A method for preparing hollow rod-like calcium carbonate for styrene-butadiene rubber

Abstract

The application discloses a preparation method of hollow rod-shaped calcium carbonate for filling styrene-butadiene rubber, and comprises the following steps: S1: calcining limestone to obtain quicklime, and performing a digestion reaction on the quicklime and water to obtain Ca(OH)2, and then preparing Ca(OH)2 suspension; S2: adding a crystal form control agent into the Ca(OH)2 suspension, and performing a carbonation reaction on the Ca(OH)2 suspension by introducing a mixed gas of CO2, and stopping the introduction of CO2 when the pH of the reaction suspension is less than or equal to 7; S3: adding an appropriate amount of oxalic acid solution into the suspension; S4: adding an appropriate amount of glacial acetic acid solution into the suspension; S5: performing pressure filtration on the suspension, washing the suspension, performing pressure filtration again, and preparing the suspension again; S6: adding an appropriate amount of lead acetate solution into the suspension; and S7: finally performing pressure filtration, drying at 500 DEG C, and sieving, so as to obtain the hollow rod-shaped calcium carbonate for filling the styrene-butadiene rubber. The hollow rod-shaped calcium carbonate prepared by the application can replace the commonly used vulcanizing activator zinc oxide for rubber, and can enhance the tensile strength and elongation at break of the styrene-butadiene rubber.

Description

Technical Field

[0001] This invention relates to the field of calcium carbonate preparation technology, specifically a hollow rod-shaped calcium carbonate for use in styrene-butadiene rubber. Background Technology

[0002] The main reasons for using calcium carbonate in rubber are its high whiteness, ease of processing, ability to increase volume and weight, and cost reduction. However, its lack of reinforcing properties in rubber limits its application. With advancements in calcium carbonate preparation technology, it has been discovered that nano-calcium carbonate, chain-like calcium carbonate, and cubic calcium carbonate have semi-reinforcing effects when added to styrene-butadiene rubber (SBR). Nevertheless, research progress on the application of rod-shaped calcium carbonate in rubber remains slow.

[0003] Chinese patent CN 107555460A discloses a method for preparing nano-calcium carbonate for rubber tires. The method involves preparing a nano-calcium carbonate suspension using a bubbling method, surface modification with sodium polystyrene sulfonate, rosin, and pentaerythritol stearate, followed by pressure filtration and drying to obtain the nano-calcium carbonate for rubber tires. When filled into rubber tires, it can significantly improve the tire's reinforcement and wear resistance. This method pertains to the application of nano-calcium carbonate in rubber but does not involve rod-shaped calcium carbonate, thus offering little contribution to research progress on the application of rod-shaped calcium carbonate in rubber.

[0004] Chinese patent CN 109911925B discloses a method for preparing rubber-specific nano-calcium carbonate. The method involves preparing a chain-like nano-calcium carbonate suspension using a bubbling method, coating the chain-like nano-calcium carbonate with silica using a partially soluble silicon-containing substance, and then surface-coating it with a fatty acid-based substance. After pressure filtration and drying, the resulting rubber-specific nano-calcium carbonate is obtained. This method pertains to the application of chain-like nano-calcium carbonate in rubber and does not involve rod-shaped calcium carbonate, thus offering little contribution to the research progress of rod-shaped calcium carbonate applications in rubber.

[0005] Chinese patent CN 104609453B discloses a method for preparing cubic precipitated calcium carbonate. The method involves preparing a nano-calcium carbonate suspension using a bubbling method, using urea-based substances as a curing agent to accelerate curing, surface treatment with sodium stearate, and then pressure filtration and drying to obtain a cubic precipitated calcium carbonate. This method for preparing cubic precipitated calcium carbonate does not involve rubber applications and does not significantly contribute to research progress on the application of rod-shaped calcium carbonate in rubber.

