Layered calcium hydroxide with high specific surface area as well as preparation method and application thereof

Abstract

The invention provides lamellar high-specific-surface-area calcium hydroxide as well as a preparation method and application thereof in order to solve the problem that an existing calcium hydroxide preparation process cannot consider production efficiency and grain morphology at the same time, and belongs to the technical field of calcium hydroxide preparation. The preparation method comprises the following steps: pretreating a quick lime raw material; preparing a digestion solution from a composite modifier containing an alcohol amine compound and water; adding a quick lime raw material into the digestion solution for digestion reaction, and adding a saturated aluminum chloride aqueous solution; and carrying out calcium hydroxide post-treatment. The lamellar calcium hydroxide with the high specific surface area is prepared by the method and can be used for flue gas desulfurization. The composite modifier and aluminum chloride are introduced in the slaking reaction process of the quick lime, the crystallization process of the calcium hydroxide is controlled, the lamellar calcium hydroxide with the high specific surface area is obtained, and the method has the advantages of being simple in process, high in production efficiency, convenient to operate, high in economic benefit and suitable for industrial production.

Description

Technical Field

[0001] The invention relates to the technical field of calcium hydroxide preparation, and in particular to lamellar calcium hydroxide with high specific surface area and a preparation method and application thereof. Background Art

[0002] Calcium hydroxide has a wide range of applications due to its alkalinity, antibacterial properties, absorption of carbon dioxide, and reinforcement in polymers. For example, calcium hydroxide is widely used in the repair of historical and cultural buildings and murals, due to its alkalinity and low cost, and is widely used in waste incineration and desulfurization and denitrification of factory flue gas. Due to its antibacterial properties, it is also an important filler in current root canal treatment of teeth.

[0003] Currently, the methods commonly used to prepare calcium hydroxide generally include lime slaking method and solution method.

[0004] The Chinese invention patent (name: "A method for preparing high-purity nano calcium hydroxide", publication number: CN111573704B, announcement date: 20230106) discloses a method for preparing high-purity nano calcium hydroxide, and specifically discloses that the size of calcium hydroxide crystals can be improved by adding a variety of organic active agents for compounding and slowing down the crystal growth rate. This method is easy to produce, but it is difficult to control the grain morphology.

[0005] The Chinese invention patent application (name: "A method for preparing dendritic calcium hydroxide", publication number: CN101168446A, publication date:) discloses a method for preparing dendritic calcium hydroxide, and specifically records that calcium chloride is used as a raw material, and calcium hydroxide crystals are precipitated by changing the solution environment to alkaline. In the presence of an activator, the crystallization rate of calcium hydroxide can be controlled, thereby controlling the crystal form. This method is easy to control the grain morphology of the calcium hydroxide product, but the production rate is slow and it is difficult to produce in large quantities. Summary of the invention

[0006] The invention aims to solve the problem that the existing calcium hydroxide preparation process cannot take into account both production efficiency and grain morphology, and provides a lamellar calcium hydroxide with a high specific surface area and a preparation method and application thereof. The invention introduces a composite modifier and aluminum chloride in the quicklime digestion reaction process to control the crystallization process of calcium hydroxide, so as to obtain the lamellar calcium hydroxide with a high specific surface area. The invention has the characteristics of simple process, high production efficiency, convenient operation, high economic benefit and suitability for industrial production.

[0007] The technical solution adopted by the present invention is:

[0008] A method for preparing lamellar high specific surface area calcium hydroxide comprises the following steps:

[0009] Step S1, pretreatment of quicklime raw materials: crushing, grinding, ball milling and screening the quicklime raw materials;

[0010] Step S2, preparing a digestive solution: preparing a digestive solution by mixing a composite modifier containing an alcoholamine compound and water in a mass ratio of 1:40-60, and maintaining the temperature of the digestive solution at a stable temperature of 75-85° C.;

[0011] Step S3, digestion reaction: according to the mass ratio of the composite modifier to the quicklime raw material pretreated in the step S1 of 1:20-25, under stirring, the quicklime raw material is added to the digestion solution prepared in the step S1 in batches or slowly, and the digestion reaction temperature is maintained stable at 85-95° C.; at the same time, a saturated aluminum chloride aqueous solution accounting for 1-10% of the total mass of the lime raw material is added to the digestion solution in batches or slowly; after the lime raw material is added, the digestion reaction is continued for 50-70 minutes to obtain a suspension slurry;

[0012] Step S4, post-treatment of calcium hydroxide: filter pressing, washing, drying and sieving the suspension slurry in step S3 to obtain a lamellar calcium hydroxide product with a high specific surface area.

