CN107814404A - A kind of production method of cube nano-calcium carbonate - Google Patents

Abstract

The invention discloses a kind of production method of cube nano-calcium carbonate, this method comprises the following steps：1) take lime stone and coke to be calcined in shaft kiln and produce calcium oxide and kiln gas；2) calcium hydroxide suspension of purification kiln gas and compound concentration for 5~15wt% is taken；3) it is aged after carrying out two-stage carbonization using supergravity reactor；4) it is modified at a temperature of 40~80 DEG C；5) filtering, dry, broken, classification, obtain cube nano-calcium carbonate.The production method production efficiency of the present invention is high, raw material sources are wide, cost is low, and the production method realizes the continuous production of nano-calcium carbonate, meanwhile the auxiliary agents such as chemical additives need not be added in production process granularity can be prepared in 10~80nm narrow particle size distribution and form, the cube nano-calcium carbonate of steady quality.

Description

A kind of production method of cubic nano calcium carbonate

technical field

The invention relates to the technical field of nanometer material preparation. More specifically, it relates to a cubic nano-calcium carbonate and a production method thereof.

Background technique

Calcium carbonate is widely used in many industries such as plastics, rubber, coatings, inks, paper, silicone rubber, and automobiles. In recent years, with the continuous development of calcium carbonate nanometerization and surface modification technology, the application value of calcium carbonate is expected to be greatly improved. Cubic nano-calcium carbonate is added to plastics, rubber, and paper as a filler, which can improve the mechanical properties of the material, and has become the most widely used nano-calcium carbonate. Therefore, it is of great significance to develop the industrial production technology of nano-calcium carbonate with regular shape and narrow particle size distribution.

The research and development of nano-calcium carbonate in my country began in the early 1980s. The following methods are mainly used for production, including intermittent bubbling carbonization method, continuous bubbling carbonization method, continuous spray carbonization method, supergravity method, porous membrane method, etc.

At present, the production methods of nano-calcium carbonate at home and abroad mainly include:

1 Intermittent bubbling carbonization method

According to whether there is a stirring device in the carbonization tower, the method is divided into ordinary intermittent bubbling carbonization method and stirring intermittent bubbling carbonization method. Add refined calcium hydroxide suspension and appropriate crystal form control agent into the carbonization tower, and then feed carbon dioxide from the bottom of the tower until the pH value becomes 7 to obtain calcium carbonate product. This method has low investment and simple operation, but the production is discontinuous, the degree of automation is low, the particle size distribution of the product is uneven, the average particle size is large, and the repeatability of different batches of products is poor.

2 continuous bubbling carbonization method

This method generally adopts two-stage or three-stage carbonization in series, that is, the refined calcium hydroxide suspension is partially carbonized in the first-stage carbonization tower to obtain a reaction mixture, and then enters the second-stage carbonization after adding appropriate additives in the slurry tank. The product is carbonized in the tower or enters the third carbonization tower to get the final product. Since the carbonization process is carried out step by step, the surface activity treatment is carried out between stages, and the carbonization temperature can be controlled by refrigeration, so the nucleation, growth process and surface treatment of the crystal form are also controlled in stages, and smaller particle size and Particle size distribution. Now, domestic manufacturers using this technology can produce products with required crystal forms and particle sizes by strictly controlling slurry concentration, carbonization temperature, additive types and dosage according to user requirements. However, the process conditions of this method are complicated, and the control is very difficult. It also needs to add additives such as crystal form control agents, and the particle size distribution of the obtained product also has problems of relatively poor distribution and poor product repeatability. The reason is that the carbonization tower Caused by inhomogeneous microscopic mixing.

