TWM569752U - Synthesizing system for in-situ producing calcium carbonate whisker with adhering particles - 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

Synthesis system for in situ generation of particle-coated defective calcium carbonate whiskers

This work is generally related to a synthesis system of calcium carbonate whiskers, more specifically, to a synthesis system for in-situ formation of calcium carbonate whiskers and globular calcium carbonates and their in situ resolve resolution.

Calcium carbonate is one of the most abundant mineral resources in the earth's crust. It plays an important role in many industrial production applications. For example, calcium carbonate micropowder has been widely used as an inorganic filler in plastics, rubber, ink, paper and other industries. use. At present, calcium carbonate products used in industry mainly include heavy calcium and light calcium. Among them, 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 formed by the reaction of carbonate (CO ^3- ) and calcium ions (Ca ²⁺ ) to precipitate the formation of light calcium carbonate. Although the molecular composition of calcium carbonate is the same, it will produce different crystal forms or structures during the formation and precipitation, and the physicochemical properties exhibited will be significantly different.

Many years ago, the industry discovered that fiber-type inorganic minerals have special material strengthening functions, such as polymer-based composite materials such as fiber-reinforced plastic (FRP), and recent studies have found whiskers. The type of calcium carbonate has very good strengthening and toughening properties. Whisker refers to short fibers grown in single crystal form. Due to the few defects in crystalline form, it has extremely high strength, elastic modulus, heat and heat insulation properties, and is better as a reinforcing material than short fiber materials. The processing property, but the presence of appropriate surface defects or whiskers with appropriate amount of impurities, does not have much influence on its own strength, can slightly increase the specific surface area, facilitate the combination of polymer substrate and whisker, and give semi-crystalline polymer more More nucleation points make the reinforcement effect more obvious. The use of calcium carbonate whiskers as fillers can improve the mechanical, flame retardant, heat and processing properties of plastic products, or improve the gloss and transparency of inks for the preparation of high-grade paper, and can be used as a friction material 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 production of whiskers, reduce the amount of additives required to save costs and avoid pollution, and carry out calcium carbonate whiskers. Surface modification to further enhance its efficacy and the like. How to achieve these demands is now an urgent need for researchers in the field to research developers.

In order to give readers a basic understanding of the purpose of this creation, the following paragraphs present a brief description of the creation. This summary is not an exhaustive overview of the present disclosure, and is not intended to identify all of the key or essential elements of the present invention or to limit the scope of the present invention. The only claim is to describe the details of the present invention which will be discussed later. Some of these concepts are presented in a simplified form.

The purpose of the novel is to propose a calcium carbonate whisker synthesis system and a related process thereof, which are capable of synthesizing defective calcium carbonate whiskers and in-situ formation of spherical calcium carbonate adhered to the surface of the calcium carbonate whiskers, and the process thereof Less additives are required to save costs and avoid contamination.

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

Another aspect of the present invention is to provide an in-situ synthesis method for forming calcium carbonate whiskers and a spherical calcium carbonate, the steps comprising: heating and decomposing limestone into quicklime and carbon dioxide waste gas in a high temperature environment, and digesting the quicklime into water by adding water. Calcium and lime milk, the calcium hydroxide milk and the water-soluble magnesium salt as a crystal form inducer are mixed into a mixed liquid in a certain ratio, and the carbon dioxide waste gas is introduced into the mixed liquid for aeration reaction to be synthesized in situ a defective calcium carbonate whisker and a spherical spherical calcium carbonate attached to the surface of the calcium carbonate whisker, wherein a surface defect of the defective calcium carbonate whisker and the spherical calcium carbonate increase the surface roughness of the calcium carbonate whisker The surface area of the calcium carbonate whiskers is increased by at least 150%.

This and other objects and advantages of the present invention will become more apparent from the detailed description of the preferred embodiments.

In the following detailed description of the present invention, the component symbols are marked as part of the accompanying drawings, and are described in the manner of the specific examples in which the embodiments can be practiced. Such embodiments will be described in sufficient detail to enable those of ordinary skill in the art to practice. For the sake of clarity, some of the components may be exaggerated in thickness. The reader is aware that other embodiments may be utilized and structural, logical, and electrical changes may be made without departing from the embodiments. Therefore, the following detailed description is not to be considered as a limitation, and the embodiments included herein are defined by the scope of the accompanying claims.