[0006] Chinese patent CN 115072757A discloses a method for preparing fine rod-shaped aragonite-type calcium carbonate. The method involves reacting acetic acid with several calcium-containing waste residues to obtain a calcium acetate solution. Carbon dioxide is then introduced into the calcium acetate solution at a specific temperature and pH under specific pressure. The resulting suspension is then subjected to solid-liquid separation and dried to obtain fine rod-shaped aragonite-type calcium carbonate. This method for preparing rod-shaped calcium carbonate does not involve applications in rubber and does not significantly contribute to research progress on its application in rubber.

[0007] Chinese patent CN 110844930A discloses a method for preparing hollow rod-shaped calcium carbonate. The method involves dissolving calcium oxide in water, heating, stirring, allowing it to stand for digestion, sieving, and concentrating to obtain a raw material calcium hydroxide slurry. Using sodium D-gluconate as a crystal form control agent, the temperature and rotation speed are controlled, and CO is introduced to induce a gas reaction, yielding a product slurry. After pressure filtration and drying, hollow rod-shaped calcium carbonate is obtained. This method for preparing hollow rod-shaped calcium carbonate does not involve rubber applications and does not significantly contribute to research progress on the application of rod-shaped calcium carbonate in rubber.

[0008] In summary, current research progress on the application of rod-shaped calcium carbonate in rubber is still in a slow stage, and the existing methods for preparing rod-shaped calcium carbonate are still not sufficient for its effective use in rubber. Summary of the Invention

[0009] In view of the technical problems existing in the background art, the present invention will provide a method for preparing hollow rod-shaped calcium carbonate for styrene-butadiene rubber. The hollow rod-shaped calcium carbonate prepared by this method can replace zinc oxide, a commonly used vulcanizing activator for rubber, and enhances the tensile strength and elongation at break of styrene-butadiene rubber.

[0010] To achieve the above objectives, the technical solution adopted by the present invention is as follows:

[0011] This invention provides a method for preparing hollow rod-shaped calcium carbonate for styrene-butadiene rubber, comprising the following steps:

[0012] S1: Limestone is calcined at 1000~1200℃ to obtain quicklime. Quicklime and water are reacted to obtain Ca(OH)2. The mixture is sieved and allowed to stand, and then prepared into a Ca(OH)2 suspension with a solid content of 5.0%~15.0%.

[0013] S2: Add MgCl2, a crystal form control agent, to the Ca(OH)2 suspension, and introduce a CO2 mixture to carry out a carbonation reaction. When the pH of the reaction suspension is ≤7, stop introducing CO2; to obtain a calcium carbonate suspension.

[0014] S3: Add oxalic acid to the calcium carbonate suspension and react for 1-3 hours. The amount of oxalic acid solution added is 20%-40% of the dry basis of calcium carbonate.

[0015] S4: Add glacial acetic acid to the calcium carbonate suspension and stir for 1-3 hours;

[0016] S5: Finally, the above calcium carbonate suspension is subjected to pressure filtration, washed with water, and then pressure filtered again to prepare a calcium carbonate suspension with a calcium carbonate to water ratio of 1:10~20.

[0017] S6: Add a 10-20% lead acetate solution to the calcium carbonate suspension and stir for 1-3 hours;

[0018] S7: Finally, after pressure filtration, drying, and sieving, hollow rod-shaped calcium carbonate for filling styrene-butadiene rubber is obtained.

[0019] As a preferred technical solution of the present invention: the amount of MgCl2 added in step S2 is 0.2% to 0.5% of Ca(OH)2.

[0020] As a preferred embodiment of the present invention: the CO2 concentration in the mixed gas in step S2 is 20-40%, and the flow rate of the CO2 mixed gas is 0.01-0.10 m³ / s. 2 / h, the carbonation reaction temperature is controlled at 50~100℃ and the stirring speed is 500~1000r / min.

[0021] As a preferred technical solution of the present invention: the concentration of oxalic acid in step S3 is 60%~80%, the amount of oxalic acid solution added is 20%~40% of the dry basis of calcium carbonate; the dropping speed is 50~500mL / min; and the stirring speed is 100~500r / min.

