System and method for preparing light calcium carbonate by co2 recycling absorption-mineralization

Abstract

The application provides a system and a method for preparing light calcium carbonate through CO2 recycling absorption-mineralization, the system is highly integrated, absorption pre-mineralization equipment can efficiently complete carbon capture of low-concentration CO2 industrial flue gas by an absorbent, and can complete flotation separation of light impurities such as flotation residual carbon in alkaline solid waste and decarburization flue gas in the pre-mineralization process, staggered baffles can enhance the pre-mineralization effect, and the baffles can guide particulate matter to smoothly discharge from the bottom outlet through flow guiding, and will not cause obstruction to the upward movement of flue gas microbubbles; a mineralization separator simultaneously completes three processes of CO2 mineralization, absorbent recovery and light calcium carbonate separation through high-speed cyclone action. The system and the method realize capture, utilization and sequestration of low-concentration CO2 in industrial flue gas, resource utilization of calcium-based solid waste to prepare by-product light calcium carbonate in the process, recycling of the CO2 absorbent, fast reaction rate of CO2 mineralization, high CO2 conversion rate, good mineralization effect and good economic benefit.

Description

TECHNICAL FIELD

[0001] The application belongs to the technical field of solid waste resource utilization, and relates to a CO2 absorption-mineralization system and method. BACKGROUND

[0002] The CO2 mineralization technology is to use the calcium and magnesium rich ore or alkaline solid waste to carry out carbonation reaction with CO2 in industrial flue gas, and to permanently store CO2 in the form of solid product carbonate.

[0003] The coal, steel, chemical, papermaking and other industries produce a large amount of fly ash, steel slag, phosphogypsum, white mud, calcium carbide slag and other solid wastes every year, and the greenhouse gas CO2 emission is also large. If the CO2 mineralization is realized on site by using alkaline solid waste and plant flue gas as raw materials, the problem of solid waste accumulation and disposal can be effectively solved, the transportation and treatment cost can be reduced, and the CO2 emission reduction of these industries can be positively affected. The CO2 mineralization technology is to use the calcium and magnesium rich ore or alkaline solid waste to carry out carbonation reaction with CO2 in industrial flue gas, and to permanently store CO2 in the form of solid product carbonate. However, at present, there are few special equipment for alkaline solid waste-CO2 mineralization on the market, the reaction rate of CO2 mineralization is slow by combining the mineralization system, the conversion rate of CO2 is low, the mineralization effect is not ideal, and the economic benefit of system operation needs to be improved. SUMMARY

[0004] In order to solve the problems in the background art, the application provides a system and method for preparing light calcium carbonate by CO2 cyclic absorption-mineralization.

[0005] The system of the application comprises an absorption pre-mineralization device, a rich liquid slurry buffer tank, a rich liquid slurry pump, a mineralization separator, an absorbent lean liquid tank and a feeding pump.

[0006] The middle part of the absorption pre-mineralization device is provided with a plurality of baffle plates distributed in staggered manner, the top part of the absorption pre-mineralization device is provided with a liquid inlet and a gas product outlet, the lower part of the absorption pre-mineralization device is provided with a flue gas inlet, and the bottom part of the absorption pre-mineralization device is connected to the rich liquid slurry buffer through a pipeline to deliver the absorbent rich liquid slurry; the rich liquid slurry buffer tank is connected to the mineralization separator through the rich liquid slurry pump and a pipeline to deliver the absorbent rich liquid slurry.

[0007] The middle part of the absorption pre-mineralization device is provided with a plurality of baffle plates distributed in staggered manner, the top part of the absorption pre-mineralization device is provided with a liquid inlet and a gas product outlet, the lower part of the absorption pre-mineralization device is provided with a flue gas inlet, and the bottom part of the absorption pre-mineralization device is connected to the rich liquid slurry buffer through a pipeline to deliver the absorbent rich liquid slurry; the rich liquid slurry buffer tank is connected to the mineralization separator through the rich liquid slurry pump and a pipeline to deliver the absorbent rich liquid slurry.