The contents of the novel, which will be mentioned hereinafter, in particular the steps and other details of the synthesis method for producing defective calcium carbonate whiskers and spherical calcium carbonate attached to the surface of the calcium carbonate whiskers, should be understood Technical details and specific examples are also applicable to the novel product and its use.

In the terms used in this creation, the words "slurry" or "suspension" contain insoluble solids and water and optionally other additives, and usually contain a large amount of solids and are therefore more viscous and typically have Higher density than the liquid from which it is formed.

In the event that the term "comprising" is used in the context of the present specification and claims, it does not exclude other non-specific elements that are of primary or secondary functional importance. If a group is defined below to include at least a certain number of specific examples, it is also understood to disclose a group that is preferably only composed of such specific examples. Whenever the terms "containing" or "having" are used, these terms are equivalent to "including" as defined above.

Unless otherwise specified, in the case of a singular noun (such as "a" or "the"), the plural or plural is used.

The following are non-limiting examples of the novel. The novel calcium carbonate whisker in-situ synthesis method 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 globular calcium carbonate in a batch production mode according to an embodiment of the present invention. At the beginning of the process, calcium oxide is first prepared as a raw material for the reaction. The limestone raw material is first decomposed into lime (calcium oxide, CaO) and high-temperature high-concentration carbon dioxide (CO ₂ ) waste gas in the lime furnace 101, and the reaction formula is as follows (1):

CaCO ₃ → CaO + CO ₂ (1) Natural rocks with calcium carbonate (CaCO ₃ ) as the main component, such as limestone, chalk, dolomite, etc., can be used as limestone raw materials to produce lime in this step. . The lime furnace 101 can be a high-temperature heating device such as a mechanized vertical kiln, a semi-mechanized vertical kiln, a rotary kiln or a boiling furnace, and the limestone raw material is calcined and decomposed at a temperature of 850 ° C to 1100 ° C. The concentration of carbon dioxide 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 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. The reaction raw material of the method is as follows: (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 the bottom sedimentation coarse particles and the dross are removed through a plurality of sedimentation classification and slag removal operations to obtain a refined raw material slurry. The lime digestion reaction will exotherm, and the digestion temperature is preferably maintained between 45 ° C and 65 ° C. The specific surface area (BET) of the calcium hydroxide product obtained by the above reaction needs to be between 8 and 15 m ² /g (square Between the ft / g) to meet the adsorption efficiency required in the subsequent reaction of the raw materials.

After the preparation of the lime milk of the calcium hydroxide is completed, the lime milk is cooled to near normal temperature, and then the calcium hydroxide lime milk and the water-soluble magnesium salt as the crystal form inducer are fixed in the crystal type inducer mixing tank 104. The ratio is mixed into a mixture. The water-soluble magnesium salt selected from magnesium chloride (MgCl _2), an aqueous magnesium chloride _{(MgCl 2 • 6H 2 O)} , magnesium fluoride, or (MgBr ₂₎ and other components of one or two or more combinations, present in the milk of lime It will promote the orientation growth of the metastable acicular aragonite calcium carbonate crystal formed in the subsequent process to become a whisker. In this mixing step, the concentration of the milk of the lime and the concentration of the crystal form inducer are controlled such that the ratio of the magnesium ion (Mg ²⁺ ) to the calcium ion (Ca ²⁺ ) in the mixed solution is between about 2 and 6. . Too little magnesium salt will be added, resulting in serious batch differences in the reaction and too little product yield. Excessive magnesium salt will increase the cost of the entire process and its waste liquid treatment is not easy. The crystal form inducer preparation tank 104 may include a recovery transfer tank, a recovery treatment tank, and a concentration control tank. In the process, magnesium ions are not consumed, and the remaining part of the product is washed away in the subsequent washing process, and the crystal form inducer tank 10 can recover and reuse the reacted crystal form inducer to reduce magnesium. Salt usage and treatment costs.