[0022] As a preferred technical solution of the present invention: the concentration of glacial acetic acid in step S4 is 20~40%, the amount of glacial acetic acid solution added is 50%~100% of the dry basis of calcium carbonate; the dropping speed is 50~500mL / min; and the stirring speed is 100~500r / min.

[0023] As a preferred technical solution of the present invention: the amount of lead acetate solution added in step S6 is 30%~50% of the dry basis of calcium carbonate, the concentration of lead acetate solution is 10~20%, and the amount of lead acetate solution added is 20%~40% of the dry basis of calcium carbonate; the dropping speed is 50~500mL / min; and the stirring speed is 100~500r / min.

[0024] As a preferred technical solution of the present invention: the mass content of calcium carbonate in the limestone in step S1 is ≥95%, and the mass ratio of quicklime to water is 1:10~20.

[0025] As a preferred technical solution of the present invention: the drying temperature in step S7 is 400~600℃ and the time is 1~5h.

[0026] Compared with the prior art, the advantages and beneficial effects of the present invention include:

[0027] 1. The method of this invention, by controlling the concentration, temperature, and dropping rate of oxalic acid, reacts oxalic acid with rod-shaped calcium carbonate to generate rod-shaped calcium oxalate coating calcium carbonate; calcium carbonate is dissolved with glacial acetic acid to obtain hollow rod-shaped calcium oxalate; then, lead acetate reacts with the hollow rod-shaped calcium oxalate to generate lead oxalate coating hollow rod-shaped calcium oxalate; finally, by controlling the temperature and time, the lead oxalate coating hollow rod-shaped calcium oxalate is decomposed to obtain lead monoxide coating hollow rod-shaped calcium carbonate. This is an innovation in the microstructure of calcium carbonate, breaking through the technical bottleneck of the prior art which has not yet produced lead monoxide coating hollow rod-shaped calcium carbonate.

[0028] 2. The lead monoxide-coated hollow rod-shaped calcium carbonate prepared in this invention can replace the vulcanizing activator zinc oxide in styrene-butadiene rubber (SBR), reducing the positive vulcanization time of SBR and thus accelerating the preparation efficiency. Secondly, by coating the hollow rod-shaped calcium carbonate with lead monoxide, which is distributed on the surface of the calcium carbonate, the calcium carbonate is tightly bound, and the lead monoxide can also connect to the SBR. This special property enhances the tensile strength and elongation at break of the SBR. Attached Figure Description

[0029] Figure 1 SEM image of hollow rod-shaped calcium carbonate prepared in Example 1; Implementation

[0030] The technical solutions of the present invention will be clearly and completely described below with reference to the embodiments of the present invention. Obviously, the described embodiments are only some embodiments of the present invention, and not all embodiments. Based on the embodiments of the present invention, all other embodiments obtained by those of ordinary skill in the art without creative effort are within the scope of protection of the present invention. Example

[0031] A method for preparing hollow rod-shaped calcium carbonate for use as a filler in styrene-butadiene rubber includes the following steps:

[0032] S1: Limestone is calcined at 1000℃ to obtain quicklime. Quicklime and water are reacted to obtain Ca(OH)2. The mixture is then sieved, allowed to stand, and then prepared into a Ca(OH)2 suspension with a solid content of 5.0%.

[0033] S2: Add MgCl2, a crystal form control agent, to the Ca(OH)2 suspension. The amount of MgCl2 added is 0.2% of the Ca(OH)2. A mixed gas with a CO2 concentration of 20% is introduced to carry out the carbonation reaction, and the flow rate of the CO2 mixed gas is controlled at 0.01 m³ / min. 2 / h, when the pH of the reaction suspension is ≤7, stop the CO2 flow; to obtain a calcium carbonate suspension;

[0034] S3: Add 60% oxalic acid to the calcium carbonate suspension. The amount of oxalic acid solution added is 20% of the dry basis of calcium carbonate. The dropping rate is 50 mL / min. The stirring speed is 100 r / min. The stirring time is 1 h.

