Device for preparing calcium carbonate whiskers
By designing a double-tower carbonation reactor, the preparation and synthesis of calcium carbonate whiskers in two reactors were carried out respectively, and the problem of high production costs of existing equipment was solved, and low-cost and high-regular calcium carbonate whisker production was achieved.
Patent Information
- Application Number
- CN202422469777.4
- Authority / Receiving Office
- CN · China
- Patent Type
- Utility models(China)
- Current Assignee / Owner
- Filing Date
- 2024-10-12
- Publication Date
- 2025-06-24
- Estimated Expiration
- 2034-10-12
AI Technical Summary
The cost of producing calcium carbonate whiskers in existing equipment is high, limiting its industrialized large-scale production.
A double tower carbonation reactor was designed. By conducting seed preparation and calcium carbonate synthesis in two reactors, a CO2 intake system combined with a serrated and porous distributor, and an emulsification stirrer, the reaction uniformity and regularity of calcium carbonate whiskers were improved.
It effectively reduces the production cost of calcium carbonate whiskers, improves the regularity and content of the product, is suitable for industrial automation and control production, and has good economic and social benefits.
Smart Images
Figure CN223017038U_ABST
Abstract
Description
Technical Field
[0001] The utility model relates to the technical field of calcium carbonate whisker production, and particularly relates to a device for preparing calcium carbonate whiskers. Background Art
[0002] Inorganic whiskers, a unique new material, stand out with their needle-like, rod-like or fibrous morphology. Thanks to their nearly perfect crystal structure, with an orderly arrangement of internal atoms and few defects, their strength and modulus almost reach the theoretical limit, showing excellent properties comparable to those of complete whisker materials. In addition, inorganic whiskers also have excellent heat resistance and heat insulation characteristics, making them an ideal choice for enhancing the toughness and flame retardancy of materials.
[0003] So far, industrial production has covered various inorganic whiskers such as ZnO, SiC, SiN, mullite and aluminum borate. Although they have made remarkable achievements in technology, the high production cost limits their wide application, and they can only be found in a few specific fields and are difficult to achieve large-scale popularization.
[0004] In contrast, calcium carbonate whiskers have attracted great interest and extensive research in the domestic and international scientific research communities due to their significant advantages such as low raw material cost, rich resources and controllable growth process. Exploring the preparation paths of calcium carbonate whiskers mainly focuses on five methods currently: the double decomposition method, the thermal decomposition method of Ca(HCO3)2, the sol-gel method, the urea hydrolysis method, and the most popular and mature carbonation method. Among them, the carbonation method successfully prepares calcium carbonate whiskers by introducing carbon dioxide into a calcium hydroxide suspension and supplemented with a crystal form control agent. This process not only coincides with the synthesis path of nano calcium carbonate in industry, but also is regarded as a strong candidate for promoting the large-scale industrial production of calcium carbonate whiskers due to its simple process and controllable cost.
[0005] It is worth mentioning that Patent CN111926386A proposed an innovative strategy for preparing calcium carbonate whiskers. Based on high-purity nano calcium oxide, after reacting with deionized water to form a slurry, silk fibroin and gum arabic are ingeniously introduced as crystal form regulators, and then the carbonation reaction is completed in a high-gravity carbonation reactor, finally generating calcium carbonate whiskers. This method has a relatively high cost for producing calcium carbonate whiskers because it uses a high-gravity reactor for reaction and has a high reaction temperature. Content of the Utility Model
[0006] The purpose of the utility model is to provide a device for preparing calcium carbonate whiskers to solve problems such as the relatively high cost of producing calcium carbonate whiskers by existing equipment.