[0008] The side of the mineralization separator is provided with a slurry inlet, the top side of the mineralization separator is provided with a lean liquid outlet, and the bottom part of the mineralization separator is provided with a light calcium carbonate outlet.

[0009] Further, the absorption pre-mineralizer comprises a main tank, an atomizing sprayer arranged on the top of the main tank, and a micro-porous flue gas wind chamber arranged at the lower part of the main tank; a plurality of baffles are arranged in the main tank; a liquid inlet and a gas product outlet are arranged above the atomizing sprayer; and a flue gas inlet is arranged on the side of the micro-porous flue gas wind chamber. The atomizing sprayer makes the liquid entering the main tank more evenly fall on the baffles, and the micro-porous flue gas wind chamber makes the flue gas entering the main tank more evenly contact with the liquid, thereby further improving the absorption pre-mineralization effect of CO2.

[0010] Further, the baffles comprise a plurality of downwardly inclined upper baffles and a bottom baffle, the upper baffles and the bottom baffle are arranged on the inner wall of the main tank in a staggered manner, and the bottom of the bottom baffle is provided with a flow guide plate.

[0011] Further, the mineralization separator comprises a cylindrical tank and a conical tank, a slurry inlet is arranged on the joint line of the cylindrical tank and the conical tank in a tangential manner, a lean liquid outlet is arranged on the side of the top of the cylindrical tank, and a light calcium carbonate outlet is arranged at the bottom of the conical tank. The tangential arrangement of the slurry inlet enables the entering mineralization separator to rotate downward along the tangent at a high speed, so as to achieve the best mineralization effect.

[0012] Further, the diameter of the cylindrical tank is D, the diameter of the slurry inlet is 0.15D-0.35D, the diameter of the lean liquid outlet is 0.3D-0.5D, the diameter of the light calcium carbonate outlet is 0.2D-0.3D, and the top angle of the conical tank is 10°-30°.

[0013] The method of the present application comprises the following steps:

[0014] In step one, the mixed solution of the calcium-based alkaline solid waste leaching liquid and the lean liquid of the CO2 absorbent is introduced into the absorption pre-mineralizer from the atomizing sprayer at the top, and the mixed solution flows downward along the baffles; the industrial flue gas is introduced into the absorption pre-mineralizer from the micro-porous flue gas wind chamber at the lower part, to form the upward movement of the flue gas micro-bubbles; the downward flowing mixed solution and the upward moving flue gas micro-bubbles collide in countercurrent in the main tank at the middle part of the absorption pre-mineralizer, the flue gas micro-bubbles react with the calcium-based alkaline solid waste leaching liquid to produce pre-mineralization, the CO2 in the flue gas micro-bubbles is absorbed by the lean liquid of the CO2 absorbent; the produced floating residual carbon and the decarburized flue gas move upward to the upper part of the atomizing sprayer and are discharged, and the produced slurry of the absorbent rich liquid is discharged from the bottom;

[0015] Step two, after the absorption agent rich liquid slurry is merged into the rich liquid slurry buffer tank for homogenization, the rich liquid slurry is transported to the middle side slurry inlet of the mineralization separator through the rich liquid slurry pump, the rich liquid slurry enters the mineralization separator to strengthen the CO2 mineralization reaction to generate products: light calcium carbonate and CO2 absorption agent poor liquid, after the solid-liquid separation of the products in the mineralization separator, the light calcium carbonate is discharged through the bottom light calcium carbonate outlet of the mineralization separator, and the CO2 absorption agent poor liquid is discharged through the poor liquid outlet on the top side of the mineralization separator;

[0016] Step three, the CO2 absorption agent poor liquid discharged from the poor liquid outlet is merged into the absorption agent poor liquid tank, the calcium-based alkaline solid waste leaching liquid is introduced into the absorption agent poor liquid tank, and the mixed liquid of the calcium-based alkaline solid waste leaching liquid and the CO2 absorption agent poor liquid is transported to the atomizing sprayer through the feed pump.

[0017] Further, in the step one, the solid-liquid ratio of the absorption agent rich liquid slurry is 1:(4-10).

[0018] Further, in the step two, the feeding pressure of the rich liquid slurry pump is 0.02-0.2 MPa.