[0013] Further, in step S1, the quicklime raw material has an effective calcium content of 80-85% and an activity of 300-350 ml / 4N-HCl. The calcium content will affect the formation rate of calcium hydroxide, and the activity will affect the reaction conditions of calcium hydroxide to a certain extent, thereby affecting the specific surface area of ​​calcium hydroxide. Quicklime is fired from natural mineral materials, and its effective calcium content and activity are in a range, which are often different in different batches. The quality control of the quicklime raw material in the present invention is conducive to obtaining a lamellar calcium hydroxide product with better quality and high specific surface area.

[0014] Furthermore, in step S1, the particle size of the quicklime raw material after pretreatment is 100-300 meshes. In the present invention, the particle size of the quicklime raw material after pretreatment is controlled, which is beneficial to controlling the quicklime digestion reaction process, thereby controlling the growth rate and microscopic morphology of calcium hydroxide crystals.

[0015] Furthermore, in step S2, the composite modifier also includes an ionic surfactant and a polyol.

[0016] Further, in step S2, the alcoholamine compound is one or more of triethanolamine, diethanolamine and ethanolamine;

[0017] The ionic surfactant is one or more selected from sodium dodecylbenzene sulfonate, sodium dodecyl sulfonate, sodium dodecyl sulfate, sodium hexadecyl sulfonate, dodecyltrimethylammonium bromide, and hexadecyltrimethylammonium bromide;

[0018] The polyol is one or more of ethylene glycol, propylene glycol, glycerol, diethylene glycol, triethylene glycol, polyethylene glycol, polypropylene glycol, butanediol, and cyclohexanehexol.

[0019] The composite modifier in the present invention comprises an alcoholamine compound, an ionic surfactant and a polyol, etc. The alcoholamine compound can adjust the reaction rate of lime digestion, and the ionic surfactant and the polyol can reduce the surface energy of calcium hydroxide, avoid agglomeration, improve the dispersion of calcium hydroxide, reduce the grain size of calcium hydroxide formed in the digestion reaction, and increase the specific surface area, thereby giving the calcium hydroxide the characteristics of high specific surface area and high activity.

[0020] Furthermore, the composite modifier is prepared by mixing triethanolamine, cyclohexanehexol and hexadecyltrimethylammonium bromide in a mass ratio of 1:0.2-0.5:0.1-0.3.

[0021] Furthermore, in step S3, the stirring speed is controlled at 200-300 r / min during the digestion reaction.

[0022] The control of the stirring speed during the digestion reaction in the present invention is beneficial to controlling the heat of the digestion reaction and maintaining the digestion reaction temperature stable on the one hand; on the other hand, it is beneficial to controlling the size of the calcium hydroxide grains.

[0023] Based on the same inventive concept, the present invention also provides a lamellar high specific surface area calcium hydroxide, which is prepared by the above-mentioned preparation method of lamellar high specific surface area calcium hydroxide.

[0024] Furthermore, the microscopic morphology of calcium hydroxide is lamellar, with a specific surface area of ​​55~60m 2 / g, particle size distribution: D(90) = 11 ~ 20μm, D(50) = 1.5 ~ 2μm, D(10) = 0.6 ~ 0.9μm.

[0025] Based on the same inventive concept, the present invention also provides an application of lamellar calcium hydroxide with a high specific surface area, and the lamellar calcium hydroxide with a high specific surface area is used for flue gas desulfurization.

[0026] The beneficial effects of the present invention are:

[0027] 1. The present invention is to solve the problem that the existing calcium hydroxide preparation process cannot take into account both production efficiency and grain morphology, and provide a method for preparing calcium hydroxide with a lamellar high specific surface area. The present invention uses a composite modifier to slow down the lime digestion reaction rate during the quicklime digestion reaction, slow down the growth rate of calcium hydroxide crystals, so as to improve the size of calcium hydroxide crystals and make the calcium hydroxide crystal particle size distribution more uniform. At the same time, aluminum chloride is also introduced into the quicklime digestion reaction process of the present invention, and aluminum chloride can be crystallized in the form of aluminum hydroxide under an alkaline environment, and the precipitation rate of aluminum hydroxide is much lower than the generation rate of calcium hydroxide. The aluminum chloride crystallization process and the calcium hydroxide grain growth process are carried out simultaneously, and a trace amount of aluminum hydroxide crystals are mixed into the calcium hydroxide crystals, so that the final calcium hydroxide crystal morphology is lamellar, which increases the specific surface area of ​​calcium hydroxide and has no significant effect on the purity of calcium hydroxide. The preparation method in the present invention has simple process, high production efficiency, convenient operation, high economic benefit, and is suitable for industrial production.

