Preparation method, application and device of surface modified nano CaCO3 and CaCO3-Fe3O4

Abstract

The invention provides a preparation method, an application and a device of surface modified nano CaCO3 and CaCO3 coated Fe3O4. The preparation method of the surface modified nano CaCO3 comprises the following steps: S1, taking a certain volume of brine, and detecting that the content of Ca < 2 + > in the brine is 100-800mg / l; s2, a (NH4) 2CO3 solution with the concentration being 0.1 mol / l to 0.5 mol / l and a sodium pyrophosphate solution with the concentration being 0.5 mol / l to 2.5 mol / l are prepared; according to the preparation method of the surface-modified nano CaCO3, provided by the invention, the surface-modified nano CaCO3 is prepared by applying in-situ modification in the process of preparing the spherical nano CaCO3, the surface-modified nano CaCO3 is superior to the nano CaCO3 which is small in particle and more in surface active sites, and due to the chemical property of the nano CaCO3, the adsorption of F <-> in brine can be completed through physical and chemical adsorption; nano CaCO3 particles are prepared from Ca < + > existing in the brine, and the prepared nano CaCO3 particles can be also suitable for removing fluorine ions in the brine, so that the effect of double benefits is achieved, and a calcium source does not need to be additionally obtained.

Description

Technical Field

[0001] The present invention relates to the field of nano-CaCO3 preparation, and in particular to a preparation method, use and device of surface-modified nano-CaCO3 and CaCO3@Fe3O4. Background Art

[0002] Battery-grade lithium carbonate is an essential lithium salt for the manufacture of lithium-ion batteries. Its production process begins with the key steps of lepidolite leaching, concentration, and synthesis. Fluoride ions diffuse from the lepidolite ore into the brine during leaching. To prevent the impact of fluoride ions on product quality, deep defluoridation is required. Nano-calcium carbonate is a new solid material with three crystal forms: calcite, aragonite, and vaterite. Vaterite nano-calcium carbonate has a high specific surface area, low density, and good solubility and dispersibility, making it widely used in fluoride removal.

[0003] In the prior art, the preparation methods of nano calcium carbonate include carbonization method, double decomposition method, microemulsion method and mechanochemical method. Among them, double decomposition method is the most widely used method for preparing nano calcium carbonate. Calcium chloride is used as the calcium source and a crystal form control agent is added to prepare spherical nano calcium carbonate. This method requires additional calcium source. 2+ As a calcium source, nano calcium carbonate is obtained by adding a crystal control agent, so there is still room for improvement in saving the acquisition of calcium sources.

[0004] Therefore, it is necessary to provide a preparation method of surface-modified nano-CaCO3 to solve the above technical problems. Summary of the Invention

[0005] The present invention provides a preparation method of surface-modified nano-CaCO3, which solves the problem that calcium chloride is usually needed as a calcium source in the current preparation of spherical nano-calcium carbonate, and there is still room for improvement in saving the acquisition of calcium source.

[0006] To solve the above technical problems, the present invention provides a method for preparing surface-modified nano-CaCO3, comprising the following steps:

[0007] S1. Take a certain volume of brine and detect the Ca content in the brine. 2+ The content is 100-800 mg / l;

[0008] S2, respectively prepare 0.1-0.5 mol / l (NH4)2CO3 solution and 0.5-2.5 mol / l sodium pyrophosphate solution;

[0009] S3, uniformly mixing the prepared (NH4)2CO3 solution, sodium pyrophosphate solution and anhydrous ethanol to form a crystal form control agent solution;

[0010] S4. Add the brine dropwise to the crystal form control agent solution at a rate of 10 ml / min to 20 ml / min through a peristaltic pump to obtain a white suspension;

[0011] S5. Add 0.25-2.50 g of sodium lauryl sulfate, 0.25-2.50 g of sodium stearate and 0.25-2.50 g of hexadecyltrimethylammonium bromide to the suspension and stir at 60-100° C. for 20-50 min.

[0012] S6. The white precipitate obtained by filtering the solution in S5 is washed and dried to obtain surface-modified nano-CaCO3.

[0013] Preferably, the volume of the (NH4)2CO3 solution is 3-10% of the volume of the brine, the volume of the sodium pyrophosphate solution is 4-6% of the volume of the brine, and the volume of the anhydrous ethanol is 2-4% of the volume of the brine.

[0014] Preferably, the surface-modified nano-CaCO3 is prepared into nano-CaCO3 with a porous structure, comprising the following steps:

[0015] S01, taking the prepared nano-CaCO3 and placing it in a container, and then adding ZnCl2 into the container, wherein the mixing ratio of nano-CaCO3 and ZnCl2 is between 1:3 and 1:6;

[0016] S02, shaking the container with an oscillator to mix evenly so that self-assembly occurs between the nano-CaCO3 and ZnCl2;

[0017] S03, placing the mixed materials in S02 in a high-temperature tube furnace, burning in a protective gas at a temperature of 300-800°C until the powdered material is obtained;

[0018] S04. Wash the powdered material three times with anhydrous ethanol and deionized water, and dry it to obtain spherical nano-CaCO3 with a porous structure.

[0019] The present invention also provides a preparation method of surface-modified nano-CaCO3@Fe3O4, comprising the following steps:

[0020] T1. Place 10-50 ml of ethylene glycol solution in a container, weigh 5.404-6.755 g of FeCl3·6H2O and dissolve it in the ethylene glycol solution;

[0021] T2. Dissolve 0.05-0.2 mol / l sodium acetate solution in ethylene glycol solution, and the amount of sodium acetate added is 1-5% of the volume of ethylene glycol;

[0022] T3. Take polyethylene glycol solution and slowly add it dropwise to the mixed solution, stirring for 30 to 60 minutes. The amount of polyethylene glycol solution added is 1 to 10% of the volume of ethylene glycol.

