Method for preparing lightweight high-strength ceramsite based on lithium slag and secondary aluminum ash ingredients

Abstract

The invention discloses a method for preparing light high-strength ceramsite based on lithium slag and secondary aluminum ash. The used raw materials comprise 30.0 to 60.0 percent of lithium slag, 30.0 to 70.0 percent of secondary aluminum ash and 0 to 30.0 percent of high-silicon raw material. Weighing the raw materials according to the proportion of the lithium slag, the secondary aluminum ash and the high-silicon raw material, and stirring to obtain a mixture; loading the mixture and a medium into ore grinding equipment, and grinding for a certain time to obtain a raw material; adding a proper amount of water into the raw material to prepare spherical particles, and drying at low temperature; and placing the prepared spherical particles in calcining equipment such as a high-temperature furnace or a rotary kiln, heating to a certain temperature at a certain rate, and carrying out foaming molding, so as to obtain the lightweight high-strength ceramsite. The chemical composition characteristics of the lithium slag and the secondary aluminum ash are fully utilized, pores are generated through decomposition reaction in the high-temperature calcination process, no extra pore forming agent needs to be added, the production process is simplified, and the production cost is reduced.

Description

Technical Field

[0001] The present invention belongs to the technical field of comprehensive utilization of solid waste. More specifically, the present invention relates to a method for preparing lightweight and high-strength ceramsite by using lithium slag and secondary aluminum ash as raw materials. Background Art

[0002] With the rapid development of industrialization and the intensification of resource consumption, the amount of solid waste generated increases year by year. How to realize the harmless treatment and resource utilization of solid waste has become an important issue in the current environmental protection field. Among many industrial solid wastes, lithium slag and secondary aluminum ash are two representative wastes, and their efficient utilization is of great significance for environmental protection and resource conservation.

[0003] Lithium slag is a by-product generated during the production of lithium salts using lithium mica or spodumene as raw materials. Its main components are silicate, aluminate, calcium sulfate, and a small amount of elements such as lithium, sodium, and potassium. Secondary aluminum ash is a solid waste generated during the aluminum smelting process. Its main components include metallic aluminum, aluminum oxide, aluminum nitride (AlN), aluminum carbide (Al4C3), and a small amount of salts (such as NaCl, KCl) and heavy metal impurities. The active components (such as AlN, Al4C3) in secondary aluminum ash are prone to hydrolysis reactions in a humid environment, releasing harmful gases such as ammonia (NH3) and methane (CH4), causing environmental pollution. In addition, the residual fluoride and heavy metal elements in secondary aluminum ash may also pose potential hazards to the ecological environment. At present, the treatment methods of secondary aluminum ash mainly include wet treatment and high-temperature calcination, but these methods generally have problems such as complex processes, high costs, or low resource utilization rates.

[0004] High-strength ceramsite is a lightweight and porous material with excellent properties such as high strength, low density, heat insulation, and sound insulation, and is widely used in fields such as construction, horticulture, and sewage treatment. The production of traditional ceramsite mainly relies on natural mineral raw materials (such as bauxite, etc.), which not only consumes a large amount of natural resources but also faces the problem of rising raw material costs. In recent years, the research on preparing ceramsite using industrial solid waste has gradually increased, which can not only reduce the production cost of ceramsite but also realize the resource utilization of solid waste. However, in the prior art, there are few studies on preparing ceramsite using lithium slag and secondary aluminum ash, and there are problems such as complex processes and unstable product performance. Summary of the Invention

[0005] An object of the present invention is to solve at least the above problems and / or defects and provide at least the advantages described hereinafter.

[0006] To achieve these objects and other advantages according to the present invention, a method for preparing lightweight and high-strength ceramsite by using lithium slag and secondary aluminum ash as raw materials is provided. The raw materials used include: 30.0 - 60.0% of lithium slag, 30.0 - 70.0% of secondary aluminum ash, and 0 - 30.0% of high-silicon raw materials. The sum of the weight percentages of each component in the raw materials is 100.0%.

[0007] Preferably, the chemical composition of the lithium slag includes: 50.0 - 60.0% SiO2, 20.0 - 30.0% Al2O3, 8.0 - 12.0% CaO, 8.0 - 12.0% SO3, 0 - 5.0% Fe2O3, 0 - 5.0% P2O5, 0 - 0.5% MnO, 0 - 0.5% Na2O.

