A method for preparing super-hydrophobic nano calcium carbonate by in-situ modification

Abstract

The invention relates to the technical field of super-hydrophobic nano-calcium carbonate preparation, and discloses a method for preparing super-hydrophobic nano-calcium carbonate by in-situ modification. The method for preparing super-hydrophobic nano-calcium carbonate by in-situ modification can make the surface of the nano-calcium carbonate have super-hydrophobic characteristics by selecting anionic surfactant as a modifier and optimizing reaction conditions, improve the dispersibility and stability of the nano-calcium carbonate in an organic medium, and effectively reduce the cost. Meanwhile, by strictly controlling the reaction temperature and time, the particle size distribution is uniform and the morphology is regular, thereby ensuring the performance of the product. The method for preparing super-hydrophobic nano-calcium carbonate by in-situ modification adopts an in-situ modification mode, simultaneously performs surface modification in the calcium carbonate synthesis process, does not require a separate modification step, simplifies the process flow, reduces the production cost, and realizes continuous production and improves the production efficiency by carefully selecting and preparing equipment.

Description

Technical Field

[0001] The invention relates to the technical field of super-hydrophobic nano-calcium carbonate preparation, in particular to a method for preparing super-hydrophobic nano-calcium carbonate by in-situ modification. Background Art

[0002] With the continuous development of science and technology, nanomaterials are increasingly used in various fields. As an important inorganic material, calcium carbonate has the advantages of wide sources, low price, non-toxicity and harmlessness, and has important applications in industries such as plastics, rubber, coatings, and papermaking. However, the traditional calcium carbonate surface is hydrophilic and oleophobic, and has poor dispersibility and easy agglomeration in organic media, which limits its application in some fields.

[0003] In order to improve the performance of calcium carbonate and meet the needs of different fields, surface modification of calcium carbonate has become a hot topic of research. In-situ modification is a method of surface modification during the synthesis of calcium carbonate, which has the advantages of good modification effect, simple process and low cost. Through in-situ modification, specific functional groups can be introduced on the surface of calcium carbonate to make it super-hydrophobic, thereby improving its dispersibility and stability in organic media.

[0004] At present, there have been some research reports on the in-situ modification preparation of super-hydrophobic nano-calcium carbonate, but these methods still have some shortcomings. For example, the reaction conditions are harsh and the product performance is unstable. Therefore, it is necessary to develop a more efficient and stable in-situ modification method for preparing super-hydrophobic nano-calcium carbonate. Summary of the invention

[0005] The object of the present invention is to provide a method for preparing super-hydrophobic nano-calcium carbonate by in-situ modification, so as to solve the problems raised in the above-mentioned background technology.

[0006] To achieve the above object, the present invention provides the following technical solution: a method for preparing super-hydrophobic nano-calcium carbonate by in-situ modification, the method for preparing super-hydrophobic nano-calcium carbonate by in-situ modification comprising the following specific steps: S1. Prepare the reactor, agitator, heating and cooling equipment, separation equipment, drying equipment, testing and analysis equipment and storage equipment, check whether all equipment is operating normally, ensure that the equipment is in a clean and dry state, and conduct strict inspections on each equipment to ensure that it is operating normally and in the best clean and dry state, thus ensuring the smooth progress of the entire process; S2, preparing calcium hydroxide, a modifier and carbon dioxide, adding calcium hydroxide and the modifier into a reactor, introducing the prepared carbon dioxide gas, heating the reactor by a heating and cooling device, and stirring the added materials in the reactor with a stirrer to react; S3. After the reaction is completed, the reaction product is separated and dried by a separation device and a drying device to obtain super-hydrophobic nano-sodium carbonate; S4. Testing and analyzing the prepared super-hydrophobic nano-calcium carbonate, including performance index tests of particle size, morphology, and contact angle, and storing the qualified super-hydrophobic nano-calcium carbonate in a storage device.

[0007] Preferably, the modifier is an anionic surfactant.

