A kind of ultrafine modified calcium carbonate and preparation method thereof

Abstract

The present invention provides a method for preparing ultrafine modified calcium carbonate. Step 1: Add Ca(OH)2 slurry to a carbonization tower. In addition, input CO2 gas into the carbonization tower for full contact. At the same time, add stearic acid modifier to the slurry for modification. The added weight of stearic acid modifier is 0.1% to 1% of the net content of Ca(OH)2. Step 2: Transfer the mixed material of step 1 to a filtering device for filtering, collect the solid material and wash it with water for multiple times. Step 3: Dry the solid material and finally grind it to obtain ultrafine powder modified calcium carbonate. By adding Ca(OH) 2 When the slurry is added to the carbonization tower, CO is transported to the carbonization tower. 2 gas, making CO 2 Gas and Ca(OH) 2 The slurry is fully contacted, and the stearic acid modifier is added to the slurry at the same time, so that the stearic acid modifier is attached to the surface in advance during the formation of calcium carbonate. In addition, the reaction process and the modification process are integrated into an integrated structure, which reduces the links and improves the production efficiency.

Description

Technical Field

[0001] The present invention relates to the technical field of calcium carbonate preparation, and in particular to a technology for continuously preparing calcium carbonate. Background Art

[0002] Calcium carbonate (chemical formula: CaCO3) is an inorganic compound, commonly known as limestone, limestone, stone powder, marble, etc. It is neutral, slightly soluble in water, and is one of the most common substances on earth. It exists in rocks such as aragonite, calcite, chalk, limestone, and travertine, and is also the main component of animal bones or shells.

[0003] The intermittent bubbling method is used in the preparation of calcium carbonate. In layman's terms, a certain amount of Ca(OH)2 slurry is added to the carbonization tower, and CO2 gas is allowed to enter the carbonized carbon. At this time, the Ca(OH)2 slurry in the carbonization tower contacts and reacts with the CO2 gas to form calcium carbonate. The amount of calcium carbonate prepared each time in this preparation method is fixed. After the Ca(OH)2 slurry in the carbonization tower contacts and reacts with the CO2 gas and is discharged from the carbonization tower, the next batch of calcium carbonate can be prepared. This is called the intermittent bubbling method.

[0004] However, in the prior art, in order to obtain ultrafine calcium carbonate, a modifier, such as a stearic acid modifier, is generally added after the reaction when preparing calcium carbonate. The addition of this modifier can improve the fluidity of calcium carbonate. However, in the prior art, the modifier is usually added after the reaction, that is, the modification process and the process of forming calcium carbonate by reaction are divided into two reactions, which significantly reduces the modification efficiency. If the stearic acid modifier attached to the surface can be applied during the formation of calcium carbonate, the distribution of the modifier will be more uniform, while reducing the production cost. Summary of the invention

[0005] In order to solve the problems existing in the above-mentioned technology, the present invention provides a calcium carbonate preparation technology in which the reaction process and the modification process are continuously carried out.

[0006] Step 1: Adding Ca(OH)2 slurry into a carbonization tower, and inputting CO2 gas into the carbonization tower for full contact, and adding stearic acid modifier to the slurry for modification, wherein the added weight of the stearic acid modifier is 0.1% to 1% of the net content of Ca(OH)2;

[0007] Step 2: Transfer the mixture from step 1 to a filtering device for filtering, collect the solid material and wash it with water for multiple times;

[0008] Step 3: Dry the solid material and grind it to obtain ultrafine powder of modified calcium carbonate.

[0009] The above scheme has the beneficial effect that when Ca(OH)2 slurry is added into the carbonization tower, CO2 gas is transported into the carbonization tower so that CO2 gas is fully in contact with Ca(OH)2 slurry, and stearic acid modifier is added into the slurry at the same time, so that the stearic acid modifier is attached to the surface in advance during the formation of calcium carbonate. In addition, the reaction process and the modification process are integrated into an integrated structure, which reduces the links and improves the production efficiency.

[0010] The present invention uses an existing carbonization tower to introduce Ca(OH)2 slurry and CO2 gas for full contact to form calcium carbonate, and a stearic acid modifier is present in the reaction solution. This method is different from the existing method which is divided into two steps, that is, there is no need to synthesize calcium carbonate first and then add stearic acid for modification, but stearic acid is directly added during the reaction process, so that the stearic acid can be directly distributed and adsorbed on the surface of calcium carbonate, thereby improving the properties of calcium carbonate.

