Device for preparing calcium hydroxide from carbide slag and use method of device

Abstract

The invention provides a device for preparing calcium hydroxide from carbide slag and a using method thereof.The device comprises a dispersing device and a screening device which are sequentially communicated in the material flow direction, the screening device is provided with a discharging port and a discharging port, and the discharging port is communicated with a rotational flow device; the cyclone device is provided with an overflow outlet and an underflow outlet, the overflow outlet is sequentially communicated with the reaction device, the superfine grinding device and the first filtering and drying device, and the underflow outlet and the discharge port are communicated with the coarse slag storage tank; and the reaction device is used for carrying out surface modification treatment on the carbide slag. The calcium hydroxide product with high purity and high specific surface area can be produced by using the device provided by the invention in cooperation with the use method, the problems of low specific surface area and the like of calcium hydroxide prepared from the carbide slag are effectively solved, and the device has the advantages of good dispersion effect, simple equipment, low cost and the like, and is beneficial to realizing high-value utilization of the carbide slag.

Description

Technical Field

[0001] This invention belongs to the field of solid waste resource utilization technology, and relates to an apparatus for preparing calcium hydroxide from carbide slag and its usage method. Background Technology

[0002] Calcium carbide slag is an industrial solid waste generated during acetylene production, with annual emissions exceeding 30 million tons. Its main component is calcium hydroxide, which is widely used in power plant flue gas desulfurization and the preparation of calcium hydroxide powder. In the increasingly mature flue gas desulfurization process, calcium hydroxide is primarily used to neutralize acidic gases and ions such as sulfur dioxide, sulfur trioxide, fluoride ions, and chloride ions, ensuring that the sulfur content in flue gas emissions meets environmental standards. The desulfurization effect is directly influenced by the properties of calcium hydroxide; its specific surface area is a crucial factor determining the desulfurization effect. Generally, the larger the specific surface area of ​​calcium hydroxide, the better the desulfurization effect.

[0003] Calcium hydroxide prepared from carbide slag is used for desulfurization, but it is prone to agglomeration during the pulping process, affecting product quality. Therefore, improving the dispersibility and stability of calcium hydroxide crystals and preparing calcium hydroxide with a large specific surface area is of great significance for meeting the practical needs of flue gas purification and related applications.

[0004] CN202210514260.5 discloses a method for producing high specific surface area calcium hydroxide, including crushing, digestion, and screening. The quicklime has a calcium oxide content of over 93% by weight. The crusher is a hammer crusher or a roller crusher. The digesting agent is an aqueous solution of a hydroxyl-containing organic compound. The weight ratio of the digesting agent to the granular quicklime is 5:1. The vibrating screen is a filtration-type mechanical separation device with a mesh size of 100-200 mesh. CN201911390295.7 discloses a method for preparing highly dispersible high specific surface area calcium hydroxide. The method uses quicklime as raw material, adds natural nanocellulose with abundant oxygen-containing groups as a template and sodium carboxymethyl cellulose surfactant during the digestion process, performs high-speed shearing for thorough mixing, and achieves calcium hydroxide nucleation and growth based on ultrasonic action. After washing, centrifugation, drying, and grinding, high specific surface area calcium hydroxide is obtained.

[0005] However, the above methods are costly, use quicklime as the raw material, and involve cumbersome steps in preparing high specific surface area calcium hydroxide, which is not conducive to the further utilization of calcium hydroxide. Therefore, providing an apparatus for directly preparing high specific surface area calcium hydroxide from carbide slag is of great significance for realizing the high-value utilization of carbide slag. Summary of the Invention

[0006] To address the shortcomings of existing technologies, the present invention aims to provide an apparatus and method for preparing calcium hydroxide from carbide slag. Using the apparatus and method provided by this invention, calcium hydroxide products with high content and high specific surface area can be produced, wherein the purity of calcium hydroxide can reach over 90 wt% and the specific surface area can reach 30 m². 2 / g~60m 2 / g, effectively solves the problem of low specific surface area of ​​calcium hydroxide prepared from carbide slag, and has the advantages of good dispersion effect, simple equipment and low cost, which is conducive to the further high-value utilization of carbide slag.

