A method and device for impurity separation-high-efficiency mineralization-solid-liquid separation of calcium-based solid waste

Abstract

The application belongs to the technical field of CO2 capture and utilization, and provides a method and device for impurity separation-high-efficiency mineralization-solid-liquid separation of calcium-based solid waste. The method comprises an impurity separation device, an efficient mineralization device and a solid-liquid separation device. The calcium-based solid waste is purified by using the primary separation device and the slurry reactor to remove floating coke powder impurities and remove silicon-iron impurities by magnetic separation. The calcium-based solid waste after primary purification is mixed with water from the water tank in the slurry reactor by stirring to form calcium-based solid waste slurry and release calcium ions. The calcium-based solid waste slurry is introduced into the mineralization reactor with CO2 to complete the mineralization reaction and form CaCO3 suspension. The suspension is introduced into the plate and frame filter press for solid-liquid separation to obtain CaCO3. The gas-liquid-solid three-phase reaction occurs simultaneously, the process flow is simple, the time consumption is short, the efficiency is high, the equipment investment and operation cost are low, the reagent can be recycled, there is no secondary pollution, the production energy consumption is low, the product quality is good, carbon emission reduction can be realized, and the like.

Description

Technical Field

[0001] This invention belongs to the field of CO2 capture and utilization technology, specifically relating to a method and apparatus for impurity separation, efficient mineralization, and solid-liquid separation of calcium-based solid waste. Background Technology

[0002] Calcium-based solid waste refers to solid waste containing a large amount of calcium. Common calcium-based solid wastes include carbide slag, steel slag, and desulfurization gypsum. They have both carbon fixation capabilities and certain reactivity, and can fix CO2 into thermodynamically stable carbonates for permanent storage, or synthesize commercially valuable products such as high-quality calcium carbonate, fuels, and polymers.

[0003] The main components of calcium-based solid waste are CaO and Ca(OH)2. In addition, it also contains unreacted carbon particles, SiO2, Al2O3, sulfides, oxides and hydroxides of metals such as magnesium and iron, and a small amount of organic matter. Impurities in calcium-based solid waste affect the treatment process and cost. For example, the presence of large ferrosilicon particles may damage the filter cloth and increase the frequency of filter cloth replacement. On the other hand, the presence of impurities reduces the purity of calcium hydroxide, affecting the subsequent utilization of calcium-based solid waste, such as its application in coatings, as lime in chemical production, as lime in desulfurization, and as calcium carbide slag recycling in the production of calcium carbide.

[0004] With the depletion of fossil fuels, atmospheric CO2 concentrations have increased year by year, leading to a more severe greenhouse effect. Between 1906 and 2005, the global average near-surface atmospheric temperature rose by 0.74°C. This global temperature increase has resulted in changes in sea level rise and rainfall, which will contribute to more frequent extreme weather events such as floods, droughts, heat waves, and hurricanes. Furthermore, it will lead to decreased crop yields, glacial retreat, species extinction, and rampant diseases. Large-scale CO2 storage and fixation are the main pathways for CO2 emission reduction, primarily including geological storage, marine storage, and mineral carbonation fixation. Mineral carbonation fixation of CO2 mimics the natural mineral absorption process of CO2, namely, the reaction of CO2 with ores containing alkaline or alkaline earth metal oxides to form permanent and more stable carbonates. Summary of the Invention

[0005] The purpose of this invention is to provide a method and apparatus for impurity separation, efficient mineralization, and solid-liquid separation of calcium-based solid waste.

[0006] The present invention is achieved by the following technical solution: a device for impurity separation, high-efficiency mineralization, and solid-liquid separation of calcium-based solid waste, the device comprising an impurity separation device, a high-efficiency mineralization device, and a solid-liquid separation device;

[0007] The impurity separation device is a primary separation device. The water tank and the primary separation device are connected to the slurry reactor via hydraulic pumps. A spiral stirrer is installed inside the slurry reactor. Magnets are installed on the inner wall of the primary separation device or on the spiral stirrer.

[0008] The high-efficiency mineralization device is a mineralization reactor connected to the outlet of the slurry reactor sidewall. The mineralization reactor is connected to a CO2 storage tank via a pressure pump, and a CO2 recovery device is connected to the top of the mineralization reactor.