[0035] S4: Add 20% glacial acetic acid to the calcium carbonate suspension. The amount of glacial acetic acid solution added is 50% of the dry basis of calcium carbonate. The dropping rate is 50 mL / min. The stirring speed is 100 r / min. The stirring time is 1 h.

[0036] S5: The above calcium carbonate suspension is then subjected to pressure filtration, washed with water, and then pressure filtered again to prepare a calcium carbonate suspension with a calcium carbonate to water ratio of 1:10.

[0037] S6: Add a 10% lead acetate solution to the calcium carbonate suspension, with the amount of lead acetate solution added being 30% of the dry basis of the calcium carbonate; the dropping rate is 50 mL / min; the stirring speed is 100 r / min; and the stirring time is 1 h.

[0038] S7: Finally, filter under pressure, dry at 400℃ for 1 hour, and sieve to obtain hollow rod-shaped calcium carbonate for filling styrene-butadiene rubber. Example

[0039] A method for preparing hollow rod-shaped calcium carbonate for use as a filler in styrene-butadiene rubber includes the following steps:

[0040] S1: Limestone is calcined at 1100℃ to obtain quicklime. Quicklime and water are reacted to obtain Ca(OH)2. The mixture is then sieved, allowed to stand, and then prepared into a Ca(OH)2 suspension with a solid content of 10%.

[0041] S2: Add MgCl2, a crystal form control agent, to the Ca(OH)2 suspension. The amount of MgCl2 added is 0.35% of the Ca(OH)2. A mixed gas with a CO2 concentration of 30% is introduced to carry out the carbonation reaction, and the flow rate of the CO2 mixed gas is controlled at 0.05 m³ / min. 2 / h, when the pH of the reaction suspension is ≤7, stop the CO2 flow; to obtain a calcium carbonate suspension;

[0042] S3: Add 70% oxalic acid to the calcium carbonate suspension. The amount of oxalic acid solution added is 30% of the dry basis of calcium carbonate. The dropping rate is 200 mL / min. The stirring speed is 200 r / min. The stirring time is 2 h.

[0043] S4: Add 30% glacial acetic acid to the calcium carbonate suspension. The amount of glacial acetic acid solution added is 75% of the dry basis of calcium carbonate. The dropping rate is 200 mL / min. The stirring speed is 200 r / min. The stirring time is 0 h.

[0044] S5: The above calcium carbonate suspension is subjected to pressure filtration, water washing, and pressure filtration again to prepare a calcium carbonate suspension with a calcium carbonate to water ratio of 1:15.

[0045] S6: Add a 15% lead acetate solution to the calcium carbonate suspension, with the amount of lead acetate solution added being 40% of the dry basis of the calcium carbonate; the dropping rate is 200 mL / min; the stirring speed is 200 r / min; and the stirring time is 2 h.

[0046] S7: Finally, filter under pressure and dry at 500℃ for 3 hours. After sieving, hollow rod-shaped calcium carbonate for filling styrene-butadiene rubber is obtained. Example

[0047] A method for preparing hollow rod-shaped calcium carbonate for use as a filler in styrene-butadiene rubber includes the following steps:

[0048] S1: Limestone is calcined at 1200℃ to obtain quicklime. Quicklime and water are reacted to obtain Ca(OH)2. The mixture is then sieved, allowed to stand, and then prepared into a Ca(OH)2 suspension with a solid content of 15.0%.

[0049] S2: Add MgCl2, a crystal form control agent, to the Ca(OH)2 suspension. The amount of MgCl2 added is 0.5% of the Ca(OH)2. A mixed gas with a CO2 concentration of 40% is introduced to carry out the carbonation reaction, and the flow rate of the CO2 mixed gas is controlled at 0.10 m³ / s. 2 / h, when the pH of the reaction suspension is ≤7, stop the CO2 flow; to obtain a calcium carbonate suspension;

[0050] S3: Add 80% oxalic acid to the calcium carbonate suspension, with the amount of oxalic acid solution added being 40% of the dry basis of calcium carbonate; the dropping rate is 500 mL / min; the stirring speed is 500 r / min; and the stirring time is 3 h.

