TWI678336B - Synthesizing system for in-situ producing calcium carbonate whisker with adhering particles and method of producing the same - Google Patents

Abstract

The invention proposes an in-situ synthesis system for producing calcium carbonate whiskers, which comprises a lime furnace to heat and decompose limestone into quicklime and carbon dioxide exhaust gas, a lime digestion tank with water to digest the quicklime into calcium hydroxide lime milk, and a crystal form induction An agent preparation tank mixes the calcium hydroxide lime milk with a water-soluble magnesium salt as a crystal form inducer into a mixed solution, and an in-situ synthesis reaction tank passes the carbon dioxide exhaust gas into the mixed solution as a reaction gas for aeration reaction. In order to form a defect-type calcium carbonate whisker with particle coating, the surface area of the defect-type calcium carbonate whisker with particle coating is smaller than that of a pure phase non-defective calcium carbonate whisker that is not coated with such spherical calcium carbonate. Increase surface area by at least 150%.

Description

Synthesis system for in-situ generation of defective calcium carbonate whiskers with particle coating Cum in situ synthesis

The present invention relates generally to a synthetic system of calcium carbonate whiskers, and more specifically, it relates to a synthetic system capable of generating calcium carbonate whiskers and spheroidal calcium carbonate in-situ 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 in plastics, rubber, ink, papermaking and other industries as an inorganic filler. use. At present, there are two types of calcium carbonate products used in industry: heavy calcium and light calcium. Among them, heavy calcium mainly comes from natural mineral resources, such as calcite, limestone and marble. Light calcium, also called precipitated calcium carbonate, is mainly light calcium carbonate 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 in the process of formation and precipitation, and the physical and chemical properties displayed will also have significant differences.

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, research has even found whiskers. Type calcium carbonate has very good strengthening and toughening properties. Whiskers are short fibers grown in the form of single crystals. High strength, elastic modulus, heat resistance and heat insulation performance, and better processing performance than short fiber material when used as a reinforcing material, but there are a certain amount of surface defects or whiskers with a certain amount of impurities attached, which have little effect on its strength It can slightly increase the specific surface area, which is conducive to the combination of the polymer substrate and the whiskers, and gives more nucleation points to the semi-crystalline polymer, so that the reinforcing effect is 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-end paper, and can be used as friction materials to improve wear resistance. Therefore, today's calcium carbonate whiskers have broad application prospects.

There is still room for improvement in the production of calcium carbonate whiskers in the industry today, such as how to effectively increase the yield of whiskers, reduce the amount of additives needed to save costs and avoid pollution, and Surface modification to further enhance its efficacy, etc. How to achieve these demands is urgently needed by researchers in the field to research developers.

In order for readers to have a basic understanding of the aspects of the present invention, the following paragraphs provide a brief description of the present invention. This summary is not an exhaustive overview of the content of the present invention, and is not intended to indicate all the key or necessary elements of the present invention or to limit the scope of the present invention. The claim is only to describe the details of the present invention to be discussed later. The simplified form proposes some of these concepts.

The purpose of the present invention is to provide a calcium carbonate whisker synthesis system and related processes, which can synthesize defective calcium carbonate whiskers and generate in-situ spherical calcium carbonate adhered to the surface of the calcium carbonate whiskers. Fewer additives are needed, which can effectively save costs and avoid contamination.

One aspect of the present invention is to propose an in-situ synthesis system for producing calcium carbonate whiskers, which includes a lime furnace that can heat and decompose limestone into quicklime and carbon dioxide waste gas in a high temperature environment, and a lime digestion tank, which can be digested by adding water. Quick lime becomes a calcium hydroxide lime milk and a crystal form inducer mixing tank, and the calcium hydroxide lime milk can be mixed with a water-soluble magnesium salt as a crystal form inducer in a certain ratio. It becomes a mixed liquid and an in-situ synthesis reaction tank. The carbon dioxide exhaust gas is passed into the mixed liquid as a reaction gas to perform an aeration reaction, and at the same time, defective calcium carbonate whiskers and spherical calcium carbonate are formed. Spherical calcium carbonate is wrapped around the defective calcium carbonate whiskers in the form of particles, so that the surface area of the defective calcium carbonate whiskers with particle coating is less than that of pure phases not coated with such spherical calcium carbonate. Increase the surface area of defective calcium carbonate whiskers by at least 150%.

