Preparation method of high-strength ceramsite

Abstract

The invention relates to the field of building materials, in particular to a preparation method of high-strength ceramsite, which comprises the following steps: uniformly mixing brick powder, Bayer process red mud, ardealite and titanium gypsum to obtain mixed powder, adding a binder, uniformly mixing to prepare raw nodules, sequentially forming a transition layer and a shell layer on the surfaces of the raw nodules, drying, sintering and cooling to obtain the high-strength ceramsite. The prepared ceramsite is low in water absorption rate and excellent in mechanical strength, the core-shell structure can effectively inhibit release of chloride ions, solid waste is fully utilized, environmental pressure is relieved, waste is turned into wealth, two purposes are achieved, and the ceramsite has certain social, economic and ecological benefits.

Description

TECHNICAL FIELD

[0001] The application relates to the field of building materials, and particularly relates to a preparation method of high-strength ceramic granules. BACKGROUND

[0002] Phosphogypsum is a solid waste produced in a wet-process phosphoric acid process, and titanium gypsum is a precipitate produced by adding an alkaline substance to neutralize acidic wastewater when titanium white is produced by a sulfuric acid method. At present, the effective utilization rate of phosphogypsum and titanium gypsum is low, and most of them can only be stacked and treated, which not only occupies a large amount of land, but also pollutes the environment.

[0003] Using phosphogypsum and titanium gypsum as raw materials to prepare building ceramic granules can not only break the resource constraints, but also reduce the environmental pressure. However, the dissolution of chlorine ions in the phosphogypsum and titanium gypsum not only affects the strength and water resistance of the ceramic granules, but also seriously affects the durability and safety of the building structure due to the corrosion of the steel bars, and the strength of the prepared ceramic granules is also difficult to meet the use requirements. SUMMARY

[0004] The application aims at the above technical problems, and provides a preparation method of high-strength ceramic granules.

[0005] The technical scheme adopted is as follows:

[0006] The preparation method of the high-strength ceramic granules is as follows:

[0007] Brick powder, Bayer process red mud, phosphogypsum and titanium gypsum are uniformly mixed to obtain mixed powder, a binder is added, and the mixed powder is uniformly mixed to prepare green balls, then a transition layer and a shell layer are formed on the surface of the green balls in sequence, and after drying, sintering and cooling, the high-strength ceramic granules are obtained.

[0008] The transition layer is composed of the following components:

[0009] Vanadium-titanium iron tailings powder, fly ash, calcium oxide, potassium feldspar, sodium feldspar and borax.

[0010] The shell layer is composed of the following components:

[0011] Vanadium-titanium iron tailings powder, fly ash, aluminum fluoride and calcium fluoride.

[0012] Further, the mass ratio of the brick powder, the Bayer process red mud, the phosphogypsum and the titanium gypsum is 1-3:1-3:0.5-1:0.5-1.

[0013] Further, the mass ratio of the vanadium-titanium iron tailings powder, the fly ash, the calcium oxide, the potassium feldspar, the sodium feldspar and the borax in the transition layer is 20-40:20-40:1-5:1-5:1-5:0.1-1.

[0014] Further, the mass ratio of vanadium-titanium iron tailings powder, fly ash, aluminum fluoride and calcium fluoride in the shell layer composition is 40-60:40-60:1-3:3-6.

[0015] Further, the binder is polyvinyl alcohol aqueous solution.

[0016] Further, the solid-liquid mass ratio of the mixed powder and the binder is 1:0.1-0.2.

[0017] Further, when preparing the transition layer, wet ball milling is used to prepare slurry from vanadium-titanium iron tailings powder, fly ash, calcium oxide, potassium feldspar, sodium feldspar and borax, and then raw material balls are dipped in the slurry for coating, and then dried.