[0051] S4: Add 40% glacial acetic acid to the calcium carbonate suspension. The amount of glacial acetic acid solution added is 100% of the dry basis of calcium carbonate. The dropping rate is 500 mL / min. The stirring speed is 500 r / min. The stirring time is 3 h.

[0052] S5: Finally, the above calcium carbonate suspension is subjected to pressure filtration, washed with water, and then pressure filtered again to prepare a calcium carbonate suspension with a calcium carbonate to water ratio of 1:20.

[0053] S6: Add a 20% lead acetate solution to the calcium carbonate suspension, with the amount of lead acetate solution added being 50% of the dry basis of the calcium carbonate; the dropping rate is 500 mL / min; the stirring speed is 500 r / min; and the stirring time is 3 h.

[0054] S7: Finally, filter under pressure and dry at 600℃ for 5 hours. After sieving, hollow rod-shaped calcium carbonate for filling styrene-butadiene rubber is obtained.

[0055] S1: Limestone is calcined at 900℃ to obtain quicklime. Quicklime and water are reacted to obtain Ca(OH)2. The mixture is then sieved, allowed to stand, and then prepared into a Ca(OH)2 suspension with a solid content of 4.0%.

[0056] S2: Add MgCl2, a crystal form control agent, to the Ca(OH)2 suspension. The amount of MgCl2 added is 0.1% of the Ca(OH)2. A mixed gas with a CO2 concentration of 20% is introduced to carry out the carbonation reaction, and the flow rate of the CO2 mixed gas is controlled at 0.01 m³ / min. 2 / h, when the pH of the reaction suspension is ≤7, stop the CO2 flow; to obtain a calcium carbonate suspension;

[0057] S3: Add 40% oxalic acid to the calcium carbonate suspension. The amount of oxalic acid solution added is 10% of the dry basis of calcium carbonate. The dropping rate is 10 mL / min. The stirring speed is 10 r / min. The stirring time is 1 h.

[0058] S4: Add 10% glacial acetic acid to the calcium carbonate suspension. The amount of glacial acetic acid solution added is 50% of the dry basis of calcium carbonate. The dropping rate is 10 mL / min. The stirring speed is 10 r / min. The stirring time is 1 h.

[0059] S5: The above calcium carbonate suspension is then subjected to pressure filtration, washed with water, and then pressure filtered again to prepare a calcium carbonate suspension with a calcium carbonate to water ratio of 1:10.

[0060] S6: Add a 10% lead acetate solution to the calcium carbonate suspension, the amount of lead acetate solution added being 10% of the dry basis of calcium carbonate; the dropping rate is 10 mL / min; the stirring speed is 10 r / min; the stirring time is 1 h;

[0061] S7: Finally, filter under pressure, dry at 400℃ for 1 hour, and then sieve to obtain calcium carbonate.

[0062] S1: Limestone is calcined at 1300℃ to obtain quicklime. Quicklime and water are reacted to obtain Ca(OH)2. The mixture is then sieved, allowed to stand, and then prepared into a Ca(OH)2 suspension with a solid content of 20%.

[0063] S2: Add MgCl2, a crystal form control agent, to the Ca(OH)2 suspension at 2% of the Ca(OH)2 concentration. Introduce a mixed gas with a CO2 concentration of 50% to carry out a carbonation reaction, controlling the CO2 flow rate to 2m³ / min. 2 / h, when the pH of the reaction suspension is ≤7, stop the CO2 flow; to obtain a calcium carbonate suspension;

[0064] S3: Add 90% oxalic acid to the calcium carbonate suspension. The amount of oxalic acid solution added is 50% of the dry basis of the calcium carbonate. The dropping rate is 1000 mL / min. The stirring speed is 1000 r / min. The stirring time is 5 h.

[0065] S4: Add 50% glacial acetic acid to the calcium carbonate suspension. The amount of glacial acetic acid solution added is 120% of the dry basis of calcium carbonate. The dropping rate is 1000 mL / min. The stirring speed is 1000 r / min. The stirring time is 5 h.

