferably, the drying temperature is 60-80℃, and the drying time is, for example, 3-5 hours.

[0026] A second aspect of the present invention provides ceramsite prepared by the above-described method for preparing ceramsite from gasification slag.

[0027] The technical solution provided by this invention has the following beneficial effects:

[0028] (1) This invention uses a first component with high moisture content and a specific dry basis carbon content, which is combined with the second, third, and fourth components to prepare ceramsite. No external water is required, and the resulting ceramsite has a stable bulk density (600-900 kg / m³). 3 High strength (≥5.0MPa) and low water absorption (≤20%);

[0029] (2) In this invention, the gasification slag has a high moisture content, making full use of the original moisture in the gasification slag. No additional water is needed in the raw material preparation, reducing water pollution. Furthermore, the ceramsite produced by using gasification slag with a suitable moisture content has a stable bulk density, meaning that the ceramsite can maintain good strength while achieving a lightweight effect. The carbon in the gasification slag forms a large number of pores in the ceramsite balls, reducing the density of the ceramsite and thus achieving a lightweight material. Maintaining a specific dry basis carbon content in the gasification slag ensures that the ceramsite produced has a stable bulk density, allowing the ceramsite to maintain good strength while achieving a lightweight material.

[0030] (3) In the second component of the present invention, the sufficiently high total aluminum and silicon content ensures that the amount of silicon-aluminum tetrahedral structure formed after the mineral phase transformation at high temperature is sufficient, and the silicon-aluminum tetrahedral structure ensures the strength of the ceramsite after calcination; however, the higher the Al2O3 content, the higher the calcination temperature, which leads to an increase in energy consumption. This application needs to reduce the calcination temperature of the ceramsite, and the higher the Al2O3 content, the higher the bulk density of the ceramsite will be, thus failing to achieve the effect of lightweight materials. Therefore, it is necessary to control the Al2O3 content to be kept at a low level.

[0031] (4) The ceramsite preparation process of the present invention is different from the traditional method. It adopts direct extrusion granulation after mixing, which allows the gasification slag to contain a large amount of water, making full use of the original moisture in the gasification slag. No external water needs to be added in the raw material preparation, reducing water pollution. Moreover, unlike the traditional dry granulation, the extrusion granulation method of this application results in stable ceramsite bulk density, making it easier to obtain lightweight materials.

[0032] (5) This invention fully utilizes the inherent characteristics of coal chemical ash and slag solid waste to achieve synergistic utilization of solid waste. It utilizes the reaction between the gasification slag generated by the coal chemical plant and the mineral phase of fly ash at high temperatures to achieve high strength in the prepared ceramsite. In this invention, bentonite is used to improve the porosity of the ceramsite, achieving low water absorption and low density. The high carbon content of the gasification slag is utilized to reduce the firing temperature of the ceramsite preparation, thereby reducing calcination energy consumption. Detailed Implementation

[0033] The present invention will be further illustrated below with specific embodiments. These embodiments are merely illustrative and do not imply that the scope of the invention is limited thereto.

[0034] In the following embodiments, the method for preparing ceramsite from gasification slag includes the following steps:

[0035] (1) Mix the first component, the second component, the third component and the fourth component and stir evenly to obtain a mixture;

[0036] (2) The mixture is extruded and granulated to obtain granules;

[0037] (3) Polish the particles to obtain raw material balls;

[0038] (4) The raw material balls are calcined and cooled to obtain the ceramsite;

[0039] The raw materials for preparing ceramsite comprise the following components by weight: 31-60 parts of component one, 39-68 parts of component two, 1-20 parts of component three, and 0.1-1 parts of component four; the first component is gasification slag with a moisture content of 50-70 wt% and a dry basis carbon content of 35-45 wt%; preferably, the gasification slag has a moisture content of 55-65 wt%, a dry basis carbon content of 38-42 wt%, and a preferred particle size D90 ≤ 30 mesh; the second component is fly ash and / or engineering slag, wherein the total content of Al2O3 and SiO2 in the second component is ≥ 60 wt%, and The content of Al2O3 is ≤25wt%; preferably, in the second component, the total content of Al2O3+SiO2 is ≥65wt%, and the content of Al2O3 is ≤23wt%; the content of Fe2O3 is ≤8wt%; the content of CaO is ≤12wt%; the particle size D90 of the second component is ≤200um; preferably, the particle size D90 is ≤150um; the third component is bentonite and / or kaolin; the particle size D90 of the third component is ≤75um; the fourth component is a plasticizer; the plasticizer is selected from one or more of cellulose ether, starch ether, and guar gum.

[0040] The polishing speed is 600-1000 rpm / min, and the polishing time is 15-30 min; the calcination temperature is 800-900℃, and the calcination time is 30-60 min.