[0018] Further, when preparing the shell layer, wet ball milling is used to prepare slurry from vanadium-titanium iron tailings powder, fly ash, aluminum fluoride and calcium fluoride, and then raw material balls are dipped in the slurry for coating, and then dried.

[0019] Further, the mass percentage of V2O5 in the vanadium-titanium iron tailings powder is ≥0.5%.

[0020] Further, the sintering temperature is 1200-1250℃.

[0021] The beneficial effects of the present application are:

[0022] The present application provides a preparation method of high-strength ceramic granules, which uses brick powder as a siliceous raw material, Bayer red mud as an aluminous raw material, and phosphogypsum and titanium gypsum as calcareous raw materials to prepare building ceramic granules, which can not only break the resource constraints, but also reduce environmental pressure. However, the dissolution of chloride ions in phosphogypsum and titanium gypsum not only affects the strength and water resistance of the ceramic granules, but also seriously affects the durability and safety of the building structure due to the corrosion of the steel bars, and the strength of the prepared ceramic granules also cannot meet the use requirements.

[0023] The present application can effectively avoid the dissolution of chloride ions by the design of the core-shell structure, and the core-shell structure can also effectively improve the mechanical strength of the ceramic granules and reduce the water absorption. The vanadium-titanium iron tailings powder in the shell layer provides the basic mineral composition, ensures the mechanical strength and stability of the shell layer, the fly ash provides active SiO2 and Al2O3, forms a glass phase at high temperature, fills the surface pores, enhances the density and strength, and generates mullite whiskers under the combined action of V2O5 in the vanadium-titanium iron tailings powder and aluminum fluoride, further increases the mechanical strength of the shell layer of the ceramic granules, and the calcium fluoride acts as a fluxing agent, significantly reduces the sintering temperature of the shell layer material, promotes the generation of liquid phase, and optimizes the sintering process.

[0024] Because the raw material ball has large gas emission in the sintering process, the expansion rates of the shell part and the core part are difficult to match, which easily causes the shell layer to break, thereby reducing the strength of the ceramsite, a transition layer is designed between the shell part and the core part, a large amount of liquid phase can be generated in the sintering of the transition layer, and the shell part and the core part are reacted, the two are tightly bonded, and stress buffering is provided, the gradient design can better match the performance between the layers, reduce the internal stress, so that higher strength is obtained on the whole, the vanadium-titanium iron tailings powder and fly ash in the transition layer can participate in the reaction in the shell sintering process, the calcium oxide can not only provide an alkaline environment, stimulate the potential activity of fly ash and other materials, and serve as a fluxing component to reduce the melting temperature, but also react with the raw material ball to generate chlorine-containing compounds, improve the bonding strength while realizing the solidification of chloride ions, the potassium feldspar, sodium feldspar and borax cooperatively reduce the melting temperature of the system, accelerate the formation of glass phase, and promote the combination of the shell part and the core part.

[0025] The ceramsite prepared in the application not only has low water absorption rate, but also excellent mechanical strength, and the core-shell structure can effectively inhibit the release of chloride ions, which not only makes full use of solid waste and relieves environmental pressure, but also turns waste into treasure, achieves both purposes at once, and has certain social, economic and ecological benefits. DETAILED DESCRIPTION

[0026] Unless specific conditions are specified in the examples, the conventional conditions or the conditions recommended by the manufacturers are used. The reagents or instruments used are not specified by the manufacturers, and are all conventional products that can be purchased on the market. The technologies not mentioned in the application are referred to the prior art. Unless otherwise specified, the following examples and comparative examples are parallel tests, and the same treatment steps and parameters are used.