[0011] The stearic acid used in the present invention is a common long carbon chain saturated fatty acid, which has a long carbon chain lipophilic end and a carboxyl hydrophilic end. The stearic acid is attached to the surface of nano calcium carbonate, which can greatly improve its lipophilicity, enhance the dispersibility of the material, and easily form ultrafine powder materials during the grinding process. In addition, when the modified calcium carbonate material can be filled in rubber, plastic, high-grade ink, and coating, its large specific surface area and high specific surface energy are conducive to the firm combination between calcium carbonate particles and organic polymer molecules, and can make the product surface bright and have excellent reinforcement performance.

[0012] The research on the modification mechanism of stearic acid on calcium carbonate has been disclosed in the prior art and will not be repeated here.

[0013] A preferred solution is that the modified calcium carbonate obtained by grinding to obtain ultrafine powder is a powder with a size less than 10 μm; the grinding equipment is a turbine sand mill or an ultrafine powder grinder.

[0014] A preferred solution is that a three-way valve is provided at the lower end of the carbonization tower, the upper port of the three-way valve is connected to the discharge port of the carbonization tower, and the lower port of the three-way valve is connected to the cylinder of the filtering equipment, the cylinder is provided with a rotatable filter cylinder, the filter cylinder is provided with a scraper, and the scraper can switch modes and can be used to scrape the side wall or bottom wall of the filter cylinder. Through the action of the three-way valve, the mixture and clean water can enter the filter cylinder respectively, the filter cylinder rotates, and the clean water cleans the mixture. Since the mixture needs to be cleaned multiple times, solid material will remain on the side wall or bottom wall of the filter cylinder. At this time, the scraper with switchable modes is used to make the scraper touch the side wall or bottom wall of the filter cylinder, and the solid material is scraped off the side wall or bottom wall of the filter cylinder.

[0015] A preferred solution is that a rotating shaft is connected to the bottom of the filter cartridge, and the rotating shaft is connected to a motor. The motor drives the rotating shaft to rotate the filter cartridge, thereby leaving the solid material in the filter cartridge and throwing out the liquid.

[0016] A preferred solution is that the scraper has two groups, the scraper is an L-shaped plate, the inner end of the scraper is connected to the connecting plate, the outer side of the upper end of the connecting plate is provided with a first rotating rod, the inner side of the upper end of the scraper is provided with a second rotating rod, the inner end of the second rotating rod has a first tooth portion, the first tooth portion cooperates with the second tooth portion, the second tooth portion is connected to the lifting block, the lifting block is connected to the telescopic rod of the cylinder, the lifting block is driven to rise and fall through the extension of the cylinder, and the lifting block descends, at this time, the second rotating rod is rotated through the cooperation of the second tooth portion and the first tooth portion, and the second rotating rod drives the connecting plate to rotate, and at the same time the first rotating rod The movable rod rotates accordingly, and the connecting plate drives the L-shaped plate to move outward, so that the vertical plate of the L-shaped plate contacts the side wall of the filter cartridge. At this time, the solid material on the side wall of the filter cartridge can be scraped off. When the lifting block descends, the second rotating rod rotates through the cooperation of the second tooth portion and the first tooth portion, and the second rotating rod drives the connecting plate to rotate. At the same time, the first rotating rod rotates accordingly, and the connecting plate drives the L-shaped plate to move inward, so that the horizontal plate of the L-shaped plate contacts the bottom wall of the filter cartridge. At this time, the solid material on the bottom wall of the filter cartridge can be scraped off, and the contact strength between the scraper and the side wall or bottom wall of the filter cartridge is also adjusted at the same time.

[0017] A preferred solution is to provide a buffer between the scraper and the connecting plate, wherein the buffer is a spring, so that when the scraper is performing a scraping action, the spring can play a buffering role. BRIEF DESCRIPTION OF THE DRAWINGS

[0018] Figure 1 It is a structural schematic diagram of a plan view of a method for preparing ultrafine modified calcium carbonate of the present invention;

[0019] Figure 2 It is a structural schematic diagram of a partial plan view and a side sectional view of a method for preparing ultrafine modified calcium carbonate of the present invention;

[0020] Figure 3 yes Figure 2 Another state structure diagram of .