[0023] T4. Place the solution in T3 in a polytetrafluoroethylene-lined autoclave, seal it, and place it in an electric oven to keep warm for 6 to 12 hours;

[0024] T5. After the insulation is completed, the liquid is removed, the reaction product is transferred to a container, and the product is washed three times by oscillation using ethanol and ultrasonic waves;

[0025] T6. Mix the prepared wet magnetic nano-Fe3O4 and nano-CaCO3, add deionized water to form a slurry, and stir for 30 to 60 minutes;

[0026] T7. Dry the mixed slurry in a vacuum oven to obtain surface-modified nano-CaCO3@Fe3O4 particles with a porous structure.

[0027] The present invention also provides a use of surface-modified nano-CaCO3@Fe3O4, wherein the surface-modified nano-CaCO3@Fe3O4 is used to adsorb and remove F in liquid. - .

[0028] The present invention also provides a surface-modified nano-CaCO3 preparation device, which is used to filter and wash the white precipitate in step S6;

[0029] Includes: bracket;

[0030] A cleaning filter cartridge is installed on the bracket, a support is provided inside the cleaning filter cartridge, and a valve is installed at the discharge end of the cleaning filter cartridge;

[0031] A filter assembly, the filter assembly being detachably mounted on the support;

[0032] A lifting device, the lifting device is mounted on the bracket through a mounting frame and is suspended on the cleaning filter cartridge;

[0033] A stirring assembly is installed at the output end of the lifting device.

[0034] Preferably, the stirring assembly includes an assembly frame, a motor, a stirring shaft and a stirring blade, the assembly frame is installed at the output end of the lifting device, the motor is installed on the assembly frame, the stirring shaft is fixedly connected to the output end of the motor, and the stirring blade is installed on the stirring shaft.

[0035] Preferably, the filter assembly includes a base, a pressure ring and a filter element, the pressure ring is detachably connected to the base, and the filter element is located between the pressure ring and the base.

[0036] Preferably, the filter assembly further comprises a pleated bag, the base comprises a mounting ring, a support ring and a plurality of convex shafts, the support ring is rotatably connected within the mounting ring, the plurality of convex shafts are mounted around the support ring, and the sides of the filter element are sleeved on the plurality of convex shafts;

[0037] The bottom of the pressure ring is provided with a receiving groove, one end of the folding bag is connected to the receiving groove, and the other end is connected to the support ring, and the mounting ring is threadedly connected to the pressure ring;

[0038] A driving sleeve is symmetrically installed on the pressure ring, and the stirring assembly also includes two L-shaped shafts, which are installed clockwise at the bottom of the two stirring blades, and the distance between the two L-shaped shafts is the same as the distance between the two driving sleeves.

[0039] Preferably, the support includes a support ring and multiple positioning shafts, the support ring is installed inside the cleaning filter cartridge, and the multiple positioning shafts are installed around the support ring. A positioning hole is opened at the bottom of the mounting ring, and the positioning hole is sleeved on the positioning shaft.

[0040] Compared with the related art, the preparation method of surface-modified nano-CaCO3 provided by the present invention has the following beneficial effects:

[0041] The present invention provides a preparation method of surface-modified nano-CaCO3. The surface-modified nano-CaCO3 is prepared by applying in-situ modification during the preparation of spherical nano-CaCO3. The surface-modified nano-CaCO3 has the advantages of small particles and many surface active sites. Due to its own chemical properties, it can complete the adsorption of F in brine by physical and chemical adsorption. - Adsorption, using Ca in brine + Nano-CaCO3 particles are prepared, and the prepared nano-calcium carbonate can be used to remove fluoride ions in brine, achieving a two-pronged effect without the need for additional calcium sources. BRIEF DESCRIPTION OF THE DRAWINGS

[0042] Figure 1 A flowchart of the steps for preparing surface-modified nano-CaCO3 provided by the present invention;

[0043] Figure 2 A flowchart of the steps for preparing nano-CaCO3 with a porous structure provided by the present invention;

[0044] Figure 3 Schematic diagram of the steps for preparing surface-modified nano-CaCO3@Fe3O4 provided by the present invention

[0045] Figure 4 A schematic diagram of the structure of the device for preparing surface-modified nano-CaCO3 provided by the present invention;

[0046] Figure 5 A cross-sectional view of the cleaning filter cartridge provided by the present invention;

[0047] Figure 6 for Figure 5 An enlarged schematic diagram of part A is shown;

[0048] Figure 7 This is a schematic diagram of the use status of the filter assembly provided by the present invention, wherein: Figure 7 (a) is a schematic diagram of the state of the filter component as a filter. Figure 7 (b) is a schematic diagram of the filter assembly as a bag body;

[0049] Figure 8 This is a schematic diagram of the state after the pressure ring provided by the present invention is separated from the base and the folding bag is disassembled;

[0050] Figure 9 for Figure 8 A schematic diagram of another perspective of the filter assembly shown;

[0051] Figure 10 A schematic diagram of the assembly of the L-shaped shaft and the driving sleeve provided by the present invention;

[0052] Figure 11 This is a schematic diagram of the lifting device provided by the present invention lifting the stirring assembly to drive the foldable bag to unfold.