[0066] S5: The above calcium carbonate suspension is subjected to pressure filtration, water washing, and pressure filtration again to prepare a calcium carbonate suspension with a calcium carbonate to water ratio of 1:30.

[0067] S6: Add a 30% lead acetate solution to the calcium carbonate suspension, with the amount of lead acetate solution added being 60% of the dry basis of the calcium carbonate; the dropping rate is 1000 mL / min; the stirring speed is 1000 r / min; and the stirring time is 5 h.

[0068] S7: Finally, filter under pressure, dry at 600℃ for 6 hours. After sieving, calcium carbonate is obtained.

[0069] The difference from Example 1 is that the operation step S6 in Example 1 was not performed; that is, the surface of the obtained hollow rod-shaped calcium carbonate does not have lead monoxide coating.

[0070] The differences from Comparative Example 1 are as follows: First, the S6 operation step in Example 1 was not performed; that is, the surface of the obtained hollow rod-shaped calcium carbonate did not have lead monoxide coating. Second, 3 parts of zinc oxide vulcanizing activator were added during the subsequent filling with styrene-butadiene rubber.

[0071] The hollow rod-shaped calcium carbonate obtained in Examples 1-3 and the calcium carbonate obtained in Comparative Examples 1-4 were used as fillers for styrene-butadiene rubber. The formulation of the styrene-butadiene rubber is as follows:

[0072] Table 1: Styrene-butadiene rubber formulation used in this invention (without the addition of vulcanizing activator zinc oxide)

[0073]

[0074] The rolled styrene-butadiene rubber samples were tested at 160℃ for the positive vulcanization time t90, and the styrene-butadiene rubber was vulcanized using a flat vulcanizing apparatus according to the positive vulcanization time. Finally, the samples were cut and tested according to the national standard. The test results are shown in Table 2.

[0075] Table 2: Performance test results of styrene-butadiene rubber strips prepared using calcium carbonate according to the present invention

[0076]

[0077] The data in Table 2 shows that:

[0078] (1) Compared with Comparative Examples 1-2, the hollow rod-shaped calcium carbonate prepared by the method of Examples 1-3 of the present invention, when used to fill styrene-butadiene rubber, still achieves excellent vulcanization performance, i.e., short vulcanization time T90 and fast vulcanization speed, without the addition of the vulcanizing activator zinc oxide. At the same time, it has better tensile strength and elongation at break.

[0079] This is because in Comparative Example 1, the concentrations of various solutions were low and the dropping speed was slow, so the prepared calcium carbonate was not completely hollow rod-shaped, but rather some independently formed various morphologies. The irregular morphology caused the lead monoxide to coat the calcium carbonate unevenly, thus failing to serve as a good connection point between the calcium carbonate and the styrene-butadiene rubber, thereby reducing the tensile strength and elongation at break.

[0080] This is because in Comparative Example 2, the high concentration and fast dropping speed of the various solutions resulted in the prepared calcium carbonate not being entirely hollow rods, but containing a small number of solid rods. The lack of a hollow structure reduced the contact area between styrene-butadiene rubber and calcium carbonate, thus lowering the tensile strength and elongation at break.

[0081] (2) Compared with Comparative Example 3, the hollow rod-shaped calcium carbonate prepared by the methods of Examples 1-3 of the present invention, when used to fill styrene-butadiene rubber, exhibits excellent vulcanization performance, i.e., short vulcanization time T90 and fast vulcanization speed, without the addition of the vulcanizing activator zinc oxide. At the same time, it also has very good tensile strength and elongation at break.

[0082] This is because in Comparative Example 3, the hollow rod-shaped calcium carbonate was not coated with lead monoxide. In the absence of lead monoxide and the addition of the vulcanizing activator zinc oxide, the positive vulcanization time was significantly prolonged. Furthermore, the lack of lead monoxide as a bonding point between the calcium carbonate and styrene-butadiene rubber greatly reduced the tensile strength and elongation at break.