[0021] Figure 4 It is an enlarged schematic diagram of the local structure.

[0022] Figure 5 It is a schematic diagram of the preferred embodiment. DETAILED DESCRIPTION

[0023] First embodiment:

[0024] Step 1: Adding Ca(OH)2 slurry into a carbonization tower, and inputting CO2 gas into the carbonization tower for full contact, and adding stearic acid modifier to the slurry for modification, wherein the added weight of the stearic acid modifier is 0.1% to 1% of the net content of Ca(OH)2;

[0025] Step 2: Transfer the mixture from step 1 to a filtering device for filtering, collect the solid material and wash it with water for multiple times;

[0026] Step 3: Dry the solid material and grind it to obtain ultrafine powder of modified calcium carbonate.

[0027] The modified calcium carbonate obtained by grinding to obtain ultrafine powder is a powder with a size less than 10 μm; the grinding equipment adopts a turbine sand mill or an ultrafine powder grinder.

[0028] When Ca(OH)2 slurry is added into the carbonization tower, CO2 gas is transported into the carbonization tower so that CO2 gas fully contacts with Ca(OH)2 slurry, and stearic acid modifier is added into the slurry at the same time, so that stearic acid modifier is attached to the surface in advance during the formation of calcium carbonate. In addition, the reaction process and the modification process are integrated into an integrated structure, which reduces the links and improves the production efficiency.

[0029] The present invention uses an existing carbonization tower to introduce Ca(OH)2 slurry and CO2 gas for full contact to form calcium carbonate, and a stearic acid modifier is present in the reaction solution. This method is different from the existing method which is divided into two steps, that is, there is no need to synthesize calcium carbonate first and then add stearic acid for modification, but stearic acid is directly added during the reaction process, so that the stearic acid can be directly distributed and adsorbed on the surface of calcium carbonate, thereby improving the properties of calcium carbonate.

[0030] The stearic acid used in the present invention is a common long carbon chain saturated fatty acid, which has a long carbon chain lipophilic end and a carboxyl hydrophilic end. The stearic acid is attached to the surface of nano calcium carbonate, which can greatly improve its lipophilicity, enhance the dispersibility of the material, and easily form ultrafine powder materials during the grinding process. In addition, when the modified calcium carbonate material can be filled in rubber, plastic, high-grade ink, and coating, its large specific surface area and high specific surface energy are conducive to the firm combination between calcium carbonate particles and organic polymer molecules, and can make the product surface bright and have excellent reinforcement performance.

[0031] Second embodiment:

[0032] In the preferred embodiment, in this embodiment, Figures 1 to 4As shown, a three-way valve 11 is provided at the lower end of the carbonization tower 10, an upper port 12 of the three-way valve 11 is connected to the discharge port of the carbonization tower 10, a lower port 13 of the three-way valve 11 is connected to the cylinder 21 of the filtering device 20, and a side pipe 14 of the three-way valve 11 is connected to a water supply structure to provide a water source for soaking and washing solid calcium carbonate.

[0033] A rotatable filter cartridge 22 is provided in the cylinder body 21, and a scraper 23 is provided inside the filter cartridge 22. The scraper 23 can switch modes and can be used to scrape the side wall or bottom wall of the filter cartridge 22. Through the action of the three-way valve 11, the mixture and clean water can enter the filter cartridge 22 respectively. The filter cartridge 22 rotates, and the clean water washes the mixture. Since the mixture needs to be washed multiple times, solid materials will remain on the side wall or bottom wall of the filter cartridge 22. At this time, the scraper 23 with switchable modes is used to make the scraper 23 touch the side wall or bottom wall of the filter cartridge 22, and the solid materials are scraped off the side wall or bottom wall of the filter cartridge 22.

[0034] Preferably, a rotating shaft 31 is connected to the bottom of the filter cartridge 22, and the rotating shaft 31 is connected to a motor 32. The motor 32 drives the rotating shaft 31 to rotate the filter cartridge 22, thereby leaving the solid material (ie, calcium carbonate) in the filter cartridge 22 and throwing out the liquid.