[0027] Brick powder: taken from a construction waste storage yard, crushed and sieved, and the chemical composition is shown in the following table:

[0028]

[0029] Bayer process red mud: taken from a red mud storage yard of an aluminum plant, and the chemical composition is shown in the following table:

[0030]

[0031] Phosphogypsum: taken from Hunan Bazhou Phosphorus Industry Chemical Technology Co., Ltd., and the chemical composition is shown in the following table:

[0032]

[0033] Titanium gypsum: taken from Hunan Xinhongda Vanadium Industry Co., Ltd., and the chemical composition is shown in the following table:

[0034]

[0035] Vanadium titanium iron tailings powder: from Hunan Xinhongda Vanadium Industry Co., Ltd., and its chemical composition is shown in the following table:

[0036]

[0037] Fly ash: Grade 1, purchased from Hebei Huisun Mining Co., Ltd.

[0038] Calcium oxide: purity ≥ 99%, purchased from Langfang Qianyao Technology Co., Ltd.

[0039] Potassium feldspar: purchased from Tianjin Hongqiao Tianbaohaitong Stone Processing Factory.

[0040] Sodium feldspar: purchased from Tianjin Hongqiao Tianbaohaitong Stone Processing Factory.

[0041] Borax: purchased from Shandong Zhuoxuan New Material Co., Ltd.

[0042] Aluminum fluoride: purchased from Langfang Qianyao Technology Co., Ltd.

[0043] Calcium fluoride: purchased from Langfang Qianyao Technology Co., Ltd.

[0044] Example 1:

[0045] A method for preparing high-strength ceramic pellets:

[0046] The raw materials were weighed and dried, and the mixed powder was obtained by thoroughly mixing the brick powder, bayer red mud, phosphogypsum and titanium gypsum in a mass ratio of 2:2:0.5:0.5. A 5% polyvinyl alcohol aqueous solution was added to the mixed powder as a binder in a solid-liquid mass ratio of 1:0.15, and the mixture was uniformly mixed in a balling machine to form green balls with a diameter of 10±1 mm. The vanadium titanium iron tailings powder, fly ash, calcium oxide, potassium feldspar, sodium feldspar and borax were uniformly mixed in a mass ratio of 30:30:3:2:2:0.2 to obtain a mixed powder, which was added to a ball mill tank with water as the ball milling medium in a solid-liquid mass ratio of 1:1 and sodium hexametaphosphate as the dispersant at a dosage of 2.5% of the mass of the mixed powder. After ball milling for 5 h, a slurry was obtained. The green balls were immersed in the slurry at room temperature for 5 min, then taken out and drained, and then dried in an oven at 100°C for 5 h to obtain green pellets. The vanadium titanium iron tailings powder, fly ash, aluminum fluoride and calcium fluoride were uniformly mixed in a mass ratio of 50:50:2:5 to obtain a mixed powder, which was added to a ball mill tank with water as the ball milling medium in a solid-liquid mass ratio of 1:1 and sodium hexametaphosphate as the dispersant at a dosage of 2.5% of the mass of the mixed powder. After ball milling for 5 h, a slurry was obtained. The green pellets were immersed in the slurry at room temperature for 5 min, then taken out and drained, and then immersed again for 5 min to allow the slurry to fully coat the surface of the green pellets. Subsequently, the green pellets were dried in an oven at 100°C for 5 h, and then sintered in a sintering furnace at a rate of 1°C / min to 1230°C for 2 h, and then naturally cooled to room temperature in the furnace.

[0047] Example 2:

[0048] A method for preparing high-strength ceramic granules

[0049] The raw materials are weighed and dried, and the mixed powder is obtained by thoroughly mixing the brick powder, bayer red mud, phosphogypsum and titanium gypsum in a mass ratio of 3:3:1:1. A 5% polyvinyl alcohol aqueous solution is added to the mixed powder as a binder in a solid-liquid mass ratio of 1:0.2, and the mixture is uniformly mixed in a balling machine to form green balls with a diameter of 10±1mm. The vanadium-titanium iron tailings powder, fly ash, calcium oxide, potassium feldspar, sodium feldspar and borax are mixed uniformly in a mass ratio of 40:40:5:5:5:1 to obtain a mixed powder. The mixed powder is added to a ball mill tank, water is used as the ball milling medium, the solid-liquid mass ratio is 1:1, sodium hexametaphosphate is used as the dispersant, and the amount of sodium hexametaphosphate is 2.5% of the mass of the mixed powder. After ball milling for 5h, a slurry is obtained. The green balls are immersed in the slurry at room temperature for 5min, then taken out and drained, and then dried in an oven at 100℃ for 5h to obtain a green body. The vanadium-titanium iron tailings powder, fly ash, aluminum fluoride and calcium fluoride are mixed uniformly in a mass ratio of 60:60:3:6 to obtain a mixed powder. The mixed powder is added to a ball mill tank, water is used as the ball milling medium, the solid-liquid mass ratio is 1:1, sodium hexametaphosphate is used as the dispersant, and the amount of sodium hexametaphosphate is 2.5% of the mass of the mixed powder. After ball milling for 5h, a slurry is obtained. The green body is immersed in the slurry at room temperature for 5min, then taken out and drained, and then immersed again for 5min to allow the slurry to fully coat the surface of the green body. Subsequently, the green body is dried in an oven at 100℃ for 5h, and then sintered in a sintering furnace at a rate of 1℃ / min to 1250℃ for 2h, and then naturally cooled to room temperature in the furnace.

[0050] Example 3:

[0051] A method for preparing high-strength ceramic granules

[0052] Each raw material is weighed and dried, and a mixed powder is obtained by mixing brick powder, bayer red mud, phosphogypsum and titanium gypsum in a mass ratio of 1:1:0.5:0.5. A polyvinyl alcohol aqueous solution with a mass concentration of 5% is added to the mixed powder as a binder in a solid-liquid mass ratio of 1:0.2, and the mixture is uniformly mixed in a ball former to form green balls with a diameter of 10±1mm. Vanadium-titanium iron tailings powder, fly ash, calcium oxide, potassium feldspar, sodium feldspar and borax are uniformly mixed in a mass ratio of 20:20:1:1:1:0.1 to obtain a mixed powder. The mixed powder is added to a ball mill tank, water is used as the ball milling medium, the solid-liquid mass ratio is 1:1, sodium hexametaphosphate is used as a dispersant, and the amount of sodium hexametaphosphate is 2.5% of the mass of the mixed powder. After ball milling for 5h, a slurry is obtained. The green balls are immersed in the slurry at room temperature for 5min, then taken out and drained, and then dried in an oven at 100℃ for 5h to obtain a green compact. Vanadium-titanium iron tailings powder, fly ash, aluminum fluoride and calcium fluoride are uniformly mixed in a mass ratio of 40:40:1:3 to obtain a mixed powder. The mixed powder is added to a ball mill tank, water is used as the ball milling medium, the solid-liquid mass ratio is 1:1, sodium hexametaphosphate is used as a dispersant, and the amount of sodium hexametaphosphate is 2.5% of the mass of the mixed powder. After ball milling for 5h, a slurry is obtained. The green compact is immersed in the slurry at room temperature for 5min, then taken out and drained, and then immersed again for 5min to allow the slurry to fully coat the surface of the green compact. Subsequently, the green compact is dried in an oven at 100℃ for 5h, and then sintered in a sintering furnace at a rate of 1℃ / min to 1200℃ for 2h, and then naturally cooled to room temperature in the furnace.

[0053] Comparative Example 1

[0054] The same as Example 1, except that there is no transition layer.