[0028] 2. The present invention also provides a lamellar calcium hydroxide with a high specific surface area, which has a lamellar microscopic morphology and a high specific surface area and can be used in fields such as flue gas desulfurization. BRIEF DESCRIPTION OF THE DRAWINGS

[0029] In order to more clearly illustrate the embodiments of the present application or the technical solutions in the prior art, the drawings required for use in the embodiments or the description of the prior art will be briefly introduced below. Obviously, the drawings described below are only some embodiments of the present application. For ordinary technicians in this field, other drawings can be obtained based on these drawings without paying creative work.

[0030] Figure 1 This is the SEM scanning electron microscope image of the product. DETAILED DESCRIPTION

[0031] In the description of the present invention, it should be understood that the terms "center", "longitudinal", "lateral", "length", "width", "thickness", "up", "down", "front", "back", "left", "right", "vertical", "horizontal", "top", "bottom", "inside", "outside", "clockwise", "counterclockwise", "axial", "radial", "circumferential" and the like indicate orientations or positional relationships based on the orientations or positional relationships shown in the accompanying drawings, and are only for the convenience of describing the present invention and simplifying the description, and do not indicate or imply that the referred device or element must have a specific orientation, be constructed and operated in a specific orientation, and therefore should not be understood as limiting the present invention.

[0032] The disclosure below provides many different embodiments or examples to realize different structures of the present invention. In order to simplify the disclosure of the present invention, the parts and settings of specific examples are described below. Of course, they are only examples, and the purpose is not to limit the present invention.

[0033] The embodiments of the invention are described in detail below with reference to the accompanying drawings.

[0034] Example 1

[0035] A method for preparing lamellar high specific surface area calcium hydroxide comprises the following steps:

[0036] (1) The quicklime raw material (the effective calcium content measured by hydrochloric acid titration method is 80-85%, and the activity is 300-350 ml / 4N-HCl) is crushed and ground, and then put into a drum ball mill for ball milling. The quicklime raw material is then purified by vibration screening, and the quicklime raw material powder with a particle size distribution in the range of 100-200 mesh is selected for use.

[0037] (2) Triethanolamine, cyclohexanehexol and hexadecyltrimethylammonium bromide are mixed in a mass ratio of 1:0.2:0.1 to obtain a composite modifier, and then the composite modifier is mixed with water in a mass ratio of 1:60. Finally, the composite modifier is fully mixed by high-speed shearing (for example, a speed of 500 r / min) and heated to a constant temperature of 75°C to obtain a digestion solution.

[0038] (3) Add quicklime raw materials with a mass 20 times that of the composite modifier into the digestion solution in 5 batches under stirring (e.g., a speed of 300 r / min), with the mass of quicklime raw materials added in each batch being the same, and performing digestion reaction at intervals between each batch, and controlling the digestion reaction temperature to be stable at 85°C; while adding the lime raw materials, slowly (e.g., dropwise) add saturated aluminum chloride aqueous solution accounting for 5% of the total mass of the quicklime raw materials into the digestion solution. After the quicklime raw materials are added, continue the digestion reaction for 50 minutes to obtain a suspension slurry.

[0039] (4) The suspension is filtered to obtain a calcium hydroxide precipitate, and then the calcium hydroxide precipitate is washed with water or anhydrous ethanol for three times. The calcium hydroxide precipitate is then dried at 200° C. and passed through a 300-mesh sieve to obtain a lamellar calcium hydroxide product with a high specific surface area.

[0040] The product test results are as follows: the effective calcium content measured by hydrochloric acid titration method is >97%, the particle size distribution measured by laser particle size analyzer is: D(10)=0.7μm, D(50)=2μm, D(90)=20μm, specific surface area=55 m 2 / g.

[0041] The lamellar high specific surface area calcium hydroxide product in this embodiment has a large specific surface area and can be used for flue gas desulfurization.