After mixing a mixture of calcium hydroxide milk and a crystal form inducer, an aeration reaction of calcium hydroxide and carbon dioxide is carried out next. The carbon dioxide waste gas collected in the previous limestone forging process will be introduced into the in-situ synthesis reaction tank 105 at this stage to react with the calcium hydroxide in the mixed liquid in the tank, and the reaction formula is as follows (3):

Ca (OH) ₂ + CO ₂ → CaCO ₃ (3)

The calcium carbonate formed by this aeration reaction is aragonite which exists in metastable state, and it will be converted into the most stable calcite in a very short time under normal conditions, but due to the magnesium base crystal When the type of inducer is added, the energy barrier between the metastable state and the most stable state of calcium carbonate will increase, preventing the calcium carbonate from continuing to develop in the most steady state and continuing to grow in the aragonite state, eventually becoming whiskers. The in-situ synthesis reaction tank 105 used in this stage may be a stainless steel tube tank, which is easy to realize a reactor having a high aspect ratio of at least 10 or more, and meets industrial production requirements. The in-situ synthesis reaction tank 105 may have a plurality of aeration manifolds. As shown in FIG. 3, the ring is disposed at the bottom of the in-situ synthesis reaction tank 105 and is formed as a groove bottom with the side wall 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 mixture of the calcium hydroxide lime milk and the crystal form inducer, and can perform the switching operation of the individual aeration manifolds 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, wherein the flow rate of the exhaust gas into the mixed liquid can be 100 L/min. - 1000 L/min (liters per minute), wherein the concentration of carbon dioxide in the exhaust gas is about 8% to 25%. The crystal growth environment of the in-situ synthesis reaction tank 105 can increase the time for the reaction gas to remain in the reaction liquid, and the turbulent flow of carbon dioxide gas generated by the aeration manifold can pulverize the mixed 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 gas, or directly using a heater. The in-situ synthesis reaction tank 105 has a spontaneous powder particle size and a passivation surface regulation mechanism, and the powder of the initial nucleation in the reaction liquid is subjected to the gas flow and the liquid flow in the tank, and is suspended in the reaction liquid. Until it grows to a specific particle size, it sinks due to weight gain and leaves the main reaction zone. Therefore, the particle size of the prepared calcium carbonate whiskers is quite concentrated. In addition, in the course of the reaction, if the lime milk is heated by means of steaming, the concentration of the magnesium ion inducer in the reaction liquid can be gradually diluted, thereby achieving the formation condition of the spherical calcium carbonate required for the creation, so that This type of spherical calcium carbonate is formed in situ and adheres to the surface of calcium carbonate whiskers to form primary surface-modified calcium carbonate whiskers, which will be described in detail in the examples to be described later.

After the calcium carbonate whisker reaction is completed, the reaction liquid is subjected to filtration and washing at the filtered water washing machine 106, the primary product is collected by filtration, and the filtrate is recovered to the crystal form inducer mixing tank 104 to make the crystal form inducer. It can be reused, and the initial product water is washed to remove residual inducer. Finally, the filtered reaction product is dried at a temperature of 140 ° C to 180 ° C in the water storage dryer 107 to remove moisture, thereby finally obtaining calcium carbonate whiskers having uniform particle diameter and high purity. The calcium carbonate whiskers have a length to diameter ratio of between about 10 and 25 and a diameter of between 0.5 and 5 um.

Referring now to Figure 2, there is illustrated an in situ synthesis process for the formation of calcium carbonate whiskers and globular calcium carbonate in a continuous production mode in accordance with an embodiment of the present invention. The embodiment shown in Fig. 2 is similar to the embodiment of Fig. 1, except that only one slurry splitting unit 108 is added to achieve a continuous production effect. The slurry splitting unit 108 may be a water cyclone separator, and the slurry after the water cyclone separation is divided into a slurry having a high concentration of a coarse particle diameter, and a slurry having a low concentration and a small particle diameter, wherein the high concentration slurry and the low concentration The ratio of the slurry is about 8-11. The slurry splitting unit 108 is started in the continuous production mode after the reaction is carried out for a period of time, and the low-concentration product slurry having a diameter of 3 μm or less is returned to the crystal form inducer mixing tank 104 to prepare for the in-situ synthesis reaction again. . At the same time, the high-concentration slurry containing the product having a diameter of more than 3 μm is continuously sent to the filtering water washing machine 106 and the water drying machine 107 for filtration, washing, and drying operations. The advantage of such a particle size distribution mechanism is that it can provide a continuous production effect, and it is not necessary to complete the subsequent treatment of the mixed liquid of the whole tank as in the batch production mode, and it is also necessary to preheat the large amount of materials when the batch reaction is improved. The power cost, as well as the uniformity of the calcium carbonate whisker product.