[0019] Compared with the prior art, the system for preparing light calcium carbonate by CO2 recycling absorption-mineralization is highly integrated, the absorption pre-mineralization device can efficiently complete the carbon capture of the low-concentration CO2 industrial flue gas by the absorption agent, and can complete the flotation separation of the flotation residual carbon in the alkaline solid waste and the decarburization flue gas, which are light impurities, in the pre-mineralization process, the staggered baffle plates can prolong the residence time of the calcium-based solid waste leaching liquid to enhance the pre-mineralization effect, and can guide the particulate matter to smoothly discharge from the bottom outlet through the step-by-step flow guiding mode, so as to avoid the blockage of the micropores of the microporous flue gas wind chamber caused by the particulate matter accumulated at the bottom; the staggered baffle plates can ensure the flow guiding effect while not blocking the upward movement of the flue gas bubbles; the mineralization separator can complete the CO2 mineralization, absorption agent recovery and light calcium carbonate separation through the high-speed cyclone effect. Through the system and method of the application, the low-concentration CO2 in the industrial flue gas is captured, utilized and stored, the calcium-based solid waste is resourceized to prepare the by-product light calcium carbonate, the CO2 absorption agent poor liquid can be recycled, the CO2 mineralization reaction rate is high, the CO2 conversion rate is high, the mineralization effect is good, and the economic benefit is good. BRIEF DESCRIPTION OF DRAWINGS

[0020] Figure 1 It is a schematic diagram of the system of the application.

[0021] Figure 2 It is a structural schematic diagram of the baffle plate.

[0022] Figure 3 It is a structural schematic diagram of the mineralization separator.

[0023] Wherein: 1-absorption pre-mineralizer; 1.1-atomizing sprayer; 1.2-main tank; 1.3-upper baffle; 1.31-upper mounting frame; 1.32-upper baffle sub-plate; 1.4-guiding baffle; 1.41-bottom mounting frame; 1.42-bottom baffle sub-plate; 1.43-guiding plate; 1.5-micro-porous flue gas wind chamber; 2-rich liquid slurry buffer tank; 3-rich liquid slurry pump; 4-mineralization separator; 4.1-cylindrical pipe; 4.2-conical tank; 4.3-slurry inlet; 4.4-lean liquid outlet; 4.5-light calcium carbonate outlet; 5-absorbent lean liquid tank; 6-feed pump; 101-calcium-based solid waste leaching solution; 102-CO2absorbent lean liquid; 103-mixed liquid; 104-industrial flue gas; 105-absorbent rich liquid slurry; 106-flotation residual carbon; 107-decarbonized flue gas; 201-light calcium carbonate. DETAILED DESCRIPTION

[0024] The embodiments of the present application will be described in detail with reference to the drawings, but they do not constitute limitations to the present application, and are only examples. Through the description, the advantages of the present application will be more clearly understood. All the modifications directly derived or thought from the disclosure of the present application should be considered as the protection scope of the present application. The positional relationships described in the embodiments are consistent with those shown in the drawings, and the other parts not described in detail in the embodiments are prior art.

[0025] 1. System for preparing light calcium carbonate by CO2 recycling absorption-mineralization

[0026] The system as a whole is shown in Figure 1 The system as a whole is shown in

[0027] The tank body of the absorption pre-mineralizer 1 is composed of the main tank 1.2, the atomizing sprayer 1.1 and the micro-porous flue gas wind chamber 1.5; the main tank 1.2 is provided with multiple baffle plates staggered and distributed therein, the atomizing sprayer 1.1 is arranged at the top of the main tank 1.2, and the micro-porous flue gas wind chamber 1.5 is arranged at the bottom of the main tank 1.2. The inlet of the mixed liquid 103 and the outlets of the flotation residual carbon 106 and the decarbonized flue gas 107 are all arranged above the atomizing sprayer 1.2; the inlet of the industrial flue gas 104 is arranged at the side of the micro-porous flue gas wind chamber 1.5, and the industrial flue gas 104 can form micro-bubbles to rise to the main tank 1.2 via the micro-porous flue gas wind chamber 1.5.