[0083] (3) Compared with Comparative Example 4, the hollow rod-shaped calcium carbonate prepared by the methods of Examples 1 to 3 of the present invention, when used to fill styrene-butadiene rubber, exhibits similar vulcanization performance, i.e., the vulcanization time T90 is comparable, even without the addition of the vulcanizing activator zinc oxide. At the same time, the tensile strength and elongation at break are also comparable.

[0084] Because Comparative Example 4 did not involve lead monoxide coating and instead included 3 parts of zinc oxide as a vulcanizing activator, the hollow rod-shaped calcium carbonate prepared by the methods of Examples 1-3 of this invention exhibits comparable performance when used as a filler for styrene-butadiene rubber. Therefore, it can be determined that the hollow rod-shaped calcium carbonate prepared by the methods of Examples 1-3 of this invention can replace 3 parts of zinc oxide as a vulcanizing activator when used as a filler for styrene-butadiene rubber.

[0085] The above description, in conjunction with specific / preferred embodiments, provides a further detailed explanation of the present invention. It should not be construed that the specific implementation of the present invention is limited to these descriptions. For those skilled in the art, various substitutions or modifications can be made to these described embodiments without departing from the inventive concept, and all such substitutions or modifications should be considered within the scope of protection of the present invention.

Claims

1. A method for preparing hollow rod-shaped calcium carbonate for styrene-butadiene rubber, characterized in that: Includes the following steps: S1: Limestone is calcined at 1000~1200℃ to obtain quicklime. Quicklime and water are reacted to obtain Ca(OH)2. The mixture is sieved and allowed to stand, and then prepared into a Ca(OH)2 suspension with a solid content of 5.0%~15.0%. S2: Add MgCl2, a crystal form control agent, to the Ca(OH)2 suspension, and introduce a CO2 mixture to carry out a carbonation reaction. When the pH of the reaction suspension is ≤7, stop introducing CO2; to obtain a calcium carbonate suspension. S3: Add oxalic acid to the calcium carbonate suspension and react for 1-3 hours. The amount of oxalic acid solution added is 20%-40% of the dry basis of calcium carbonate. S4: Add glacial acetic acid to the calcium carbonate suspension and stir for 1-3 hours; S5: Finally, the above calcium carbonate suspension is subjected to pressure filtration, washed with water, and then pressure filtered again to prepare a calcium carbonate suspension with a calcium carbonate to water ratio of 1:10~20. S6: Add a 10-20% lead acetate solution to the calcium carbonate suspension and stir for 1-3 hours; S7: Finally, after pressure filtration, drying, and sieving, hollow rod-shaped calcium carbonate for filling styrene-butadiene rubber is obtained. In step S3, the concentration of oxalic acid is 60%~80%, the dropping rate is 50~500 mL / min, and the stirring speed is 100~500 r / min; In step S4, the concentration of glacial acetic acid is 20-40%, and the amount of glacial acetic acid solution added is 50%-100% of the dry basis of calcium carbonate; the dropping rate is 50-500 mL / min; and the stirring speed is 100-500 r / min. The amount of lead acetate solution added in step S6 is 30%~50% of the dry basis of calcium carbonate, the concentration of lead acetate solution is 10~20%, the dropping rate is 50~500mL / min, and the stirring speed is 100~500r / min; The drying temperature in step S7 is 400~600℃, and the time is 1~5h; In step S2, the amount of MgCl2 added is 0.2% to 0.5% of Ca(OH)2.

2. The method for preparing hollow rod-shaped calcium carbonate for styrene-butadiene rubber according to claim 1, characterized in that: In step S2, the CO2 concentration in the mixed gas is 20-40%, and the flow rate of the CO2 mixed gas is 0.01-0.10 m³ / s. 2 / h, the carbonation reaction temperature is controlled at 50~100℃ and the stirring speed is 500~1000r / min.

3. The method for preparing hollow rod-shaped calcium carbonate for styrene-butadiene rubber according to claim 1, characterized in that: The limestone in step S1 contains ≥95% calcium carbonate by mass, and the mass ratio of quicklime to water is 1:10~20.

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