[0009] The mineralization reactor is equipped with an exhaust gas outlet at the top, which is connected to a CO2 recovery device; a CO2 gas inlet is located at the bottom of the mineralization reactor; an aeration tray is located at the top of the CO2 gas inlet; a calcium-based solid waste slurry inlet is located on the bottom side wall of the mineralization reactor corresponding to the aeration tray, and a mineralization product outlet is located on the opposite side wall; a stirring cylinder is located inside the mineralization reactor corresponding to the top of the aeration tray, a paddle agitator is located at the center of the stirring cylinder, several return channels are spaced apart on the side wall of the stirring cylinder, and several baffles are spaced apart extending outward from the wall of the stirring cylinder; two pH meters are symmetrically arranged on the inner side wall of the lower section of the stirring cylinder.

[0010] The solid-liquid separation device is a plate and frame filter press connected to the bottom of the mineralization reactor.

[0011] The CO2 gas inlet is an inverted cone-shaped CO2 gas channel, with a CO2 gas pipe at the bottom of the channel and a CO2 gas inlet on the side wall of the pipe.

[0012] The aeration chassis is provided with several aeration holes at intervals.

[0013] Furthermore, the aeration holes are arranged in a ring at equal intervals outward from the center of the aeration base.

[0014] The calcium-based solid waste is dry calcium-based solid waste, and the primary separation device is a cyclone separator. The inner wall of the cyclone separator (1) is equipped with a magnet and connected to an external air pump; the slurry reactor is a stirred reactor.

[0015] The calcium-based solid waste is wet calcium-based solid waste, the primary separation device is a wet calcium-based solid waste storage tank, the slurry reactor is an aeration tank, a scraping device is installed at the top of the aeration tank, a spiral agitator is installed in the center of the interior, a magnet is installed on the spiral agitator, and the top of the aeration tank is connected to a wastewater sedimentation tank.

[0016] A method for separating impurities, efficiently mineralizing, and separating solids from calcium-based solid waste using the aforementioned apparatus includes the following steps:

[0017] (1) Primary purification: The calcium-based solid waste is purified by using a primary separation device and a slurry reactor to remove floating coke powder impurities and magnetic separation to remove ferrosilicon impurities.

[0018] (2) Releasing calcium ions from calcium-based solid waste: The calcium-based solid waste after initial purification is mixed with water from the water tank in the slurry reactor, and the solid-liquid ratio is adjusted to form calcium-based solid waste slurry, thereby releasing calcium ions;

[0019] (3) High-efficiency mineralization of calcium-based solid waste slurry: The calcium-based solid waste slurry that releases calcium ions in step (2) is introduced into the mineralization reactor with CO2 to complete the mineralization reaction and form CaCO3 suspension;

[0020] (4) Separation of CaCO3: The suspension is passed into a plate and frame filter press for solid-liquid separation to remove water and obtain CaCO3, which is homogeneous calcite (the dry calcium-based solid waste mineralization product is rod-shaped, and the wet calcium-based solid waste mineralization product is block-shaped).

[0021] In step (2), the solid-liquid ratio of the calcium-based solid waste slurry is controlled to be 1:100-1:10; in step (3), the CO2 flow rate is controlled to be 5m / s-20m / s; in step (4), the water content of the CaCO3 obtained after pressure filtration and dewatering is less than 10%.

[0022] The calcium-based solid waste is dry calcium-based solid waste, and the primary separation device is a cyclone separator with a feeding speed of 5m / s-15m / s.

[0023] In step (3), CO2 input is stopped when the pH of the CaCO3 suspension is 6.5-7.5.

[0024] In this invention, the impurity separation device removes impurities such as dry powder, coke powder, and ferrosilicon from the calcium-based solid waste to obtain relatively pure calcium-based solid waste. In the high-efficiency mineralization device, CO2 reacts chemically with the calcium-based solid waste slurry input from the impurity separation device to generate calcium carbonate, thus achieving CO2 fixation. In the high-efficiency mineralization device, a reflux channel is used for slurry recirculation back to the mineralization reactor for further reaction, and a baffle plate is used for separating the mineralization products and the slurry. The reflux channel and baffle plate allow for simultaneous collection of mineralization products and recirculation of unreacted slurry. The aeration chassis is used to change the size of the introduced gas bubbles and prevent mineralization products from accumulating at the bottom of the reactor.