[0053] Numbers in the figure:

[0054] 1. Bracket; 11. Mounting frame;

[0055] 2. Clean the filter cartridge; 21. Support; 22. Positioning ear; 23. Feed pipe; 24. Valve;

[0056] 211, support ring; 212, positioning shaft;

[0057] 3. Lifting device;

[0058] 4. Stirring assembly; 41. Assembly frame; 42. Motor; 43. Stirring shaft; 44. Stirring blade; 45. L-shaped shaft; 431. Support block;

[0059] 5. Filter assembly; 51. Base; 52. Press ring; 53. Filter element; 54. Pleated bag;

[0060] 511, mounting ring; 512, support ring; 513, protruding shaft; 510, positioning hole;

[0061] 521, driving sleeve; 522, receiving groove; 523, cylindrical hole;

[0062] 6. Pressure cover; 61. Limiting shaft. DETAILED DESCRIPTION

[0063] The following will clearly and completely describe the technical solutions in the embodiments of the present invention in conjunction with the accompanying drawings. Obviously, the described embodiments are only part of the embodiments of the present invention, not all of the embodiments. All other embodiments obtained by ordinary technicians in this field based on the embodiments of the present invention without making any creative efforts shall fall within the scope of protection of the present invention.

[0064] The present invention provides a preparation method, application and device of surface-modified nano-CaCO3 and CaCO3@Fe3O4.

[0065] See also Figure 1 In one embodiment of the present invention, the preparation method of the surface-modified nano-CaCO3 is characterized by comprising the following steps:

[0066] S1. Take a certain volume of brine and detect the Ca content in the brine. 2+ The content is 100-800 mg / l;

[0067] S2, respectively prepare 0.1 ~ 0.5 mol / l (NH4) 2CO3 solution and 0.5 ~ 2.5 mol / l sodium pyrophosphate solution;

[0068] S3, uniformly mixing the prepared (NH4)2CO3 solution, sodium pyrophosphate solution and anhydrous ethanol to form a crystal form control agent solution;

[0069] S4. Add the brine dropwise to the crystal form control agent solution at a rate of 10 ml / min to 20 ml / min through a peristaltic pump to obtain a white suspension;

[0070] S5. Add 0.25-2.50 g of sodium lauryl sulfate, 0.25-2.50 g of sodium stearate and 0.25-2.50 g of hexadecyltrimethylammonium bromide to the suspension and stir at 60-100° C. for 20-50 min.

[0071] S6. The white precipitate obtained by filtering the solution in S5 is washed and dried to obtain surface-modified nano-CaCO3.

[0072] The present invention obtains surface-modified nano-CaCO3 by applying in-situ modification during the preparation of spherical nano-CaCO3. The nano-CaCO3 has the advantages of small particles and many surface active sites. Due to its own chemical properties, it can complete the absorption of F in brine by physical and chemical adsorption.- Adsorption, using Ca in brine 2+ Nano-CaCO3 particles are prepared, and the prepared nano-calcium carbonate can be used to remove fluoride ions in brine, achieving a two-pronged effect without the need for additional calcium sources.

[0073] The volume of the (NH4)2CO3 solution is 3-10% of the volume of the brine, the volume of the sodium pyrophosphate solution is 4-6% of the volume of the brine, and the volume of the anhydrous ethanol is 2-4% of the volume of the brine.

[0074] In this embodiment, when 500 ml of brine is taken, the Ca content in the brine is 2+ The content is 100-800 mg / l;

[0075] As a preferred embodiment of this embodiment, 25 ml of 0.3 mol / l (NH4)2CO3 solution, 25 ml of 1.5 mol / l sodium pyrophosphate solution and 15 ml of anhydrous ethanol are measured and mixed into a uniform solution, namely the crystal form controller solution, and then 500 ml of brine is added dropwise to the crystal form controller solution at a rate of 15 ml / min using a peristaltic pump. After about 30 minutes, a white suspension is obtained, and then 1.5 g each of sodium lauryl sulfate, sodium stearate and hexadecyltrimethylammonium bromide are added thereto, and the mixture is stirred at 80°C and 700 rpm for 45 minutes. After the stirring is completed, solid-liquid separation is carried out, and the solid is dried at 40°C for 6 hours to obtain the surface-modified nano-CaCO3.

[0076] Then take 100ml of concentrated brine and place it in a conical flask, and measure its F - The content is 497.35 mg / l, add 2.5 g modified nano-CaCO3, shake at 35 ° C for 30 minutes, after adsorption is completed, centrifuge and take the supernatant to measure its F - The content is 44.76 mg / l and the adsorption rate is 91.00%;

[0077] See also Figure 2 As a preferred method of this embodiment, the surface-modified nano-CaCO3 is prepared into nano-CaCO3 with a porous structure, comprising the following steps:

[0078] S01, taking the prepared nano-CaCO3 and placing it in a container, and then adding ZnCl2 into the container, wherein the mixing ratio of nano-CaCO3 and ZnCl2 is between 1:3 and 1:6;

[0079] S02, shaking the container with an oscillator to mix evenly so that self-assembly occurs between the nano-CaCO3 and ZnCl2;

[0080] S03, placing the mixed materials in S02 in a high-temperature tube furnace, burning in a protective gas at a temperature of 300-800°C until the powdered material is obtained;

[0081] S04. Wash the powdered material three times with anhydrous ethanol and deionized water, and dry it to obtain spherical nano-CaCO3 with a porous structure.