[0055] A method for preparing a high-strength ceramic pellet:

[0056] Each raw material is weighed and dried, and a mixed powder is obtained by mixing brick powder, bayer red mud, phosphogypsum and titanium gypsum in a mass ratio of 1:1:0.5:0.5. A polyvinyl alcohol aqueous solution with a mass concentration of 5% is added to the mixed powder as a binder in a solid-liquid mass ratio of 1:0.15, and the mixture is uniformly mixed in a ball former to form green balls with a diameter of 10±1mm. Vanadium-titanium iron tailings powder, fly ash, aluminum fluoride and calcium fluoride are uniformly mixed in a mass ratio of 50:50:2:5 to obtain a mixed powder. The mixed powder is added to a ball mill tank, water is used as the ball milling medium, the solid-liquid mass ratio is 1:1, sodium hexametaphosphate is used as a dispersant, and the amount of sodium hexametaphosphate is 2.5% of the mass of the mixed powder. After ball milling for 5h, a slurry is obtained. The green balls are immersed in the slurry at room temperature for 5min, then taken out and drained, and then immersed again for 5min to allow the slurry to fully coat the surface of the green balls. Subsequently, the green balls are dried in an oven at 100℃ for 5h, and then sintered in a sintering furnace at a rate of 1℃ / min to 1230℃ for 2h, and then naturally cooled to room temperature in the furnace.

[0057] Comparative Example 2:

[0058] The same as Example 1, except that the vanadium-titanium iron tailings powder is replaced by iron tailings powder.

[0059] The iron tailings powder is from a certain iron mine in Hunan Province, and its chemical composition is shown in the following table:

[0060]

[0061] A method for preparing a high-strength ceramsite:

[0062] The raw materials are weighed and dried, and the mixed powder is obtained by fully mixing the brick powder, bayer red mud, phosphogypsum and titanium gypsum in a mass ratio of 2:2:0.5:0.5. A polyvinyl alcohol aqueous solution with a mass concentration of 5% is added to the mixed powder as a binder in a solid-liquid mass ratio of 1:0.15, and the mixture is uniformly mixed in a balling machine to form green balls with a diameter of 10±1mm. The iron tailings powder, fly ash, calcium oxide, potassium feldspar, sodium feldspar and borax are mixed in a mass ratio of 30:30:3:2:2:0.2 to obtain a mixed powder, which is added to a ball mill tank with water as the ball milling medium in a solid-liquid mass ratio of 1:1 and sodium hexametaphosphate as the dispersant, and the amount of sodium hexametaphosphate is 2.5% of the mass of the mixed powder. After ball milling for 5h, a slurry is obtained. The green balls are immersed in the slurry at room temperature for 5min, then taken out and drained, and then dried in a 100℃ oven for 5h to obtain a green body. The iron tailings powder, fly ash, aluminum fluoride and calcium fluoride are mixed in a mass ratio of 50:50:2:5 to obtain a mixed powder, which is added to a ball mill tank with water as the ball milling medium in a solid-liquid mass ratio of 1:1 and sodium hexametaphosphate as the dispersant, and the amount of sodium hexametaphosphate is 2.5% of the mass of the mixed powder. After ball milling for 5h, a slurry is obtained. The green body is immersed in the slurry at room temperature for 5min, then taken out and drained, and then immersed again for 5min to allow the slurry to fully coat the surface of the green body. Subsequently, the green body is dried in a 100℃ oven for 5h, and then sintered in a sintering furnace at a rate of 1℃ / min to 1230℃ for 2h, and then naturally cooled to room temperature in the furnace.

[0063] Comparative Example 3:

[0064] The same as Example 1, except that the titanium gypsum is replaced by phosphogypsum.

[0065] A method for preparing a high-strength ceramsite:

[0066] The raw materials are weighed and dried thoroughly. A mixed powder is obtained by thoroughly mixing brick powder, Bayer red mud and phosphogypsum in a mass ratio of 2:2:1. A polyvinyl alcohol aqueous solution with a mass concentration of 5% is added to the mixed powder as a binder in a solid-liquid mass ratio of 1:0.15, and the mixture is uniformly mixed in a balling machine to form green balls with a diameter of 10±1 mm. Vanadium-titanium iron tailings powder, fly ash, calcium oxide, potassium feldspar, sodium feldspar and borax are uniformly mixed in a mass ratio of 30:30:3:2:2:0.2 to obtain a mixed powder. The mixed powder is added to a ball mill tank, water is used as the ball milling medium, the solid-liquid mass ratio is 1:1, sodium hexametaphosphate is used as a dispersant, and the amount of sodium hexametaphosphate is 2.5% of the mass of the mixed powder. After ball milling for 5 h, a slurry is obtained. The green balls are immersed in the slurry at room temperature for 5 min, then taken out and drained, and then dried in an oven at 100°C for 5 h to obtain a green body. Vanadium-titanium iron tailings powder, fly ash, aluminum fluoride and calcium fluoride are uniformly mixed in a mass ratio of 50:50:2:5 to obtain a mixed powder. The mixed powder is added to a ball mill tank, water is used as the ball milling medium, the solid-liquid mass ratio is 1:1, sodium hexametaphosphate is used as a dispersant, and the amount of sodium hexametaphosphate is 2.5% of the mass of the mixed powder. After ball milling for 5 h, a slurry is obtained. The green body is immersed in the slurry at room temperature for 5 min, then taken out and drained, and then immersed again for 5 min to allow the slurry to fully coat the surface of the green body. Subsequently, the green body is dried in an oven at 100°C for 5 h. The green body is sintered in a sintering furnace at a rate of 1°C / min to a temperature of 1230°C for 2 h, and then naturally cooled to room temperature in the furnace.

[0067] Comparative Example 4

[0068] The same as Example 1, except that titanium gypsum is used instead of phosphogypsum.

[0069] A method for preparing a high-strength ceramic particle:

[0070] The raw materials are weighed and dried thoroughly. A mixed powder is obtained by thoroughly mixing brick powder, Bayer red mud and titanium gypsum in a mass ratio of 2:2:1. A polyvinyl alcohol aqueous solution with a mass concentration of 5% is added to the mixed powder as a binder in a solid-liquid mass ratio of 1:0.15, and the mixture is uniformly mixed in a balling machine to form green balls with a diameter of 10±1 mm. Vanadium-titanium iron tailings powder, fly ash, calcium oxide, potassium feldspar, sodium feldspar and borax are uniformly mixed in a mass ratio of 30:30:3:2:2:0.2 to obtain a mixed powder. The mixed powder is added to a ball mill tank, water is used as the ball milling medium, the solid-liquid mass ratio is 1:1, sodium hexametaphosphate is used as a dispersant, and the amount of sodium hexametaphosphate is 2.5% of the mass of the mixed powder. After ball milling for 5 h, a slurry is obtained. The green balls are immersed in the slurry at room temperature for 5 min, then taken out and drained, and then dried in an oven at 100°C for 5 h to obtain a green body. Vanadium-titanium iron tailings powder, fly ash, aluminum fluoride and calcium fluoride are uniformly mixed in a mass ratio of 50:50:2:5 to obtain a mixed powder. The mixed powder is added to a ball mill tank, water is used as the ball milling medium, the solid-liquid mass ratio is 1:1, sodium hexametaphosphate is used as a dispersant, and the amount of sodium hexametaphosphate is 2.5% of the mass of the mixed powder. After ball milling for 5 h, a slurry is obtained. The green body is immersed in the slurry at room temperature for 5 min, then taken out and drained, and then immersed again for 5 min to allow the slurry to fully coat the surface of the green body. Subsequently, the green body is dried in an oven at 100°C for 5 h. The green body is sintered in a sintering furnace at a rate of 1°C / min to a temperature of 1230°C for 2 h, and then naturally cooled to room temperature in the furnace.

[0071] Comparative Example 5

[0072] The same as Example 1, except that no aluminum fluoride is added.