[0007] In order to achieve the above technical purposes, the utility model adopts the following technical solutions:
[0008] An apparatus for preparing calcium carbonate whiskers, comprising a main reaction kettle and an auxiliary reaction kettle. Inside the kettle body of the main reaction kettle, there is a main reaction kettle inner cylinder, which is fixed to the reaction kettle body through a bracket. Inside the inner cylinder, there is a spiral stirrer. At the bottom of the stirrer, there is a serrated distributor, and the distributor is placed above a porous distributor, and the porous distributor is connected to a CO2 inlet; at the upper part of the kettle body, there are a stirring motor I, a main reaction kettle feed pipe, a pH regulator and a tap water inlet, a CO2 inlet, a main reaction kettle tail gas discharge port, an ultrasonic level gauge interface I, and a temperature sensor interface I; at the lower part of the kettle body, there are a temperature sensor interface II, a pH sensor interface I, a discharge port, and a main reaction kettle slurry inlet; inside the reaction kettle, there is a main reaction kettle inner cylinder, and the inner cylinder is connected to the kettle body through an inner cylinder bracket I; the stirring shaft passes through the inner cylinder and is connected to the stirring motor I at the upper part of the reaction kettle. A spiral stirrer is installed on the stirring shaft, and a lower bearing is installed at the lower part of the stirring shaft. The bearing is connected to the reaction kettle body through a bearing bracket. At the end of the stirring shaft is a circular serrated distributor; at the upper part of the auxiliary reaction kettle, there are an ultrasonic level gauge interface II, an auxiliary reaction kettle inlet, an auxiliary reaction kettle exhaust port, a water inlet, and a Ca(OH)2 slurry inlet; at the lower part of the kettle body, there are a temperature sensor interface III, a pH sensor interface II, an auxiliary reaction kettle discharge port, a stirring motor II, and an inspection port; inside the reaction kettle, there is an auxiliary reaction kettle inner cylinder, and the inner cylinder is connected to the auxiliary reaction kettle body through an inner cylinder bracket II; CO2 enters from the auxiliary reaction kettle inlet and is connected to a bottom umbrella-shaped distributor through a pipe, and the pipe passes through the middle of the auxiliary reaction kettle inner cylinder.
[0009] Further, the main reaction kettle is a cylindrical tank body with arc-shaped heads at both the upper and lower parts.
[0010] Further, the diameter of the distributor is 1.1 - 1.35 times the inner diameter of the main reaction kettle inner cylinder.
[0011] Further, the CO2 inlet is connected to the bottom porous distributor plate through a pipe.
[0012] Further, the pH regulator and the tap water inlet are connected to the inside of the main reaction kettle through a pipe, and 4 - 12 spiral nozzles I are provided on the pipe.
[0013] Further, the discharge port is arranged at the bottom of the main reaction kettle, and a discharge valve I is provided.
[0014] Further, the main reaction kettle tail gas discharge port is connected to the auxiliary reaction kettle inlet through a pipe, and then connected to the umbrella-shaped distributor at the bottom of the reaction kettle.
[0015] Further, the auxiliary reaction kettle is a cylindrical tank body with arc-shaped heads at both the upper and lower parts, and its volume is 2 / 3 - 6 / 7 of that of the main reaction kettle.
[0016] Furthermore, the diameter of the umbrella-shaped distributor is 1.2 - 1.5 times the inner diameter of the inner cylinder of the secondary reaction kettle.
[0017] Furthermore, the water inlet is connected to the inside of the secondary reaction kettle through a pipeline, and 4 - 12 spiral nozzles II are arranged on the pipeline.
[0018] Furthermore, the stirring motor II is introduced into the secondary reaction kettle from the bottom, and an emulsifying stirrer is provided.
[0019] Furthermore, the discharge port of the secondary reaction kettle communicates with the feed port of the main reaction kettle through a pipeline, and a discharge valve II and a leak detection port are arranged on the pipeline.
[0020] Compared with the prior art, the present utility model has the following advantages:
[0021] 1. The present utility model designs a double-tower carbonation reaction kettle, which has a simple structure and is convenient to install. It well solves the problem of industrial production of calcium carbonate whiskers, is especially suitable for industrial automatic control production, has low production cost, and has good economic and social benefits.