[0082] By preparing nano-CaCO3 with a porous structure and CaCO3 with bare pores, agglomeration is greatly reduced and it has a higher specific surface area and a large surface free energy, providing more active sites, which is more conducive to F - adsorption.

[0083] As a preferred embodiment of the present invention, the preparation process of surface-modified nano-CaCO3 is the same as that described above. Alternatively, appropriately dried nano-CaCO3 is mixed with ZnCl2 in a ratio of 1:4.5, and then placed in an oscillation bottle for 2.5 hours to allow self-assembly. The mixed material is then placed in a high-temperature tubular furnace with a protective gas N2 flow rate of 200 ml / min, a heating rate of 5°C / min, and a final temperature of 600°C for calcination. After calcination, a powdered material is obtained, which is then washed three times with an appropriate amount of anhydrous ethanol and deionized water, and then dried at 60°C for 8 hours to obtain a surface-modified nano-CaCO3 with a porous structure.

[0084] Then take 100ml of concentrated brine and place it in a conical flask, and measure its F - The content is 497.35 mg / l, 2.5 g of surface modified nano-CaCO3 with porous structure is added, and it is shaken at 35 ° C for 30 minutes. After the adsorption is completed, it is centrifuged and the supernatant is taken to measure its F - The content is 24.87 mg / l and the adsorption rate is 95.00%.

[0085] See also Figure 3 The present invention also provides a preparation method of surface-modified nano-CaCO3@Fe3O4.

[0086] Please refer to the figure, a preparation method of surface-modified nano-CaCO3@Fe3O4 includes the following steps:

[0087] T1. Place 10-50 ml of ethylene glycol solution in a container, weigh 5.404-6.755 g of FeCl3·6H2O and dissolve it in the ethylene glycol solution;

[0088] T2. Dissolve 0.05-0.2 mol / l sodium acetate solution in ethylene glycol solution, and the amount of sodium acetate added is 1-5% of the volume of ethylene glycol;

[0089] T3. Take polyethylene glycol solution and slowly add it dropwise to the mixed solution, stirring for 30 to 60 minutes. The amount of polyethylene glycol solution added is 1 to 10% of the volume of ethylene glycol.

[0090] T4. Place the solution in T3 in a polytetrafluoroethylene-lined autoclave, seal it, and place it in an electric oven to keep warm for 6 to 12 hours;

[0091] T5. After the insulation is completed, the liquid is removed, the reaction product is transferred to a container, and the product is washed three times by oscillation using ethanol and ultrasonic waves;

[0092] T6. Mix the prepared wet magnetic nano-Fe3O4 with the nano-CaCO3 according to any one of claims 1 to 3, add deionized water to form a slurry, and stir for 30 to 60 minutes;

[0093] T7. Dry the mixed slurry in a vacuum oven to obtain surface-modified nano-CaCO3@Fe3O4 particles with a porous structure.

[0094] Due to the ultrafine particles of nano-CaCO3, the surface electronic structure of its crystal structure has changed. Nano-calcium carbonate has quantum size effect, small size effect, surface effect, and macroscopic quantum tunneling effect that ordinary CaCO3 does not have. Nano-CaCO3 also has a high specific surface area and a high surface activation rate. After activation and surface modification, its original high specific surface area is further improved. In addition, the modifier is adsorbed on the surface of nano-CaCO3 to form charge repulsion, which makes its dispersion better, making it difficult for nano-carbon to agglomerate. After the modification operation, the hydrophilicity of nano-CaCO3 changes to hydrophobicity, and the adsorption effect and activation are improved and enhanced. In addition to physical adsorption based on electrostatic interaction and van der Waals force and chemical adsorption due to nano-calcium carbonate itself, F in brine - The surface-modified nano-CaCO3 also enhances the adsorption effect through hydrogen bond interaction.

[0095] After the activation of nano-CaCO3, the CaCO3 with bare pores greatly reduces the agglomeration and has a better specific surface area and a large surface free energy, which will provide more active sites and is more conducive to F - The adsorption changes its surface structure and after activation, Fe3O4 is used to load it, so that nano calcium carbonate not only has the ability of magnetic separation, but also nano Fe3O4 can also adsorb a part of F - At the same time, its magnetic properties enable it to be adsorbed twice to achieve the purpose of recycling.

[0096] As a preferred embodiment of this embodiment, the surface modified nano-CaCO with porous structure Preparation process is the same as above. Separately get 5.404g FeCl 6H O and pour in the polytetrafluoroethylene liner that fills 25ml ethanol, then add 0.75ml sodium acetate, and slowly drip 1.25ml polyethylene glycol, continue to stir 45min, subsequently the polytetrafluoroethylene liner is sealed and placed in the stainless steel reactor in an electric drying oven, and is incubated at 180 ℃ for 30min. After question reaction is completed, pour away waste liquid, use ethanol and ultrasonic oscillation to clean three times, obtain wet magnetic nano Fe O , subsequently with wet magnetic nano Fe O With nano-CaCO Mix in a ratio of 2: 1, add appropriate amount of deionized water, make it form slurry-like, and stir 40min, subsequently with the mixed slurry in 60 ℃ baking oven dry 12h, obtain the surface modified nano-CaCO with porous structure @Fe O Particle.

[0097] Then, 100 ml of concentrated leaching brine was placed in a conical flask, and its F- content was measured to be 497.35 mg / l. 2.5 g of surface-modified nano-CaCO3@Fe3O4 with a porous structure was added and shaken at 35°C for 30 minutes. After the adsorption was completed, centrifugation was performed and the supernatant was taken to measure its F- - The content is 15.36 mg / l, and the adsorption rate is 96.92%. Then 2 mol / l NaOH is used to desorb and wash away F. - Then repeat the above adsorption operation using the desorbed adsorbent, and take the supernatant to measure its F - It is 39.79 mg / l and the adsorption rate is 91.95%.