[0042] In this embodiment, the detection of the effective calcium content and activity of the quicklime raw material is carried out with reference to GB / T 5762-2012 "Chemical Analysis Methods for Limestone, Quicklime and Slaked Lime for Building Materials". The detection of the effective calcium content of calcium hydroxide is carried out with reference to GB / T5762-2012 "Chemical Analysis Methods for Limestone, Quicklime and Slaked Lime for Building Materials". The detection of the effective calcium content and activity in the subsequent embodiments is also carried out with reference to GB / T 5762-2012 "Chemical Analysis Methods for Limestone, Quicklime and Slaked Lime for Building Materials".

[0043] Example 2

[0044] A method for preparing lamellar high specific surface area calcium hydroxide comprises the following steps:

[0045] (1) The quicklime raw material (the effective calcium content measured by hydrochloric acid titration method is 80-85%, and the activity is 300-350 ml / 4N-HCl) is crushed and ground, and then put into a drum ball mill for ball milling. The quicklime raw material is then purified by vibration screening, and the quicklime raw material powder with a particle size distribution in the range of 200-300 mesh is selected for later use.

[0046] (2) Triethanolamine, cyclohexanehexol and hexadecyltrimethylammonium bromide are mixed in a mass ratio of 1:0.4:0.2 to obtain a composite modifier, and then the composite modifier is mixed with water in a mass ratio of 1:60. Finally, the composite modifier is fully mixed by high-speed shearing (for example, a speed of 500 r / min) and heated to a constant temperature of 80°C to obtain a digestion solution.

[0047] (3) Add quicklime raw materials with a mass 20 times that of the composite modifier into the digestion solution in 5 batches under stirring (e.g., a speed of 300 r / min), with the mass of quicklime raw materials added in each batch being the same, and performing digestion reaction at intervals between each batch, and controlling the digestion reaction temperature to be stable at 90°C; while adding the lime raw materials, slowly (e.g., dropwise) add saturated aluminum chloride aqueous solution accounting for 8% of the total mass of the quicklime raw materials into the digestion solution. After the quicklime raw materials are added, continue the digestion reaction for 60 minutes to obtain a suspension slurry.

[0048] (4) The suspension is filtered to obtain a calcium hydroxide precipitate, and then the calcium hydroxide precipitate is washed with water or anhydrous ethanol for three times. The calcium hydroxide precipitate is then dried at 200° C. and passed through a 300-mesh sieve to obtain a lamellar calcium hydroxide product with a high specific surface area.

[0049] The product test results are as follows: the effective calcium content measured by hydrochloric acid titration method is >96%, and the particle size distribution measured by laser particle size analyzer is: D(10)=0.7μm, D(50)=1.8μm, D(90)=17μm, and the specific surface area is 60m 2 / g.

[0050] The lamellar high specific surface area calcium hydroxide product in this embodiment has a large specific surface area and can be used for flue gas desulfurization.

[0051] Example 3

[0052] A method for preparing lamellar high specific surface area calcium hydroxide comprises the following steps:

[0053] (1) The quicklime raw material (the effective calcium content measured by hydrochloric acid titration method is 80-85%, and the activity is 300-350 ml / 4N-HCl) is crushed and ground, and then put into a drum ball mill for ball milling. The quicklime raw material is then purified by vibration screening, and the quicklime raw material powder with a particle size distribution in the range of 200-300 mesh is selected for later use.

[0054] (2) Triethanolamine, cyclohexanehexol and hexadecyltrimethylammonium bromide are mixed in a mass ratio of 1:0.5:0.3 to obtain a composite modifier, and then the composite modifier is mixed with water in a mass ratio of 1:60. Finally, the composite modifier is fully mixed by high-speed shearing (for example, a speed of 500 r / min) and heated to a constant temperature of 85°C to obtain a digestion solution.

[0055] (3) Add quicklime raw materials with a mass 25 times that of the composite modifier into the digestion solution in 5 batches under stirring (e.g., a speed of 300 r / min), with the mass of quicklime raw materials added in each batch being the same, and performing digestion reaction at intervals between each batch, and controlling the digestion reaction temperature to be stable at 95°C; while adding the lime raw materials, slowly (e.g., dropwise) add saturated aluminum chloride aqueous solution accounting for 10% of the total mass of the quicklime raw materials into the digestion solution. After the quicklime raw materials are added, continue the digestion reaction for 70 minutes to obtain a suspension slurry.

[0056] (4) The suspension is filtered to obtain a calcium hydroxide precipitate, and then the calcium hydroxide precipitate is washed with water or anhydrous ethanol for three times. The calcium hydroxide precipitate is then dried at 200° C. and passed through a 300-mesh sieve to obtain a lamellar calcium hydroxide product with a high specific surface area.