[0008] Preferably, the chemical composition of the secondary aluminum ash includes: 10.0 - 20.0% SiO2, 50.0 - 60.0% Al2O3, 10.0 - 12.0% CaO, 1.0 - 3.0% SO3, 1.0 - 3.0% Fe2O3, 0 - 0.5% MnO, 0.5 - 1.0% MgO, 2.0 - 2.5% Na2O.

[0009] Preferably, the content of SiO2 in the high-silicon raw material is greater than 90%.

[0010] Preferably, the phase composition of the secondary aluminum ash mainly includes aluminum, aluminum oxide, aluminum nitride, aluminum carbide, and salts, and the salts include NaCl and KCl.

[0011] Preferably, the phase composition of the lithium slag includes leached spodumene, feldspar, and gypsum dihydrate.

[0012] Preferably, the high-silicon raw material includes high-grade quartz or silica fume.

[0013] Preferably, it is characterized by including the following steps:

[0014] Step 1: Weigh the raw materials according to the ratio of lithium slag, secondary aluminum ash, and high-silicon raw materials, and obtain a mixture through stirring;

[0015] Step 2: Load the mixture and corundum balls into a grinding device at a material-ball ratio of 1:3 and grind for a certain time to obtain raw meal;

[0016] Step 3: Add appropriate water to the raw meal, make it into spherical particles, and dry them at a low temperature;

[0017] Step 4: Place the spherical particles prepared in Step 3 in a calcination device such as a high-temperature furnace or a rotary kiln, and foam and form at a certain rate to a certain temperature to obtain lightweight and high-strength ceramsite;

[0018] Step 5: Collect the waste gas generated during granulation and calcination and treat it using an activated carbon adsorption device and an exhaust gas tower.

[0019] Preferably, in Step 2, the grinding time is 1 - 5 h;

[0020] In Step 3, the amount of water used is 20 - 40% of the mass of the raw meal. The particle size of the spherical particles does not exceed 25 mm. The specific method of drying at a low temperature is as follows: dry at 80 - 90 °C for 0.2 - 1 h, and then dry at 100 - 110 °C;

[0021] In Step 4, the heating rate is 5 °C / min, the heating temperature is 1100 - 1300 °C, the holding time is 0.5 - 2 h, and after holding, it is cooled to room temperature at a cooling rate of 5 °C / min.

[0022] Preferably, the physical and chemical properties of the prepared lightweight and high-strength ceramsite are tested according to GB / T17431 - 1998. Its bulk density is 400 - 900 kg / m 3 , the water absorption rate is between 0 - 8%, and the cylinder compressive strength is 5.00 - 30.00 MPa.

[0023] In order to further improve the bulk density and cylinder compressive strength of the lightweight and high-strength ceramsite and reduce the water absorption rate of the lightweight and high-strength ceramsite, 2 - 10% of the modified polyacrylic acid fiber powder by the mass of the raw materials is added in Step 1. The preparation method of the modified polyacrylic acid powder includes:

[0024] S1: Put alumina fibers and polyacrylic acid fibers with a breaking strength of 40 - 100 cN / dtex into a ball mill. The mass ratio of alumina fibers to polyacrylic acid fibers is 1 - 2:5 - 10; use zirconia as the grinding balls, and the mass of the grinding balls is 2 - 5 times the total mass of alumina fibers and polyacrylic acid fibers; add 2 - 10% of polyethylene glycol - 400 by the mass of polyacrylic acid fibers as the ball milling lubricant, rotate at 500 - 800 rpm, and ball mill for 6 - 12 h; after ball milling, perform solid-liquid separation, wash the solid material with deionized water and then dry to obtain the composite fiber powder;

[0025] S2. Disperse the composite fiber powder in deionized water to obtain a mixed suspension. The dosage ratio of the composite fiber powder to deionized water is 1 - 20 g: 200 - 500 mL; add γ-aminopropyltriethoxysilane accounting for 1 - 5 wt% of the composite fiber powder; stir at a speed of 200 - 600 rpm for 20 - 40 min, raise the temperature to 60 - 80 °C, and let it stand for 12 - 24 h; after standing, filter, wash and dry, then put it into a twin-screw extruder for melt blending. The temperature of the feeding section is 160 - 180 °C, the temperature of the melting section is 200 - 240 °C, the temperature of the discharging section is 170 - 190 °C, the screw speed is 150 - 300 rpm, and after cooling, it is pulverized to obtain modified polyacrylic fiber powder.