[0022] 2. The present utility model innovatively carries out seed preparation and calcium carbonate synthesis in two reaction kettles respectively, solves the problems of the harsh conditions required for whisker seed synthesis and the synthesis of amorphous calcium carbonate using low-concentration tail gas, and in the later reaction, uses whiskers to induce the conversion of amorphous calcium carbonate into calcium carbonate whiskers, effectively increasing the content of calcium carbonate whiskers.
[0023] 3. In the present utility model, the gas inlet part of the main reaction kettle adopts a combination of a serrated distributor and a porous distributor, which can disperse the introduced CO2 mixed gas into small bubbles. Under the action of the spiral stirring gas, the CO2 small bubbles react more uniformly with Ca(OH)2. At the same time, the stirrer only has a simple axial flow, which only slightly improves the mixing effect and will not perform high-intensity shearing on the slurry, so that the prepared calcium carbonate whiskers are more regular.
[0024] 4. The secondary reaction kettle of the present utility model adopts an emulsifying stirrer. Through the action of the emulsifying stirrer, amorphous calcium carbonate can be well dispersed in Ca(OH)2.
[0025] 5. The present utility model has the characteristics of environmental optimization and reasonable utilization of resources. It is mainly reflected in that after the reaction in the secondary reaction kettle is completed, a certain amount of water is added to the reaction kettle, which can be used as the tail gas treatment device of the main reaction kettle. The particulate matter-containing tail gas generated by the reaction of the main reaction kettle is washed and then discharged, which can effectively solve the problem of a large amount of particulate matter in the tail gas. The recovered particulate matter is concentrated and filter-pressed and can be sold as a by-product. BRIEF DESCRIPTION OF THE DRAWINGS
[0026] Figure 1This is a schematic structural diagram of the device for preparing calcium carbonate whiskers of the present utility model.
[0027] In the figure, 1 is the main reaction kettle, 100 is the main reaction kettle body, 101 is the stirring motor I, 102 is the main reaction kettle material inlet, 103 is the pH regulator and tap water inlet, 104 is the CO2 inlet, 105 is the temperature sensor interface I, 106 is the temperature sensor interface II, 107 is the pH sensor interface I, 108 is the discharge port, 109 is the main reaction kettle tail gas discharge port, 110 is the ultrasonic level gauge interface I, 111 is the stirring shaft, 112 is the spiral nozzle I, 113 is the inner cylinder of the main reaction kettle, 114 is the spiral stirrer, 115 is the inner cylinder support I, 116 is the lower bearing of the stirrer, 117 is the lower bearing support of the stirrer, 118 is the serrated distributor, 119 is the porous distributor, 120 is the discharge valve I, 2 is the auxiliary reaction kettle, 200 is the auxiliary reaction kettle body, 201 is the ultrasonic level gauge interface II, 202 is the connecting valve, 203 is the auxiliary reaction kettle inlet, 204 is the auxiliary reaction kettle exhaust port, 205 is the water inlet, 206 is the Ca(OH)2 slurry inlet, 207 is the temperature sensor interface III, 208 is the pH sensor interface II, 209 is the maintenance port, 210 is the spiral nozzle II, 211 is the inlet pipe of the auxiliary reaction kettle, 212 is the inner cylinder of the auxiliary reaction kettle, 213 is the inner cylinder support II, 214 is the umbrella-shaped gas distributor, 215 is the emulsifying stirrer, 216 is the stirring motor II, 217 is the discharge port of the auxiliary reaction kettle, 218 is the discharge valve II, 219 is the leak detection port, 220 is the slurry inlet of the main reaction kettle. Specific embodiments
[0028] The following further describes the present utility model in detail with reference to the accompanying drawings and examples:
[0029] Example 1
[0030] As Figure 1 shown, a device for preparing calcium carbonate whiskers is composed of a main reaction kettle 1 and an auxiliary reaction kettle 2; the main reaction kettle 1 is provided with two parts, namely a main reaction kettle body 100 and an inner cylinder 113 of the main reaction kettle. Among them, a stirring motor I 101, a main reaction kettle material inlet 102, a main reaction kettle tail gas discharge port 109 and an ultrasonic level gauge interface I 110 are arranged at the top of the main reaction kettle body 100; a pH regulator and tap water inlet 103, a CO2 inlet 104, a temperature sensor interface I 105, a temperature sensor interface II 106 and a pH sensor interface I 107 are arranged on the outer side of the main reaction kettle body 100. Among them, the pH regulator and tap water inlet 103 is directly connected to the inside of the reaction kettle by a pipeline and is provided with a plurality of spiral nozzles I 112 for adding a pH regulator or cleaning the inside of the reaction kettle; a discharge port 108 is arranged at the bottom of the main reaction kettle body 100. After the reaction is completed, by opening the discharge valve I 120, the material can be discharged.