[0008] Preferably, the preparation of super-hydrophobic nano-calcium carbonate in S2 comprises the following specific steps: S2.1. Detect calcium hydroxide to ensure its purity and quality, grind the tested calcium hydroxide into fine particles, prepare modifiers and high-purity carbon dioxide gas, ensure the stability and adequacy of carbon dioxide gas supply, connect the container filled with carbon dioxide gas to the reactor through a connecting pipe, detect calcium hydroxide to ensure its purity and quality meet high standards, and carefully grind the tested calcium hydroxide into fine particles, which can effectively increase its reaction activity; S2.2. Close all inlet and outlet valves of the reactor and fill the reactor with nitrogen of a certain pressure to check the tightness of the reactor and ensure that the reactor body, lid and sealing gasket are intact and have no leakage points. After the inspection, clean and dry the reactor and remove impurities, dust and moisture in the reactor; S2.3, open the feed port of the reactor, slowly add the prepared calcium hydroxide into the reactor, and add the modifier after the calcium hydroxide is added; S2.4, first introduce a small amount of nitrogen into the reactor to replace the air in the reactor, which can effectively prevent the influence of impurities such as oxygen in the air on the reaction, introduce carbon dioxide gas into the reactor, and turn on the agitator at the same time to make the carbon dioxide gas fully contact and react with the calcium hydroxide and the modifier; S2.5. During the reaction, the reactor is heated by using a heating and cooling device to make the temperature in the reactor reach the set reaction temperature, and the pressure in the reactor is monitored in real time during the reaction. The pressure in the reactor is controlled to be within the set range by adjusting the flow rate of carbon dioxide gas and the exhaust valve of the reactor; S2.6. After the reaction is completed, close the valve of the carbon dioxide gas container, stop introducing carbon dioxide gas, and simultaneously turn off the agitator and heating and cooling equipment of the reactor, so that the material in the reactor is naturally cooled to room temperature, open the discharge port of the reactor, slowly release the product after the reaction, collect the product, and after collection, wash and dry the collected product to remove impurities and moisture on the surface to obtain the final super-hydrophobic nano-calcium carbonate.

[0009] Preferably, in S2.6, when the discharge port of the reactor is opened to slowly release the product after the reaction, if the product is a suspension, the solid product needs to be separated out by a separation device, and if the product is a solid powder, the product can be directly collected.

[0010] Preferably, in S4, the particle size, morphology and contact angle of the super-hydrophobic nano-calcium carbonate are tested by a laser particle size analyzer, an electron microscope and a sessile drop method.

[0011] Preferably, when performing the particle size test, an appropriate amount of super-hydrophobic nano-calcium carbonate sample is weighed and dispersed in a dispersant to form a uniform suspension, and then a laser particle size analyzer is used to perform particle size analysis; When performing the morphology test, the super-hydrophobic nano-calcium carbonate sample is dried to remove the moisture in the sample, and the super-hydrophobic nano-calcium carbonate sample is crushed and ground into powder. After grinding, it is pasted on a conductive adhesive and tested using an electron microscope. When conducting the contact angle test, the super-hydrophobic nano-calcium carbonate sample is made into a flat solid to ensure that the sample surface is clean and flat, and free of impurities and pollutants. Deionized water is dropped on the surface of the super-hydrophobic nano-calcium carbonate sample to form droplets. The shape of the droplets on the sample surface is observed through the camera of the instrument, and the contact angle between the droplets and the sample surface is measured. Multiple measurements are performed at different positions and directions, and the average value is taken as the final contact angle result.

[0012] Preferably, the calcium hydroxide, modifier and carbon dioxide gas in S2.5 need to react in the reactor for 5-8h, and sampling operations need to be performed at different time points during the process to observe the extent of the reaction. The reaction can be stopped when the performance of the product meets the expected requirements, which can effectively ensure the performance of the prepared super-hydrophobic nano-calcium carbonate.

[0013] Preferably, when the reactor is heated by the heating and cooling equipment in S2.5, the temperature in the reactor needs to be controlled between 50° C. and 65° C., so as to ensure the stability of the reaction and the quality of the product.

[0014] Preferably, in order to ensure the dispersion effect during the particle size test, ultrasonic dispersion is used to disperse the dispersant and the super-hydrophobic nano-calcium carbonate sample, and the dispersion time is 10-30 minutes.