[0025] The calcium-based solid waste described in this invention is an industrial solid waste rich in calcium components. Compared with the prior art, the impurity separation method and device provided by this invention can effectively retain the calcium-containing components in the calcium-based solid waste. Moreover, this invention can realize the simultaneous occurrence and execution of gas-liquid-solid three-phase reactions. The process is simple, time-consuming, efficient, and has low equipment investment and operating costs. The reagents can be recycled, there is no secondary pollution, the production energy consumption is low, the product quality is good, and carbon emission reduction can be achieved to a certain extent. It is an environmentally friendly engineering process. Attached Figure Description

[0026] Figure 1 This is a schematic diagram of the structure of the device for impurity separation, high-efficiency mineralization, and solid-liquid separation of dry calcium-based solid waste according to the present invention.

[0027] Figure 2 This is a schematic diagram of the internal structure of a high-efficiency mineralization device.

[0028] Figure 3 Top view of a high-efficiency mineralization unit;

[0029] Figure 4 Top view of a spiral mixer;

[0030] Figure 5 This is a schematic diagram of the aeration chassis;

[0031] Figure 6 Microscopic morphology of mineralized products after dry calcium-based solid waste treatment;

[0032] Figure 7 A device for impurity separation, high-efficiency mineralization, and solid-liquid separation of wet calcium-based solid waste;

[0033] Figure 8 This is a microscopic morphology image of the mineralized products after wet treatment of calcium-based solid waste.

[0034] In the diagram: 1-Cyclone separator; 2-Water tank; 3-Hydraulic pump; 4-Stirred reactor; 5-Spiral agitator; 6-Air pump; 7-Mineralization reactor; 8-Pressure pump; 9-CO2 storage tank; 10-Plate and frame filter press; 11-Paddle agitator; 12-pH meter; 13-Aeration chassis; 14-Return channel; 15-Baffle plate; 16-Wastewater sedimentation tank. Detailed Implementation

[0035] To make the objectives, technical solutions, and advantages of the embodiments of the present invention clearer, the technical solutions in the embodiments of the present invention will be clearly and completely described below. Obviously, the described embodiments are some embodiments of the present invention, but not all embodiments. Based on the embodiments of the present invention, all other embodiments obtained by those skilled in the art without creative effort are within the scope of protection of the present invention.

[0036] 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 invention pertains, and all materials publicly cited herein and cited by them are incorporated herein by reference.

[0037] Equivalent technologies of the specific embodiments described herein that are readily apparent to those skilled in the art through routine experimentation are included in this application.

[0038] Unless otherwise specified, the experimental methods used in the following examples are conventional methods. Unless otherwise specified, the instruments and equipment used in the following examples are all standard laboratory instruments and equipment; unless otherwise specified, the experimental materials used in the following examples were all purchased from regular biochemical reagent stores.

[0039] Example 1: A schematic diagram of the apparatus provided by this invention for impurity separation, high-efficiency mineralization, and solid-liquid separation of dry calcium-based solid waste is shown below. Figure 1 As shown. The device includes an impurity separation unit, a high-efficiency mineralization unit, and a solid-liquid separation unit;

[0040] The impurity separation device is a cyclone separator 1. The water tank 2 and the cyclone separator 1 are respectively connected to the stirred tank reactor 4 via a hydraulic pump 3. The stirred tank reactor 4 is equipped with a spiral stirrer 5. The inner wall of the cyclone separator 1 is equipped with a magnet and connected to an external air pump 6.

[0041] like Figure 2-4 As shown, the high-efficiency mineralization device is a mineralization reactor 7 connected to the outlet of the side wall of the stirred tank reactor 4. The mineralization reactor 7 is connected to the CO2 storage tank 9 via a pressurization pump 8, and a CO2 recovery device is connected to the top of the mineralization reactor 7.

[0042] The mineralization reactor 7 is provided with an exhaust gas outlet at the top; a CO2 gas inlet at the bottom; an aeration tray 13 at the top of the CO2 gas inlet; a calcium-based solid waste slurry inlet at the bottom side wall of the mineralization reactor 7 corresponding to the aeration tray 13, and a mineralization product outlet at the opposite side wall; a stirring cylinder is provided inside the mineralization reactor 7 corresponding to the top of the aeration tray 13, a paddle agitator 11 is provided at the center of the stirring cylinder, several return channels 14 are provided at intervals on the side wall of the stirring cylinder, and several baffles 15 are provided at intervals extending outward from the wall of the stirring cylinder; two pH meters 12 are symmetrically arranged on the inner side wall of the lower section of the stirring cylinder.

[0043] The solid-liquid separation device is a plate and frame filter press 10 connected to the bottom of the mineralization reactor 7.