[0073] A method for preparing a high-strength ceramic particle

[0074] The raw materials are weighed and dried, and a mixed powder is obtained by mixing brick powder, Bayer red mud, phosphogypsum and titanium gypsum in a mass ratio of 2:2:0.5:0.5. A polyvinyl alcohol aqueous solution with a mass concentration of 5% is added to the mixed powder as a binder in a solid-liquid mass ratio of 1:0.15, and the mixture is uniformly mixed in a balling machine to form green balls with a diameter of 10±1 mm. Vanadium-titanium iron tailings powder, fly ash, calcium oxide, potassium feldspar, sodium feldspar and borax are uniformly mixed in a mass ratio of 30:30:3:2:2:0.2 to obtain a mixed powder. The mixed powder is added to a ball mill tank, water is used as the ball milling medium, the solid-liquid mass ratio is 1:1, sodium hexametaphosphate is used as a dispersant, the amount of sodium hexametaphosphate is 2.5% of the mass of the mixed powder, and the slurry is obtained after ball milling for 5 hours. The green balls are immersed in the slurry at room temperature for 5 minutes, then drained and dried in an oven at 100℃ for 5 hours to obtain a green body. Vanadium-titanium iron tailings powder, fly ash and calcium fluoride are uniformly mixed in a mass ratio of 50:50:5 to obtain a mixed powder. The mixed powder is added to a ball mill tank, water is used as the ball milling medium, the solid-liquid mass ratio is 1:1, sodium hexametaphosphate is used as a dispersant, the amount of sodium hexametaphosphate is 2.5% of the mass of the mixed powder, and the slurry is obtained after ball milling for 5 hours. The green body is immersed in the slurry at room temperature for 5 minutes, then drained and immersed again for 5 minutes to allow the slurry to fully coat the surface of the green body. Subsequently, the green body is dried in an oven at 100℃ for 5 hours, and then sintered in a sintering furnace at a rate of 1℃ / min to 1230℃ for 2 hours, and then naturally cooled to room temperature in the furnace.

[0075] Comparative Example 6:

[0076] The same as Example 1, except that the green balls are directly sintered.

[0077] A method for preparing high-strength ceramic particles:

[0078] The raw materials are weighed and dried, and a mixed powder is obtained by mixing brick powder, Bayer red mud, phosphogypsum and titanium gypsum in a mass ratio of 2:2:0.5:0.5. A polyvinyl alcohol aqueous solution with a mass concentration of 5% is added to the mixed powder as a binder in a solid-liquid mass ratio of 1:0.15, and the mixture is uniformly mixed in a balling machine to form green balls with a diameter of 10±1 mm. The green balls are dried in an oven at 100℃ for 5 hours, and then sintered in a sintering furnace at a rate of 1℃ / min to 1230℃ for 2 hours, and then naturally cooled to room temperature in the furnace.

[0079] Performance test:

[0080] The high-strength ceramic particles prepared in Examples 1-4 and Comparative Examples 1-5 of the present application are used as test samples for performance testing.

[0081] The bulk density, water absorption and cylinder compressive strength of the sample are determined according to Lightweight Aggregate and Its Test Methods (GB / T17431.1-2010, GB / T17431.2-2010).

[0082] The sample is added into water according to the solid-liquid mass ratio of 1:10, and the leaching solution is prepared according to the method in Solid Waste Leaching Toxicity Leaching Method-Horizontal Oscillation Method (GB 5086.2-1997), and the chlorine ion concentration in the leaching solution is determined by using a CLS-10A portable chlorine meter.

[0083] The test results are shown in Table 1 below:

[0084] Table 1:

[0085]

[0086]

[0087] As shown in Table 1 above, the ceramic particles prepared by the application have low water absorption and excellent mechanical strength, and the core-shell structure can effectively inhibit the release of chloride ions.

[0088] As shown by the comparison between Example 1 and Comparative Example 1, the transition layer can greatly reduce the water absorption of the ceramic particles and improve the mechanical strength.