[0057] The product test results are: the effective calcium content measured by hydrochloric acid titration method is >95%, the particle size distribution measured by laser particle size analyzer is: D(10)=0.6μm, D(50)=1.5μm, D(90)=10μm, specific surface area=65m 2 / g.

[0058] The SEM scanning electron microscope image of the product in this embodiment is shown in the attached Figure 1 As shown in the figure, it can be clearly seen that the microscopic morphology is lamellar.

[0059] The lamellar high specific surface area calcium hydroxide product in this embodiment has a large specific surface area and can be used for flue gas desulfurization.

[0060] Example 4

[0061] A method for preparing lamellar high specific surface area calcium hydroxide comprises the following steps:

[0062] (1) The quicklime raw material (the effective calcium content measured by hydrochloric acid titration method is 80-85%, and the activity is 300-350 ml / 4N-HCl) is crushed and ground, and then put into a drum ball mill for ball milling. The quicklime raw material is then purified by vibration screening, and the quicklime raw material powder with a particle size distribution in the range of 150-250 mesh is selected for use.

[0063] (2) Triethanolamine, cyclohexanehexol and hexadecyltrimethylammonium bromide are mixed in a mass ratio of 1:0.5:0.1 to obtain a composite modifier, and then the composite modifier is mixed with water in a mass ratio of 1:60. Finally, the composite modifier is fully mixed by high-speed shearing (for example, a speed of 500 r / min) and heated to a constant temperature of 85°C to obtain a digestion solution.

[0064] (3) Add quicklime raw materials with a mass 25 times that of the composite modifier into the digestion solution in 5 batches under stirring (e.g., a speed of 300 r / min), with the mass of quicklime raw materials added in each batch being the same, and performing digestion reaction at intervals between each batch, and controlling the digestion reaction temperature to be stable at 85°C; while adding the lime raw materials, slowly (e.g., dropwise) add saturated aluminum chloride aqueous solution accounting for 9% of the total mass of the quicklime raw materials into the digestion solution. After the quicklime raw materials are added, continue the digestion reaction for 70 minutes to obtain a suspension slurry.

[0065] (4) The suspension is filtered to obtain a calcium hydroxide precipitate, and then the calcium hydroxide precipitate is washed with water or anhydrous ethanol for three times. The calcium hydroxide precipitate is then dried at 200° C. and passed through a 300-mesh sieve to obtain a lamellar calcium hydroxide product with a high specific surface area.

[0066] The product test results are as follows: the effective calcium content measured by hydrochloric acid titration method is >94%, the particle size distribution measured by laser particle size analyzer is: D(10)=0.9μm, D(50)=1.9μm, D(90)=12μm, specific surface area=58m 2 / g.

[0067] The lamellar high specific surface area calcium hydroxide product in this embodiment has a large specific surface area and can be used for flue gas desulfurization.

[0068] Example 5

[0069] A method for preparing lamellar high specific surface area calcium hydroxide comprises the following steps:

[0070] (1) The quicklime raw material (the effective calcium content measured by hydrochloric acid titration method is 80-85%, and the activity is 300-350 ml / 4N-HCl) is crushed and ground, and then put into a drum ball mill for ball milling. The quicklime raw material is then purified by vibration screening, and the quicklime raw material powder with a particle size distribution in the range of 100-200 mesh is selected for use.

[0071] (2) Triethanolamine, cyclohexanehexol and hexadecyltrimethylammonium bromide are mixed in a mass ratio of 1:0.3:0.2 to obtain a composite modifier, and then the composite modifier is mixed with water in a mass ratio of 1:60. Finally, the composite modifier is fully mixed by high-speed shearing (for example, a speed of 500 r / min) and heated to a constant temperature of 75°C to obtain a digestion solution.

[0072] (3) Add quicklime raw materials with a mass 25 times that of the composite modifier into the digestion solution in 5 batches under stirring (e.g., a speed of 300 r / min), with the mass of quicklime raw materials added in each batch being the same, and performing digestion reaction at intervals between each batch, and controlling the digestion reaction temperature to be stable at 90°C; while adding the lime raw materials, slowly (e.g., dropwise) add saturated aluminum chloride aqueous solution accounting for 7% of the total mass of the quicklime raw materials into the digestion solution. After the quicklime raw materials are added, continue the digestion reaction for 60 minutes to obtain a suspension slurry.