[0044] Furthermore, the CO2 gas inlet is an inverted cone-shaped CO2 gas channel, with a CO2 gas pipe at the bottom of the channel and a CO2 gas inlet on the side wall of the pipe.

[0045] like Figure 5 As shown, the aeration base 13 is provided with a plurality of aeration holes at intervals. The aeration holes are arranged in a ring at equal intervals outward with the center of the aeration base 13 as the axis of symmetry.

[0046] The apparatus described in Example 1 is used for impurity separation, high-efficiency mineralization, and solid-liquid separation of dry calcium-based solid waste. Figure 6 As shown, the mineralization products are uniformly shaped rod-shaped CaCO3, and their crystal form is calcite.

[0047] Example 2: Using carbide slag as raw material, the Ca(OH)2 content is approximately 80%, and the density is 2.24 g / cm³. 3 The density of coke powder is 0.4-0.5 g / cm³. 3 By utilizing the difference in density, cyclone separation can be used to remove coke powder impurities.

[0048] The calcium carbide slag storage device is connected in parallel to the air inlet pipe of the cyclone separator. When the cyclone separator starts to intake air, the calcium carbide slag is carried into the cyclone separator for air separation. The feed speed of the calcium carbide slag is controlled at 10.0 m / s, and the removal efficiency of coke powder impurities in the calcium carbide slag is 89.1%.

[0049] The feed rate of carbide slag was controlled at 15.0 m / s, and the removal efficiency of coke powder impurities in the carbide slag was 90.3%.

[0050] Example 3: Using steel slag as raw material, which contains a small amount of ferrosilicon impurities, magnetic separation was used to remove these impurities. Magnets were placed on the inner wall of the cyclone dust collector inlet, and magnetic separation was used to adsorb the ferrosilicon impurities. The removal efficiency of ferrosilicon impurities in the steel slag was 88.2%.

[0051] By changing the position of the magnet and placing it on the inner wall of the middle part of the cyclone dust collector, the ferrosilicon impurities in the steel slag were adsorbed by magnetic separation, and the removal efficiency of ferrosilicon impurities in the steel slag was 86.7%.

[0052] By changing the position of the magnet and placing it on the inner wall at the outlet of the cyclone dust collector, the ferrosilicon impurities in the steel slag were adsorbed by magnetic separation, and the removal efficiency of ferrosilicon impurities in the steel slag was 85.2%.

[0053] Magnets were placed on the inner walls of the cyclone dust collector at the inlet, middle and outlet. Magnetic separation was used to adsorb ferrosilicon impurities, and the removal efficiency of ferrosilicon impurities in steel slag was 91.4%.

[0054] Example 4: Using the carbide slag removed by the cyclone dust collector in Example 2 as raw material, it is mixed with water input from the water tank in a stirred reactor to form carbide slag slurry, so as to release calcium ions in the carbide slag.

[0055] When the ratio of dry carbide slag to water is 1:50, the calcium ion release rate in the carbide slag can reach 87.7%.

[0056] When the ratio of dry carbide slag to water is 1:20, the calcium ion release rate in the carbide slag can reach 89.8%.

[0057] When the ratio of dry carbide slag to water is 1:10, the calcium ion release rate in the carbide slag can reach 93.4%.

[0058] Example 5: Using desulfurized gypsum slurry input from the impurity separation device as raw material. CO2 is introduced into the mineralization reactor from the CO2 storage tank to react chemically with the desulfurized gypsum slurry. When the pH of the mineralization reaction reaches about 7, the CO2 supply is stopped, the mineralization reaction is completed, and a CaCO3 suspension is obtained.

[0059] When the CO2 flow rate is 5.0 L / min, the CO2 absorption rate is 89.2%.

[0060] When the CO2 flow rate is 10.0 L / min, the CO2 absorption rate is 91.4%.

[0061] When the CO2 flow rate is 15.0 L / min, the CO2 absorption rate is 93.1%.

[0062] Example 6: A schematic diagram of the apparatus provided by the present invention for impurity separation, high-efficiency mineralization, and solid-liquid separation of wet calcium-based solid waste is shown below. Figure 7 As shown. The device includes an impurity separation unit, a high-efficiency mineralization unit, and a solid-liquid separation unit;

[0063] The impurity separation device consists of a water tank 2 and a wet calcium-based solid waste storage tank, which are connected to the aeration tank via a hydraulic pump 3. A scraping device is installed at the top of the aeration tank, and a spiral agitator 5 is installed at the center inside. A magnet is installed on the spiral agitator 5. The top of the aeration tank is connected to the wastewater sedimentation tank 16.