[0089] As shown by the comparison between Example 1 and Comparative Example 2, compared with iron tailings powder, the vanadium-titanium iron tailings powder used in the application can effectively reduce the water absorption of the ceramic particles and improve the mechanical strength.

[0090] As shown by the comparison between Example 1 and Comparative Examples 3-4, the combined use of phosphogypsum and titanium gypsum plays a positive role in reducing the water absorption of the ceramic particles and improving the mechanical strength.

[0091] As shown by the comparison between Example 1 and Comparative Example 5, the addition of aluminum fluoride can effectively reduce the water absorption of the ceramic particles and improve the mechanical strength.

[0092] As shown by the comparison between Example 1 and Comparative Example 6, the core-shell structure greatly reduces the water absorption of the ceramic particles, improves the mechanical strength, and effectively inhibits the release of chloride ions.

[0093] The above examples are only used to illustrate the technical solutions of the application, but not to limit it; although the application has been described in detail with reference to the foregoing examples, those skilled in the art should understand that they can still modify the technical solutions recorded in the foregoing examples, or make equivalent replacements for part of the technical features; and these modifications or replacements do not make the essence of the corresponding technical solutions deviate from the spirit and scope of the technical solutions of the embodiments of the application.

Claims

1. A method for preparing high-strength ceramsite, characterized in that, Specifically as follows: Brick powder, Bayer red mud, phosphogypsum, and titanium gypsum are mixed to obtain a mixed powder. A binder is added and mixed to form raw material balls. A transition layer and a shell layer are then formed on the surface of the raw material balls. After drying, the mixture is sintered and cooled. The transition layer consists of the following components: Vanadium-titanium iron tailings powder, fly ash, calcium oxide, potassium feldspar, sodium feldspar, borax; The shell is composed of the following components: Vanadium-titanium iron tailings powder, fly ash, aluminum fluoride, and calcium fluoride.

2. The method for preparing high-strength ceramsite as described in claim 1, characterized in that, The mass ratio of brick powder, Bayer red mud, phosphogypsum, and titanium gypsum is 1-3:1-3:0.5-1:0.5-1.

3. The method for preparing high-strength ceramsite as described in claim 1, characterized in that, The mass ratio of vanadium-titanium iron tailings powder, fly ash, calcium oxide, potassium feldspar, sodium feldspar, and borax in the transition layer composition is 20-40:20-40:1-5:1-5:1-5:0.1-1.

4. The method for preparing high-strength ceramsite as described in claim 1, characterized in that, The mass ratio of vanadium-titanium iron tailings powder, fly ash, aluminum fluoride, and calcium fluoride in the shell composition is 40-60:40-60:1-3:3-6.

5. The method for preparing high-strength ceramsite as described in claim 1, characterized in that, The adhesive is an aqueous solution of polyvinyl alcohol.

6. The method for preparing high-strength ceramsite as described in claim 1, characterized in that, The solid-liquid mass ratio of the mixed powder to the binder is 1:0.1-0.

2.

7. The method for preparing high-strength ceramsite as described in claim 1, characterized in that, During the preparation of the transition layer, vanadium-titanium iron tailings powder, fly ash, calcium oxide, potassium feldspar, sodium feldspar, and borax are made into a slurry by wet ball milling. The raw material balls are then impregnated in the slurry to coat the material, and then dried.

8. The method for preparing high-strength ceramsite as described in claim 7, characterized in that, During shell preparation, vanadium-titanium-iron tailings powder, fly ash, aluminum fluoride, and calcium fluoride are made into a slurry by wet ball milling. The raw material balls are then impregnated in the slurry to coat the shell, and then dried.

9. The method for preparing high-strength ceramsite as described in claim 1, characterized in that, The mass percentage of V2O5 in the vanadium-titanium iron tailings powder is ≥0.5%.

10. The method for preparing high-strength ceramsite as described in claim 1, characterized in that, The sintering temperature is 1200-1250℃.

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