TW202000596A - Synthesizing system for in-situ producing calcium carbonate whisker with adhering particles and method of producing the same - Google Patents

Abstract

An synthesizing system for in-situ producing calcium carbonate whisker, which including a limestone furnace for thermally decomposing limestone into quicklime and carbon dioxide exhaust, a lime slaking tank for slaking the quicklime into milky calcium hydroxide limewater, a crystallization inducer tank for mixing the calcium hydroxide limewater and water-soluble magnesium salts as crystallization inducer into mixed liquor, and an in-situ synthesizing tank for blowing the carbon dioxide exhaust into the mixed liquor to form defective calcium carbonate whiskers with spherical-like calcium carbonate particles adhering therearound, wherein the surface area of defective calcium carbonate whisker has increased by at least 150% in comparison to the one of pure phase calcium carbonate whisker without adhering calcium carbonate particles.

Description

Synthetic system for generating in-situ defective calcium carbonate whiskers with particle coating and its in-situ synthesis method

The present invention is generally related to a calcium carbonate whisker synthesis system, more specifically, it relates to an in-situ synthesis system for calcium carbonate whiskers and globular calcium carbonate and its in situ resolve resolution.

Calcium carbonate is one of the most abundant mineral resources in the earth's crust, and it plays an important role in many industrial production applications. For example, calcium carbonate fine powder has been widely used as an inorganic filler in plastics, rubber, ink, paper and other industries use. At present, the industrially used calcium carbonate products are mainly heavy calcium and light calcium, of which heavy calcium is mainly derived from natural mineral resources, such as calcite, limestone and marble. Light calcium, also known as precipitated calcium carbonate, is mainly light calcium carbonate that is precipitated through the reaction of carbonate (CO ^3- ) and calcium ions (Ca ²⁺ ). Although the molecular composition of calcium carbonate is the same, it will produce different crystal forms or structures during the process of formation and precipitation, and the physical and chemical properties displayed will also be significantly different.

The industry has discovered that fiber-type inorganic minerals have special material strengthening functions many years ago. For example, fiber-reinforced plastic (FRP) and other polymer-based composite materials are currently used. In recent years, researches have found whiskers The type of calcium carbonate has very good strengthening and toughening properties. Whisker refers to short fibers grown in the form of single crystals. Because there are few defects in the crystalline form, they will have extremely high strength, elastic modulus, heat resistance and heat insulation performance, and when used as a reinforcing material, they have better performance than short fiber materials. Processing performance, but there are a certain amount of surface defects or whiskers attached with an appropriate amount of impurities, which does not have much impact on its strength. It can slightly increase the specific surface area, which is conducive to the combination of polymer substrates and whiskers, and gives semi-crystalline polymers more More nucleation points make the reinforcement effect more obvious. Using calcium carbonate whiskers as fillers can improve the mechanical, flame retardant, heat resistance and processing characteristics of plastic products, or improve the gloss and transparency of inks for the preparation of high-grade paper, and can be used as friction materials to improve wear resistance. Therefore, calcium carbonate whiskers now have a broad application prospect.

In the industry today, there is still room for improvement in the production of calcium carbonate whiskers, such as how to effectively increase the output of whiskers, reduce the amount of additives needed to save costs and avoid pollution, and conduct calcium carbonate whiskers. Surface modification to further enhance its efficacy and so on. How to achieve the above-mentioned demands is now urgently needed by researchers and developers in the field.

In order to give readers a basic understanding of the orientation of the present invention, the following paragraphs present a brief description of the present invention. This summary is not an exhaustive overview of the content of the present invention, and it is not intended to indicate all the key or necessary elements of the present invention or to limit the scope of the present invention. Its appeal is only to describe the details of the invention that will be discussed later. The simplified form presents some of these concepts.

The purpose of the present invention is to propose a calcium carbonate whisker synthesis system and related processes, which can synthesize defective calcium carbonate whiskers and generate in-situ spherical calcium carbonate attached to the surface of the calcium carbonate whiskers, and its process Less additives need to be used, which can effectively save costs and avoid pollution.