[0028] As shown in Figure 2As shown, the baffle plate consists of multiple downward-sloping upper baffle plates 1.3 and one bottom baffle plate 1.4. The bottom baffle plate 1.4 is located at the lowest part inside the main tank 1.2 to guide the flow. The upper baffle plates 1.3 and the bottom baffle plate 1.4 are staggered and installed on the inner wall of the main tank 1.2. Specifically, the upper baffle plate 1.3 consists of an upper mounting frame 1.31 and multiple upper baffle plates 1.32 spaced apart and installed inside the upper mounting frame 1.31. The two ends of the upper baffle plates 1.32 are fixedly connected to the inner side of the upper mounting frame 1.31. In this embodiment, the two ends of the long side of the upper baffle plates 1.32 are fixedly connected to the inner side of the upper mounting frame 1.31, and the three sides of the upper mounting frame 1.31 are fixedly connected to the inner wall of the main tank 1.2. The bottom baffle plate 1.4 consists of a bottom mounting frame 1.41, multiple upper baffle plates 1.32 spaced apart and installed inside the upper mounting frame 1.31. The system consists of a guide plate 1.43 and multiple bottom baffle plates 1.42 mounted inside the bottom mounting frame 1.41. The two ends of the bottom baffle plates 1.42 and the guide plate 1.43 are fixedly connected to the inside of the bottom mounting frame 1.41. In this embodiment, the two ends of the long side of the bottom baffle plate 1.42 and the two ends of the long side of the guide plate 1.43 are fixedly connected to the inside of the bottom mounting frame 1.41. The guide plate 1.43 is provided with a triangular guide constriction. The three sides of the bottom mounting frame 1.41 are fixedly connected to the inner wall of the main tank 1.2.

[0029] The bottom of the pre-mineralizer 1 is connected to the rich liquid slurry 105 of the absorbent through a pipeline to the rich liquid slurry buffer tank 2, which is used to homogenize the rich liquid slurry 105 of the absorbent. The rich liquid slurry buffer tank 2 is connected to the mineralization separator 4 through the rich liquid slurry pump 3 and pipeline.

[0030] like Figure 3 As shown, the mineralization separator 4 consists of a cylindrical tank 4.1 and a conical tank 4.2 joined together. A tangentially arranged slurry inlet 4.3 is located above the junction of the cylindrical tank 4.1 and the conical tank 4.2, through which the absorbent-rich slurry 105 is injected into the mineralization separator 4. A lean liquid outlet 4.4 for discharging the CO2 absorbent lean liquid 102 is located on the top side of the cylindrical tank 4.1, and a light calcium carbonate outlet 4.5 for conveying light calcium carbonate 201 is located at the bottom of the conical tank 4.2. More specifically, to achieve better mineralization, the diameter of the cylindrical tank 4.1 is D, the diameter of the slurry inlet 4.3 is 0.15D-0.35D, the diameter of the lean liquid outlet 4.4 is 0.3D-0.5D, the diameter of the light calcium carbonate outlet 4.5 is 0.2D-0.3D, and the cone apex angle of the conical tank 4.2 is 10°-30°.

[0031] The lean liquid outlet 4.4 of the mineralization separator 4 is connected to the side of the absorbent lean liquid tank 5 through a pipeline, and the top of the absorbent lean liquid tank 5 is provided with an inlet of the calcium-based alkaline solid waste leaching liquid 101; the mixed liquid 103 of the calcium-based alkaline solid waste leaching liquid 101 and the CO2 absorbent lean liquid 102 is connected to the mixed liquid 103 inlet of the absorption pre-mineralization device 1 through a feed pump 6 and a pipeline, so as to realize the circulation connection of the system.