[0007] To achieve this objective, the present invention adopts the following technical solution:

[0008] In a first aspect, the present invention provides an apparatus for preparing calcium hydroxide from carbide slag, the apparatus comprising a dispersing device and a screening device connected sequentially along the material flow direction, the screening device being provided with a discharge port and a discharge outlet, the discharge port being connected to a cyclone device;

[0009] The cyclone device is provided with an overflow outlet and an underflow outlet. The overflow outlet is connected in sequence to the reaction device, the ultrafine grinding device and the first filtration and drying device. The underflow outlet and the discharge port are connected to the coarse slag storage tank. The reaction device is used to perform surface modification treatment on the carbide slag.

[0010] In this invention, the calcium carbide slag slurry first undergoes surface modification treatment in a reaction device. After modification, the particles become hydrophobic, reducing water molecule adsorption and decreasing the slurry viscosity by more than 50%, thereby improving the kinetic energy transfer efficiency of the grinding media in the subsequent ultrafine grinding device. Then, the surface-modified slurry enters the ultrafine grinding device, where the particles in the calcium carbide slag slurry achieve intense micro-mixing and continuous circulation, significantly improving the particle crushing efficiency. Simultaneously, during particle crushing, the surface modifier can stabilize the newly generated fine particles produced by ultrafine grinding through adsorption, reducing surface energy, and providing electrostatic / steric repulsion forces, preventing particle agglomeration and growth. This avoids fine particles enveloping large particles to form a "cushion," allowing mechanical force to directly reach the uncrushed particles, resulting in micron-sized calcium carbide slag particles. This significantly increases the specific surface area of ​​the calcium carbide slag, solving the agglomeration and clumping problem of calcium carbide slag-based calcium hydroxide in the desulfurization process.

[0011] The following are preferred technical solutions of the present invention, but are not intended to limit the technical solutions provided by the present invention. The technical objectives and beneficial effects of the present invention can be better achieved and realized through the following preferred technical solutions.

[0012] As a preferred embodiment of the present invention, the dispersing device includes a slurry tank and a stirrer.

[0013] A first pump is provided between the dispersing device and the screening device, the first pump being used to transport the slurry from the dispersing device to the screening device.

[0014] As a preferred embodiment of the present invention, the screening device includes a drum screen.

[0015] The drum screen is installed at an angle on the frame.

[0016] The drum screen includes a rotating cylinder and a screen fixed inside the rotating cylinder.

[0017] The screen includes any one of metal screens, synthetic material screens, or special material screens.

[0018] It should be noted that the above-mentioned synthetic materials refer to polyethylene (PE), polypropylene (PP), nylon (PA) or polyester (PET), etc., while special material screens refer to stainless steel, titanium alloy, ceramic, glass fiber, carbon fiber composite mesh or polytetrafluoroethylene, etc.

[0019] The mesh size of the screen is 1.8mm to 2.2mm, for example, 1.8mm, 1.9mm, 2mm, 2.1mm or 2.2mm.

[0020] The discharge port is located at the lowest radial point of the rotating cylinder, and the discharge outlet is located at the lowest axial point of the rotating cylinder.

[0021] Understandably, in this invention, the electric motor is connected to the rotating cylinder via a reducer and a coupling, driving the rotating cylinder to rotate around its axis. When the carbide slag slurry enters the drum screen, the tilting and rotation of the drum screen causes the carbide slag slurry on the screen surface to tumble and roll, so that qualified material (undersize product) is discharged through the discharge port at the lowest radial point of the rotating cylinder, and unqualified material (oversize product) is discharged through the discharge port at the lowest axial point of the rotating cylinder.

[0022] As a preferred technical solution of the present invention, a second pump is provided between the screening device and the cyclone device, the second pump being used to transport the slurry at the discharge port to the cyclone device.

[0023] The swirling device includes a swirler.

[0024] The number of cyclones is two.

[0025] The overflow outlet is located at the top of the vortex device, and the underflow outlet is located at the bottom of the vortex device.

[0026] As a preferred embodiment of the present invention, the reaction apparatus includes a reaction tank and a stirrer.

[0027] The ultrafine grinding device includes a sand mill.

[0028] A third pump is provided between the reaction device and the ultrafine grinding device, and the third pump is used to transport the slurry from the outlet of the reaction device to the ultrafine grinding device.

[0029] The ultrafine grinding device includes a first outlet and a second outlet. The first outlet is connected to the first filtration and drying device, and the second outlet is connected to the reaction device.