[0073] (4) The suspension is filtered to obtain a calcium hydroxide precipitate, and then the calcium hydroxide precipitate is washed with water or anhydrous ethanol for three times. The calcium hydroxide precipitate is then dried at 200° C. and passed through a 300-mesh sieve to obtain a lamellar calcium hydroxide product with a high specific surface area.

[0074] The product test results are: the effective calcium content measured by hydrochloric acid titration method is >96%, the particle size distribution measured by laser particle size analyzer is: D(10)=0.7μm, D(50)=1.9μm, D(90)=16μm, specific surface area=57m 2 / g.

[0075] The lamellar high specific surface area calcium hydroxide product in this embodiment has a large specific surface area and can be used for flue gas desulfurization.

[0076] Example 6

[0077] A method for preparing lamellar high specific surface area calcium hydroxide comprises the following steps:

[0078] (1) The quicklime raw material (the effective calcium content measured by hydrochloric acid titration method is 80-85%, and the activity is 300-350 ml / 4N-HCl) is crushed and ground, and then put into a drum ball mill for ball milling. The quicklime raw material is then purified by vibration screening, and the quicklime raw material powder with a particle size distribution in the range of 200-300 mesh is selected for later use.

[0079] (2) Triethanolamine, cyclohexanehexol and hexadecyltrimethylammonium bromide are mixed in a mass ratio of 1:0.5:0.3 to obtain a composite modifier, and then the composite modifier is mixed with water in a mass ratio of 1:60. Finally, the composite modifier is fully mixed by high-speed shearing (for example, a speed of 500 r / min) and heated to a constant temperature of 80°C to obtain a digestion solution.

[0080] (3) Add quicklime raw materials with a mass 25 times that of the composite modifier into the digestion solution in 5 batches under stirring (e.g., a speed of 300 r / min), with the mass of quicklime raw materials added in each batch being the same, and performing digestion reaction at intervals between each batch, and controlling the digestion reaction temperature to be stable at 95°C; while adding the lime raw materials, slowly (e.g., dropwise) add saturated aluminum chloride aqueous solution accounting for 5% of the total mass of the quicklime raw materials into the digestion solution. After the quicklime raw materials are added, continue the digestion reaction for 50 minutes to obtain a suspension slurry.

[0081] (4) The suspension is filtered to obtain a calcium hydroxide precipitate, and then the calcium hydroxide precipitate is washed with water or anhydrous ethanol for three times. The calcium hydroxide precipitate is then dried at 200° C. and passed through a 300-mesh sieve to obtain a lamellar calcium hydroxide product with a high specific surface area.

[0082] The product test results are: the effective calcium content measured by hydrochloric acid titration method is >97%, the particle size distribution measured by laser particle size analyzer is: D(10)=0.6μm, D(50)=1.7μm, D(90)=13μm, specific surface area=61m 2 / g.

[0083] The lamellar high specific surface area calcium hydroxide product in this embodiment has a large specific surface area and can be used for flue gas desulfurization.

[0084] Example 7

[0085] A method for preparing lamellar high specific surface area calcium hydroxide comprises the following steps:

[0086] (1) The quicklime raw material (the effective calcium content measured by hydrochloric acid titration method is 80-85%, and the activity is 300-350 ml / 4N-HCl) is crushed and ground, and then put into a drum ball mill for ball milling. The quicklime raw material is then purified by vibration screening, and the quicklime raw material powder with a particle size distribution in the range of 150-250 mesh is selected for use.

[0087] (2) Triethanolamine, cyclohexanehexol and hexadecyltrimethylammonium bromide are mixed in a mass ratio of 1:0.4:0.2 to obtain a composite modifier, and then the composite modifier is mixed with water in a mass ratio of 1:60. Finally, the composite modifier is fully mixed by high-speed shearing (for example, a speed of 500 r / min) and heated to a constant temperature of 80°C to obtain a digestion solution.

[0088] (3) Add quicklime raw materials with a mass 25 times that of the composite modifier into the digestion solution in 5 batches under stirring (e.g., a speed of 300 r / min), with the mass of quicklime raw materials added in each batch being the same, and performing digestion reaction at intervals between each batch, and controlling the digestion reaction temperature to be stable at 95°C; while adding the lime raw materials, slowly (e.g., dropwise) add saturated aluminum chloride aqueous solution accounting for 10% of the total mass of the quicklime raw materials into the digestion solution. After the quicklime raw materials are added, continue the digestion reaction for 70 minutes to obtain a suspension slurry.