[0031] The inner cylinder 113 of the main reactor is fixed on the reactor body 100 through the inner cylinder support I 115. A spiral stirrer 114 is arranged inside the inner cylinder. The stirrer is connected to the stirring motor I 101 through the stirring shaft 111, and a serrated distributor 118 is arranged at the bottom of the stirrer. During the stirring process, the serrated distributor 118 rotates with the stirring shaft 111 to shear and disperse the CO2-containing mixed gas introduced. During the stirring process, in order to avoid the problem of shaking and eccentricity of the stirring shaft 111, a lower bearing 116 of the stirrer is arranged at the bottom of the stirring shaft and is connected to the main reactor body 100 through the lower bearing support 117 of the stirrer; directly below the serrated distributor 118 is a porous distributor 119, which is connected to the CO2 inlet 104 through a pipeline, so that the CO2-containing mixed gas is introduced into the bottom of the reactor from outside the reactor for reaction.
[0032] The secondary reactor 2 includes two parts, namely the secondary reactor body 200 and the inner cylinder 212 of the secondary reactor. The top of the secondary reactor body 200 is provided with an ultrasonic level gauge interface II 201, a secondary reactor inlet 203, and a secondary reactor exhaust port 204. The CO2-containing mixed gas that has reacted in the main reactor enters the secondary reactor exhaust port 204 through the main reactor tail gas discharge port 109 and then enters the bottom of the secondary reactor through the secondary reactor inlet pipe 211 and is dispersed by the umbrella-shaped gas distributor 214. The outside of the secondary reactor body 200 is provided with a water inlet 205, a Ca(OH)2 slurry inlet 206, a temperature sensor interface III 207, and a pH sensor interface II 208. The water inlet 205 is directly connected to the inside of the reactor through a pipeline, and a plurality of spiral nozzles II 210 are arranged for cleaning the reactor. The inner cylinder 212 of the secondary reactor is arranged inside the secondary reactor body 200 and is connected and fixed by the inner cylinder support II 213. The middle of the inner cylinder has a secondary reactor inlet pipe 211 passing through from the top to the bottom. After the CO2-containing mixed gas enters the secondary reactor, it is stirred up and down under the action of the inner cylinder 212 of the secondary reactor. The bottom of the secondary reactor body 200 is provided with a stirring motor II 216, a secondary reactor discharge port 217, a discharge valve II 218, a leak detection port 219, and a maintenance port 209. The emulsifying stirrer 215 connected to the stirring motor II 216 is arranged at the umbrella-shaped gas distributor 214 for emulsifying and homogenizing the reaction between the CO2-containing mixture and the Ca(OH)2 slurry. The secondary reactor discharge port 217 is communicated with the main reactor slurry inlet 220, and the amorphous calcium carbonate prepared by the reaction is transported to the main reactor 1 through the secondary reactor discharge port 217 for the next step of reaction.