[0026] The present invention has at least the following beneficial effects:

[0027] The present invention provides a method for preparing lightweight and high-strength ceramsite by mixing lithium slag and secondary aluminum ash for batching. This method makes full use of the chemical composition characteristics of lithium slag and secondary aluminum ash, generates pores through decomposition reactions during high-temperature calcination, without the need to add additional pore-forming agents, simplifies the production process and reduces the production cost. Specifically, the silicate and aluminate components in lithium slag form a molten phase at high temperature, which helps to improve the strength and stability of the ceramsite; the calcium sulfate dihydrate in lithium slag and components such as AlN and Al4C3 in secondary aluminum ash decompose and release gases at high temperature, forming a uniformly distributed pore structure, further optimizing the lightweight and heat insulation performance of the ceramsite. Moreover, secondary aluminum ash replaces traditional bauxite as the aluminum source for high-strength ceramsite, further reducing the production cost. The calcination and tail gas treatment system can use high-temperature harmless treatment equipment for secondary aluminum ash, without the need to add new equipment.

[0028] The present invention adds modified polyacrylic fiber powder to lithium slag, secondary aluminum ash, and high-silica raw materials, further improving the bulk density and cylinder compressive density of the lightweight and high-strength ceramsite, and reducing the water absorption of the lightweight and high-strength ceramsite. Among them, the modified polyacrylic fiber powder is obtained by ball milling and mixing with alumina fiber, then modifying with γ-aminopropyltriethoxysilane, and finally modifying by melt blending, so that the prepared modified polyacrylic fiber powder takes into account both high strength and low water absorption. After modification with γ-aminopropyltriethoxysilane, the binding ability between the polyacrylic fiber powder, alumina fiber and lithium slag, secondary aluminum ash, and high-silica raw materials is enhanced. The polyacrylic fiber powder and alumina fiber form a three-dimensional network structure inside the lightweight and high-strength ceramsite. At the same time, the modified polyacrylic fiber can prevent crack propagation and enhance the binding force between particles, thereby improving the cylinder compressive strength of the ceramsite and weakening the water absorption ability of the ceramsite particles; at the same time, after the polyacrylic fiber powder and alumina fiber are mixed and modified and then mixed with lithium slag, secondary aluminum ash, and high-silica raw materials, through ball milling and calcination, the internal pore structure of the ceramsite is optimized, making the ceramsite denser, thereby increasing the bulk density of the ceramsite.

[0029] Other advantages, objectives, and features of the present invention will be partially reflected by the following description and partially understood by those skilled in the art through the research and practice of the present invention. Detailed implementation manners

[0030] The following provides a further detailed description of the present invention so that those skilled in the art can implement it with reference to the text of the specification.

[0031] The chemical composition of the secondary aluminum ash used in each example and comparative example includes: 20.0% SiO2, 60.0% Al2O3, 10.0% CaO, 3.0% SO3, 3.0% Fe2O3, 0.5% MnO, 1.0% MgO, 2.5% Na2O.

[0032] The chemical composition of the lithium slag includes: 60.0% SiO2, 20.0% Al2O3, 8.0% CaO, 8.0% SO3, 2.5% Fe2O3, 0.5% P2O5, 0.5% MnO, 0.5% Na2O.

[0033] Example 1

[0034] This example provides a method for preparing lightweight and high-strength ceramsite based on the batching of lithium slag and secondary aluminum ash, including the following steps:

[0035] Step 1: Stir and mix 50 g of secondary aluminum ash, 20 g of lithium slag, and 30 g of quartz to obtain a mixed material;

[0036] Step 2: Load the mixed material and corundum balls into a grinding device at a material-ball ratio of 1:3 and grind for 2 hours to obtain raw materials;

[0037] Step 3: Add 30% water to the raw materials to make granular raw materials with a particle size not exceeding 25 mm, bake at 85 °C for 0.5 h, and then dry at 105 °C;

[0038] Step 4: Place the granular raw materials obtained in Step 3 in a high-temperature furnace and calcine to obtain the final product. The heating rate is 5 °C / min, hold at 1220 °C for 1 h, and then cool to room temperature, with a cooling rate of 5 °C / min.

[0039] Step 5: Collect the waste gas generated during the granulation and calcination processes and treat it with an environmental protection device.