One aspect of the present invention is to propose an in-situ synthesis system for producing calcium carbonate whiskers, which includes a lime furnace, which can heat and decompose limestone into quick lime and carbon dioxide waste gas under a high temperature environment, and a lime digestion tank, which can be digested with water Quicklime becomes a calcium hydroxide lime milk and a crystal form inducer mixing tank. The calcium hydroxide lime milk and a water soluble magnesium salt as a crystal form inducer can be mixed in a certain ratio to form a mixed solution and an in-situ synthesis reaction tank. The mixed liquid is fed with the carbon dioxide waste gas as a reaction gas to perform aeration reaction, and at the same time form defective calcium carbonate whiskers and spherical calcium carbonate, wherein a plurality of the spherical calcium carbonate are coated in the form of particles in the defect Around the calcium carbonate whiskers, the surface area of the defect-type calcium carbonate whiskers with particle coating is increased by at least 150% compared to the surface area of the pure phase defect-free calcium carbonate whiskers not coated with the spherical calcium carbonate.

Another aspect of the present invention is to propose an in-situ synthesis method for forming calcium carbonate whiskers and globular calcium carbonate. The steps include heating and decomposing limestone into quick lime and carbon dioxide waste gas under high temperature environment, adding water to digest the quick lime to become hydroxide Calcium lime milk, the calcium hydroxide lime milk and the water-soluble magnesium salt as a crystal form inducer are mixed in a certain ratio to form a mixed liquid, and the carbon dioxide waste gas is passed into the mixed liquid to perform aeration reaction to be synthesized in situ Defective calcium carbonate whiskers and spherical calcium carbonate attached to the surface of the calcium carbonate whiskers, wherein the surface defects of the defective calcium carbonate whiskers and the spherical calcium carbonate increase the surface roughness of the calcium carbonate whiskers and Increase the surface area of the calcium carbonate whiskers by at least 150%.

Such and other objects of the present invention will inevitably become more apparent after the reader has read the detailed description of the preferred embodiments described below with various figures and drawings.

In the detailed description of the present invention below, element symbols will be marked as part of the accompanying drawings, and will be expressed in a special way of describing this embodiment. Such embodiments will illustrate enough details to enable those of ordinary skill in the art to implement them. For clarity of illustration, the thickness of some components may be exaggerated in the illustration. The reader should understand that other embodiments can be used in the present invention or structural, logical, and electrical changes can be made without departing from the embodiments. Therefore, the detailed description below is not intended to be regarded as a limitation; on the contrary, the embodiments contained therein will be defined by the scope of the accompanying patent application.

The content of the present invention which will be mentioned in the following, especially the steps and other details of the synthesis method for the production of defective calcium carbonate whiskers and spherical calcium carbonate attached to the surface of the calcium carbonate whiskers, should be aware of these Technical details and specific examples also apply to the products of the invention and their uses.

In the terminology used in the present invention, the words "slurry" or "suspension" include insoluble solids and water and other additives as appropriate, and usually contain a large amount of solids and are therefore more viscous and typically have Higher density than the liquid forming it.

In the case where the term "comprising" is used in the description of the present invention and the scope of patent application, it does not exclude other non-specific elements having primary or secondary functional importance. If, in the following, a group is defined as including at least a certain number of specific examples, then this is also understood as disclosing a group consisting of such specific examples. Whenever the terms "containing" or "having" are used, these terms mean equivalent to "including" as defined above.

Unless otherwise specified, in the case of the use of indefinite or definite articles when referring to singular nouns (such as "a" or "the"), this includes the plural of that noun.

The following are non-limiting examples of the invention. The in-situ synthesis method of calcium carbonate whiskers of the present invention contains two modes of batch production and continuous production, and the flow block diagrams thereof are disclosed in FIG. 1 and FIG. 2 respectively.