Another aspect of the present invention is to provide an in-situ synthesis method for forming calcium carbonate whiskers and spheroidal calcium carbonate. The steps include heating and decomposing limestone into quicklime and carbon dioxide waste gas under high temperature environment, and adding water to digest the quicklime to become hydroxide. Calcium lime milk, the calcium hydroxide lime milk and a water-soluble magnesium salt as a crystal form inducer are mixed at a certain ratio to form a mixture solution, and the carbon dioxide exhaust gas is passed into the mixture solution for aeration reaction to synthesize in situ Defective calcium carbonate whiskers and spherical calcium carbonate adhered 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 whisker by at least 150%.

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

101‧‧‧lime stove

102‧‧‧lime furnace exhaust gas

103‧‧‧lime digester

104‧‧‧ Crystalline inducer preparation tank

105‧‧‧ in-situ synthesis reaction tank

106‧‧‧Filter washing machine

107‧‧‧Dehydration dryer

108‧‧‧ slurry distribution unit

110‧‧‧aeration manifold

This specification contains drawings and constitutes a part of this specification in the text, so that readers have a further understanding of the embodiments of the present invention. These illustrations depict some embodiments of the invention and together with the description, explain the principles. In these diagrams: FIG. 1 illustrates an in-situ synthesis method for forming calcium carbonate whiskers and spheroidal calcium carbonate in a batch production mode according to an embodiment of the present invention; and FIG. 2 illustrates an in-situ synthesis of calcium carbonate whiskers and spherical calcium carbonate. Example Formation of calcium carbonate whiskers and spheres in continuous production mode Method for in-situ synthesis of type calcium carbonate; Figure 3 shows the arrangement of an aeration manifold in an in-situ synthesis reaction tank; Figures 4 and 5 show the calcium carbonate whisker products of the present invention in smaller sizes. Scanning electron microscope images at magnifications and larger magnifications; and Figure 6 is a scanning electron microscope image of general calcium carbonate whisker products at smaller magnifications.

It should be noted that all the illustrations in this manual are of the nature of illustrations. For clarity and convenience of illustration, the components in the illustrations may be exaggerated or reduced in size and proportion. Generally speaking, the illustrations The same reference symbols will be used to identify corresponding or similar element features in modified or different embodiments.

In the following detailed description of the present invention, the component symbols will be marked as part of the accompanying drawings, and will be represented in a special description manner that can implement this embodiment. Such an embodiment would illustrate enough details to enable a person of ordinary skill in the art to implement it. For the sake of clarity, the thickness of some components in the illustration may be exaggerated. The reader must understand that other embodiments can also be used in the present invention, or structural, logical, and electrical changes can be made without departing from the described embodiments. Therefore, the following detailed description is not intended to be regarded as a limitation. On the contrary, the embodiments included therein will be defined by the scope of the accompanying patent application.

The content of the present invention, which will be mentioned below, in particular, the steps and other details of the synthetic method for producing spherical calcium carbonate containing defective calcium carbonate whiskers and the surface of the calcium carbonate whiskers, should be understood Technical details and specific examples are also applicable 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 optional additives, and usually contain a large amount of solids and are therefore more viscous and typically have Higher density than the liquid forming it.

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

This includes the plural of an indefinite or definite article when referring to a singular noun (such as "a / an" or "the"), unless otherwise specified.

The following are non-limiting examples of the present invention. The method for in-situ synthesis of calcium carbonate whiskers according to the present invention includes 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 reaction raw material. The limestone raw material is firstly decomposed into limestone (calcium oxide, CaO) and high-temperature high-concentration carbon dioxide (CO ₂ ) exhaust gas in the lime furnace 101 at high temperature. The reaction formula is shown in the following manner (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 materials to produce lime in this step. The lime furnace 101 may be a high-temperature heating equipment such as a mechanized vertical kiln, a semi-mechanical vertical kiln, a rotary kiln, and a boiling furnace. The limestone raw materials are calcined and decomposed at a temperature of 850 ° C to 1100 ° C. The carbon dioxide concentration in the exhaust gas after the decomposition reaction is between about 35% and 50%.