[0032] 2. A method for preparing light calcium carbonate by CO2 cyclic absorption-mineralization

[0033] Firstly, the mixed liquid 103 of the calcium-based alkaline solid waste leaching liquid 101 and the CO2 absorbent lean liquid 102 is introduced into the absorption pre-mineralization device 1 from the top atomizing sprayer 1.2, and the mixed liquid 103 flows downward along the baffle; the industrial flue gas 104 is introduced into the absorption pre-mineralization device 1 from the lower microporous flue gas air chamber 1.5, and the flue gas micro-bubbles flow upward; the downward mixed liquid 103 and the upward flue gas micro-bubbles collide in the main tank 1.2 in the middle part of the absorption pre-mineralization device 1, the flue gas micro-bubbles react with the calcium-based alkaline solid waste leaching liquid 101 to pre-mineralize, and the CO2 in the flue gas micro-bubbles is absorbed by the CO2 absorbent lean liquid 102; the generated floating residual carbon 106 and the decarburized flue gas 107 flow upward above the atomizing sprayer 1.2 and are discharged, and the generated absorbent rich liquid slurry 105 is discharged from the bottom; wherein the solid-liquid ratio of the absorbent rich liquid slurry 105 is 1:(4-10).

[0034] Then, the absorbent rich liquid slurry 105 is introduced into the rich liquid slurry buffer tank 2 for homogenization, and then is transported to the slurry inlet 4.3 in the middle side of the mineralization separator 4 through the rich liquid slurry pump 3, the feeding pressure of the rich liquid slurry pump 3 is 0.02-0.2 MPa, the rich liquid slurry 105 enters the mineralization separator 4 to strengthen the CO2 mineralization reaction to generate products: light calcium carbonate 201 and CO2 absorbent lean liquid 102, and the products are separated into solid and liquid in the mineralization separator 4, the light calcium carbonate 201 is discharged through the light calcium carbonate outlet 4.5 at the bottom of the mineralization separator 4, and the CO2 absorbent lean liquid 102 is discharged through the lean liquid outlet 4.4 at the top side of the mineralization separator 4.

[0035] Finally, the CO2 absorbent lean liquid 102 discharged from the lean liquid outlet 4.4 is introduced into the absorbent lean liquid tank 5, the calcium-based alkaline solid waste leaching liquid 101 is introduced into the absorbent lean liquid tank 5, and the mixed liquid 103 of the calcium-based alkaline solid waste leaching liquid 101 and the CO2 absorbent lean liquid 102 is transported to the atomizing sprayer 1.2 through the feed pump 6.

[0036] Therefore, through the above steps, the low-concentration CO2 in the industrial flue gas 104 is captured, utilized and sequestrated, the calcium-based solid waste is resourceized to prepare the by-product light calcium carbonate 201, and the cyclic utilization of the CO2 absorbent lean liquid 102 is realized.

[0037] 3. Example

[0038] The paper mill lime mud was used as the calcium-based alkaline solid waste raw material. The chemical composition of the lime mud was 80.31% CaCO3, 1.82% residual NaOH, 7.13% active CaO, 8.02% SiO2, and 1.45% residual carbon. The calcium-based alkaline solid waste leaching solution 101 was separated from the pretreated lime mud and was used later.

[0039] The absorption pre-mineralizer 1 was a 400 L volume reactor. The paper mill lime mud leaching solution flow rate was 200 L / h. The CO2absorbent lean solution 102 was prepared from an organic amine and an amino acid, and the flow rate was 800 L / h. The mixed solution 103 obtained by mixing the calcium-based alkaline solid waste leaching solution 101 and the CO2absorbent lean solution 102 was introduced into the main tank 1.2 of the absorption pre-mineralizer 1 from the top of the atomizing sprayer 1.2. The industrial flue gas 104 was introduced into the main tank 1.2 of the absorption pre-mineralizer 1 from the lower microporous flue gas chamber 1.5. The pre-mineralization reaction time was about 30 minutes. The generated absorbent rich solution slurry 105 containing a small amount of newly generated CaCO3and lime mud CaCO3was discharged from the bottom and was collected into the rich solution slurry buffer tank 2. The absorbent rich solution slurry 105 had a solid-liquid ratio of 1:8. Then, the absorbent rich solution slurry 105 was pumped into the mineralization separator 4 through the rich solution slurry pump 3 at a feeding pressure of 0.1 MPa. The mineralization separator 4 had a volume of about 600 L. The diameter of the cylindrical tank 4.1 of the mineralization separator was 500 mm. The diameter of the slurry inlet 4.3 was 80 mm. The diameter of the lean solution outlet 4.4 was 100 mm. The diameter of the light calcium carbonate outlet 4.5 was 90 mm. The conical top angle of the conical tank 4.2 was 15°.