[0030] As a preferred embodiment of the present invention, the outlet of the coarse slag storage tank is connected to a second filtration and drying device.

[0031] The first filtration and drying device and the second filtration and drying device each independently include a solid product outlet and a liquid product outlet, and the liquid product outlet is connected to the interior of the dispersion device.

[0032] In a second aspect, the present invention provides a method of using the apparatus for preparing calcium hydroxide from carbide slag as described in the first aspect, the method comprising:

[0033] (1) Add carbide slag and water to the dispersion device to disperse the particles and obtain carbide slag slurry. The slurry enters the screening device for preliminary separation of impurity particles. The slurry at the discharge port enters the cyclone device for secondary separation of impurity particles. The slurry at the overflow outlet enters the reaction device. The slurry at the underflow outlet and the discharge port enters the coarse slag storage tank.

[0034] (2) Add the surface modifier to the reaction device described in step (1), mix evenly, and then transport it to the ultrafine grinding device for particle crushing and dispersion. Finally, it enters the first filtration and drying device to obtain the first filtrate and calcium hydroxide powder.

[0035] The entire preparation process of this invention is simple to operate, economical, efficient, and environmentally friendly, significantly improving the feasibility and economy of preparing high specific surface area calcium hydroxide from carbide slag.

[0036] As a preferred technical solution of the present invention, the concentration of the carbide slag slurry in the dispersion device in step (1) is 5wt%~25wt%, for example 5wt%, 8wt%, 10wt%, 15wt%, 18wt%, 20wt% or 25wt%, etc.

[0037] In this invention, by controlling the concentration of the carbide slag slurry in the dispersion device within the above-mentioned preferred range, it can be ensured that the carbide slag is fully dispersed in water to form a uniform slurry, which helps in the subsequent impurity removal process and improves the removal efficiency of impurities in the carbide slag.

[0038] The dispersion described in step (1) is carried out by stirring.

[0039] The dispersion time in step (1) is 20 min to 600 min, for example, 20 min, 1 h, 2 h, 3 h, 4 h, 5 h, 6 h, 7 h, 8 h, 9 h or 10 h.

[0040] The stirring speed is 50 rpm to 300 rpm, for example, 50 rpm, 100 rpm, 150 rpm, 200 rpm, 250 rpm or 300 rpm.

[0041] The temperature of the carbide slag slurry in the dispersion device in step (1) is 20℃~70℃, for example, 20℃, 30℃, 40℃, 50℃, 60℃ or 70℃.

[0042] In this invention, by controlling the stirring speed, temperature, and time during the dispersion process, the overall effect of impurity removal from carbide slag can be significantly improved. The aforementioned stirring speed ensures sufficient dispersion of the carbide slag in water, avoiding particle agglomeration, and also reduces the risk of material damage caused by excessive shearing. The aforementioned temperature helps improve processing efficiency while preventing unnecessary side reactions or component volatilization losses due to excessively high temperatures. The aforementioned time ensures that all components reach an optimal mixing state.

[0043] The feed flow rate of the cyclone device in step (1) is 2m³. 3 / h~3m 3 / h, for example, 2m 3 / h, 2.1m 3 / h, 2.2m 3 / h, 2.3m 3 / h, 2.5m 3 / h, 2.7m 3 / h, 2.8m 3 / h or 3m 3 / h, etc., with a feed pressure of 0.2MPa~1MPa, such as 0.2MPa, 0.3MPa, 0.5MPa, 0.7MPa, 0.8MPa or 1MPa, etc.

[0044] As a preferred technical solution of the present invention, the slurry after being crushed and dispersed by the ultrafine grinding device in step (2) is returned to the reaction device to continue reacting with the surface modifier.

[0045] Perform the return process 3 to 5 times, for example, 3, 4 or 5 times.

[0046] The surface modifier in step (2) includes any one or a combination of at least two of the following: coupling agent, surfactant, organic oligomer, unsaturated organic acid, water-soluble polymer or n-butanol.

[0047] It should be noted that, in this invention, organic oligomers refer to low molecular weight polymers formed by a small number of monomer molecules linked by covalent bonds, typically containing 2 to 20 monomer units.