Please refer to FIG. 1, which illustrates an in-situ synthesis method for forming calcium carbonate whiskers and spherical calcium carbonate in a batch production mode according to an embodiment of the present invention. At the beginning of the step, calcium oxide is first prepared as a raw material for the reaction. The limestone raw material will be firstly decomposed into quick lime (calcium oxide, CaO) and high-temperature high-concentration carbon dioxide (CO ₂ ) waste gas in the lime furnace 101, and its reaction formula is as follows (1): CaCO ₃ → CaO + CO ₂ ( 1)

Any natural rock with calcium carbonate (CaCO ₃ ) as the main component, such as limestone, chalk rock, dolomite, etc., can be used as a source of limestone raw material to produce lime in this step. The lime furnace 101 may be a mechanized vertical kiln, a semi-mechanized vertical kiln, a rotary kiln, a boiling furnace and other high-temperature heating equipment, in which the limestone raw material is burnt and decomposed at a temperature of 850°C to 1100°C. After the decomposition reaction, the carbon dioxide concentration in the exhaust gas is about 35%-50%.

After the limestone is decomposed at high temperature to form quicklime, the formed quicklime is digested with water in the lime digestion tank 103 to form calcium hydroxide (Ca(OH) ₂ ) lime milk, also known as slaked lime or slaked lime, as a subsequent in-situ synthesis The reaction raw materials of the method are shown in the following formula (2): CaO + H ₂ O → Ca(OH) ₂ (2)

Water and quick lime can be mixed in the ratio of 1:4~1:9. The formed calcium hydroxide lime milk is evenly stirred at a high speed in the lime digestion tank 103, and the bottom sedimentation coarse particles and residues are removed through multiple sedimentation classification and slag removal operations to obtain a refined raw material slurry. Lime will be exothermic in the digestion reaction, and its digestion temperature is preferably maintained at 45℃~65℃. The specific surface area (BET) of the calcium hydroxide product obtained by the above reaction needs to be between 8~15m ² /g (square meter Feet/g) to meet the adsorption efficiency required in the subsequent reaction of raw materials.

After the preparation of calcium hydroxide lime milk is completed, wait for the lime milk to cool down to near normal temperature, and then in the crystal form inducing agent mixing tank 104, the calcium hydroxide lime milk and the water soluble magnesium salt as the crystal form inducing agent must be Proportionally mixed into a mixed solution. The water-soluble magnesium salt may be selected from magnesium chloride (MgCl ₂ ), aqueous magnesium chloride (MgCl ₂ •6H ₂ O), or magnesium fluoride (MgBr ₂ ) and other components, which are present in lime milk It will promote the directional growth of the metastable needle-like aragonite calcium carbonate crystals formed in the subsequent process to become whiskers. In this compounding step, the concentration of lime milk and the concentration of the crystal form inducing agent will be controlled, so that the molar ratio of magnesium ion (Mg ²⁺ ) and calcium ion (Ca ²⁺ ) fed in the mixed solution is between 2 and 6 . If too little magnesium salt is added, there will be serious batch differences in the reaction, and the product yield is too small. Too much magnesium salt will cause the entire process cost to increase and its waste liquid treatment is not easy. The crystal type inducer preparation tank 104 may include a recovery transfer tank, a recovery processing tank, and a concentration control tank. Magnesium ions will not be consumed in the manufacturing process, and the part remaining in the product will be washed away in the subsequent water washing process. The crystal type inducer preparation tank 10 can recover and reuse the crystal type inducer after the reaction to reduce magnesium Salt usage and treatment costs.

After mixing the mixed liquid of calcium hydroxide lime milk and crystal form inducer, the aeration reaction of calcium hydroxide and carbon dioxide is carried out next. The carbon dioxide waste gas collected in the previous limestone calcination process will pass into the in-situ synthesis reaction tank 105 at this stage to react with the calcium hydroxide in the mixed liquid in the tank. The reaction formula is as follows (3): Ca (OH) ₂ + CO ₂ → CaCO ₃ (3)