[0098] The present invention also provides a use of surface-modified nano-CaCO3@Fe3O4.

[0099] A use of surface-modified nano-CaCO3@Fe3O4, wherein the surface-modified nano-CaCO3@Fe3O4 is used for adsorbing and removing F in liquid - .

[0100] In this embodiment, CaCO3@Fe3O4 is used to adsorb F in brine. - In other embodiments, CaCO3@Fe3O4 can also be used to adsorb and remove F from other wastewater or sewage. - .

[0101] The present invention also provides a device for preparing surface-modified nano-CaCO3.

[0102] See also Figure 4 and Figure 5, a surface-modified nano-CaCO3 preparation device, the surface-modified nano-CaCO3 preparation device is used to filter and wash the white precipitate in step S6;

[0103] Including: bracket 1;

[0104] A cleaning filter cartridge 2 is installed on the bracket 1 , a support 21 is provided inside the cleaning filter cartridge 2 , and a valve 24 is installed at the discharge end of the cleaning filter cartridge 2 ;

[0105] A filter assembly 5, wherein the filter assembly 5 is detachably mounted on the support 21;

[0106] A lifting device 3, the lifting device 3 is mounted on the bracket 1 through a mounting frame 11 and is suspended on the cleaning filter cartridge 2;

[0107] A stirring assembly 4 is installed at the output end of the lifting device 3.

[0108] In this embodiment, the discharge end of the clean filter cartridge 2 is connected to the liquid storage container via a pipe, and the input end of the vacuum pump is connected to the liquid storage container. The vacuum pump extracts the gas inside the liquid storage container to generate a negative pressure, which can control the speed at which the solution in the clean filter cartridge 2 passes through the filter assembly 5, so that the white precipitate is located on the filter assembly 5.

[0109] During operation, the lifting device 3 lowers the stirring assembly 4 into the cleaning filter cartridge 2. Figure 5 , then the white precipitate and solution to be filtered are continuously added into the clean filter cartridge 2 through the feed pipe 23, the valve 24 is opened, and the solution passes through the filter component 5 and is discharged through the discharge end, and the white precipitate remains in the filter component 5. During the filtration process, the stirring component 4 can stir the solution so that the white precipitate can be suspended to avoid accumulation on the filter component 5, which causes the solution to be unable to flow down at a normal speed. When the filtered solution is added to the inside of the clean filter cartridge 2, the stirring component 4 stops working, waits for the last solution to flow out, and then closes the valve 24;

[0110] Add deionized water into the cleaning filter cartridge 2 through the feed pipe 23, and the stirring component 4 continues to work to stir and clean the white precipitate. After stirring for a preset time, open the valve 24 and the cleaning liquid flows out. The cleaning operation should be repeated for at least three times.

[0111] Therefore, the device can be used to realize the process and cleaning of white precipitate, without the need to set up transfer cleaning of white precipitate, thereby improving the efficiency of filtration and cleaning.

[0112] As an optional method of this embodiment, in order to improve the cleaning efficiency, an ultrasonic cleaning device can be set on the side wall of the cleaning filter cartridge 2 to cooperate with the stirring component 4 to improve the cleaning efficiency.

[0113] See also Figure 5 In this embodiment, the stirring assembly 4 includes an assembly frame 41, a motor 42, a stirring shaft 43 and a stirring blade 44. The assembly frame 41 is installed at the output end of the lifting device 3, the motor 42 is installed on the assembly frame 41, the stirring shaft 43 is fixedly connected to the output end of the motor 42, and the stirring blade 44 is installed on the stirring shaft 43.

[0114] When the stirring assembly 4 is working, the motor 42 drives the stirring shaft 43 to rotate, and the stirring shaft 43 drives the stirring blade 44 to rotate, thereby achieving the stirring function;

[0115] When the stirring shaft 43 and the stirring blade 44 need to be cleaned and the white precipitate inside needs to be taken out, the lifting device 3 lifts the assembly frame 41 to drive the stirring shaft 43 and the stirring blade 44 to move out of the cleaning filter cartridge 2.

[0116] The lifting device 3 can be a pneumatic cylinder, a hydraulic cylinder or an electric push cylinder.

[0117] There are two stirring blades 44 symmetrically mounted at both ends of the stirring shaft 43 .

[0118] See also Figure 6 and Figure 8 As a preferred embodiment of this embodiment, the filter assembly 5 includes a base 51, a pressure ring 52 and a filter element 53. The pressure ring 52 is detachably connected to the base 51, and the filter element 53 is located between the pressure ring 52 and the base 51.

[0119] By detachably installing the filter element 53 between the base 51 and the pressure ring 52, when the filter element 53 needs to be cleaned or replaced, the base 51 and the pressure ring 52 can be disassembled, and then the filter element 53 can be cleaned or replaced with a new one, while retaining the use of the base 51 and the pressure ring 52, which is more environmentally friendly.

[0120] The filter element 53 may be a filter membrane or a filter screen.