[0033] The working principle of the application of the device of the present utility model:
[0034] Step 1: Introduce Ca(OH)2 added with a crystal form inhibitor and at a temperature of (50 - 70)°C into the secondary reaction kettle. At the same time, start the emulsifying stirrer to disperse and homogenize the slurry. Then open the connecting valve between the main reaction kettle and the secondary reaction kettle. Wait until the tail gas of the mixed gas with a CO2 concentration of about 30% after reacting in the main reaction kettle is introduced into the secondary reaction kettle, so that the mixed gas with a low CO2 concentration reacts with Ca(OH)2 to prepare an amorphous calcium carbonate intermediate. Then the gas pushes the slurry upward from the outside of the inner cylinder of the secondary reaction kettle, and the liquid in the middle of the inner cylinder of the secondary reaction kettle flows downward to form a circulating flow of the slurry. The prepared amorphous calcium carbonate intermediate is evenly distributed in calcium hydroxide under the disturbance of the gas.
[0035] Step 2: Add tap water to the main reaction kettle, and the addition amount is 1 / 10 - 1 / 7 of the volume of the main reaction kettle. Then introduce a mixed solution of calcium chloride and magnesium chloride with a mass concentration of (1 - 10)% and a ratio of calcium chloride:magnesium chloride = (1 - 5):1 into the main reaction kettle. At the same time, introduce a pH regulator, start the spiral stirrer to stir the materials, and adjust the pH value of the solution in the main reaction kettle to between 10.5 and 11.5. Then introduce a mixed gas with a CO2 concentration of about 30% for reaction. During the reaction process, the pH value remains unchanged all the time. When the pH value is low, reduce the flow rate of the calcium chloride:magnesium chloride mixed solution and increase the flow rate of the pH regulator. When the pH value is high, increase the flow rate of the calcium chloride:magnesium chloride mixed solution and reduce the flow rate of the pH regulator to prepare calcium carbonate whisker seeds. The tail gas after the reaction is transported to the secondary reaction kettle through the tail gas discharge port of the main reaction kettle.
[0036] Step 3: When the pH of the secondary reaction kettle drops to 9.8 - 10.2, close the CO2 inlet, the spiral stirrer and the connecting valve of the main reaction kettle. At the same time, stop adding the calcium chloride:magnesium chloride mixed solution and the pH regulator to the main reaction kettle. Then open the discharge valve II at the bottom of the secondary reaction kettle and close the leak detection valve, so that the calcium carbonate whisker seeds in the main reaction kettle are mixed with the Ca(OH)2 solution containing amorphous calcium carbonate in the secondary reaction kettle. Then introduce compressed air from the tail gas port of the secondary reaction kettle to press all the materials in the secondary reaction kettle into the main reaction kettle.
[0037] Step 4: When all the materials in the secondary reaction kettle enter the main reaction kettle, close the discharge valve II at the bottom of the secondary reaction kettle, open the leak detection valve, stop introducing compressed air, open the tail gas port, the connecting valve and the water inlet of the secondary reaction kettle to clean the secondary reaction kettle, and add 1 / 2 of tap water to the secondary reaction kettle.
[0038] Step 5: Start the spiral stirrer of the main reactor, and introduce a mixed gas with a CO2 concentration of about 30% into the materials in the main reactor for reaction. When the pH of the solution = 7.2, stop the reaction, that is, prepare a calcium carbonate whisker slurry. After that, send the slurry to dehydration, drying, crushing and packaging to obtain a calcium carbonate whisker product. The morphology of the calcium carbonate whisker product is tested according to the method of GB / T19590-2023 "Nano Calcium Carbonate". The morphology of calcium carbonate is needle-shaped (whisker), and the content exceeds 90%.