[0089] (4) The suspension is filtered to obtain a calcium hydroxide precipitate, and then the calcium hydroxide precipitate is washed with water or anhydrous ethanol for three times. The calcium hydroxide precipitate is then dried at 200° C. and passed through a 300-mesh sieve to obtain a lamellar calcium hydroxide product with a high specific surface area.

[0090] The product test results are as follows: the effective calcium content measured by hydrochloric acid titration method is >94%, the particle size distribution measured by laser particle size analyzer is: D(10)=0.8μm, D(50)=1.6μm, D(90)=11μm, specific surface area=55m 2 / g.

[0091] The lamellar high specific surface area calcium hydroxide product in this embodiment has a large specific surface area and can be used for flue gas desulfurization.

[0092] Example 8

[0093] A method for preparing lamellar high specific surface area calcium hydroxide comprises the following steps:

[0094] (1) The quicklime raw material (the effective calcium content measured by hydrochloric acid titration method is 80-85%, and the activity is 300-350 ml / 4N-HCl) is crushed and ground, and then put into a drum ball mill for ball milling. The quicklime raw material is then purified by vibration screening, and the quicklime raw material powder with a particle size distribution in the range of 200-300 mesh is selected for later use.

[0095] (2) Triethanolamine, cyclohexanehexol and hexadecyltrimethylammonium bromide are mixed in a mass ratio of 1:0.3:0.3 to obtain a composite modifier, and then the composite modifier is mixed with water in a mass ratio of 1:40. Finally, the composite modifier is fully mixed by high-speed shearing (for example, a speed of 500 r / min) and heated to a constant temperature of 85°C to obtain a digestion solution.

[0096] (3) Add quicklime raw materials with a mass 20 times that of the composite modifier into the digestion solution in 5 batches under stirring (e.g., a speed of 300 r / min), with the mass of quicklime raw materials added in each batch being the same, and performing digestion reaction at intervals between each batch, and controlling the digestion reaction temperature to be stable at 90°C; while adding the lime raw materials, slowly (e.g., dropwise) add saturated aluminum chloride aqueous solution accounting for 9% of the total mass of the quicklime raw materials into the digestion solution. After the quicklime raw materials are added, continue the digestion reaction for 70 minutes to obtain a suspension slurry.

[0097] (4) The suspension is filtered to obtain a calcium hydroxide precipitate, and then the calcium hydroxide precipitate is washed with water or anhydrous ethanol for three times. The calcium hydroxide precipitate is then dried at 200° C. and passed through a 300-mesh sieve to obtain a lamellar calcium hydroxide product with a high specific surface area.

[0098] The product test results are as follows: the effective calcium content measured by hydrochloric acid titration method is >94%, the particle size distribution measured by laser particle size analyzer is: D(10)=0.7μm, D(50)=1.8μm, D(90)=14μm, specific surface area=62m 2 / g.

[0099] The lamellar high specific surface area calcium hydroxide product in this embodiment has a large specific surface area and can be used for flue gas desulfurization.

[0100] Example 9

[0101] A method for preparing lamellar high specific surface area calcium hydroxide comprises the following steps:

[0102] (1) The quicklime raw material (the effective calcium content measured by hydrochloric acid titration method is 80-85%, and the activity is 300-350 ml / 4N-HCl) is crushed and ground, and then put into a drum ball mill for ball milling. The quicklime raw material is then purified by vibration screening, and the quicklime raw material powder with a particle size distribution in the range of 200-300 mesh is selected for later use.

[0103] (2) Triethanolamine, cyclohexanehexol and hexadecyltrimethylammonium bromide are mixed in a mass ratio of 1:0.4:0.2 to obtain a composite modifier, and then the composite modifier is mixed with water in a mass ratio of 1:50. Finally, the composite modifier is fully mixed by high-speed shearing (for example, a speed of 500 r / min) and heated to a constant temperature of 80°C to obtain a digestion solution.

[0104] (3) Add quicklime raw materials with a mass 23 times that of the composite modifier into the digestion solution in 5 batches under stirring (e.g., a speed of 300 r / min), with the mass of quicklime raw materials added in each batch being the same, and performing digestion reaction at intervals between each batch, and controlling the digestion reaction temperature to be stable at 90°C; while adding the lime raw materials, slowly (e.g., dropwise) add saturated aluminum chloride aqueous solution accounting for 8% of the total mass of the quicklime raw materials into the digestion solution. After the quicklime raw materials are added, continue the digestion reaction for 70 minutes to obtain a suspension slurry.