[0048] In this invention, the surface modifier can cope with the complex mineral composition of calcium carbide slag, reduce the surface energy of calcium hydroxide, and further improve the dispersion rate between particles. In practical applications, different types of surface modifiers can be selected according to the medium environment, thereby achieving flexible adaptation to different process conditions and meeting the needs of preparing calcium hydroxide with high specific surface area.

[0049] The mass ratio of carbide slag to surface additive in the reaction device in step (2) is 1:(0.005~0.05), for example 1:0.005, 1:0.008, 1:0.01, 1:0.02, 1:0.03, 1:0.04 or 1:0.05, etc.

[0050] In this invention, by controlling the mass ratio of carbide slag and surface modifier within the aforementioned preferred range, sufficient surface modifier can be ensured to participate in the reaction, improving the dispersion effect of carbide slag particles and achieving a significant increase in their specific surface area. Simultaneously, unnecessary side reactions caused by excessive use of surface modifier are avoided. This achieves a significant increase in the specific surface area of ​​carbide slag while also considering cost-effectiveness, maximizing economic efficiency.

[0051] The slurry at the outlet of the coarse slag storage tank is subjected to a second filtration and drying to obtain a second filtrate and coarse slag.

[0052] The first and second filtrates are each independently returned to the dispersion device for recycling.

[0053] As a preferred technical solution of the present invention, the stirring speed of the ultrafine grinding device in step (2) is 1500rpm~2500rpm, for example 1500rpm, 1600rpm, 1800rpm, 2000rpm, 2200rpm, 2400rpm or 2500rpm.

[0054] The grinding time of the ultrafine grinding device in step (2) is 25 min to 35 min each time, for example 25 min, 26 min, 30 min, 31 min, 32 min, 33 min, 34 min or 35 min, etc.

[0055] As a preferred technical solution of the present invention, the coupling agent includes any one or a combination of at least two of titanate coupling agents, silane coupling agents, and aluminate coupling agents.

[0056] The surfactant includes any one or a combination of at least two of anionic surfactants, cationic surfactants, or nonionic surfactants.

[0057] The organic oligomer includes any one or a combination of at least two of polyolefin oligomers, polyethylene wax, or epoxy resin.

[0058] The unsaturated organic acid includes any one or a combination of at least two of acrylic acid, methacrylic acid, or butenoic acid.

[0059] The water-soluble polymer includes any one or a combination of at least two of polyacrylamide, polyethylene glycol, or polyvinyl alcohol.

[0060] In this invention, some groups in the coupling agent can react with various functional groups on the surface of carbide slag to form strong chemical bonds; surfactants can significantly reduce the surface tension of carbide slag slurry, changing the surface state of the system to produce wetting and anti-wetting; organic oligomers can form good wetting, adhesion, and coating effects with carbide slag powder; unsaturated organic acids have both unsaturated double bonds and carboxyl groups, which can better disperse carbide slag materials; water-soluble polymers are hydrophilic polymer materials containing a large number of hydrophilic groups, which is beneficial for the performance control of subsequent resource-based products; n-butanol can be adsorbed on the surface of carbide slag slurry, with its hydrophilic groups extending into the aqueous phase and its hydrophobic groups extending into the air phase, which can significantly reduce the surface tension of the liquid, thereby effectively dispersing particles in the carbide slag slurry. Furthermore, among the above types, n-butanol has the best effect, followed by water-soluble polymer materials, such as polyethylene glycol and / or polyvinyl alcohol.

[0061] As a preferred embodiment of the present invention, the specific surface area of ​​the calcium hydroxide powder is 30 m². 2 / g~60m 2 / g, for example 30m 2 / g、35m 2 / g、40m 2 / g、45m 2 / g, 50m 2 / g、55m 2 / g or 60m 2 / g etc.

[0062] The water content of the calcium hydroxide powder is ≤1wt%, for example, 0.1wt%, 0.2wt%, 0.4wt%, 0.5wt%, 0.6wt%, 0.8wt%, or 1wt%.

[0063] The D90 of the calcium hydroxide powder is 1.8μm to 2.2μm, for example, 1.8μm, 1.9μm, 2μm, 2.1μm or 2.2μm.

[0064] The purity of the calcium hydroxide is ≥90wt%, for example, 90wt%, 92wt%, 94wt%, 95wt%, 96wt%, etc.

[0065] The numerical range described in this invention includes not only the point values ​​listed above, but also any point values ​​within the numerical ranges not listed above. Due to space limitations and for the sake of brevity, this invention will not exhaustively list all the specific point values ​​included in the range.