[0040] Result: The physical and chemical properties of the ceramsite were tested according to GB / T17431-1998, and its bulk density was 802 kg / m 3 , the water absorption rate was 1.88%, and the cylinder compressive strength was 23.40 MPa.

[0041] Example 2

[0042] This embodiment provides a method for preparing lightweight and high-strength ceramsite based on the batching of lithium slag and secondary aluminum ash, comprising the following steps:

[0043] Step 1: Mix 40 g of secondary aluminum ash, 30 g of lithium slag and 30 g of quartz evenly to obtain a mixed material;

[0044] Step 2: Load the mixed material and corundum balls into a grinding equipment at a material-ball ratio of 1:3 and grind for 2 hours to obtain raw material;

[0045] Step 3: Add 30% water to the raw material to make granular raw material with a particle size not exceeding 25 mm, dry it at 85 °C for 0.5 h and then dry it at 105 °C;

[0046] Step 4: Place the granular raw material obtained in Step 3 in a high-temperature furnace and calcine to obtain the final product. The heating rate is 5 °C / min, hold at 1220 °C for 1 h and then cool to room temperature, and the cooling rate is 5 °C / min.

[0047] Step 5: Collect the waste gas generated during the granulation and calcination processes and treat it with an environmental protection device.

[0048] Result: The physical and chemical properties of the ceramsite are tested according to GB / T17431-1998, its bulk density is 790 kg / m 3 , the water absorption rate is 1.20%, and the cylinder compressive strength is 12.29 MPa.

[0049] Example 3

[0050] This embodiment provides a method for preparing lightweight and high-strength ceramsite based on the batching of lithium slag and secondary aluminum ash, comprising the following steps:

[0051] Step 1: Mix 40 g of secondary aluminum ash, 40 g of lithium slag and 20 g of quartz evenly to obtain a mixed material;

[0052] Step 2: Load the mixed material and corundum balls into a grinding equipment at a material-ball ratio of 1:3 and grind for 2 hours to obtain raw material;

[0053] Step 3: Add 30% water to the raw material to make granular raw material with a particle size not exceeding 25 mm, dry it at 85 °C for 0.5 h and then dry it at 105 °C;

[0054] Step 4: Place the granular raw material obtained in Step 3 in a high-temperature furnace and calcine to obtain the final product. The heating rate is 5 °C / min, hold at 1220 °C for 1 h and then cool to room temperature, and the cooling rate is 5 °C / min.

[0055] Step 5: Collect the waste gas generated during the granulation and calcination processes and treat it with an environmental protection device.

[0056] Result: The physical and chemical properties of the ceramsite were tested according to GB / T 17431-1998. Its bulk density was 775 kg / m 3 , water absorption was 0.78%, and cylinder compressive strength was 13.00 MPa.

[0057] Example 4

[0058] This example provides a method for preparing lightweight and high-strength ceramsite based on the proportioning of lithium slag and secondary aluminum ash, including the following steps:

[0059] Step 1: Mix 50 g of secondary aluminum ash, 20 g of lithium slag, and 30 g of quartz evenly to obtain a mixture;

[0060] Step 2: Load the mixture and corundum balls into a grinding equipment at a material-ball ratio of 1:3 and grind for 2 hours to obtain raw material;

[0061] Step 3: Add 30% water to the raw material to make granular raw material with a particle size not exceeding 25 mm, dry it at 85 °C for 0.5 h, and then dry it at 105 °C;

[0062] Step 4: Place the granular raw material obtained in Step 3 in a high-temperature furnace and calcine to obtain the final product. The heating rate is 5 °C / min, keep it at 1200 °C for 1 h and then cool it to room temperature, and the cooling rate is 5 °C / min.

[0063] Step 5: Collect the waste gas generated during the granulation and calcination processes and treat it with environmental protection equipment.

[0064] Result: The physical and chemical properties of the ceramsite were tested according to GB / T 17431-1998. Its bulk density was 867 kg / m 3 , water absorption was 3.49%, and cylinder compressive strength was 7.27 MPa.

[0065] The firing system of this example is to heat up to 1200 °C at a rate of 5 °C / min and keep it for 1 h. The bulk density of this example is 867 kg / m 3 , water absorption is 3.49%, and cylinder compressive strength is 7.27 MPa.