3 multi-stage spray carbonization method

The basic steps for preparing nano-calcium carbonate by multi-stage spray carbonization method are: prepare the refined calcium hydroxide suspension to the concentration required by the process, add an appropriate amount of additives, mix well, and then pump it into the atomizer on the top of the spray carbonization tower. Under the action of huge centrifugal force generated by high-speed rotation, the slurry is atomized into fine droplets; the purified carbon dioxide-containing gas enters from the bottom of the tower, and is evenly dispersed in the tower through the gas distributor, and the droplets are in the tower at the same time. The gas undergoes instantaneous reverse contact to generate calcium carbonate through a chemical reaction. The particle size of the calcium carbonate product prepared by the multi-stage spray carbonization method is fine and uniform, the average particle size is in the range of 30-40nm, and the crystal form of the particles can be adjusted and controlled. The disadvantage is that the equipment investment is large, the nozzle is easy to block, the technology is more complicated, and the operation is more difficult, which limits its industrial application and promotion.

4 Porous membrane microreactor carbonization method

Tsinghua University and Shandong Shanda Technology Co., Ltd. developed a membrane-dispersed microstructure reactor for the preparation of nano-calcium carbonate. A membrane material with a pore size of a few microns or tens of microns is used as a dispersion medium to promote mass transfer and rapid reaction through enhanced micro-mixing, so that the prepared calcium carbonate has a small particle size and a uniform distribution. By adjusting parameters such as slurry concentration, gas-liquid flow, and pressure, the particle size and crystal form of the product can be better controlled. However, because the size of the membrane material is too small, the membrane material may be blocked due to scaling due to a little carelessness during operation. Therefore, the concentration of calcium hydroxide slurry is low during carbonization, and the intermittent operation mode is adopted, so the operation process is complicated. , high cost issues.

5 high gravity carbonization method

The High Gravity Engineering Research Center of Beijing University of Chemical Technology has developed a new technology for the production of nano-calcium carbonate by the high gravity method. The high gravity environment generated by rotation is much greater than the earth's gravitational acceleration, which greatly strengthens the transfer process and microscopic mixing between the gas and liquid phases. process, and through the modulation of process parameters, the carbonization reaction process and crystallization process can be effectively controlled, and nano-calcium carbonate powder with small particle size and uniform distribution can be prepared. However, since nano-calcium carbonate is easy to scale on the filler, the equipment must be cleaned after a period of operation, which not only increases the workload of workers, but also complicates the operation process.

Therefore, need a kind of new, the method for preparing nano-calcium carbonate that can overcome above-mentioned deficiency.

Contents of the invention

First object of the present invention is to provide a kind of production method of cubic nano-calcium carbonate, the method production efficiency is high, the source of raw material is wide, cost is low, safe and environment-friendly, and this production method has realized the continuous production of nano-calcium carbonate, At the same time, cubic nano-calcium carbonate with a particle size of 10-80nm, narrow particle size distribution, stable shape and quality can be prepared without adding auxiliary agents such as crystal form control agents in the production process.

Second object of the present invention is to provide the cubic nanometer calcium carbonate that above-mentioned production method produces.

In order to achieve the above-mentioned first object, the present invention adopts the following technical solutions:

A production method of cubic nano-calcium carbonate, comprising the steps of:

1) Limestone and coke are calcined in a vertical kiln to produce calcium oxide and kiln gas;

2) cooling, dedusting and desulfurizing the above kiln gas to obtain purified kiln gas with a carbon dioxide concentration of 15-40%; using the above-mentioned calcium oxide as a raw material, preparing a calcium hydroxide suspension with a concentration of 5-15 wt%;