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

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

After the preparation of the calcium hydroxide lime milk is completed, the lime milk is cooled to a temperature close to normal temperature, and then the calcium hydroxide lime milk is mixed with the water-soluble magnesium salt as the crystal form inducer in the crystal form inducer preparation tank 104 to a certain extent. Proportionally blend into a blending solution. The water-soluble magnesium salt may be selected from one or a combination of two or more components such as magnesium chloride (MgCl ₂ ), aqueous magnesium chloride (MgCl ₂ ‧ 6H ₂ O), or magnesium fluoride (MgBr ₂ ), which are present in the milk of lime The metastable acicular aragonite calcium carbonate crystals formed in subsequent processes can be directionally grown to become whiskers. In this preparation step, the concentration of lime milk and the concentration of the crystal form inducer are controlled, so that the molar ratio of the magnesium ion (Mg ²⁺ ) to the calcium ion (Ca ²⁺ ) in the mixed solution is between 2 and 6. . Too little magnesium salt will cause serious batch differences in the reaction and too little product yield. Too much magnesium salt will increase the cost of the entire process and make it difficult to treat the waste liquid. The crystal form inducer preparation tank 104 may include a recovery transfer tank, a recovery processing tank, and a concentration control tank. Magnesium ions are not consumed during the manufacturing process, and the remaining part of the product will be washed away in the subsequent water washing process. The crystal form inducer preparation tank 10 can recover and reuse the crystal form inducer after the reaction to reduce magnesium. Salt usage and processing costs.

After the mixed solution of calcium hydroxide lime milk and crystal form inducer is prepared, the next step is to perform an aeration reaction of calcium hydroxide and carbon dioxide. 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 shown in the following manner (3): Ca (OH) ₂ + CO ₂ → CaCO ₃ (3)

The calcium carbonate generated by this aeration reaction is aragonite that exists in a metastable state. Under normal conditions, it will be converted to the most stable calcite in a short period of time. As a result of 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 calcium carbonate from developing to the most stable state and continuing to grow in the direction of aragonite, eventually becoming a whisker. The in-situ synthesis reaction tank 105 used at this stage may be a stainless steel tube tank body, and it is easy to realize a reactor having a height-to-diameter ratio of at least 10 or more, and 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, the ring is arranged at the bottom of the in-situ synthesis reaction tank 105 and will form a one-way groove bottom with the side wall of the in-situ synthesis reaction tank 105. Tilt angle, such as 30-70 °. The aeration manifold 110 can pass the carbon dioxide exhaust gas into the mixed solution of the calcium hydroxide lime milk and the 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 setting toward the bottom of the tank can generate a regular air flow in the mixed liquid to make the aeration reaction more uniform. The exhaust gas flow into the mixed liquid can be 100 L / min. -1000L / min (liters / minute), wherein 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 solution, and the turbulent flow of the carbon dioxide gas generated by the aeration manifold can stir the mixture 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 water vapor, high temperature carbon dioxide exhaust gas, or directly using a heater. This in-situ synthesis reaction tank 105 has a spontaneous powder particle size and passivation surface regulation mechanism. The primary nucleated powder in the reaction solution will be brought up by the air and liquid in the tank, and it will be suspended in the reaction solution. Until it grows to a specific particle size, it sinks away from the main reaction zone due to weight gain. Therefore, the particle size of the obtained calcium carbonate whiskers is quite concentrated. In addition, during the reaction, if the lime milk is heated by steaming, this can gradually dilute the concentration of the magnesium ion inducer in the reaction solution, and then achieve the conditions for the generation of spherical calcium carbonate such as 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 a primary surface-modified calcium carbonate whisker. This feature will be described in detail in the examples described later.

After the calcium carbonate whisker reaction is completed, the reaction solution will be carried out in the filter washing machine 106. The action of filtering and washing collects the primary product through filtration, and recovers the filtrate to the crystal form inducer preparation tank 104 so that the crystal form inducer can be reused, and the primary product water is washed to remove the residual inducer. Finally, the reaction product after filtering and washing is dried at the storage dryer 107 at a temperature of 140 ° C. to 180 ° C. 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 between about 10-25, and the diameter is between 0.5-5um.