[0121] See also Figures 6 to 9 As a preferred embodiment of this embodiment, the filter assembly 5 further includes a folded bag 54, the base 51 includes a mounting ring 511, a support ring 512 and a plurality of protruding shafts 513, the support ring 512 is rotatably connected to the mounting ring 511, the plurality of protruding shafts 513 are circumferentially mounted on the support ring 512, and the sides of the filter element 53 are sleeved on the plurality of protruding shafts 513;

[0122] The bottom of the pressure ring 52 is provided with a receiving groove 522 , one end of the folding bag 54 is connected to the receiving groove 522 , and the other end is connected to the support ring 512 , and the mounting ring 511 is threadedly connected to the pressure ring 52 ;

[0123] A driving sleeve 521 is symmetrically installed on the pressure ring 52, and the stirring assembly 4 also includes two L-shaped shafts 45, which are symmetrically installed at the bottom of the two stirring blades 44, and the bottom ends of the two L-shaped shafts 45 face oppositely, and the spacing between the two L-shaped shafts 45 is the same as the spacing between the two driving sleeves 521.

[0124] The axis of the stirring shaft 43 is concentric with the center line of the cleaning filter cartridge 2 .

[0125] See also Figure 5 When the stirring assembly 4 is stirring the white precipitate, the L-shaped shaft 45 at the bottom end of the stirring blade 44 is located above the filtering assembly 5;

[0126] When the white precipitate is cleaned and needs to be taken out, the lifting device 3 lowers the stirring assembly 4 so that the L-shaped shaft 45 is flush with the height of the driving sleeve 521. At this time, the motor 42 drives the stirring shaft 43 to rotate, and the stirring shaft 43 drives the stirring blades 44 to rotate accordingly. The stirring blades 44 drive the two L-shaped shafts 45 to be inserted into the interior of the two driving sleeves 521 accordingly. Subsequently, the motor 42 continues to rotate, and the L-shaped shaft 45 drives the pressure ring 52 to rotate through the driving sleeve 521. Since the pressure ring 52 is threadedly connected to the mounting ring 511, the pressure ring 52 rotates and is separated from the mounting ring 511 by thread. Subsequently, the lifting device 3 lifts the stirring assembly 4, and the L-shaped shaft 45 drives the pressure ring 52 to move up through the driving sleeve 521. The pressure ring 52 drives the folding bag 54 to follow and unfold, forming a storage space. Figure 7 (b) and Figure 11 At this time, the white precipitate will gradually enter the folding bag 54. Subsequently, the lifting device 3 lifts the stirring assembly 4 to move the upper end of the folding bag 54 out of the cleaning filter cartridge 2, making it easier to disassemble the L-shaped shaft 45 and the driving sleeve 521 and take out the white precipitate.

[0127] That is, at this time, the filter assembly 5 forms a bag body to hold the white precipitate, and the filter assembly 5 can be taken out later to realize the discharge of the white precipitate, which is easy to operate;

[0128] During this process, the lifting device 3 cooperates with the stirring assembly 4 to form a mechanical arm for lifting the filter assembly 5, and when the stirring assembly 4 switches from the stirring function to the mechanical arm function for lifting the filter assembly 5, the base 51 and the pressure ring 52 can be unlocked, so that the filter assembly 5 can form a bag function;

[0129] Since the side of the filter element 53 is sleeved on the protruding shaft 513, the protruding shaft 513 supports the filter element 53. After the pressure ring 52 is separated from the base 51, the filter element 53 can still support the white precipitate.

[0130] Preferably, before the last cleaning liquid is discharged, the white precipitate is suspended in the cleaning liquid, and the L-shaped shaft 45 and the driving sleeve 521 are assembled.

[0131] When the L-shaped shaft 45 needs to be assembled with the driving sleeve 521, it is preferred to stop rotating after the two stirring blades 44 and the two driving sleeves 521 are in a vertical state, and then continue to rotate the stirring blades 44 ninety degrees counterclockwise to assemble the L-shaped shaft 45 with the driving sleeve 521. Subsequently, according to the number of thread turns on the surface of the pressure ring 52 and the mounting ring 511, continue to rotate the corresponding number of turns to unlock the pressure ring 52 and the mounting ring 511. If the thread is set to two turns, it can be rotated two and a half turns at this time to ensure separation.

[0132] Preferably, the length of the protruding shaft 513 is greater than the thickness of the filter element 53. In this case, a cylindrical hole 523 is provided at the bottom of the pressing ring 52. When the pressing ring 52 is installed with the base 51, the cylindrical hole 523 is sleeved on the protruding shaft 513.

[0133] Among them, in the process of driving the pressure ring 52 to rotate, since the support ring 512 is rotatably set in the installation ring 511, in the process of threaded unlocking of the pressure ring 52 and the installation ring 511, the pressure ring 52 can drive the support ring 512 to rotate through the convex shaft 513, so that the folding bag 54 will not be entangled.

[0134] The foldable bag 54 is provided with a concave folding horizontal and a convex folding horizontal at intervals. When the foldable bag 54 is put away, it can be put away along the concave folding horizontal and the convex folding horizontal. The foldable bag 54 is a tubular bag with an opening at the top and the bottom.

[0135] The outer wall of the mounting ring 511 is arranged to fit the cleaning filter cartridge 2. The tops of the pressure ring 52 and the mounting ring 511 are both provided with inclined surfaces, and the two inclined surfaces are smoothly connected, so that the white precipitate located on the tops of the pressure ring 52 and the mounting ring 511 can automatically slide along the inclined surfaces into the unfolded folding bag 54.

[0136] See also Figure 6 As an optional method of this embodiment, the support 21 includes a support ring 211 and multiple positioning shafts 212. The support ring 211 is installed inside the cleaning filter cartridge 2, and multiple positioning shafts 212 are installed around the support ring 211. A positioning hole 510 is opened at the bottom of the mounting ring 511, and the positioning hole 510 is sleeved on the positioning shaft 212.