[0105] (4) The suspension is filtered to obtain a calcium hydroxide precipitate, and then the calcium hydroxide precipitate is washed with water or anhydrous ethanol for three times. The calcium hydroxide precipitate is then dried at 200° C. and passed through a 300-mesh sieve to obtain a lamellar calcium hydroxide product with a high specific surface area.

[0106] The product test results are as follows: the effective calcium content measured by hydrochloric acid titration method is greater than 95%, and the particle size distribution measured by laser particle size analyzer is: D(10)=0.7μm, D(50)=1.8μm, D(90)=12μm, specific surface area=62m 2 / g.

[0107] The lamellar high specific surface area calcium hydroxide product in this embodiment has a large specific surface area and can be used for flue gas desulfurization.

Claims

1. A method for preparing lamellar high specific surface area calcium hydroxide, characterized in that: The following steps are involved: Step S1, pretreatment of quicklime raw materials: crushing, grinding, ball milling and screening the quicklime raw materials; Step S2, preparing a digestive solution: preparing a digestive solution by mixing a composite modifier containing an alcoholamine compound and water in a mass ratio of 1:40-60, and maintaining the temperature of the digestive solution at a stable temperature of 75-85° C.; Step S3, digestion reaction: according to the mass ratio of the composite modifier to the quicklime raw material pretreated in the step S1 of 1:20-25, under stirring, the quicklime raw material is added to the digestion solution prepared in the step S1 in batches or slowly, and the digestion reaction temperature is maintained stable at 85-95° C.; at the same time, a saturated aluminum chloride aqueous solution accounting for 1-10% of the total mass of the lime raw material is added to the digestion solution in batches or slowly; after the lime raw material is added, the digestion reaction is continued for 50-70 minutes to obtain a suspension slurry; Step S4, post-treatment of calcium hydroxide: filter pressing, washing, drying and sieving the suspension slurry in step S3 to obtain a lamellar calcium hydroxide product with a high specific surface area.

2. The method for preparing lamellar high specific surface area calcium hydroxide according to claim 1, wherein In step S1, the quicklime raw material has an effective calcium content of 80-85% and an activity of 300-350 ml / 4N-HCl.

3. The preparation method of lamellar high specific surface area calcium hydroxide according to claim 1, characterized in that, In the step S1, the particle size of the quicklime raw material after pretreatment is 100-300 meshes.

4. according to the preparation method of the lamellar high specific surface area calcium hydroxide described in any one of claims 1 to 3, it is characterized in that, In the step S2, the composite modifier further includes an ionic surfactant and a polyol.

5. The method for preparing lamellar high specific surface area calcium hydroxide according to claim 4, characterized in that, In step S2, the alcoholamine compound is one or more of triethanolamine, diethanolamine and ethanolamine; The ionic surfactant is one or more selected from sodium dodecylbenzene sulfonate, sodium dodecyl sulfonate, sodium dodecyl sulfate, sodium hexadecyl sulfonate, dodecyltrimethylammonium bromide, and hexadecyltrimethylammonium bromide; The polyol is one or more of ethylene glycol, propylene glycol, glycerol, diethylene glycol, triethylene glycol, polyethylene glycol, polypropylene glycol, butanediol, and cyclohexanehexol.

6. The method for preparing lamellar high specific surface area calcium hydroxide according to claim 5, characterized in that: The composite modifier is prepared by mixing triethanolamine, cyclohexanehexol and hexadecyltrimethylammonium bromide in a mass ratio of 1:0.2-0.5:0.1-0.

3.

7. according to the preparation method of the lamellar high specific surface area calcium hydroxide described in any one of claims 1 to 3 and 5 to 6, it is characterized in that, In step S3, the stirring speed is controlled at 200-300 r / min during the digestion reaction.

8. A lamellar high specific surface area calcium hydroxide, characterized in that: The method is prepared by the method for preparing lamellar calcium hydroxide with high specific surface area as described in any one of claims 1 to 7.

9. The lamellar high specific surface area calcium hydroxide according to claim 8, characterized in that The microscopic morphology of calcium hydroxide is lamellar, with a specific surface area of ​​55~60m 2 / g, particle size distribution: D(90) = 11 ~ 20μm, D(50) = 1.5 ~ 2μm, D(10) = 0.6 ~ 0.9μm.

10. An application of lamellar high specific surface area calcium hydroxide, characterized in that: The lamellar high specific surface area calcium hydroxide as described in claim 8 or 9 is used for flue gas desulfurization.

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