3) Carbonization section: in the start-up stage of the equipment, firstly, the calcium hydroxide suspension obtained in step 2) is pumped into the first stirred tank matched with the first-level supergravity reactor through the heat exchanger through the heat exchanger, when the second After the material in the first stirred tank reaches the predetermined volume, the feed pump is stopped, and then the material in the first stirred tank is pumped into the first-level supergravity reactor to contact with the purified kiln gas and undergo carbonization reaction, and then circulate to the first-level supergravity reactor. The pH of the slurry in the reactor is 8 to 12. After that, the aforementioned first-stage carbonization section enters a continuous operation state, and the feed pump is restarted, and the slurry in the first-stage high-gravity reactor is discharged at the same flow rate as the feed pump. It is pumped into the secondary high-gravity reactor, and contacts and reacts with the purified kiln gas from the primary high-gravity reactor, and the slurry leaving the secondary high-gravity reactor flows into the matching second stirred tank. After the slurry in the kettle reaches the preset volume, it starts to circulate. The circulating slurry is mixed with the slurry from the first-level high-gravity reactor and continues to undergo carbonization reaction in the second-level high-gravity reactor. The slurry in the second-level high-gravity reactor The pH is controlled at 6.8-7. When the slurry in the second stirred tank reaches a predetermined volume, the slurry in the secondary high-gravity reactor is sent to the aging tank according to the same amount as the input amount for aging. The aforementioned secondary The carbonization section began to enter a continuous operation state, in which the temperature of the first-level high-gravity reactor and the second-level high-gravity reactor were both controlled at 10-50°C;

4) Pump the aged slurry into the modification tank, and modify it at a temperature of 40-80°C;

5) Filtering, drying, crushing and grading the modified slurry to obtain a cubic nano calcium carbonate product.

Further, in step 2), the preparation method of calcium hydroxide suspension is: the calcium oxide obtained in step 1) is digested by adding 40-70°C hot water after removing impurities, wherein the mass ratio of calcium oxide to hot water is 1: 4 to 7, and then aged for 6 to 12 hours after screening to remove impurities, and then passed through a suspension separator to remove slag and dilute with water to obtain a calcium hydroxide suspension with a concentration of 5 to 15 wt%.

Further, in step 3), the slurry and/or material pumped into the primary high gravity reactor and the secondary high gravity reactor and the purified kiln gas are independently contacted in parallel or countercurrent, preferably For all countercurrent contact.

Further, in step 3), the primary high-gravity reactor and the secondary high-gravity reactor are independently selected from a high-gravity rotating packed bed, or a high-gravity reactor with self-pressurization, for example, Publication No. It is: the self-pressurized rotating packed bed device disclosed in CN104511235A, and the publication number is: the low-pressure-drop nano-microstructured packing rotating bed hypergravity device disclosed in CN102120172A.

Further, in step 3), the supergravity levels of the first-stage hypergravity reactor and the second-stage hypergravity reactor are respectively 30-500.

Preferably, in some embodiments of the present invention, the hypergravity levels of the first-stage hypergravity reactor and the second-stage hypergravity reactor are respectively 30-500.

In the present invention, the definition of hypergravity level is:

In the formula:

β: Hypergravity level

ω: Angular velocity, s ^-1

r _m : mean rotor radius, m

N: speed, rpm

r _in : rotor inner radius, m

r _out : rotor outer radius, m

g: gravitational acceleration, m·s ^-2 .

Further, in step 3), the filler in the packing layer of the first-level high-gravity reactor and the secondary high-gravity reactor is a modified nickel foam filler, and the treatment process of the modified nickel foam filler includes: foaming The nickel filler is soaked in sodium hydroxide solution and dilute sulfuric acid solution at ^40-70 °C in sequence, and then ultrasonically cleaned in absolute ethanol solution, and the foamed nickel filler is placed in 1- Soak in anhydrous ethanol solution of tetradecyl phosphoric acid for 40 to 60 hours, wherein the soaking temperature is 50° C., then take it out and dry it to obtain the modified nickel foam filler.