[0137] The support ring 211 can support the filter assembly 5. By setting a positioning shaft 212 to be inserted into the positioning hole 510, the axial position of the support ring 512 can be limited. When the driving sleeve 521 drives the pressure ring 52 to rotate, the driving sleeve 521 and the support ring 512 can rotate relative to each other to achieve thread unlocking.

[0138] As another optional embodiment of this embodiment, the support 21 includes a plurality of support blocks, each support block is provided with a positioning shaft 212 , and the plurality of support blocks are installed around the interior of the cleaning filter cartridge 2 .

[0139] See also Figure 5 The surface-modified nano-CaCO3 preparation device also includes a gland 6, which is sleeved on the stirring shaft 43. A support block 431 is installed on the stirring shaft 43. The support block 431 supports and limits the gland 6. A plurality of limiting shafts 61 are installed around the side of the gland 6. Correspondingly, a plurality of positioning ears 22 are provided on the side of the cleaning filter cartridge 2, and each positioning ear 22 has a limiting hole.

[0140] When the lifting device 3 lowers the stirring assembly 4, the stirring blade 44 moves down to a preset depth, such as Figure 5 At this time, the pressure cover 6 covers the top of the cleaning filter cartridge 2, and the limiting shaft 61 is inserted into the limiting hole of the positioning ear 22 to seal the top of the cleaning filter cartridge 2 to prevent the solution from splashing when the stirring blade 44 stirs.

[0141] Among them, a plurality of slide bars are provided on the top of the assembly frame 41, and the top ends of the slide bars pass through the mounting frame 11, so that a vertical sliding connection is formed between the assembly frame 41 and the mounting frame 11, thereby improving the stability of the stirring assembly 4 during the lifting and use process.

[0142] The preparation method, use and working principle of the surface-modified nano-CaCO3 and CaCO3@Fe3O4 provided by the present invention are as follows:

[0143] During operation, the lifting device 3 lowers the stirring assembly 4 into the cleaning filter cartridge 2. Figure 5 , then the white precipitate and solution to be filtered are continuously added into the clean filter cartridge 2 through the feed pipe 23, the valve 24 is opened, and the solution passes through the filter component 5 and is discharged through the discharge end, and the white precipitate remains in the filter component 5. During the filtration process, the stirring component 4 can stir the solution so that the white precipitate can be suspended to avoid accumulation on the filter component 5, which causes the solution to be unable to flow down at a normal speed. When the filtered solution is added to the inside of the clean filter cartridge 2, the stirring component 4 stops working, waits for the last solution to flow out, and then closes the valve 24;

[0144] Deionized water is added into the cleaning filter cartridge 2 through the feed pipe 23, and the stirring component 4 continues to work to stir and clean the white precipitate. After stirring for a preset time, the valve 24 is opened and the cleaning liquid flows out. The cleaning operation is performed for no less than three times.

[0145] See also Figure 5 When the stirring assembly 4 is stirring the white precipitate, the L-shaped shaft 45 at the bottom end of the stirring blade 44 is located above the filtering assembly 5;

[0146] When the white precipitate is cleaned and needs to be taken out, the lifting device 3 lowers the stirring assembly 4 so that the L-shaped shaft 45 is flush with the height of the driving sleeve 521. At this time, the motor 42 drives the stirring shaft 43 to rotate, and the stirring shaft 43 drives the stirring blades 44 to rotate accordingly. The stirring blades 44 drive the two L-shaped shafts 45 to be inserted into the interior of the two driving sleeves 521 accordingly. Subsequently, the motor 42 continues to rotate, and the L-shaped shaft 45 drives the pressure ring 52 to rotate through the driving sleeve 521. Since the pressure ring 52 is threadedly connected to the mounting ring 511, the pressure ring 52 rotates and is separated from the mounting ring 511 by thread. Subsequently, the lifting device 3 lifts the stirring assembly 4, and the L-shaped shaft 45 drives the pressure ring 52 to move up through the driving sleeve 521. The pressure ring 52 drives the folding bag 54 to follow and unfold, forming a storage space. Figure 7 (b) and Figure 11 At this time, the white precipitate will gradually enter the folding bag 54. Subsequently, the lifting device 3 lifts the stirring assembly 4 to move the upper end of the folding bag 54 out of the cleaning filter cartridge 2, making it easier to disassemble the L-shaped shaft 45 and the driving sleeve 521 and take out the white precipitate.

[0147] That is, at this time, the filter assembly 5 forms a bag body to hold the white precipitate. The filter assembly 5 can be taken out later to realize the discharge of the white precipitate, which is easy to operate.

[0148] The above descriptions are merely embodiments of the present invention and are not intended to limit the patent scope of the present invention. Any equivalent structure or equivalent process transformation made using the contents of the present invention description and drawings, or directly or indirectly applied in other related technical fields, are also included in the patent protection scope of the present invention.