[0015] Compared with the prior art, the present invention provides a method for preparing super-hydrophobic nano-calcium carbonate by in-situ modification, which has the following beneficial effects: 1. The in-situ modified method for preparing super-hydrophobic nano-calcium carbonate can make the surface of nano-calcium carbonate have super-hydrophobic properties by selecting anionic surfactant as a modifier and optimizing reaction conditions, thereby improving its dispersibility and stability in organic media and effectively reducing costs. At the same time, by strictly controlling the reaction temperature and time, the particle size distribution is uniform and the morphology is regular, thereby ensuring the performance of the product.

[0016] 2. The method for preparing super-hydrophobic nano-calcium carbonate by in-situ modification adopts an in-situ modification method to simultaneously perform surface modification during the calcium carbonate synthesis process without the need for a separate modification step, thereby simplifying the process flow and reducing production costs. At the same time, through the careful selection and preparation of equipment, continuous production can be achieved and production efficiency can be improved.

[0017] 3. The in-situ modified method for preparing super-hydrophobic nano-calcium carbonate can effectively increase its reaction activity and further improve the stability of the reaction by testing the calcium hydroxide before the reaction to ensure the purity and quality of the calcium hydroxide and grinding the tested calcium hydroxide into fine particles. BRIEF DESCRIPTION OF THE DRAWINGS

[0018] Figure 1 It is a schematic diagram of the preparation steps of the present invention. DETAILED DESCRIPTION

[0019] like Figure 1 As shown, the present invention provides a technical solution: a method for preparing super-hydrophobic nano-calcium carbonate by in-situ modification, the method for preparing super-hydrophobic nano-calcium carbonate by in-situ modification comprises the following specific steps: S1. Prepare the reactor, agitator, heating and cooling equipment, separation equipment, drying equipment, testing and analysis equipment and storage equipment, check whether all equipment is operating normally, ensure that the equipment is in a clean and dry state, and conduct strict inspections on each equipment to ensure that it is operating normally and in the best clean and dry state, thus ensuring the smooth progress of the entire process; S2, preparing calcium hydroxide, a modifier and carbon dioxide, wherein the modifier is an anionic surfactant, adding calcium hydroxide and the modifier into a reactor, introducing the prepared carbon dioxide gas, heating the reactor by a heating and cooling device, and reacting the added materials in the reactor by stirring with a stirrer; S3. After the reaction is completed, the reaction product is separated and dried by a separation device and a drying device to obtain super-hydrophobic nano-sodium carbonate; S4, the super-hydrophobic nano calcium carbonate obtained after preparation is detected and analyzed, the qualified super-hydrophobic nano calcium carbonate detected is put into storage equipment for storage, by laser particle size analyzer, electron microscope and sessile drop method, super-hydrophobic nano calcium carbonate is carried out to particle diameter, morphology, contact angle test, when carrying out particle diameter test, weigh an amount of super-hydrophobic nano calcium carbonate sample, it is dispersed in dispersant, form uniform suspension, in order to ensure the effect of dispersion, use ultrasonic dispersion mode to disperse dispersant and super-hydrophobic nano calcium carbonate sample, dispersion time is 10-30min, laser particle size analyzer can be used to carry out particle diameter analysis; When performing the morphology test, the super-hydrophobic nano-calcium carbonate sample is dried to remove the moisture in the sample, and the super-hydrophobic nano-calcium carbonate sample is crushed and ground into powder. After grinding, it is pasted on a conductive adhesive and tested using an electron microscope. When conducting the contact angle test, the super-hydrophobic nano-calcium carbonate sample is made into a flat solid to ensure that the sample surface is clean and flat, and free of impurities and pollutants. Deionized water is dropped on the surface of the super-hydrophobic nano-calcium carbonate sample to form droplets. The shape of the droplets on the sample surface is observed through the camera of the instrument, and the contact angle between the droplets and the sample surface is measured. Multiple measurements are performed at different positions and directions, and the average value is taken as the final contact angle result.