[0041] Before calcination, the raw material pellets are dried; preferably, the drying temperature is 60-80℃ and the drying time is, for example, 3-5 hours.

[0042] The prepared ceramsite products were tested according to the method specified in GB / T17431.

[0043] Example 1

[0044] Prepare expanded clay aggregate according to the following steps:

[0045] (1) Place 43.1 parts by weight of gasification slag, 55.9 parts by weight of fly ash, 1 part by weight of kaolin and 0.2 parts by weight of cellulose ether into a mixing device; stir at low speed (125±10 rpm) for 30s and at high speed (62±5 rpm) for 90s to mix evenly and obtain a mixture.

[0046] The gasification slag has a moisture content of 62 wt%, a dry basis carbon content of 39 wt%, and a particle size D90 of 15-20 mesh.

[0047] In fly ash, the total content of Al2O3+SiO2 is 77.77wt%, Al2O3 is 22.19wt%, Fe2O3 is 7.49wt%, and CaO is 6.11wt%; the particle size D90 of fly ash is 120-150um;

[0048] The particle size D90 of kaolin is 50-60 μm;

[0049] (2) Extrude the mixture and granulate it to obtain granules;

[0050] (3) Polish the particles at a speed of 800 rpm / min for 15 min to obtain raw material balls;

[0051] (4) Dry the raw material balls at 60°C for 4 hours; place the dried raw material balls in a muffle furnace / rotary furnace and calcine them at 850°C for 60 minutes, and then cool them to make ceramsite.

[0052] The performance of the ceramsite samples was tested according to the method specified in GB / T17431-2010, and the results showed that the bulk density of the ceramsite was 664 kg / m³. 3 Water absorption rate 17.89%, compressive strength 5.8MPa.

[0053] Example 2

[0054] Example 2 describes the preparation of ceramsite in accordance with Example 1, except that the weight parts of the raw materials for preparing ceramsite are different. Specifically, the raw materials are: 40.3 parts by weight of gasification slag, 58.7 parts by weight of fly ash, 1 part by weight of kaolin, and 0.8 parts by weight of cellulose ether.

[0055] The performance of the ceramsite samples was tested according to the method specified in GB / T17431-2010, and the results showed that the bulk density of the ceramsite was 747 kg / m³. 3 Water absorption rate 14.68%, compressive strength 7.3 MPa.

[0056] Example 3

[0057] Example 3 refers to Example 1 for the preparation of ceramsite, with the following differences: 1) The weight parts of the raw materials for preparing ceramsite are different, including 58 parts by weight of gasification slag, 41 parts by weight of fly ash, 1 part by weight of kaolin, and 0.3 parts by weight of cellulose ether; 2) The gasification slag used is different, with a water content of 50 wt% and a dry basis carbon content of 40 wt%; 3) In the preparation step (4), calcination is carried out at 800℃ for 60 min.

[0058] The performance of the expanded clay samples was tested according to the method specified in GB / T17431-2010, and the performance of the expanded clay was found to be: bulk density 702 kg / m³. 3 Water absorption rate 15.52%, compressive strength 6.2 MPa.

[0059] Example 4

[0060] Example 4 describes the preparation of ceramsite in accordance with Example 1, with the following differences: 1) The weight parts of the raw materials for preparing ceramsite are different, including 35 parts by weight of gasification slag, 55 parts by weight of fly ash, 10 parts by weight of kaolin, and 0.1 parts by weight of cellulose ether; 2) The gasification slag used is different, with a water content of 69 wt% and a dry basis carbon content of 35 wt%; 3) In preparation step (4), calcination is carried out at 900°C for 30 min.

[0061] The performance of the expanded clay samples was tested according to the method specified in GB / T17431-2010, and the results showed that the bulk density of the expanded clay was 839 kg / m³. 3 Water absorption rate 11.05%, compressive strength 9.8 MPa.

[0062] Example 5

[0063] Example 5 refers to Example 1 for the preparation of ceramsite, the difference being: 1) the weight parts of the raw materials for preparing ceramsite are different, of which gasification slag is 35 parts by weight, fly ash is 45 parts by weight, kaolin is 20 parts by weight, and cellulose ether is 0.5 parts by weight; 2) in preparation step (4), calcination is carried out at 900℃ for 30 min.

[0064] The performance of the ceramsite samples was tested according to the method specified in GB / T17431-2010, and the results showed that the bulk density of the ceramsite was 781 kg / m³. 3 Water absorption rate 12.77%, compressive strength 8.1 MPa.

[0065] Example 6

[0066] Example 6 describes the preparation of ceramsite in accordance with Example 1, using the same kaolin and cellulose ether as in Example 1.