The calcium carbonate produced by this aeration reaction is aragonite in metastable state, which will be converted into the most stable calcite in a very short time under normal conditions, but due to the magnesium-based crystal With the addition of the type inducer, the energy barrier between the metastable state and the most stable state of calcium carbonate will increase, preventing the development of calcium carbonate to the most stable state and continuing to grow in the aragonite state, eventually becoming whiskers. The in-situ synthesis reaction tank 105 used at this stage may be a stainless steel tube tank body, which is easy to realize a reactor with a height-to-diameter ratio of at least 10 or more, to meet the needs of industrial production. There may be multiple aeration manifolds in the in-situ synthesis reaction tank 105, as shown in FIG. 3, it is looped at the bottom of the in-situ synthesis reaction tank 105 and will be in the same direction as the bottom of the in-situ synthesis reaction tank 105 The angle of inclination, such as 30-70°. The aeration manifold 110 can pass the carbon dioxide waste gas into the mixed liquid of calcium hydroxide lime milk and crystal form inducer, and can perform the switching operation of the individual aeration manifold 110. The switch configuration of the aeration manifold 110 and the annular arrangement toward the bottom of the tank can generate a regular air flow in the mixed liquid to make the aeration reaction more uniform, and the flow rate of the exhaust gas into the mixed liquid can be 100L/min -1000L/min (liters/minute), where the concentration of carbon dioxide in the exhaust gas is about 8%-25%. The high-diameter ratio crystal growth environment of the in-situ synthesis reaction tank 105 can prolong the time that the reaction gas stays in the reaction liquid, and the turbulent flow of carbon dioxide gas generated by the aeration manifold can stir the mixing liquid to increase the utilization rate of the reaction gas.

The process temperature in the in-situ synthesis reaction tank 105 is preferably maintained between 70°C and 90°C, which can be achieved by adding steam, high-temperature carbon dioxide waste gas, or directly using a heater. The in-situ synthesis reaction tank 105 has a spontaneous powder particle size and passivation surface control mechanism. The initially nucleated powder in the reaction liquid will be taken up by the air flow and liquid flow in the tank, which is suspended in the reaction liquid After growing to a specific particle size, it sinks away from the main reaction zone due to weight increase. Therefore, the particle size of the prepared calcium carbonate whiskers is quite concentrated. In addition, in the reaction process, if steam is used to heat the lime milk, this can gradually dilute the concentration of the magnesium ion inducer in the reaction liquid, thereby achieving the production conditions of spherical calcium carbonate required by the present invention, so that This type of spherical calcium carbonate is generated in situ and attached to the surface of calcium carbonate whiskers to form primary surface-modified calcium carbonate whiskers. This feature will be described in detail in the embodiments described below.

After the calcium carbonate whisker reaction is completed, the reaction solution is then filtered and washed at the filter water washing machine 106, the initial product is collected by filtration, and the filtrate is recovered to the crystal type inducer mixing tank 104 to make the crystal type inducer To be reused, the initial product water is washed again to remove the residual inducer. Finally, the filtered and washed reaction product will be dried at a temperature of 140°C~180°C in a water storage dryer 107 to remove moisture, and finally a calcium carbonate whisker with uniform particle size and high purity is obtained. The aspect ratio of the calcium carbonate whisker is about 10-25, and the diameter is 0.5-5um.

Reference is now made to FIG. 2, which illustrates an in-situ synthesis method of forming calcium carbonate whiskers and spherical calcium carbonate in a continuous production mode according to an embodiment of the present invention. The embodiment shown in FIG. 2 is similar to the embodiment shown in FIG. 1, the difference is only that there is an additional slurry distribution unit 108 to achieve a continuous production effect. The slurry distribution unit 108 may be a water cyclone separator. The slurry after the water cyclone separation will be divided into a high-concentration slurry containing coarse particles and a low-concentration slurry with small particles. Among them, the high-concentration slurry and the low-concentration slurry The ratio of slurry is about 8~11. In the continuous production mode, the slurry splitting unit 108 will start after the reaction has been carried out for a period of time, and it will return the low concentration product slurry with a diameter of less than 3 μm (micrometer) to the crystal type inducer preparation tank 104 in preparation for the in-situ synthesis reaction again. . At the same time, the high-concentration slurry containing products with a diameter greater than 3 μm continues to be sent to the filtering water washing machine 106 and the water drying machine 107 for filtering, washing, and drying operations. The advantage of such a particle size distribution mechanism is that it can provide continuous production effects. It does not need to wait for the entire tank of the mixed liquid to react completely as in batch production mode for subsequent processing, and it can also improve the batch reaction. At the same time, it can also obtain calcium carbonate whisker products with the same particle size.