Reference is now made to FIG. 2, which illustrates an in-situ synthesis method for 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 except that a slurry distribution unit 108 is added to achieve a continuous production effect. The slurry diversion unit 108 can be a water cyclone separator. After the water cyclone separation, the slurry will be divided into a slurry with a high concentration containing a coarse particle size and a slurry with a low concentration and a small particle size. The ratio of the slurry is about 8-11. In the continuous production mode, the slurry shunting unit 108 is started after the reaction has been carried out for a period of time, and it returns the low-concentration product slurry with a diameter of 3 μm (micron) or less to the crystal form inducer preparation tank 104 to prepare for in-situ synthesis reaction . At the same time, the high-concentration slurry containing products with a diameter greater than 3 μm is continuously sent to the filter water washer 106 and the water dryer 107 for filtering, washing, and drying operations. The advantage of such a particle size splitting mechanism is that it can provide continuous production effects. It does not require the entire tank to be completely reacted, as in batch production mode, before it can be processed. It can also improve the batch reaction by heating a large amount of material in advance. At the same time, it can also obtain calcium carbonate whisker products with uniform particle size.

The following paragraphs will individually explain 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. The magnesium ion (Mg ²⁺ ) and calcium ion (Ca ²⁺ ) fed in the crystal form inducer preparation tank 104 are used. The molar ratio is between 1 and 3, and the weight percentage of calcium hydroxide in the overall mixed solution is 1 to 10%. The exhaust gas flow from the aeration manifold 110 is about 150 ~ 800L / min, the carbon dioxide concentration is about 8 ~ 25%, and the temperature is about 20 ~ 50 degrees. The entire in-situ synthesis reaction uses constant steam heating, so that the concentration of the magnesium ion inducer in the reaction solution can be gradually diluted while maintaining the reaction temperature. As the concentration of magnesium ions as a crystal form inducer is gradually diluted during the reaction, 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 2 μm. Moreover, the structure of the calcium carbonate whisker product is shown in FIG. 4 and FIG. 5, which are scanning electron microscope (SEM) images of the calcium carbonate whisker at a smaller magnification and at a larger magnification, respectively. It can be seen from Figure 4 that the calcium carbonate whiskers generated in this non-constant reaction environment will have surface defects, and the uneven surface will increase its roughness and surface area. On the other hand, as shown in Figure 5, because the magnesium ion concentration gradually decreases during the reaction, this reaction will also synthesize a spherical calcium carbonate in situ, which is directly attached to the defective calcium carbonate in the form of small particles. The surface of the whiskers increases the surface area of the entire 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 synthesis, modification, and functional secondary product (spherical calcium carbonate) are simultaneously generated at the same time when the product is synthesized, 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. The magnesium ion (Mg ²⁺ ) and calcium ion (Ca ²⁺ ) fed in the crystal form inducer preparation tank 104 are used. The mole ratio of) is between about 1 ~ 3, and the weight percentage of calcium hydroxide in the whole mixed solution 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%, and the temperature is about 20 ~ 50 degrees. Different from the foregoing Example 1, the synthetic 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 is not changed by dilution. The structure of the final calcium carbonate whisker product is shown in Fig. 6. The calcium carbonate whisker generated under this constant reaction environment is relatively thick and short, with an aspect ratio of only about 10 and a diameter of about 3.5 μm. In addition, this type of calcium carbonate whisker does not produce the effect of surface modification and modification, its surface is flat and free of defects, and there is no spherical calcium carbonate produced simultaneously as a functional second product, and the surface area of the overall calcium carbonate product has not been improved. The specific surface area (BET) is only between 0.8 and 1.2 m ² / g, and the yield is about 90%.

[Example 2]

In this embodiment, a continuous production mode is used. The slurry splitting unit 108 uses a water cyclone to concentrate and split the mixed liquid. The effective reaction volume of the entire in situ synthesis reaction tank 105 is about 100 liters. The molar ratio of magnesium ion (Mg ²⁺ ) to calcium ion (Ca ²⁺ ) in the crystal form inducer mixing tank 104 is about 3 ~ 4. In between, the weight percentage of calcium hydroxide in the overall mixed solution is 1 to 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, and the high temperature carbon dioxide passed in can be used to maintain the system reaction at the same time. temperature. After the reaction has been carried out for a period of time, the slurry shunting unit 108 is started, and 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 washer 106 and the water removal dryer 107 The process of filtering, washing, and drying is performed. The low-concentration slurry containing calcium carbonate whiskers having a diameter of less than 3 μm is refluxed together to the crystal form inducer preparation tank 104 to prepare for another reaction. The slurry shunt unit 108 will continue during the reaction period, and will be closed after 1 to 4 cycles of the overall processing system machine, and 0.5kg to 2kg will be taken every 3 to 4 hours. During the period, the crystal form inducer preparation tank 104 will continuously feed to maintain the pH of the system between 8 and 9.5. The advantage of this continuous production method is that it can achieve the production mode without interrupting the reaction at the time of receiving, particle size control, stable reaction system, and reuse of inducer. Its output is larger than the batch production method, but it is maintained by high temperature gas instead of water vapor. The method of the reaction temperature is less capable of highlighting the advantages of the in-situ formation of a spherical second calcium carbonate functional secondary product.