[0067] The differences are as follows: 1) The raw materials for preparing ceramsite are: 32 parts by weight of gasification slag, 66.2 parts by weight of engineering slag, 1 part by weight of kaolin, and 0.8 parts by weight of cellulose ether; 2) The gasification slag used is different. The water content of the gasification slag is 67wt%, and the dry basis carbon content is 39wt%; 3) In the engineering slag, the total content of Al2O3+SiO2 is 68.37wt%, Al2O3 is 12.32wt%, Fe2O3 is 5.55wt%, and CaO is 10.94wt%; the particle size D90 of the engineering slag is 140-180um; 4) In the preparation step (4), calcination is carried out at 800℃ for 30min.

[0068] The performance of the ceramsite samples was tested according to the method specified in GB / T17431-2010, and the performance of the ceramsite was as follows: bulk density 748 kg / m³. 3 Water absorption rate 17.28%, compressive strength 7.6 MPa.

[0069] Comparative Example 1

[0070] The differences between Comparative Example 1 and Example 1 are as follows: 1) The raw materials for preparing ceramsite are 20 parts by weight of dry gasification slag, 79 parts by weight of fly ash, 1 part by weight of kaolin, 0.3 parts by weight of cellulose ether, and 33 parts by weight of water; 2) The gasification slag used is different. Here, dry gasification slag is selected due to process reasons, and the carbon content of the dry gasification slag is 39 wt%; 3) Comparative Example 1 adopts a process that is significantly different from that of Examples 1-5: Comparative Example 1 adopts a dry forming method, and the gasification slag is in a dry state with a moisture content of 0%. After the gasification slag and other raw material dry powders are mixed evenly, the mixed powder is continuously added to the dry granulator, and additional water is sprayed in while rotating; and the calcination steps are different. The dried raw material pellets are placed in a muffle furnace / rotary furnace and calcined at 960°C for 30 minutes, and then cooled to produce ceramsite.

[0071] The performance of the ceramsite samples was tested according to the method specified in GB / T17431-2010, and the performance of the ceramsite was as follows: bulk density 1084 kg / m³. 3 The water absorption rate is 18.42%, and the compressive strength of the cylinder is 12.56 MPa. Example 1 uses an additional water addition method, which increases the process and the risk of water pollution; moreover, it is difficult to control the bulk density of the ceramsite by adding additional water, which may lead to excessive bulk density and make it impossible to obtain lightweight materials.

[0072] Comparative Example 2

[0073] The difference between Comparative Example 2 and Example 1 is as follows: 1) The raw materials for preparing ceramsite are 30 parts by weight of gasification slag, 69 parts by weight of fly ash, 1 part by weight of kaolin and 0.2 parts by weight of cellulose ether; 2) The gasification slag used is different, with a water content of 75 wt% and a dry basis carbon content of 35 wt%; 3) In the preparation step (4), calcination is carried out at 900°C for 30 min.

[0074] The performance of the ceramsite samples was tested according to the method specified in GB / T17431-2010, and the results showed that the bulk density of the ceramsite was 972 kg / m³. 3 The water absorption rate was 16.68%, and the cylinder compressive strength was 11.2 MPa. The gasification slag in Comparative Example 2 had a higher moisture content than that in Examples 1-5, resulting in a higher bulk density of ceramsite that was difficult to meet the requirements for lightweight materials.

[0075] Comparative Example 3

[0076] The difference between Comparative Example 3 and Example 1 is as follows: 1) The raw materials for preparing ceramsite are 65 parts by weight of gasification slag, 35 parts by weight of fly ash, 1 part by weight of kaolin and 0.5 parts by weight of cellulose ether; 2) In preparation step (4), calcination is carried out at 900°C for 60 minutes, and ceramsite is prepared after cooling.

[0077] The performance of the expanded clay samples was tested according to the method specified in GB / T17431-2010, and the performance of the expanded clay was found to be: bulk density 624 kg / m³. 3 The water absorption rate was 29.81%, and the compressive strength was 4.1 MPa. Comparative Example 3 used a larger amount of gasification slag and a smaller amount of fly ash, resulting in ceramsite material with excessive porosity, excessively high water absorption, and insufficient strength.

[0078] Comparative Example 4

[0079] The difference between Comparative Example 4 and Example 1 is as follows: 1) The raw materials for preparing ceramsite are 43.1 parts by weight of gasification slag, 55.9 parts by weight of fly ash, 1 part by weight of kaolin and 0.8 parts by weight of cellulose ether; 2) The gasification slag used is different, with a water content of 45 wt% and a dry basis carbon content of 40 wt%; 3) In the preparation step (4), calcination is carried out at 900°C for 30 min, and ceramsite is prepared after cooling.

[0080] The performance of the expanded clay samples was tested according to the method specified in GB / T17431-2010, and the performance of the expanded clay was obtained as follows: bulk density 596 kg / m³. 3 The water absorption rate was 32.60%, and the cylinder compressive strength was 3.5 MPa. Comparative Example 4, due to the low water content of the gasification slag, although raw material pellets could be extruded, resulted in ceramsite with excessively low bulk density, a loose system, excessively high water absorption, and low cylinder compressive strength.