The following paragraphs will individually describe the embodiments of the present invention:

[Example 1]

This embodiment uses a batch production mode, the effective reaction volume of the entire in-situ synthesis reaction tank 105 is about 100 liters, and the magnesium ion (Mg ²⁺ ) and calcium ion (Ca ²⁺ ) fed into the crystal type inducing agent mixing tank 104 The molar ratio is about 1 to 3, and the weight percentage of calcium hydroxide in the overall mixed liquid is 1 to 10%. The flow rate of the exhaust gas passing from the aeration manifold 110 is about 150-800 L/min, the carbon dioxide concentration therein is about 8-25%, and the temperature is about 20-50 degrees. The entire in-situ synthesis reaction is heated constantly by steaming, so that the concentration of the magnesium ion inducer in the reaction solution can be gradually diluted while maintaining the reaction temperature. During the reaction, the concentration of magnesium ions as a crystal form inducer is gradually diluted. The final product will obtain defective calcium carbonate whiskers with surface defects and particle coatings. The aspect ratio is increased to about 20, and the diameter is about 2μm. Furthermore, the structure of the calcium carbonate whisker product is shown in Figure 4 and Figure 5, which are scanning electron microscope (SEM) images of the calcium carbonate whisker at a small magnification and a large magnification respectively. It can be seen from Figure 4 that the calcium carbonate whiskers generated under this non-constant reaction environment will have surface defects, and the uneven surface will increase the roughness and surface area. On the other hand, as shown in Figure 5, as the magnesium ion concentration gradually decreases during the reaction, this reaction also synthesizes spherical calcium carbonate in situ, which is directly attached to the defective calcium carbonate in the form of small particles The surface of the whisker increases the surface area of the overall calcium carbonate product by at least 150%, the specific surface area (BET) is between 2 and 3 m ² /g, and the yield is about 90%. The advantage of this batch production method is that the surface modification, modification, and functional second product (spherical calcium carbonate-like) synchronous generation are simultaneously completed at the moment of product synthesis, saving process costs and procedures, but the output will be more continuous production The way is small.

[Comparative Example 1]

This comparative example also adopts batch production mode, the effective reaction volume of the entire in-situ synthesis reaction tank 105 is about 100 liters, and the magnesium ion (Mg ²⁺ ) and calcium ion (Ca ²⁺ ) fed into the crystal type inducing agent mixing tank 104 ) The molar ratio is between 1 and 3, and the weight percentage of calcium hydroxide in the overall mixture is 1 to 10%. The flow rate of the exhaust gas flowing from the aeration manifold 110 is about 150 to 1000 L/min, the carbon dioxide concentration therein is about 8 to 25%, and the temperature is about 20 to 50 degrees. The difference from the foregoing embodiment 1 is that the synthesis reaction in this example is a constant heating method using a general heater, so that the concentration of the magnesium ion inducer in the reaction solution will not be diluted and changed. The structure of the final calcium carbonate whisker product is shown in Figure 6. The calcium carbonate whiskers produced under this constant reaction environment are relatively thick and short, with an aspect ratio of only about 10 and a diameter of about 3.5 μm. Furthermore, this type of calcium carbonate whiskers did not produce surface modification and modification effects, the surface was smooth and free of defects, and there was no spherical calcium carbonate produced as a functional second product at the same time, and the surface area of the overall calcium carbonate product did not increase. The specific surface area (BET) is only between 0.8 and 1.2 m ² /g, and the yield is about 90%.