[0064] The high-efficiency mineralization device and solid-liquid separation device are the same as those described in Example 1.

[0065] The apparatus described in Example 6 is used for impurity separation, efficient mineralization, and solid-liquid separation of wet calcium-based solid waste.

[0066] Example 7: Impurity separation device using carbide slag slurry as raw material. The density of coke powder is 0.4-0.5 g / cm³. 3 Therefore, aeration can be used to make impurities such as coke powder float on the water surface, thereby achieving the purpose of removal.

[0067] When the aeration velocity is 8 m / s, the removal efficiency of coke powder impurities in carbide slag slurry can reach 87.5%.

[0068] When the aeration velocity is 10 m / s, the removal efficiency of coke powder impurities in carbide slag slurry can reach 90.2%.

[0069] When the aeration velocity is 15 m / s, the removal efficiency of coke powder impurities in carbide slag slurry can reach 93.6%.

[0070] Example 8: Using steel slag slurry as raw material, the steel slag contains a small amount of ferrosilicon impurities, which are removed by magnetic separation. A magnet is installed on a spiral agitator to adsorb the ferrosilicon impurities in the steel slag slurry while it is being stirred with the input water.

[0071] A magnet was placed in the upper part of the spiral agitator submerged in water, and the ferrosilicon impurities were adsorbed by magnetic separation. The removal efficiency of ferrosilicon impurities in steel slag slurry was 85.1%.

[0072] A magnet was placed in the middle of the spiral agitator submerged in water, and ferrosilicon impurities were adsorbed by magnetic separation. The removal efficiency of ferrosilicon impurities in steel slag slurry was 85.4%.

[0073] A magnet was placed in the lower part of the spiral agitator submerged in water, and the ferrosilicon impurities were adsorbed by magnetic separation. The removal efficiency of ferrosilicon impurities in steel slag slurry was 86.1%.

[0074] Magnets were installed in the upper, middle and lower parts of the spiral agitator submerged in water to adsorb ferrosilicon impurities using magnetic separation. The removal efficiency of ferrosilicon impurities in steel slag slurry was 92.7%.

[0075] Example 9: Using carbide slag slurry as raw material, it is mixed with water input from the water tank in the aeration tank to release calcium ions from the carbide slag.

[0076] When the ratio of input carbide slag slurry to input water is 1:50, the calcium ion release rate in carbide slag can reach 89.7%.

[0077] When the ratio of input carbide slag slurry to input water is 1:20, the calcium ion release rate in carbide slag can reach 91.1%.

[0078] When the ratio of input carbide slag slurry to input water is 1:10, the calcium ion release rate in carbide slag can reach 92.9%.

[0079] Example 10: Using desulfurized gypsum slurry input from the impurity separation device as raw material. CO2 is input from the CO2 storage tank into the mineralization reactor to react chemically with the desulfurized gypsum slurry. When the pH of the mineralization reaction reaches about 7, the CO2 input is stopped, the mineralization reaction is completed, and a CaCO3 suspension is obtained.

[0080] When the CO2 flow rate is 5 m / s, the CO2 absorption rate is 90.2%.

[0081] When the CO2 flow rate is 10 m / s, the CO2 absorption rate is 92.4%.

[0082] When the CO2 flow rate is 15 m / s, the CO2 absorption rate is 94.1%.

[0083] The apparatus described in Example 6 is used for impurity separation, efficient mineralization, and solid-liquid separation of wet calcium-based solid waste. Figure 8 As shown, the mineralization products are uniformly shaped massive CaCO3, and their crystal form is calcite.

[0084] Finally, it should be noted that the above embodiments are only used to illustrate the technical solutions of the present invention, and not to limit them; although the present invention has been described in detail with reference to the foregoing embodiments, those skilled in the art should understand that modifications can still be made to the technical solutions described in the foregoing embodiments, or equivalent substitutions can be made to some or all of the technical features; and these modifications or substitutions do not cause the essence of the corresponding technical solutions to deviate from the scope of the technical solutions of the embodiments of the present invention.