[0066] Compared with the prior art, the present invention has the following beneficial effects:

[0067] By using the apparatus and method provided by this invention, calcium hydroxide products with high content and high specific surface area can be produced, wherein the purity of calcium hydroxide can reach over 90 wt% and the specific surface area can reach 30 m². 2 / g~60m 2 / g, effectively solves the problem of low specific surface area of ​​calcium hydroxide prepared from carbide slag, and has the advantages of good dispersion effect, simple equipment and low cost, which is conducive to the further high-value utilization of carbide slag. Attached Figure Description

[0068] Figure 1 This is a schematic diagram of the apparatus for preparing calcium hydroxide from carbide slag provided in Example 1.

[0069] In the diagram: 1-Dispersion device; 2-Sieving device; 3-Swirl device; 4-Reaction device; 5-Ultrafine grinding device; 6-First filtration and drying device; 7-Coarse residue storage tank; 8-Second filtration and drying device. Detailed Implementation

[0070] The technical solution of the present invention will be further illustrated below through specific embodiments. Those skilled in the art should understand that the embodiments described are merely illustrative of the present invention and should not be construed as limiting the invention in any way.

[0071] Unless otherwise defined, all technical and scientific terms used herein have the same meaning as commonly understood by one of ordinary skill in the art to which this application pertains; the terminology used herein is for the purpose of describing particular embodiments only and is not intended to limit the application; the terms “comprising” and “having”, and any variations thereof, in the specification and claims of this application are intended to cover non-exclusive inclusion.

[0072] Example 1

[0073] This embodiment provides an apparatus for preparing calcium hydroxide from carbide slag, such as... Figure 1As shown, the device includes a dispersing device 1 and a screening device 2 connected sequentially along the material flow direction. The screening device has a discharge port and a discharge outlet. The discharge port is connected to a cyclone device 3. The cyclone device 3 has an overflow outlet at the top and an underflow outlet at the bottom. The overflow outlet is connected sequentially to a reaction device 4, an ultrafine grinding device 5, and a first filtration and drying device 6. The underflow outlet and the discharge port are connected to a coarse slag storage tank 7 and a second filtration and drying device 8. The screening device is a drum screen, and the ultrafine grinding device is a sand mill. The sand mill has a first outlet and a second outlet. The first outlet is connected to the first filtration and drying device 6, and the second outlet is connected to the reaction device 4. The usage method is as follows:

[0074] (1) Add carbide slag and water to dispersion device 1. Under the conditions of 50℃ and 200rpm, stir with a stirrer for 1h to disperse the carbide slag slurry in the slurry tank, and obtain a carbide slag slurry with a mass concentration of 15wt%. The slurry is then pumped to screening device 2 for preliminary separation of impurity particles. The slurry at the discharge port has a feed flow rate of 2.5m. 3 / h, the feed pressure is 0.5MPa and it is pumped to the cyclone device 3 for secondary separation of impurity particles. The slurry at the overflow outlet enters the reaction device 4, and the slurry at the underflow outlet and the discharge port enters the coarse slag storage tank 7.

[0075] (2) According to the mass ratio of carbide slag to surface modifier in reaction device 4 of 1:0.02, surface modifier n-butanol is added to reaction device 4, stirred evenly, and then pumped to ultrafine grinding device 5. Grinding is carried out at 2000 rpm for 30 min to crush and disperse the particles. After the particles are crushed and dispersed, the resulting slurry is returned to reaction device 4 through the second outlet to continue to react with surfactant. This return process is carried out a total of 4 times. Then, the slurry is sent from the first outlet to the first filtration and drying device 6 for solid-liquid separation and drying to obtain solid product calcium hydroxide powder. The slurry in coarse slag storage tank 7 is sent to the second filtration and drying device 8 for solid-liquid separation to obtain solid product coarse slag. In addition, the filtrate obtained from the first filtration and drying device 6 and the second filtration and drying device 8 is returned to the dispersion device 1 for recycling.