[0066] Example 5

[0067] This example provides a method for preparing lightweight and high-strength ceramsite based on the proportioning of lithium slag and secondary aluminum ash, including the following steps:

[0068] Step 1: Mix 40 g of secondary aluminum ash, 30 g of lithium slag, and 30 g of silica fume evenly to obtain a mixture;

[0069] Step 2: Load the mixture and the medium into a grinding equipment and grind for 2 hours to obtain raw material;

[0070] Step 3: Add 30% water to the raw materials to make granular raw materials with a particle size not exceeding 25 mm, dry them at 85 °C for 0.5 h, and then dry them at 105 °C.

[0071] Step 4: Place the granular raw materials obtained in Step 3 into a high-temperature furnace and calcine to obtain the final product. The heating rate is 5 °C / min. After holding at 1200 °C for 1 h, cool it to room temperature, and the cooling rate is 5 °C / min.

[0072] Step 5: Collect the waste gas generated during granulation and calcination and treat it with an environmental protection device.

[0073] Result: The physical and chemical properties of the ceramsite were tested according to GB / T17431-1998. Its bulk density was 899 kg / m 3 , the water absorption rate was 1.69%, and the cylinder compressive strength was 7.17 MPa.

[0074] Example 6

[0075] This example provides a method for preparing lightweight and high-strength ceramsite based on lithium slag and secondary aluminum ash batching. Different from Example 1, 8 g of modified polyacrylic acid fiber powder is added in Step 1. The preparation method of the modified polyacrylic acid powder includes:

[0076] S1: Put 2 kg of alumina fiber with a breaking strength of 80 cN / dtex and 8 kg of polyacrylic acid fiber into a ball mill; use 25 kg of zirconia as grinding balls; add 0.4 kg of polyethylene glycol-400 as a ball mill lubricant, rotate at 500 rpm, and ball mill for 6 h; after the ball milling is completed, perform solid-liquid separation, wash the solid material with deionized water, and then dry it to obtain composite fiber powder;

[0077] S2: Disperse 200 g of composite fiber powder in 2000 mL of deionized water to obtain a mixed suspension; add 8 g of γ-aminopropyltriethoxysilane; stir at 300 rpm for 40 min, heat to 70 °C, and let it stand for 12 h; filter, wash and dry, and put it into a twin-screw extruder for melt blending. The temperature of the feeding section is 160 °C, the temperature of the melting section is 210 °C, the temperature of the discharging section is 180 °C, the screw rotation speed is 200 rpm, and after cooling, it is pulverized to obtain modified polyacrylic acid fiber powder.

[0078] The methods and process parameters of the remaining steps in this example are the same as those in Example 1.

[0079] Example 7

[0080] This example provides a method for preparing lightweight and high-strength ceramsite based on lithium slag and secondary aluminum ash batching. Different from Example 1, 10 g of modified polyacrylic acid fiber powder is added in Step 1. The preparation method of the modified polyacrylic acid powder includes:

[0081] S1. Put 1 kg of alumina fiber with a breaking strength of 60 cN / dtex and 9 kg of polyacrylic acid fiber into a ball mill; use 25 kg of zirconia as grinding balls; add 0.4 kg of polyethylene glycol - 400 as a ball - milling lubricant, rotate at 500 rpm, and ball - mill for 6 h; after the ball - milling is completed, perform solid - liquid separation, wash the solid material with deionized water and then dry it to obtain composite fiber powder;

[0082] S2. Disperse 200 g of composite fiber powder in 2000 mL of deionized water; add 10 g of γ - aminopropyltriethoxysilane; stir at a speed of 600 rpm for 30 min, heat up to 80 °C, and let it stand for 12 h; after standing, filter, wash and dry, then put it into a twin - screw extruder for melt - blending. The temperature of the feeding section is 180 °C, the temperature of the melting section is 240 °C, the temperature of the discharging section is 190 °C, the screw speed is 200 rpm, and after cooling, it is crushed to obtain modified polyacrylic acid fiber powder.

[0083] The methods and process parameters of the remaining steps in this comparative example are the same as those in Example 1.