[Example 2]

This embodiment uses a continuous production mode, and its slurry distribution unit 108 uses a water cyclone to concentrate and distribute the mixed liquid. The effective reaction volume of the entire in-situ synthesis reaction tank 105 is about 100 liters, and the molar ratio of magnesium ion (Mg ²⁺ ) and calcium ion (Ca ²⁺ ) fed in the crystal type inducing agent mixing tank 104 is about 3 to 4 Between, the weight percentage of calcium hydroxide in the overall mixed liquid is 1~10%. The exhaust gas flow from the aeration manifold 110 is about 150~1000L/min, the carbon dioxide concentration is about 8~25%, the temperature is about 50~90 degrees, the high temperature carbon dioxide can be used to maintain the system reaction temperature. After the reaction has proceeded for a period of time, the slurry distribution unit 108 will be started, which sends a high-concentration slurry containing calcium carbonate whisker products with an aspect ratio of about 10 and a diameter of 3 μm or more to the filter water washing machine 106 and the dewatering dryer 107 Carry out the process of filtering, washing and drying. The low-concentration slurry containing calcium carbonate whiskers with a diameter of less than 3 μm is refluxed together to the crystal-type-inducing agent preparation tank 104 to be reacted again. The slurry distribution unit 108 will continue during the reaction period, shut down after 1~4 cycles of the overall system of the treatment system, and take 0.5 kg~2kg every 3~4 hours. During the period, the crystal type inducer preparation tank 104 will continue to feed to maintain the pH value of the system between 8~9.5. The advantage of this continuous production method is that it can achieve the production mode of uninterrupted reaction, particle size control, stable reaction system, and inducing agent reuse. Its output is larger than the batch production method, but it is maintained by using high temperature gas instead of steam. The method of reaction temperature is less able to highlight the advantages of in situ generation of spherical calcium carbonate functional second product. The above are only the preferred embodiments of the present invention, and all changes and modifications made in accordance with the scope of the patent application of the present invention shall fall within the scope of the present invention.

101‧‧‧lime furnace 102‧‧‧lime furnace exhaust gas 103‧‧‧lime digestion tank 104‧‧‧crystal type inducing agent mixing tank 105‧‧‧in-situ synthesis reaction tank 106‧‧‧filter water washing machine 107‧‧‧ Dewatering dryer 108‧‧‧Slurry diversion unit 110‧‧‧Aeration manifold

This specification contains drawings and constitutes a part of this specification in order to enable the reader to have a further understanding of the embodiments of the present invention. These diagrams depict some embodiments of the present invention and illustrate the principles together with the description herein. In these figures: Figure 1 shows the in-situ synthesis method of forming calcium carbonate whiskers and spheroidal calcium carbonate in batch production mode according to an embodiment of the invention; Figure 2 shows the invention according to the invention Embodiments In-situ synthesis method of forming calcium carbonate whiskers and spheroidal calcium carbonate in a continuous production mode; FIG. 3 shows the arrangement of the aeration manifold in the in-situ synthesis reaction tank; FIG. 4 and Figure 5 is a scanning electron microscope image of the calcium carbonate whisker product of the present invention at a smaller magnification and a larger magnification; and Figure 6 is a scanning electron microscope image of a general calcium carbonate whisker product at a lower magnification Microscope image. It should be noted that all the illustrations in this specification are of the nature of illustrations. For the sake of clarity and convenience of illustration, the components in the illustrations may be exaggerated or reduced in size and proportion. Generally speaking, the drawings The same reference symbols will be used to indicate corresponding or similar element features after modification or in different embodiments.