[0076] Example 2

[0077] The difference between this embodiment and Embodiment 1 in terms of device setup is that a second filtration and drying device is not installed after the coarse slag storage tank. The usage method is as follows:

[0078] (1) Add carbide slag and water to a dispersion device. Under the conditions of 20℃ and 300rpm, stir with a stirrer for 20min to disperse the carbide slag slurry in the slurry tank, and obtain a carbide slag slurry with a mass concentration of 5wt%. The slurry is then pumped to a screening device for preliminary separation of impurity particles. The slurry at the discharge port is fed at a flow rate of 2m³ / min.3 The feed pressure is 0.2MPa. The feed is pumped into the cyclone device for secondary separation of impurity particles. The slurry at the overflow outlet enters the reaction device, and the slurry at the underflow outlet and discharge port enters the coarse slag storage tank.

[0079] (2) According to the mass ratio of carbide slag to surface modifier in the reaction device of 1:0.02, sodium polyacrylate surface modifier is added to the reaction device and stirred evenly. Then it is pumped to the ultrafine grinding device and ground at 2000 rpm for 25 min to crush and disperse the particles. After the particles are crushed and dispersed, the resulting slurry is returned to the reaction device through the second outlet to continue to react with the surfactant. After this return process is carried out a total of 4 times, the slurry is sent from the first outlet to the first filtration and drying device for solid-liquid separation and drying to obtain the solid product calcium hydroxide powder. In addition, the filtrate obtained from the first filtration and drying device is returned to the dispersion device for recycling.

[0080] Example 3

[0081] The device in this embodiment is the same as that in Embodiment 1. The method of use is as follows:

[0082] (1) Add carbide slag and water to a dispersion device, and stir for 10 hours at a temperature of 70℃ and a rotation speed of 50 rpm to disperse the carbide slag slurry in the slurry tank, thereby obtaining a carbide slag slurry with a mass concentration of 25wt%. The slurry is then pumped to a screening device for preliminary separation of impurity particles. The slurry at the discharge port is fed at a flow rate of 3m³ / h. 3 The feed pressure is 1MPa and the slurry is pumped into the hydrocyclone device for secondary separation of impurity particles. The slurry at the overflow outlet enters the reaction device, and the slurry at the underflow outlet and discharge port enters the coarse slag storage tank.

[0083] (2) According to the mass ratio of carbide slag to surface modifier in the reaction device of 1:0.02, the surface modifier stearic acid is added to the second slurry. After stirring evenly, it is pumped to the ultrafine grinding device and ground at 2000 rpm for 35 min to crush and disperse the particles. After the particles are crushed and dispersed, the slurry is returned to the reaction device through the second outlet to continue to react with the surfactant. After this return process is carried out a total of 4 times, the slurry is sent from the first outlet to the first filtration and drying device for solid-liquid separation and drying to obtain the solid product calcium hydroxide powder. The slurry at the outlet of the coarse slag storage tank is sent to the second filtration and drying device for solid-liquid separation to obtain the solid product coarse slag. In addition, the filtrate obtained from the first filtration and drying device and the second filtration and drying device is returned to the dispersion device for recycling.

[0084] Example 4

[0085] The difference between this embodiment and embodiment 1 is that the ultrafine grinding device does not have a second outlet, and the crushed and dispersed slurry is not returned to the reaction device 4 in step (2);

[0086] The remaining preparation methods and parameters are consistent with those in Example 1.

[0087] Example 5

[0088] The difference between this embodiment and embodiment 1 is that in step (2), the slurry is returned to the reaction device 4 through the second outlet to continue reacting with the surfactant. This return process is carried out once in total before the slurry is returned to the reaction device 4.

[0089] The remaining preparation methods and parameters are consistent with those in Example 1.

[0090] Example 6

[0091] The difference between this embodiment and embodiment 1 is that in step (2), the slurry is returned to the reaction device 4 through the second outlet to continue reacting with the surfactant. This return process is carried out a total of 2 times before the slurry is returned to the reaction device 4.

[0092] The remaining preparation methods and parameters are consistent with those in Example 1.

[0093] Example 7

[0094] The difference between this embodiment and embodiment 1 is that in step (2), the slurry is returned to the reaction device 4 through the second outlet to continue reacting with the surfactant. This return process is carried out a total of 3 times before the slurry is returned to the reaction device 4.

[0095] The remaining preparation methods and parameters are consistent with those in Example 1.

[0096] Example 8

[0097] The difference between this embodiment and Embodiment 1 is that the ultrafine grinding device is an ultrafine ball mill;

[0098] The remaining preparation methods and parameters are consistent with those in Example 1.