[0081] Comparative Example 5

[0082] The difference between Comparative Example 5 and Example 1 is as follows: 1) The raw materials for preparing ceramsite are 35 parts by weight of gasification slag, 45 parts by weight of fly ash, 20 parts by weight of kaolin, and 0.5 parts by weight of cellulose ether; 2) The gasification slag used is different, with a water content of 67 wt% and a dry basis carbon content of 39 wt%; 3) The fly ash used is different, with a total Al2O3+SiO2 content of 86.44 wt%, an Al2O3 content of 32.75 wt%, an Fe2O3 content of 4.92 wt%, and a CaO content of 3.17 wt%; 4) In the preparation step (4), a higher calcination temperature was used, with calcination carried out at 1150℃ for 30 min, and ceramsite was prepared after cooling.

[0083] The performance of the expanded clay samples was tested according to the method specified in GB / T17431-2010, and the performance of the expanded clay was found to be: bulk density 1067 kg / m³.3 The water absorption rate is 16.91%, and the compressive strength of the cylinder is 10.85 MPa. Compared with Examples 1-6, Comparative Example 5 has a higher Al2O3 content and a correspondingly higher calcination temperature, resulting in increased energy consumption. If the calcination temperature is not increased accordingly, the resulting ceramsite will have a high water absorption rate and be easily broken. Furthermore, a higher Al2O3 content will lead to a corresponding increase in the bulk density of the ceramsite, thus failing to achieve the effect of a lightweight material.

[0084] The properties of the ceramsite prepared in Examples 1-6 and Comparative Examples 1-5 are shown in Table 1:

[0085] Table 1

[0086]

[0087]

[0088]

[0089] Obviously, the above embodiments are merely illustrative examples for clear explanation and are not intended to limit the implementation. Those skilled in the art will recognize that other variations or modifications can be made based on the above description. It is neither necessary nor possible to exhaustively list all possible implementations here. However, obvious variations or modifications derived therefrom are still within the scope of protection of this invention.

Claims

1. A method for preparing ceramsite from gasification slag, characterized in that, The raw materials for preparing ceramsite include the following components by weight: 31-60 parts of component one, 39-68 parts of component two, 1-20 parts of component three, and 0.1-1 parts of component four. The first component is gasification slag with a water content of 50-70 wt% and a dry basis carbon content of 35-45 wt%. The second component is fly ash and / or construction waste, wherein the total content of Al2O3 and SiO2 in the second component is ≥60wt%, and the content of Al2O3 is ≤25wt%. The third component is bentonite and / or kaolinite; The fourth component is a plasticizer; The method includes the following steps: The first component, the second component, the third component, and the fourth component are mixed and stirred evenly to obtain a mixture; The mixture is extruded and granulated to obtain granules; The particles are polished to obtain raw material balls; The raw material pellets are calcined at a temperature of 800-900℃, and then cooled to obtain the ceramsite.

2. The method for preparing ceramsite from gasification slag according to claim 1, characterized in that, The gasification slag has a moisture content of 55%-65% and a dry basis carbon content of 38%-42%.

3. The method for preparing ceramsite from gasification slag according to claim 1, characterized in that, The particle size of the gasification slag is D90≤30 mesh.

4. The method for preparing ceramsite from gasification slag according to any one of claims 1-3, characterized in that, In the second component, the total content of Al2O3 and SiO2 is ≥65wt%, and the content of Al2O3 is ≤23wt%.

5. The method for preparing ceramsite from gasification slag according to any one of claims 1-3, characterized in that, In the second component, the content of Fe2O3 is ≤8wt%; the content of CaO is ≤12wt%.

6. The method for preparing ceramsite from gasification slag according to any one of claims 1-3, characterized in that, The particle size of the second component is D90≤200um; the particle size of the third component is D90≤75um.

7. The method according to claim 6, characterized in that, The particle size D90 of the second component is ≤150 μm.

8. The method for preparing ceramsite from gasification slag according to any one of claims 1-3, characterized in that, The plasticizer is selected from one or more of cellulose ether, starch ether, and guar gum.

9. The method for preparing ceramsite from gasification slag according to any one of claims 1-3, characterized in that, The polishing speed is 600-1000 rpm / min, the polishing time is 15-30 min, and the calcination time is 30-60 min.

10. The method for preparing ceramsite from gasification slag according to any one of claims 1-3, characterized in that, The raw material pellets are dried before being calcined.

11. The method according to claim 10, characterized in that, The drying temperature is 60-80℃.

12. The method according to claim 11, characterized in that, The drying time is 3-5 hours.

13. Ceramsite prepared by the method for preparing ceramsite from gasification slag according to any one of claims 1-12.

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