[0020] The preparation of super-hydrophobic nano-calcium carbonate in S2 comprises the following specific steps: S2.1. Detect calcium hydroxide to ensure its purity and quality, grind the tested calcium hydroxide into fine particles, prepare modifiers and high-purity carbon dioxide gas, ensure the stability and adequacy of carbon dioxide gas supply, connect the container filled with carbon dioxide gas to the reactor through a connecting pipe, detect calcium hydroxide to ensure its purity and quality meet high standards, and carefully grind the tested calcium hydroxide into fine particles, which can effectively increase its reaction activity; S2.2. Close all inlet and outlet valves of the reactor and fill the reactor with nitrogen of a certain pressure to check the tightness of the reactor and ensure that the reactor body, lid and sealing gasket are intact and have no leakage points. After the inspection, clean and dry the reactor and remove impurities, dust and moisture in the reactor; S2.3, open the feed port of the reactor, slowly add the prepared calcium hydroxide into the reactor, and add the modifier after the calcium hydroxide is added; S2.4, first introduce a small amount of nitrogen into the reactor to replace the air in the reactor, which can effectively prevent the influence of impurities such as oxygen in the air on the reaction, introduce carbon dioxide gas into the reactor, and turn on the agitator at the same time to make the carbon dioxide gas fully contact and react with the calcium hydroxide and the modifier; S2.5, during the reaction process, the reactor is heated by a heating and cooling device so that the temperature in the reactor reaches the set reaction temperature, and the pressure in the reactor is monitored in real time during the reaction process. The pressure in the reactor is controlled to be within the set range by adjusting the flow rate of carbon dioxide gas and the exhaust valve of the reactor. Calcium hydroxide, modifier and carbon dioxide gas need to react in the reactor for 5-8h. During the process, sampling operations need to be performed at different time points to observe the degree of reaction. When the performance of the product reaches the expected requirements, the reaction can be stopped, which can effectively ensure the performance of the prepared super-hydrophobic nano calcium carbonate. When the reactor is heated by the heating and cooling device, the temperature in the reactor needs to be controlled between 50°C and 65°C to ensure the stability of the reaction and the quality of the product. S2.6. After the reaction is completed, close the valve of the carbon dioxide gas container, stop introducing carbon dioxide gas, and simultaneously turn off the agitator and heating and cooling equipment of the reactor, so that the material in the reactor is naturally cooled to room temperature, open the discharge port of the reactor, slowly release the product after the reaction, collect the product, and after the collection is completed, wash and dry the collected product to remove surface impurities and moisture to obtain the final super-hydrophobic nano-calcium carbonate. When opening the discharge port of the reactor and slowly releasing the product after the reaction, if the product is a suspension, the solid product needs to be separated by a separation device, and if the product is a solid powder, the product can be directly collected.

[0021] The above generally describes the present invention in detail, but it is obvious to a person skilled in the art that some modifications or improvements can be made to the present invention. Therefore, modifications or improvements that do not depart from the spirit of the present invention are within the scope of protection of the present invention.

Claims

1. A method for preparing super-hydrophobic nano-calcium carbonate by in-situ modification, characterized in that: The method for preparing super-hydrophobic nano-calcium carbonate by in-situ modification comprises the following specific steps: S1. Prepare the reactor, agitator, heating and cooling equipment, separation equipment, drying equipment, testing and analysis equipment and storage equipment, check whether all equipment is operating normally, and ensure that the equipment is in a clean and dry state; S2, preparing calcium hydroxide, a modifier and carbon dioxide, adding calcium hydroxide and the modifier into a reactor, introducing the prepared carbon dioxide gas, heating the reactor by a heating and cooling device, and stirring the added materials in the reactor with a stirrer to react; S3. After the reaction is completed, the reaction product is separated and dried by a separation device and a drying device to obtain super-hydrophobic nano-sodium carbonate; S4. Testing and analyzing the prepared super-hydrophobic nano-calcium carbonate, including performance index tests of particle size, morphology, and contact angle, and storing the qualified super-hydrophobic nano-calcium carbonate in a storage device.

2. A method for preparing super-hydrophobic nano-calcium carbonate by in-situ modification according to claim 1, characterized in that: The modifier is an anionic surfactant.

3. A method for preparing super-hydrophobic nano calcium carbonate by in-situ modification according to claim 1, characterized in that: The preparation of super-hydrophobic nano-calcium carbonate in S2 comprises the following specific steps: S2.

1. Detect calcium hydroxide to ensure its purity and quality, grind the detected calcium hydroxide into fine particles, prepare modifiers and high-purity carbon dioxide gas, ensure the stability and adequacy of carbon dioxide gas supply, and connect the container containing carbon dioxide gas to the reactor through a connecting pipe; S2.