[0040] The light calcium carbonate 201 separated by the mineralization separator 4 was dried in a drying box at 105°C for 1 h. Analysis showed that the calcium carbonate content was 97.2 wt%, the particle size was 15 μm, and the whiteness was 93.1. According to the industrial precipitated calcium carbonate industry standard HG / T 2226-2010, the quality of the light calcium carbonate met the requirements for papermaking.

[0041] The preferred embodiments of the present application are described in detail above in combination with the drawings and specific examples. However, the present application is not limited to the specific details in the above-described embodiments. Within the technical concept scope of the present application, various simple modifications can be made to the technical solutions of the present application, and these simple modifications all belong to the protection scope of the present application.

Claims

1. A system for the production of light calcium carbonate by CO2 recycling absorption-mineralization, characterized by: It comprises an absorption pre-mineralizer (1), a rich liquid slurry buffer tank (2), a rich liquid slurry pump (3), a mineralization separator (4), an absorbent lean liquid tank (5) and a feed pump (6); The middle part of the absorption pre-mineralizer (1) is provided with a plurality of baffle plates distributed in staggered manner, the top of the absorption pre-mineralizer (1) is provided with a liquid inlet and a gas product outlet, the lower part of the absorption pre-mineralizer (1) is provided with a flue gas inlet, and the bottom liquid outlet of the absorption pre-mineralizer (1) is connected with the rich liquid slurry buffer tank (2) through a pipeline; the rich liquid slurry buffer tank (2) is connected with the mineralization separator (4) through the rich liquid slurry pump (3) and a pipeline; The absorption pre-mineralizer (1) comprises a main tank (1.2), an atomizing sprayer (1.1) arranged at the top of the main tank (1.2) and a microporous flue gas wind chamber (1.5) arranged at the bottom of the main tank (1.2); a plurality of baffle plates are arranged in staggered manner in the main tank (1.2); the atomizing sprayer (1.1) is provided with a liquid inlet and a gas product outlet above; the microporous flue gas wind chamber (1.5) is provided with a flue gas inlet on the side; the baffle plate comprises a plurality of downwardly inclined upper baffle plates (1.3) and a bottom baffle plate (1.4), the upper baffle plates (1.3) and the bottom baffle plate (1.4) are arranged in staggered manner on the inner wall of the main tank (1.2), and the bottom of the bottom baffle plate (1.4) is provided with a flow guide plate (1.43); the bottom baffle plate (1.4) comprises a bottom mounting frame (1.41), a flow guide plate (1.43) arranged on the inner side of the bottom mounting frame (1.41) in a spaced manner and a plurality of bottom baffle sub-plates (1.42), the two ends of the bottom baffle sub-plate (1.42) and the flow guide plate (1.43) are fixedly connected with the inner side of the bottom mounting frame (1.41); the flow guide plate (1.43) is provided with a triangular flow guide necking portion; three sides of the bottom mounting frame (1.41) are fixedly connected with the inner wall of the main tank (1.2); The middle part of the mineralization separator (4) is provided with a slurry inlet (4.3) on the side, the top of the mineralization separator (4) is provided with a lean liquid outlet (4.4) on the side, and the bottom of the mineralization separator (4) is provided with a light calcium carbonate outlet (4.5); the mineralization separator (4) comprises a jointed cylindrical tank (4.1) and a conical tank (4.2), the slurry inlet (4.3) is arranged tangentially above the joint line of the cylindrical tank (4.1) and the conical tank (4.2), the lean liquid outlet (4.4) is arranged on the side of the top of the cylindrical tank (4.1), and the light calcium carbonate outlet (4.5) is arranged on the bottom of the conical tank (4.2); The side of the absorption pre-mineralizer (1) is connected with the lean liquid outlet (4.4) through a pipeline, and the top of the absorption pre-mineralizer (1) is provided with a liquid inlet; the absorption pre-mineralizer (1) is connected with the liquid inlet of the absorption pre-mineralizer (1) through the feed pump (6) and a pipeline.