The following paragraphs are to be individually described for the new embodiment:

[Example 1]

This embodiment uses a batch production mode in which 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 ions (Ca ²⁺ ) charged in the crystal form inducer tank 104 are mixed. The molar ratio is between about 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 from the aeration manifold 110 is about 150 to 800 L/min, and the carbon dioxide concentration is about 8 to 25%, and the temperature is about 20 to 50 degrees. The entire in-situ synthesis reaction is heated by means of steam, so that the concentration of the magnesium ion inducer in the reaction solution can be gradually diluted while maintaining the reaction temperature. Since the magnesium ion concentration as a crystal form inducer is gradually diluted during the reaction, the final product will obtain defective calcium carbonate whiskers having surface defects and particle coating, and the aspect ratio is increased to about 20, and the diameter is about 2 μm. Further, the structure of the calcium carbonate whisker product is as shown in Figs. 4 and 5, which are scanning electron microscope (SEM) images of calcium carbonate whiskers at a small magnification and a large magnification, respectively. It can be seen from Fig. 4 that the calcium carbonate whiskers formed in 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 Fig. 5, due to the gradual decrease of the magnesium ion concentration during the reaction, the reaction also synthesizes a spherical-like 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 simultaneous synthesis, modification, and functional second product (spheroidal calcium carbonate) are simultaneously generated by the product synthesis, which saves process cost and process, but the output is more continuous. The way is small.

[Comparative Example 1]

This comparative example also employs a batch production mode in which 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 ions (Ca ²⁺ ) charged in the crystal type inducer preparation tank 104 are used. The molar ratio is about 1 to 3, and the weight percentage of calcium hydroxide in the whole mixture is 1 to 10%. The flow rate of the exhaust gas from the aeration manifold 110 is about 150 to 1000 L/min, and the carbon dioxide concentration is about 8 to 25%, and the temperature is about 20 to 50 degrees. Different from the foregoing embodiment 1, the synthesis reaction of this example is a method of constant heating using a general heater, so that the concentration of the magnesium ion inducer in the reaction liquid is not changed by dilution. The structure of the final calcium carbonate whisker product is as shown in Fig. 6. The calcium carbonate whisker formed in this constant reaction environment is relatively short and has a length to diameter ratio of only about 10 and a diameter of about 3.5 μm. Moreover, such calcium carbonate whiskers do not have the effect of surface modification, the surface is flat and defect-free, and there is no simultaneous generation of spherical calcium carbonate as a functional second product, and the surface area of the whole calcium carbonate product is not improved. The specific surface area (BET) is only between 0.8 and 1.2 m ² /g, and the yield is about 90%.

[Embodiment 2]

This embodiment uses a continuous production mode in which the slurry split unit 108 employs a water cyclone to concentrate and divert the mixed liquid. The effective reaction volume of the entire in-situ synthesis reaction tank 105 is about 100 liters, and the ratio of magnesium ion (Mg ²⁺ ) to calcium ion (Ca ²⁺ ) molar ratio in the crystal inducer preparation tank 104 is about 3 to 4 Between the weight percentage of calcium hydroxide in the overall mixture is 1 to 10%. The flow rate of the exhaust gas from the aeration manifold 110 is about 150~1000L/min, wherein the carbon dioxide concentration is about 8~25%, the temperature is about 50~90 degrees, and the high temperature carbon dioxide can be used to maintain the system reaction at the same time. temperature. The slurry splitting unit 108 is started after the reaction is carried out for a period of time, and the high-concentration slurry containing the calcium carbonate whisker product having an aspect ratio of about 10 and a diameter of 3 μm or more is sent to the filter washing machine 106 and the water removing dryer 107. The process of filtering and washing and drying is carried out. A low-concentration slurry containing calcium carbonate whiskers having a diameter of less than 3 μm is refluxed together to the crystal form inducer compounding tank 104 to be subjected to re-reaction. The slurry splitting unit 108 is continuously continued during the reaction, and is closed after 1 to 4 cycles of the overall system of the processing system, and 0.5 kg to 2 kg is taken every 3 to 4 hours. During the period, the crystal inducer mixing tank 104 is continuously fed 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, particle size control, stable reaction system, and inducing agent reuse. The output is larger than the batch production mode, but it is maintained by using high temperature gas instead of water vapor. The manner of the reaction temperature is less indicative of the advantages of in situ formation of a functional second product of spherical calcium carbonate.