2. Close all inlet and outlet valves of the reactor and fill the reactor with nitrogen of a certain pressure to check the tightness of the reactor and ensure that the reactor body, lid and sealing gasket are intact and have no leakage points. After the inspection, clean and dry the reactor and remove impurities, dust and moisture in the reactor; S2.3, open the feed port of the reactor, slowly add the prepared calcium hydroxide into the reactor, and add the modifier after the calcium hydroxide is added; S2.4, first introduce a small amount of nitrogen into the reactor to replace the air in the reactor, introduce carbon dioxide gas into the reactor, and turn on the agitator at the same time to allow the carbon dioxide gas to fully contact and react with the calcium hydroxide and the modifier; S2.

5. During the reaction, the reactor is heated by using a heating and cooling device to make the temperature in the reactor reach the set reaction temperature, and the pressure in the reactor is monitored in real time during the reaction. The pressure in the reactor is controlled to be within the set range by adjusting the flow rate of carbon dioxide gas and the exhaust valve of the reactor; S2.

6. After the reaction is completed, close the valve of the carbon dioxide gas container, stop introducing carbon dioxide gas, and simultaneously turn off the agitator and heating and cooling equipment of the reactor, so that the material in the reactor is naturally cooled to room temperature, open the discharge port of the reactor, slowly release the product after the reaction, collect the product, and after collection, wash and dry the collected product to remove impurities and moisture on the surface to obtain the final super-hydrophobic nano-calcium carbonate.

4. A method for preparing super-hydrophobic nano-calcium carbonate by in-situ modification according to claim 3, characterized in that: In the above S2.6, when the discharge port of the reactor is opened and the product after the reaction is slowly released, if the product is a suspension, the solid product needs to be separated out by a separation device. If the product is a solid powder, the product can be directly collected.

5. A method for preparing super-hydrophobic nano-calcium carbonate by in-situ modification according to claim 1, characterized in that: In S4, the particle size, morphology and contact angle of super-hydrophobic nano-calcium carbonate are tested by laser particle size analyzer, electron microscope and sessile drop method.

6. A method for preparing super-hydrophobic nano-calcium carbonate by in-situ modification according to claim 5, characterized in that: When the particle size test is performed, an appropriate amount of super-hydrophobic nano-calcium carbonate sample is weighed and dispersed in a dispersant to form a uniform suspension, and then a laser particle size analyzer is used to perform particle size analysis; When performing the morphology test, the super-hydrophobic nano-calcium carbonate sample is dried to remove the moisture in the sample, and the super-hydrophobic nano-calcium carbonate sample is crushed and ground into powder. After grinding, it is pasted on a conductive adhesive and tested using an electron microscope. When conducting the contact angle test, the super-hydrophobic nano-calcium carbonate sample is made into a flat solid to ensure that the sample surface is clean and flat, and free of impurities and pollutants. Deionized water is dropped on the surface of the super-hydrophobic nano-calcium carbonate sample to form droplets. The shape of the droplets on the sample surface is observed through the camera of the instrument, and the contact angle between the droplets and the sample surface is measured. Multiple measurements are performed at different positions and directions, and the average value is taken as the final contact angle result.

7. A method for preparing super-hydrophobic nano-calcium carbonate by in-situ modification according to claim 3, characterized in that: The calcium hydroxide, modifier and carbon dioxide gas in S2.5 need to react in the reactor for 5-8 hours. During the process, sampling operations need to be performed at different time points to observe the progress of the reaction. The reaction can be stopped when the performance of the product meets the expected requirements.

8. A method for preparing super-hydrophobic nano-calcium carbonate by in-situ modification according to claim 3, characterized in that: When the reactor is heated by the heating and cooling equipment in S2.5, the temperature in the reactor needs to be controlled between 50°C and 65°C.

9. A method for preparing super-hydrophobic nano-calcium carbonate by in-situ modification according to claim 6, characterized in that: When performing the particle size test, in order to ensure the dispersion effect, ultrasonic dispersion is used to disperse the dispersant and the super-hydrophobic nano-calcium carbonate sample, and the dispersion time is 10-30 minutes.

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