2. The system for preparing light calcium carbonate by CO2 recycling absorption-mineralization according to claim 1, characterized in that: The upper baffle (1.3) comprises an upper mounting frame (1.31) and a plurality of upper baffle sub-plates (1.32) which are spaced and mounted on the inner side of the upper mounting frame (1.31), and the two ends of the upper baffle sub-plate (1.32) are fixedly connected with the inner side of the upper mounting frame (1.31); three sides of the upper mounting frame (1.31) are fixedly connected with the inner wall of the main tank (1.2).

3. The system for preparing light calcium carbonate by CO2 recycling absorption-mineralization according to claim 1, characterized in that: The diameter of the cylindrical tank (4.1) is D, the diameter of the slurry inlet (4.3) is 0.15D-0.35D, the diameter of the lean liquid outlet (4.4) is 0.3D-0.5D, the diameter of the light calcium carbonate outlet (4.5) is 0.2D-0.3D, and the conical top angle of the conical tank (4.2) is 10°-30°.

4. A method for the production of light calcium carbonate by CO2 cyclic absorption-mineralization based on the system according to any one of claims 1 to 3, characterized in that, The method comprises the following steps: Step one: the mixed solution (103) of the calcium-based alkaline solid waste leaching solution (101) and the CO2 absorbent lean solution (102) is introduced into the absorption pre-mineralizer (1) from the top atomizing sprayer (1.1), and the mixed solution (103) flows downward along the baffle; the industrial flue gas (104) is introduced into the absorption pre-mineralizer (1) from the lower microporous flue gas wind chamber (1.5), and the flue gas micro-bubbles flow upward; the downward flowing mixed solution (103) and the upward flowing flue gas micro-bubbles collide in the main tank (1.2) in the middle of the absorption pre-mineralizer (1), the flue gas micro-bubbles and the calcium-based alkaline solid waste leaching solution (101) have a pre-mineralization reaction, the CO2 in the flue gas micro-bubbles is absorbed by the CO2 absorbent lean solution (102), the generated flotation residual carbon (106) and the decarburized flue gas (107) flow upward to the upper side of the atomizing sprayer (1.1) and are discharged, and the generated absorbent rich liquid slurry (105) is discharged from the bottom; Step two: after the absorbent rich liquid slurry (105) is collected into the rich liquid slurry buffer tank (2) and homogenized, the rich liquid slurry pump (3) is used to convey the absorbent rich liquid slurry (105) to the slurry inlet (4.3) on the side of the middle of the mineralization separator (4), the rich liquid slurry (105) enters the mineralization separator (4) to strengthen the CO2 mineralization reaction to generate products: light calcium carbonate (201) and CO2 absorbent lean solution (102), and after the products are separated into solid and liquid in the mineralization separator (4), the light calcium carbonate (201) is discharged from the bottom light calcium carbonate outlet (4.5) of the mineralization separator (4), and the CO2 absorbent lean solution (102) is discharged from the lean liquid outlet (4.4) on the top side of the mineralization separator (4); Step three: the CO2 absorbent lean solution (102) discharged from the lean liquid outlet (4.4) is collected into the absorbent lean solution tank (5), the calcium-based alkaline solid waste leaching solution (101) is introduced into the absorbent lean solution tank (5), and the mixed solution (103) of the calcium-based alkaline solid waste leaching solution (101) and the CO2 absorbent lean solution (102) is conveyed to the atomizing sprayer (1.1) by the feed pump (6).

5. The method for preparing light calcium carbonate by CO2 recycling absorption-mineralization according to claim 4, characterized in that: In step one, the solid-liquid ratio of the absorbent rich liquid slurry (105) is 1: (4-10).

6. The method for preparing light calcium carbonate by CO2 recycling absorption-mineralization according to claim 4 or 5, characterized in that: In step two, the feeding pressure of the rich liquid slurry pump (3) is 0.02-0.2 MPa. In step one, the solid-liquid ratio of the absorbent rich liquid slurry (105) is 1: (4-10). In step two, the feeding pressure of the rich liquid slurry pump (3) is 0.02-0.2 MPa.

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