[0084] Comparative Example 1

[0085] This comparative example provides a method for preparing lightweight and high - strength ceramsite based on the batching of lithium slag and secondary aluminum ash. Different from Example 1, in step one, 8 g of modified polyacrylic acid fiber powder is added. The preparation method of the modified polyacrylic acid powder includes:

[0086] S1. Put 2 kg of alumina fiber with a breaking strength of 80 cN / dtex and 8 kg of polyacrylic acid fiber into a ball mill; use 25 kg of zirconia as grinding balls; add 0.4 kg of polyethylene glycol - 400 as a ball - milling lubricant, rotate at 500 rpm, and ball - mill for 6 h; after the ball - milling is completed, perform solid - liquid separation, wash the solid material with deionized water and then dry it to obtain composite fiber powder;

[0087] S2. Put the composite fiber powder into a twin - screw extruder for melt - blending. The temperature of the feeding section is 160 °C, the temperature of the melting section is 210 °C, the temperature of the discharging section is 180 °C, the screw speed is 200 rpm, and after cooling, it is crushed to obtain modified polyacrylic acid fiber powder.

[0088] The methods and process parameters of the remaining steps in this comparative example are the same as those in Example 1.

[0089] Comparative Example 2

[0090] This comparative example provides a method for preparing lightweight and high-strength ceramsite based on a mixture of lithium slag and secondary aluminum ash. Different from Example 1, in this comparative example, 6.4 g of polyacrylic acid fiber powder and 1.6 g of alumina fiber with a breaking strength of 60 cN / dtex are added in Step 1.

[0091] The methods and process parameters of the remaining steps in this comparative example are the same as those in Example 1.

[0092] Comparative Example 3

[0093] This comparative example provides a method for preparing lightweight and high-strength ceramsite based on a mixture of lithium slag and secondary aluminum ash. Different from Example 1, in this comparative example, 8 g of polyacrylic acid fiber powder is added in Step 1.

[0094] The methods and process parameters of the remaining steps in this comparative example are the same as those in Example 1.

[0095] The bulk density, cylinder compressive strength, and water absorption of the lightweight and high-strength ceramsite prepared in Examples 1 - 5 are summarized in Table 1:

[0096] Table 1 Bulk density, cylinder compressive strength, and water absorption of the lightweight and high-strength ceramsite prepared in Examples 1 - 5

[0097] <![CDATA[Bulk density (kg / m 3 )]]> Cylinder compressive strength (Mpa) Water absorption rate (%) Example 1 802 23.40 1.88 Example 2 790 12.29 1.20 Example 3 775 13.00 0.78 Example 4 867 7.27 3.49 Example 5 899 7.17 1.69 Example 6 967 36.8 0.25 Example 7 953 36.2 0.33 Comparative Example 1 785 24.4 1.91 Comparative Example 2 769 20.6 2.58 Comparative Example 3 751 19.5 2.86

[0098] As can be seen from the above table, the lightweight and high-strength ceramsite prepared in Examples 1 - 7 all have relatively large bulk density and cylinder compressive strength. Among them, the main reason for the physical property differences among Examples 1 - 3 is the difference in the content of secondary aluminum ash in the mixture. As the amount of secondary aluminum ash increases, the amounts of Al2O3 and AlN in the secondary aluminum ash increase accordingly. The increase in an appropriate amount of Al2O3 can increase the cylinder compressive strength of the lightweight and high-strength ceramsite; AlN will decompose and release gas at high temperatures, so the bulk density will increase. In this process, lithium slag can be used as a foaming agent and a flux, generating pores by decomposing substances such as calcium sulfate dihydrate at high temperatures. At the same time, substances such as calcium oxide and iron oxide in the lithium slag also have the effects of promoting sintering and optimizing the mineral phase. The main reason for the physical property differences between Examples 1 - 3 and Examples 4 and 5 is that silica fume has higher reactivity than quartz and can participate in the reaction at a lower temperature. This premature and intense reaction causes the premature formation of the embryo liquid phase, destroying the structural stability. Therefore, the cylinder compressive strength of Examples 4 and 5 is less than that of Examples 1 - 3. After adding modified polyacrylic acid powder in Examples 6 - 7, the bulk density and cylinder compressive strength of the lightweight and high-strength ceramsite are further improved, and the water absorption can be reduced to 0.25%.

[0099] The number of devices and the processing scale described herein are used to simplify the description of the present invention. Applications, modifications, and variations of the present invention will be apparent to those skilled in the art.

[0100] Although the embodiments of the present invention have been disclosed above, it is not limited to the applications listed in the specification and the embodiments. It can be fully applied to various fields suitable for the present invention. For those familiar with the art, additional modifications can be easily implemented. Therefore, without departing from the general concept defined by the claims and the equivalent scope, the present invention is not limited to specific details and the examples shown and described herein.