Claims

1. A device for impurity separation, high-efficiency mineralization, and solid-liquid separation of calcium-based solid waste, characterized in that: The device includes an impurity separation unit, a high-efficiency mineralization unit, and a solid-liquid separation unit; The impurity separation device is a primary separation device (1). The water tank (2) and the primary separation device (1) are connected to the slurry reactor (4) through a hydraulic pump (3). A spiral stirrer (5) is installed inside the slurry reactor (4). Magnets are installed on the inner wall of the primary separation device (1) or on the spiral stirrer (5). The high-efficiency mineralization device is a mineralization reactor (7) connected to the side wall outlet of the slurry reactor (4). The mineralization reactor (7) is connected to the CO2 storage tank (9) through a pressure pump (8). The top of the mineralization reactor (7) is connected to a CO2 recovery device. The mineralization reactor (7) is provided with an exhaust gas outlet at the top, which is connected to a CO2 recovery device; the mineralization reactor (7) is provided with a CO2 gas inlet at the bottom; an aeration tray (13) is provided at the top of the CO2 gas inlet; a calcium-based solid waste slurry inlet is provided on the bottom side wall of the mineralization reactor (7) corresponding to the aeration tray (13), and a mineralization product outlet is provided on the opposite side wall; a stirring cylinder is provided inside the mineralization reactor (7) corresponding to the top of the aeration tray (13), a paddle agitator (11) is provided at the center of the stirring cylinder, several return channels (14) are provided at intervals on the side wall of the stirring cylinder, and several baffles (15) are provided at intervals on the outward extension of the stirring cylinder wall; two pH meters (12) are symmetrically provided on the inner side wall of the lower section of the stirring cylinder. The solid-liquid separation device is a plate and frame filter press (10) connected to the bottom of the mineralization reactor (7). The CO2 gas inlet is an inverted cone-shaped CO2 gas channel, with a CO2 gas pipe at the bottom of the channel and a CO2 gas inlet on the side wall of the pipe; the aeration base (13) is provided with several aeration holes at intervals; the aeration holes are arranged in a ring with the center of the aeration base (13) as the axis of symmetry and equidistantly outward. The calcium-based solid waste is dry calcium-based solid waste. The primary separation device (1) is a cyclone separator. The inner wall of the cyclone separator (1) is equipped with a magnet and connected to an external air pump (6). The slurry reactor (4) is a stirred tank reactor.

2. The device for impurity separation, high-efficiency mineralization, and solid-liquid separation of calcium-based solid waste according to claim 1, characterized in that: The calcium-based solid waste is wet calcium-based solid waste. The primary separation device (1) is a wet calcium-based solid waste storage tank. The slurry reactor (4) is an aeration tank. A scraping device is installed at the top of the aeration tank, and a spiral stirrer (5) is installed in the center of the tank. A magnet is installed on the spiral stirrer (5). The top of the aeration tank is connected to the wastewater sedimentation tank (16).

3. A method for impurity separation, high-efficiency mineralization, and solid-liquid separation of calcium-based solid waste using the apparatus described in claim 1 or 2, characterized in that: Includes the following steps: (1) Primary purification: The calcium-based solid waste is purified by using the primary separation device (1) and the slurry reactor (4) to remove floating coke powder impurities and remove ferrosilicon impurities by magnetic separation. (2) Releasing calcium ions from calcium-based solid waste: After initial purification, the calcium-based solid waste is mixed with water from the water tank in the slurry reactor (4) to adjust the solid-liquid ratio and form calcium-based solid waste slurry, releasing calcium ions; (3) High-efficiency mineralization of calcium-based solid waste slurry: The calcium-based solid waste slurry that releases calcium ions in step (2) is introduced into the mineralization reactor (7) with CO2 to complete the mineralization reaction and form CaCO3 suspension; (4) Separation of CaCO3: The suspension is passed into a plate and frame filter press (10) for solid-liquid separation to remove water and obtain CaCO3.

4. The method according to claim 3, characterized in that: In step (2), the solid-liquid ratio of the calcium-based solid waste slurry is controlled to be 1:100-1:10; in step (3), the CO2 flow rate is controlled to be 5m / s-20m / s; in step (4), the water content of the CaCO3 obtained after pressure filtration and dewatering is less than 10%, and its crystal form is uniform calcite. The dry calcium-based solid waste mineralization product is rod-shaped, and the wet calcium-based solid waste mineralization product is block-shaped.

5. The method according to claim 3, characterized in that: The calcium-based solid waste is dry calcium-based solid waste, and the primary separation device (1) is a cyclone separator with a feeding speed of 5m / s-15m / s.

6. The method according to claim 3, characterized in that: In step (3), CO2 input is stopped when the pH of the CaCO3 suspension is 6.5-7.5.

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