Claims

1. A method for preparing surface-modified nano-CaCO3, characterized in that: The following steps are involved: S1. Take a certain volume of brine and detect the Ca content in the brine. 2+ The content is 100-800 mg / l; S2, respectively prepare 0.1 ~ 0.5 mol / l (NH4) 2CO3 solution and 0.5 ~ 2.5 mol / l sodium pyrophosphate solution; S3, uniformly mixing the prepared (NH4)2CO3 solution, sodium pyrophosphate solution and anhydrous ethanol to form a crystal form control agent solution; S4. Add the brine dropwise to the crystal form control agent solution at a rate of 10 ml / min to 20 ml / min through a peristaltic pump to obtain a white suspension; S5. Add 0.25-2.50 g of sodium lauryl sulfate, 0.25-2.50 g of sodium stearate and 0.25-2.50 g of hexadecyltrimethylammonium bromide to the suspension and stir at 60-100° C. for 20-50 min. S6. The white precipitate obtained by filtering the solution in S5 is washed and dried to obtain surface-modified nano-CaCO3.

2. The preparation method of surface-modified nano-CaCO3 according to claim 1, characterized in that: The volume of the (NH4)2CO3 solution is 3-10% of the volume of the brine, the volume of the sodium pyrophosphate solution is 4-6% of the volume of the brine, and the volume of the anhydrous ethanol is 2-4% of the volume of the brine.

3. The preparation method of surface-modified nano-CaCO3 according to claim 1, characterized in that, The surface-modified nano-CaCO3 is prepared into nano-CaCO3 with a porous structure, comprising the following steps: S01, taking the prepared nano-CaCO3 and placing it in a container, and then adding ZnCl2 into the container, wherein the mixing ratio of nano-CaCO3 and ZnCl2 is between 1:3 and 1:6; S02, oscillating the container by an oscillator to mix and allow self-assembly to occur between the nano-CaCO3 and ZnCl2; S03, placing the mixed materials in S02 in a high-temperature tube furnace, burning in a protective gas at a temperature of 300-800°C until the powdered material is obtained; S04. Wash the powdered material three times with anhydrous ethanol and deionized water, and dry it to obtain spherical nano-CaCO3 with a porous structure.

4. A method for preparing surface-modified nano-CaCO3@Fe3O4, characterized in that: The following steps are involved: T1. Place 10-50 ml of ethylene glycol solution in a container, weigh 5.404-6.755 g of FeCl3·6H2O and dissolve it in the ethylene glycol solution; T2. Dissolve 0.05-0.2 mol / l sodium acetate solution in ethylene glycol solution, and the amount of sodium acetate added is 1-5% of the volume of ethylene glycol; T3. Take polyethylene glycol solution and slowly add it dropwise to the mixed solution, stirring for 30 to 60 minutes. The amount of polyethylene glycol solution added is 1 to 10% of the volume of ethylene glycol. T4. Place the solution in T3 in a polytetrafluoroethylene-lined autoclave, seal it, and place it in an electric oven to keep warm for 6 to 12 hours; T5. After the heat preservation is completed, the liquid is removed, the reaction product is transferred to a container, and the product is washed three times by oscillation using ethanol and ultrasonic waves; T6. Mix the prepared wet magnetic nano-Fe3O4 with the nano-CaCO3 according to any one of claims 1 to 3, add deionized water to form a slurry, and stir for 30 to 60 minutes; T7. Dry the mixed slurry in a vacuum oven to obtain surface-modified nano-CaCO3@Fe3O4 particles with a porous structure.

5. A use of surface-modified nano-CaCO3@Fe3O4, characterized in that: The surface modified nano-CaCO3@Fe3O4 is used for adsorption and removal of F in liquid - .

6. A device for preparing surface-modified nano-CaCO3, characterized in that: The surface-modified nano-CaCO3 preparation device is used to filter and wash the white precipitate in step S6; Includes: bracket; A cleaning filter cartridge is installed on the bracket, a support is provided inside the cleaning filter cartridge, and a valve is installed at the discharge end of the cleaning filter cartridge; A filter assembly, the filter assembly being detachably mounted on the support; A lifting device, the lifting device is mounted on the bracket through a mounting frame and is suspended on the cleaning filter cartridge; A stirring assembly is installed at the output end of the lifting device.

7. The device for preparing surface-modified nano-CaCO3 according to claim 6, characterized in that: The stirring assembly includes an assembly frame, a motor, a stirring shaft and a stirring blade. The assembly frame is installed at the output end of the lifting device, the motor is installed on the assembly frame, the stirring shaft is fixedly connected to the output end of the motor, and the stirring blade is installed on the stirring shaft.

8. The device for preparing surface-modified nano-CaCO3 according to claim 7, characterized in that: The filter assembly includes a base, a pressure ring and a filter element. The pressure ring is detachably connected to the base, and the filter element is located between the pressure ring and the base.

9. The device for preparing surface-modified nano-CaCO3 according to claim 8, characterized in that: The filter assembly further comprises a pleated bag, the base comprises a mounting ring, a support ring and a plurality of protruding shafts, the support ring is rotatably connected within the mounting ring, the plurality of protruding shafts are mounted around the support ring, and the sides of the filter element are sleeved on the plurality of protruding shafts; The bottom of the pressure ring is provided with a receiving groove, one end of the folding bag is connected to the receiving groove, and the other end is connected to the support ring, and the mounting ring is threadedly connected to the pressure ring; A driving sleeve is symmetrically installed on the pressure ring, and the stirring assembly also includes two L-shaped shafts, which are installed clockwise at the bottom of the two stirring blades, and the distance between the two L-shaped shafts is the same as the distance between the two driving sleeves.

10. The device for preparing surface-modified nano-CaCO3 according to claim 9, characterized in that: The support includes a support ring and multiple positioning shafts. The support ring is installed inside the cleaning filter cartridge. The multiple positioning shafts are installed around the support ring. A positioning hole is opened at the bottom of the mounting ring, and the positioning hole is sleeved on the positioning shaft.

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