[0035] Preferably, the scraper 23 has two groups, the scraper 23 is an L-shaped plate 41, the inner end of the scraper 41 is connected to the connecting plate 42, the upper end of the connecting plate 42 has a first rotating rod 43 on the outer side, the upper end of the scraper 41 has a second rotating rod 44 on the inner side, the inner end of the second rotating rod 44 has a first tooth portion 45, the first tooth portion 45 cooperates with the second tooth portion 46, the second tooth portion 46 is connected to the lifting block 47, the lifting block 47 is connected to the telescopic rod of the cylinder 48, the lifting block 47 is driven to rise and fall by the extension of the cylinder 48, and the lifting block 47 is lowered. At this time, the second rotating rod 44 is rotated by the cooperation of the second tooth portion 46 and the first tooth portion 45, and the second rotating rod 44 drives the connecting plate 42 to rotate, and the first rotating rod 44 drives the connecting plate 42 to rotate. The rotating rod 43 rotates accordingly, and the connecting plate 42 drives the L-shaped plate 41 to move outward, so that the vertical plate 49 of the L-shaped plate 41 contacts the side wall of the filter cartridge 22, and the solid material on the side wall of the filter cartridge 22 can be scraped off at this time. When the lifting block 47 is lowered, the second rotating rod 44 rotates through the cooperation of the second tooth portion 46 and the first tooth portion 45, and the second rotating rod 44 drives the connecting plate 42 to rotate. At the same time, the first rotating rod 43 rotates accordingly, and the connecting plate 42 drives the L-shaped plate 41 to move inward, so that the horizontal plate 51 of the L-shaped plate 41 contacts the bottom wall of the filter cartridge 22, and the solid material on the bottom wall of the filter cartridge 22 can be scraped off at this time, and the contact force between the scraper 23 and the side wall or bottom wall of the filter cartridge 22 is also adjusted at the same time.

[0036] In summary, driven by the lifting block 47, there are at least three states. In the first state, the scraper 23 is not in contact with the side wall and the cross plate 51 is not in contact with the bottom wall. In this state, the filter barrel 22 is in a normal rotation state for throwing out the liquid and filtering to obtain the solid calcium carbonate inside. In the second state, the scraper 23 is in contact with the side wall but the cross plate 51 is not in contact with the bottom wall. In this state, the filter barrel 22 is in a slow rotation and the solid material on the side wall can be scraped off by the scraper 23 for soaking and cleaning with clean water or taking out; in the third state, the scraper 23 is not in contact with the side wall but the cross plate 51 is in contact with the bottom wall. In this state, the filter barrel 22 is in a slow rotation and the solid material on the bottom wall can be scraped off by the cross plate 51 for soaking and cleaning with clean water. Filter cloths of different apertures can be arranged in the filter barrel 22 for filtering.

[0037] Furthermore, when soaking in clean water, in order to fully stir and crush the materials, when in the first state, the filter barrel 22 rotates, and the horizontal plate 51 can continuously contact the fixed materials, thereby breaking up large pieces of materials and making the materials more evenly dispersed.

[0038] Preferably, a buffer is provided between the scraper and the connecting plate, and the buffer is a spring, so that when the scraper is performing a scraping action, the spring can play a buffering role.

[0039] In addition, an openable closing plate is provided at the upper end of the cylinder, and the openable closing plate facilitates the subsequent removal of solid materials in the filter cylinder.

[0040] In a further preferred embodiment, Figure 5 As shown, the inner ends of the horizontal plates 51 on the left and right sides have elastic blocks 52. Through the action of the lifting block 47, the horizontal plates 51 on both sides can be reciprocated, so that the two elastic blocks 52 can move close to each other. In the process of approaching, the solid particles in the middle can be squeezed to make the solid particles smaller, thereby forming a better technical effect. After the solid material is scraped off, when it is washed by soaking in water, the clamping and hitting action of the elastic block 52 can achieve a good crushing effect, avoiding the existence of large particles, which will make the washing unclean. For the elastic block 52, two groups can work together, that is, clamping and hitting operations when moving toward the middle.

[0041] In a further preferred embodiment, the first rotating rods 43 on the left and right sides are respectively controlled by a group of lifting blocks, that is, two groups of independently controlled lifting blocks are set to independently drive the first rotating rod 43 on one side, so that the elastic block 52 below can be controlled independently. In this way, in the implementation state, the elastic block 52 on one side can be fixed as a supporting point, and then the elastic block 52 on the other side moves and strikes, and the elastic block 52 strikes in the direction of the supporting point, which can have a better striking effect on the harder block-like solid objects on the supporting point.