101‧‧‧lime stove

102‧‧‧lime furnace exhaust

103‧‧‧lime digestion tank

104‧‧‧Crystal Forming Agent Mixing Tank

105‧‧‧In-situ synthesis reactor

106‧‧‧filter washing machine

107‧‧‧Drying dryer

Claims (11)

An in-situ synthesis system for producing calcium carbonate whiskers includes: a lime furnace, which heats and decomposes limestone raw materials into quick lime and carbon dioxide waste gas under high temperature environment; a lime digestion tank, digests the quick lime with water to become hydroxide Calcium-lime milk; a crystal form inducing agent mixing tank, mixing the calcium hydroxide lime milk with the water-soluble magnesium salt as the crystal form inducing agent to form a mixed liquid; and an in-situ synthesis reaction tank, which is passed into the mixed liquid Carbon dioxide waste gas is used as a reaction gas to perform aeration reaction, and at the same time form defective calcium carbonate whiskers and spherical calcium carbonates, in which a plurality of spherical calcium carbonates are coated in the form of particles around the defective calcium carbonate whiskers The surface area of the defect-type calcium carbonate whiskers with particle coating is increased by at least 150% compared with the surface area of the pure phase defect-free calcium carbonate whiskers not coated with the spherical calcium carbonate. The in-situ synthesis system for producing calcium carbonate whiskers as described in item 1 of the patent application scope, wherein the in-situ synthesis reaction tank is fed with steam to maintain the temperature of the aeration reaction between 70°C-90°C and gradually diluted The concentration of the mixture. The in-situ synthesis system for producing calcium carbonate whiskers as described in item 1 of the scope of the patent application further includes a slurry splitting unit, which is started after the reaction is carried out for a period of time during continuous production, wherein the slurry splitting unit mixes The defective calcium carbonate whiskers with a diameter of less than 3um and a part of the mixed liquid in the liquid are returned to the crystal type inducer preparation tank, and at the same time, the defective calcium carbonate whiskers with a diameter of more than 3um and a part of the mixed liquid are sent To filter the water washing machine and dehydration dryer to obtain the product. The in-situ synthesis system for producing calcium carbonate whiskers as described in item 3 of the patent application scope, wherein the slurry splitter is a water cyclone separator. An in-situ synthesis system for producing calcium carbonate whiskers as described in item 1 of the scope of the patent application, wherein the in-situ synthesis reaction tank is a stainless steel tube tank with a height-to-diameter ratio of at least 10. The in-situ synthesis system for producing calcium carbonate whiskers as described in item 1 of the scope of the patent application further includes a plurality of aeration manifolds arranged around the bottom of the in-situ synthesis reaction tank and The side wall is inclined at an angle toward the bottom of the tank, and the aeration manifold is used to pass the carbon dioxide waste gas into the mixed liquid. The in-situ synthesis system for producing calcium carbonate whiskers as described in item 1 of the patent application scope, wherein the molar ratio of magnesium ions to calcium ions in the mixed solution is between 1 and 4. An in-situ synthesis method for forming calcium carbonate whiskers and spheroidal calcium carbonate, comprising: heating and decomposing limestone raw materials into quick lime and carbon dioxide waste gas under high temperature environment; adding water to digest the quick lime into calcium hydroxide lime milk ; Mix the calcium hydroxide lime milk with the water-soluble magnesium salt as the crystal form inducer at a certain ratio to form a mixed liquid; and pass the carbon dioxide waste gas into the mixed liquid for aeration reaction to synthesize the defective type in situ Calcium carbonate whiskers and spherical calcium carbonate attached to the surface of the calcium carbonate whiskers, wherein the surface defects of the defective calcium carbonate whiskers and the spherical calcium carbonate increase the surface roughness of the calcium carbonate whiskers and increase the carbonic acid The surface area of calcium whiskers is at least 150%. The in-situ synthesis method for forming calcium carbonate whiskers and spheroidal calcium carbonate as described in item 8 of the patent application scope, wherein the aspect ratio of the calcium carbonate whiskers is between 10-25 and the diameter is between 0.5- Between 5μm. The in-situ synthesis method for forming calcium carbonate whiskers and spheroidal calcium carbonate as described in item 8 of the patent application scope further includes passing steam into the aeration reaction during batch production to react the aeration The temperature is maintained between 70°C-90°C and the concentration of the mixture is gradually diluted. The in-situ synthesis method of forming calcium carbonate whiskers and spheroidal calcium carbonate as described in item 8 of the patent application scope, in which the flow rate of the carbon dioxide waste gas into the mixed liquid is 100L/min-1000L/min, concentration 8-25%.

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