Claims

1. A method for preparing lightweight and high-strength ceramsite by using lithium slag and secondary aluminum ash as raw materials, which is characterized in that, The raw materials used include: 30.0 - 60.0% lithium slag, 30.0 - 70.0% secondary aluminum ash, and 0 - 30.0% high-silica raw material, and the sum of the weight percentages of each component in the raw materials is 100.0%.

2. The method for preparing lightweight and high-strength ceramsite by using lithium slag and secondary aluminum ash as raw materials according to claim 1, characterized in that The chemical composition of the lithium slag includes: 50.0 - 60.0% SiO2, 20.0 - 30.0% Al2O3, 8.0 - 12.0% CaO, 8.0 - 12.0% SO3, 0 - 5.0% Fe2O3, 0 - 5.0% P2O5, 0 - 0.5% MnO, 0 - 0.5% Na2O.

3. The method for preparing lightweight and high-strength ceramsite by using lithium slag and secondary aluminum ash as raw materials according to claim 1, characterized in that, The chemical composition of the secondary aluminum ash includes: 10.0 - 20.0% SiO2, 50.0 - 60.0% Al2O3, 10.0 - 12.0% CaO, 1.0 - 3.0% SO3, 1.0 - 3.0% Fe2O3, 0 - 0.5% MnO, 0.5 - 1.0% MgO, 2.0 - 2.5% Na2O.

4. The method for preparing lightweight and high-strength ceramsite by using lithium slag and secondary aluminum ash as raw materials according to claim 1, wherein, The content of SiO2 in the high-silica raw material is greater than 90%.

5. The method for preparing lightweight and high-strength ceramsite by mixing lithium slag and secondary aluminum ash according to any one of claims 1 to 4, characterized in that, The phase composition of the secondary aluminum ash mainly includes aluminum, aluminum oxide, aluminum nitride, aluminum carbide, and salts, and the salts include NaCl and KCl.

6. The method for preparing lightweight and high-strength ceramsite by using lithium slag and secondary aluminum ash as raw materials according to any one of claims 1 to 4, characterized in that, The phase composition of the lithium slag includes leached spodumene, feldspar, and gypsum dihydrate; The high-silica raw material includes high-grade quartz or silica fume.

7. The method for preparing lightweight and high-strength ceramsite by using lithium slag and secondary aluminum ash as raw materials according to any one of claims 1 to 4, characterized in that, It includes the following steps: Step 1: Weigh the raw materials according to the ratio of lithium slag, secondary aluminum ash, and high-silica raw material, and obtain a mixed material through stirring; Step 2: Load the mixed material and corundum balls into a grinding equipment under the condition that the material-ball ratio is 1:3 and grind for a certain time to obtain raw meal; Step 3: Add an appropriate amount of water to the raw meal to make spherical particles, and dry them at a low temperature; Step 4: Place the spherical particles prepared in Step 3 in a calcination equipment such as a high-temperature furnace or a rotary kiln, and foam and form at a certain rate to a certain temperature to obtain lightweight and high-strength ceramsite; Step 5: Collect the waste gas generated during the granulation and calcination processes and treat it with an activated carbon adsorption equipment and an exhaust gas tower.

8. The method for preparing lightweight and high-strength ceramsite by using lithium slag and secondary aluminum ash as raw materials according to claim 7, characterized in that, In Step 2, the grinding time is 1 - 5 h; In Step 3, the amount of water used is 20 - 40% of the mass of the raw meal, the particle size of the spherical particles does not exceed 25 mm, and the specific method of drying at a low temperature is: dry at 80 - 90 °C for 0.2 - 1 h, and then dry at 100 - 110 °C; In Step 4, the heating rate is 5 °C / min, the heating temperature is 1100 - 1300 °C, the holding time is 0.5 - 2 h, and after holding, it is cooled to room temperature at a cooling rate of 5 °C / min.

9. The method for preparing lightweight and high-strength ceramsite by using lithium slag and secondary aluminum ash as raw materials according to claim 7, characterized in that, Add 2 - 10% of the modified polyacrylic fiber powder by mass of the raw materials in Step 1.

10. The method for preparing lightweight and high-strength ceramsite by using lithium slag and secondary aluminum ash as raw materials according to claim 7, characterized in that, The physical and chemical properties of the prepared lightweight and high-strength ceramsite are tested in accordance with GB / T 17431-1998, and its bulk density is 400-900 kg / m 3 , the water absorption rate is 0-8%, and the cylinder compressive strength is 5.00-30.00 MPa.