[0099] Example 9

[0100] The difference between this embodiment and Embodiment 1 is that the surface modifier is propylene glycol;

[0101] The remaining preparation methods and parameters are consistent with those in Example 1.

[0102] Example 10

[0103] The difference between this embodiment and embodiment 1 is that in step (2), surface modifier n-butanol is added to the reaction device 4 according to the mass ratio of carbide slag to surface modifier in the reaction device 4 being 1:0.005.

[0104] The remaining preparation methods and parameters are consistent with those in Example 1.

[0105] Comparative Example 1

[0106] The difference between this comparative example and Example 1 is that no reaction device is set up, the overflow outlet of the cyclone device 3 is directly connected to the ultrafine grinding device 5, and no surface modifier is added in step (2).

[0107] The remaining preparation methods and parameters are consistent with those in Example 1.

[0108] Comparative Example 2

[0109] The difference between this comparative example and Example 1 is that the ultrafine grinding device 5 is not set up, and the outlet of the reaction device 4 is directly connected to the first filtration and drying device 6; in step (2), after the surface modifier and slurry are fully mixed, they are directly transported to the first filtration and drying device 6.

[0110] The remaining preparation methods and parameters are consistent with those in Example 1.

[0111] Comparative Example 3

[0112] The difference between this comparative example and Example 1 is that the positions of the ultrafine grinding device 5 and the reaction device 4 are reversed; the slurry at the overflow outlet in step (1) enters the ultrafine grinding device 5, is ground and then transported to the reaction device 4 containing the surface modifier. After the reaction, the slurry returns to the ultrafine grinding device through one of the outlets of the reaction device. This return process is carried out a total of 4 times, and then it is transported to the first filtration and drying device 6 from the other outlet of the reaction device.

[0113] The remaining preparation methods and parameters are consistent with those in Example 1.

[0114] Performance testing

[0115] The specific surface area of ​​the calcium hydroxide prepared in Examples 1-10 and Comparative Examples 1-3 was tested, and the test results are shown in Table 1.

[0116] Table 1

[0117]

[0118] As can be seen from Examples 1-3 in Table 1, calcium hydroxide with high specific surface area can be directly prepared from carbide slag using the device and method of the present invention. As can be seen from the comparison of the data of Example 1 and Comparative Examples 1-3 in Table 1, in the present invention, the ultrafine grinding device and the reaction device work synergistically and are indispensable. It is also necessary to ensure that the reaction device is placed first and the ultrafine grinding device is placed later. Otherwise, the surface modifier cannot play its role in the ultrafine grinding process, and the particle agglomeration cannot be effectively prevented, resulting in a significant decrease in the specific surface area of ​​the prepared calcium hydroxide.

[0119] A comparison of the data from Examples 1 and 2-7 in Table 1 shows that returning the slurry processed by the ultrafine grinding device to the reaction device and reacting it with the surfactant again, followed by another ultrafine grinding process, and repeating this process multiple times, is more beneficial for increasing the specific surface area of ​​the product calcium hydroxide. A comparison of the data from Examples 1 and 8-10 in Table 1 shows that the type of ultrafine grinding device, the type of surfactant, and the amount of surfactant added also affect the specific surface area of ​​calcium hydroxide. By using the types and amounts of substances within the preferred range of this invention, the specific surface area of ​​calcium hydroxide can be further improved.

[0120] The applicant declares that the above description is only a specific embodiment of the present invention, but the protection scope of the present invention is not limited thereto. Those skilled in the art should understand that any changes or substitutions that can be easily conceived by those skilled in the art within the technical scope disclosed in the present invention fall within the protection and disclosure scope of the present invention.

Claims

1. An apparatus for preparing calcium hydroxide from carbide slag, characterized in that, The device includes a dispersing device and a screening device connected sequentially along the material flow direction. The screening device is provided with a discharge port and a discharge outlet, and the discharge port is connected to a cyclone device. The cyclone device is provided with an overflow outlet and an underflow outlet. The overflow outlet is connected in sequence to the reaction device, the ultrafine grinding device and the first filtration and drying device. The underflow outlet and the discharge port are connected to the coarse slag storage tank. The reaction device is used to perform surface modification treatment on the carbide slag.