The above description is only a preferred embodiment of the present invention, and all equivalent changes and modifications made in accordance with the scope of patent application of the present invention shall fall within the scope of the present invention.

Claims (9)

An in-situ synthesis system for producing calcium carbonate whiskers, comprising: a lime furnace that heats and decomposes limestone raw materials into quicklime and carbon dioxide exhaust gas under a high temperature environment; a lime digestion tank connected to the lime furnace, wherein the lime furnace The lime digestion tank is configured to add water to digest the quicklime into calcium hydroxide lime milk; a crystal form inducer formulation tank is connected to the lime digestion tank, wherein the crystal form inducer formulation tank is configured to mix the calcium hydroxide lime milk with A water-soluble magnesium salt as a crystal form inducer becomes a mixed solution; and an in-situ synthesis reaction tank, connecting the crystal form inducer preparation tank and the lime furnace, wherein the in-situ synthesis reaction tank is configured to be in the mixed solution The carbon dioxide exhaust gas was introduced as a reaction gas to perform an aeration reaction, and water vapor was introduced to maintain the temperature of the aeration reaction between 70 ° C and 90 ° C and gradually dilute the concentration of magnesium ions in the mixed solution to form defects simultaneously. Type calcium carbonate whiskers and spherical calcium carbonates, wherein a plurality of such spherical calcium carbonates are wrapped around the defective calcium carbonate whiskers in the form of particles, so that The surface area of the calcium carbonate whiskers having a defective coated particles than spherical calcium carbonate not subjected to such a defect-free coating with pure calcium carbonate whisker increased by at least 150%. The in-situ synthesis system for producing calcium carbonate whiskers described in item 1 of the scope of the patent application, further includes a slurry shunt unit, which connects the in-situ synthesis reaction tank and the crystal form inducer formulation tank, And in continuous production, the reaction is started after a period of time, wherein the slurry shunt unit returns the defective calcium carbonate whisker with a diameter of 3um or less generated in the mixed solution and a part of the mixed solution is refluxed to the crystal form inducer. And simultaneously send the defective calcium carbonate whisker with a diameter greater than 3um and a part of the mixed liquid to a filtering water washing machine and a dewatering dryer to obtain the product. The in-situ synthesis system for producing calcium carbonate whiskers as described in item 2 of the patent application scope, wherein the slurry splitter is a water cyclone separator. The 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 body 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, which are arranged around the bottom of the in-situ synthesis reaction tank and connected with the in-situ synthesis reaction tank. 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 exhaust gas into the mixed liquid. The in-situ synthesis system for producing calcium carbonate whiskers as described in the first 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 spherical calcium carbonate, comprising: heating and decomposing limestone raw materials into quicklime and carbon dioxide exhaust gas under a high temperature environment; digesting the quicklime with water to form calcium hydroxide lime milk ; Mixing the calcium hydroxide lime milk with a water-soluble magnesium salt as a crystal form inducer at a certain ratio to form a mixed solution; and passing the carbon dioxide exhaust gas into the mixed solution to perform an aeration reaction and passing water vapor to the aeration The reaction temperature is maintained between 70 ° C and 90 ° C, and the concentration of magnesium ions in the mixed solution is gradually diluted to synthesize a defective calcium carbonate whisker and a spherical calcium carbonate adhering to the surface of the calcium carbonate whisker. The surface defects of the defective calcium carbonate whisker and the spherical calcium carbonate increase the surface roughness of the calcium carbonate whisker and increase the surface area of the calcium carbonate whisker by at least 150%. The in-situ synthesis method of forming calcium carbonate whiskers and spherical calcium carbonate as described in item 7 of the scope of patent application, wherein the aspect ratio of the calcium carbonate whiskers is between 10 and 25 and the diameter is between 0.5- 5μm. The in-situ synthesis method of forming calcium carbonate whiskers and spheroidal calcium carbonate as described in item 7 of the scope of the patent application, wherein the flow rate of the carbon dioxide exhaust gas flowing into the mixed solution is 100L / min-1000L / min, the concentration It is 8-25%.