Claims

1. A method for preparing ultrafine modified calcium carbonate, characterized in that: The following steps are involved: Step 1: Adding Ca(OH)2 slurry into a carbonization tower, and inputting CO2 gas into the carbonization tower for full contact, and adding stearic acid modifier to the slurry for modification, wherein the added weight of the stearic acid modifier is 0.1% to 1% of the net content of Ca(OH)2; Step 2: Transfer the mixture from step 1 to a filtering device for filtering, collect the solid material and wash it with water for multiple times; Step 3: Dry the solid material and grind it to obtain ultrafine powder of modified calcium carbonate.

2. The method for preparing ultrafine modified calcium carbonate according to claim 1, characterized in that: The modified calcium carbonate obtained by grinding to obtain ultrafine powder is a powder with a size less than 10 μm; the grinding equipment adopts a turbine sand mill or an ultrafine powder grinder.

3. The method for preparing ultrafine modified calcium carbonate according to claim 1, characterized in that: A three-way valve is provided at the lower end of the carbonization tower, the upper port of the three-way valve is connected to the discharge port of the carbonization tower, and the lower port of the three-way valve is connected to the cylinder of the filtering equipment. A rotatable filter cylinder is provided in the cylinder, and a scraper is provided inside the filter cylinder. The scraper can switch modes and can be used to scrape the side wall or bottom wall of the filter cylinder. Through the action of the three-way valve, the mixture and clean water can enter the filter cylinder respectively. The filter cylinder rotates and the clean water cleans the mixture. Since the mixture needs to be cleaned multiple times, solid materials will remain on the side wall or bottom wall of the filter cylinder. At this time, the scraper with switchable modes is used to make the scraper touch the side wall or bottom wall of the filter cylinder to scrape the solid materials off the side wall or bottom wall of the filter cylinder.

4. The method for preparing ultrafine modified calcium carbonate according to claim 3, characterized in that: The bottom of the filter cartridge is connected with a rotating shaft, which is connected to a motor. The motor drives the rotating shaft to rotate the filter cartridge, thereby leaving the solid material in the filter cartridge and throwing the liquid out.

5. The method for preparing ultrafine modified calcium carbonate according to claim 3, characterized in that: The scraper has two groups, the scraper is an L-shaped plate, the inner end of the scraper is connected to the connecting plate, the outer side of the upper end of the connecting plate is provided with a first rotating rod, the inner side of the upper end of the scraper is provided with a second rotating rod, the inner end of the second rotating rod has a first tooth portion, the first tooth portion cooperates with the second tooth portion, the second tooth portion is connected to the lifting block, the lifting block is connected to the telescopic rod of the cylinder, the lifting block is driven to rise and fall through the extension of the cylinder, and the lifting block descends, at this time, the second rotating rod is rotated through the cooperation of the second tooth portion and the first tooth portion, and the second rotating rod drives the connecting plate to rotate, and the first rotating rod follows The connecting plate drives the L-shaped plate to move outwards, and the vertical plate of the L-shaped plate contacts the side wall of the filter cartridge. At this time, the solid material on the side wall of the filter cartridge can be scraped off. When the lifting block is lowered, the second tooth portion and the first tooth portion cooperate to make the second rotating rod rotate, and the second rotating rod drives the connecting plate to rotate. At the same time, the first rotating rod follows the rotation, and the connecting plate drives the L-shaped plate to move inwards, and the horizontal plate of the L-shaped plate contacts the bottom wall of the filter cartridge. At this time, the solid material on the bottom wall of the filter cartridge can be scraped off, and the contact strength between the scraper and the side wall or bottom wall of the filter cartridge is also adjusted at the same time.

6. The method for preparing ultrafine modified calcium carbonate according to claim 3, characterized in that: A buffer is provided between the scraper and the connecting plate, and the buffer is a spring, so that when the scraper performs a scraping action, the spring can play a buffering role.

7. An ultrafine modified calcium carbonate, characterized in that: A calcium carbonate material obtained by the preparation method according to any one of claims 1 to 6.

Images