2. The apparatus for preparing calcium hydroxide from carbide slag according to claim 1, characterized in that, The dispersion device includes a slurry tank and a stirrer; A first pump is provided between the dispersing device and the screening device, the first pump being used to transport the slurry from the dispersing device to the screening device.

3. The apparatus for preparing calcium hydroxide from carbide slag according to claim 1, characterized in that, The screening device includes a drum screen; The drum screen is installed at an angle on the frame; The drum screen includes a rotating cylinder and a screen fixed inside the rotating cylinder; The screen includes any one of metal screens, synthetic material screens, or special material screens. The mesh size of the screen is 1.8mm~2.2mm; The discharge port is located at the lowest radial point of the rotating cylinder, and the discharge outlet is located at the lowest axial point of the rotating cylinder.

4. The apparatus for preparing calcium hydroxide from carbide slag according to claim 1, characterized in that, A second pump is provided between the screening device and the cyclone device, and the second pump is used to transport the slurry at the discharge port to the cyclone device. The swirling device includes a swirler; The number of hydrocyclones is two; The overflow outlet is located at the top of the vortex device, and the underflow outlet is located at the bottom of the vortex device.

5. The apparatus for preparing calcium hydroxide from carbide slag according to claim 1, characterized in that, The reaction apparatus includes a reaction tank and a stirrer; The ultrafine grinding device includes a sand mill; A third pump is provided between the reaction device and the ultrafine grinding device, and the third pump is used to transport the slurry from the outlet of the reaction device to the ultrafine grinding device. The ultrafine grinding device includes a first outlet and a second outlet. The first outlet is connected to the first filtration and drying device, and the second outlet is connected to the reaction device.

6. The apparatus for preparing calcium hydroxide from carbide slag according to claim 1, characterized in that, The outlet of the coarse slag storage tank is connected to the second filtration and drying device. The first filtration and drying device and the second filtration and drying device each independently include a solid product outlet and a liquid product outlet, and the liquid product outlet is connected to the interior of the dispersion device.

7. A method of using the apparatus for preparing calcium hydroxide from carbide slag as described in any one of claims 1-6, characterized in that, The method of use includes: (1) Add carbide slag and water to the dispersion device to disperse the particles and obtain carbide slag slurry. The slurry enters the screening device for preliminary separation of impurity particles. The slurry at the discharge port enters the cyclone device for secondary separation of impurity particles. The slurry at the overflow outlet enters the reaction device. The slurry at the underflow outlet and the discharge port enters the coarse slag storage tank. (2) Add the surface modifier to the reaction device described in step (1), mix evenly, and then transport it to the ultrafine grinding device for particle crushing and dispersion. Finally, it enters the first filtration and drying device to obtain the first filtrate and calcium hydroxide powder.

8. The method of use according to claim 7, characterized in that, The concentration of the carbide slag slurry in the dispersion device in step (1) is 5wt%~25wt%; The dispersion described in step (1) is carried out by stirring; The dispersion time in step (1) is 20 min to 600 min; The stirring speed is 50 rpm to 300 rpm; The temperature of the calcium carbide slag slurry in the dispersion device in step (1) is 20℃~70℃; The feed flow rate of the cyclone device in step (1) is 2m³. 3 / h~3m 3 / h, with a feed pressure of 0.2MPa~1MPa.

9. The method of use according to claim 7, characterized in that, The slurry, after being crushed and dispersed by the ultrafine grinding device described in step (2), is returned to the reaction device to continue reacting with the surface modifier; Perform the return process 3 to 5 times; The surface modifier in step (2) includes any one or a combination of at least two of the following: coupling agent, surfactant, organic oligomer, unsaturated organic acid, water-soluble polymer or n-butanol; In step (2), the mass ratio of carbide slag to surface additive in the reaction device is 1:(0.005~0.05); The slurry at the outlet of the coarse slag storage tank is subjected to a second filtration and drying to obtain a second filtrate and coarse slag. The first and second filtrates are each independently returned to the dispersion device for recycling.

10. The method of use according to claim 7, characterized in that, The specific surface area of ​​the calcium hydroxide powder is 30m². 2 / g~60m 2 / g; The water content of the calcium hydroxide powder is ≤1 wt%; The D90 of the calcium hydroxide powder is 1.8 μm to 2.2 μm; The purity of the calcium hydroxide is ≥90wt%.

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