[0039] The embodiments described above are only descriptions of the preferred modes of the present invention, and do not limit the scope of the present invention. Without departing from the design spirit of the present invention, various deformations and improvements made by those of ordinary skill in the art to the technical solutions of the present invention should fall within the protection scope determined by the claims of the present invention.
Claims
1. A device for preparing calcium carbonate whiskers, characterized in that, It consists of a main reactor and a sub-reactor. The main reactor is provided with an inner cylinder of the main reactor, which is fixed on the reactor body by a bracket. A spiral agitator is provided in the inner cylinder. A serrated distributor is provided at the bottom of the agitator. The distributor is placed above the porous distributor, and the porous distributor is connected with the CO2 inlet. A stirring motor I, a main reactor feed pipeline, a pH regulator and tap water inlet, a CO2 inlet, a main reactor tail gas discharge port, an ultrasonic level meter interface I, and a temperature sensor interface I are provided on the upper part of the reactor body. A temperature sensor interface II, a pH sensor interface I, a discharge port, and a main reactor slurry inlet are provided on the lower part of the reactor body. The reactor is provided with an inner cylinder of the main reactor. The inner cylinder is connected to the kettle body through an inner cylinder bracket Ⅰ; the stirring shaft passes through the inner cylinder and is connected to the stirring motor Ⅰ on the upper part of the reactor, a spiral stirrer is installed on the stirring shaft, a lower bearing is installed at the lower part of the stirring shaft, the bearing is connected to the reactor body through a bearing bracket, and a distributor is provided at the end of the stirring shaft; an ultrasonic level device interface Ⅱ, an air inlet of the auxiliary reactor, an exhaust port of the auxiliary reactor, a water inlet, and a Ca(OH)2 slurry inlet are arranged on the upper part of the auxiliary reactor; a temperature sensor interface Ⅲ, a pH sensor interface Ⅱ, a discharge port of the auxiliary reactor, a stirring motor Ⅱ and an inspection port are arranged on the lower part of the kettle body; an auxiliary reactor inner cylinder is arranged inside the reactor, and the inner cylinder is connected to the auxiliary reactor body through an inner cylinder bracket Ⅱ.
2. The device for preparing calcium carbonate whiskers according to claim 1, wherein The main reactor is a cylindrical tank with arc-shaped heads at the top and bottom.
3. The device for preparing calcium carbonate whiskers according to claim 1, wherein The CO2 inlet is connected to the bottom porous distributor plate through a pipeline.
4. The device for preparing calcium carbonate whiskers according to claim 1, wherein The pH regulator and the tap water inlet are connected to the interior of the main reaction kettle through a pipeline, and 4-12 spiral nozzles I are arranged on the pipeline.
5. The device for preparing calcium carbonate whiskers according to claim 1, characterized in that, The discharge port is arranged at the bottom of the main reaction kettle and is provided with a discharge valve I.
6. The device for preparing calcium carbonate whiskers according to claim 1, characterized in that, The tail gas discharge port of the main reactor is connected to the air inlet of the auxiliary reactor through a pipeline, and then connected to the umbrella-shaped distributor at the bottom of the reactor.
7. The device for preparing calcium carbonate whiskers according to claim 1, characterized in that, The secondary reactor is a cylindrical tank with arc-shaped heads at the top and bottom, and its volume is 2 / 3-6 / 7 of the main reactor.
8. The device for preparing calcium carbonate whiskers according to claim 1, characterized in that, The water inlet is connected to the interior of the secondary reaction kettle through a pipeline, and 4 to 12 spiral nozzles II are arranged on the pipeline.
9. The device for preparing calcium carbonate whiskers according to claim 1, characterized in that, The stirring motor II is introduced into the secondary reaction kettle from the bottom and is provided with an emulsifying stirrer.
10. The device for preparing calcium carbonate whiskers according to claim 1, characterized in that, The discharge port of the secondary reactor is connected to the feed port of the main reactor through a pipeline, and a discharge valve II and a leak detection port are arranged on the pipeline.