The above description is only the preferred embodiment of the present invention, and all the equivalent changes and modifications made by the scope of the present patent application should fall within the scope of the present invention.

101‧‧‧ lime stove

102‧‧‧ Lime furnace exhaust

103‧‧‧Lime Digestion Tank

104‧‧‧Formation inducer mixing tank

105‧‧‧In situ synthesis reaction tank

106‧‧‧Filter washing machine

107‧‧‧Water Remover

108‧‧‧Slurry split unit

110‧‧‧Aeration tube

The present specification contains the drawings and constitutes a part of the specification in the specification, and the reader will further understand the present embodiment. The drawings depict some embodiments of the present teachings and together with the description herein. In the drawings: FIG. 1 illustrates an in-situ synthesis method for forming calcium carbonate whiskers and globular calcium carbonate in a batch production mode according to the present embodiment; FIG. 2 illustrates the present invention according to the present invention. EXAMPLES In-situ synthesis of calcium carbonate whiskers and globular calcium carbonates in a continuous production mode; Figure 3 depicts an arrangement of aeration manifolds in an in situ synthesis reaction tank; Figure 5 is a scanning electron microscope image of the new calcium carbonate whisker product at a small magnification and a large magnification, respectively; and Figure 6 is a scanning of a general calcium carbonate whisker product at a small magnification. Electron microscope image. It should be noted that all the illustrations in the specification are in the nature of the illustrations. For the sake of clarity and convenience of illustration, the components in the drawings may be exaggerated or reduced in size and proportion. Generally, in the figure The same reference symbols will be used to identify corresponding or similar component features in the modified or different embodiments.

Claims (7)

An in-situ synthesis system for producing calcium carbonate whiskers, comprising: a lime furnace for decomposing limestone raw materials into quicklime and carbon dioxide waste gas in a high temperature environment; a lime digestion tank connected to the lime furnace and adding water Digesting the quicklime into calcium hydroxide lime milk; a crystal type inducer mixing tank, connecting the lime digesting tank and mixing the calcium hydroxide milk and the water-soluble magnesium salt as a crystal form inducer into a mixed liquid; a synthesis reaction tank connected to the crystal type inducing agent mixing tank and introducing the carbon dioxide exhaust gas as a reaction gas in the mixed liquid to perform an aeration reaction, and simultaneously forming defective calcium carbonate whiskers and spherical spherical calcium carbonate, among which The spherical calcium carbonate of this kind is coated with the particle type around the defective calcium carbonate whisker, so that the surface area of the particle-coated defective calcium carbonate whisker is not covered by the spherical calcium carbonate. The surface area of the pure phase non-defective calcium carbonate whiskers is increased by at least 150%. An in-situ synthesis system for producing calcium carbonate whiskers according to claim 1, wherein the in-situ synthesis reaction tank is passed through water vapor to maintain the temperature of the aeration reaction between 70 ° C and 90 ° C and gradually dilute. The concentration of the mixture. The in-situ synthesis system for producing calcium carbonate whiskers as described in claim 1 further comprises a slurry splitting unit connected to the in-situ synthesis reaction tank and started after a reaction for a period of time in continuous production. Wherein the slurry splitting unit returns the defective calcium carbonate whisker having a diameter of 3 μm or less and a part of the mixed liquid formed in the mixed liquid to the crystal type inducer compounding tank, and at the same time, the defective carbonic acid having a diameter of more than 3 μm Calcium whiskers and a portion of the mixture are sent to a filtered water washer and a water removal dryer to obtain a product. An in-situ synthesis system for producing calcium carbonate whiskers as described in claim 3, wherein the slurry split unit is a water cyclone separator. The in-situ synthesis system for producing calcium carbonate whiskers according to claim 1, wherein the in-situ synthesis reaction tank is a stainless steel tube tank having a height to diameter ratio of at least 10. The in-situ synthesis system for producing calcium carbonate whiskers according to claim 1, further comprising a plurality of aeration manifolds disposed around the bottom of the in-situ synthesis reaction tank and with the in-situ synthesis reaction tank The side wall is inclined at an angle to the bottom of the groove, 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 according to claim 1, wherein the molar ratio of magnesium ions to calcium ions in the mixed solution is between 1 and 4.