Preferably, in some specific embodiments of the present invention, the treatment process of the modified nickel foam filler comprises:

(1) Immerse the nickel foam filler in 0.5-1.5mol L ^-1 sodium hydroxide solution, heat it to 40-70°C in a water bath, keep it warm for 30min-60min, take out the nickel foam filler and rinse it with deionized water three times ;

(2) Air-dry the rinsed nickel foam filler, immerse it in dilute H ₂ SO ₄ solution, heat it to 40-70°C in a water bath, keep it warm for 20-40 minutes, take out the foam nickel filler and rinse it with deionized water three times ;

(3) Air-dry the foamed nickel filler after washing, put it into absolute ethanol solution, and use an ultrasonic instrument to sonicate it for 10 minutes to 30 minutes;

(4) After taking out the nickel foam filler, put it directly into the absolute ethanol solution of 1-tetradecylphosphoric acid with a concentration of 0.01mol L ^-1 to 0.05mol L ^-1 and soak it for 40 to 60 hours. Heating in a water bath to keep it at 50°C;

(5) Take out the processed nickel foam filler, wash it with absolute ethanol solution, and then dry it naturally in the air to obtain the modified nickel foam filler.

Further, in step 4), the modification step includes: pumping the aged slurry into a modification tank, raising the temperature to 40-80°C, adding a surfactant, and stirring for 1-3 hours , and then let it stand for 1 to 3 hours.

Preferably, the added amount of the surfactant is 2-6% of the mass of the aged slurry.

Preferably, the surfactant is selected from one of stearic acid, sodium stearate, dioctyl phthalate, palmitic acid, glyceride, silane coupling agent, titanate coupling agent or Several kinds mixed in any proportion.

Further, in step 5), the filtration refers to press filtration or centrifugal filtration to obtain a filter product with a water content of 40-50 wt%; the drying includes performing primary drying and secondary drying on the filter product, so that the filter press The water content of the product drops below 0.5 wt%.

The present invention also protects the cubic nano-calcium carbonate obtained by the above-mentioned production method.

Further, the particle size of the cubic nano-calcium carbonate is 10-80nm, which is cubic nano-calcium carbonate.

Unless otherwise specified, the raw materials used in the present invention can be purchased from the market or obtained by conventional means in the art.

Unless otherwise specified, any range described in the present invention includes any sub-range formed by the end value or any value between the end values and any value between the end values or any value between the end values.

The beneficial effects of the present invention are as follows:

1. The production method of the present invention adopts special modified nickel foam filler, which effectively avoids the scaling of the calcium carbonate slurry obtained in the supergravity reaction on the filler surface, and solves the problem of intermittent cleaning due to scaling. problems, saving time and increasing productivity.

2. In the present invention, two-stage carbonization is adopted, and the pH drop process and stabilization process in the carbonization process are carried out in two high-gravity reactors respectively, which realizes continuous production and reduces the assistance of intermittent production feed and discharge The production time is improved, and at the same time, the quality of the obtained product is stable, which overcomes the shortcomings of differences in product performance between different batches, and reduces the cost.

Description of drawings

The specific implementation manners of the present invention will be further described in detail below in conjunction with the accompanying drawings.

Fig. 1 shows the production process flow of cubic nano-calcium carbonate of the present invention.

Fig. 2 shows the transmission electron micrograph of the cubic nano-calcium carbonate prepared in Example 2 of the present invention.

Fig. 3 shows the size distribution diagram of the cubic nano-calcium carbonate prepared in Example 2 of the present invention.

Detailed ways

In order to illustrate the present invention more clearly, the present invention will be further described below in conjunction with preferred embodiments and accompanying drawings. Similar parts in the figures are denoted by the same reference numerals. Those skilled in the art should understand that the content specifically described below is illustrative rather than restrictive, and should not limit the protection scope of the present invention.

The production process of cubic nano-calcium carbonate in the present invention is as shown in Figure 1:

Limestone and coke are calcined at high temperature in a vertical kiln to obtain calcined product calcium oxide and kiln gas, and the kiln gas is cooled, dust-removed and desulfurized to obtain purified kiln gas containing a certain concentration of carbon dioxide; calcium oxide is removed by vibrating sieve It is transported to the digestion section, and the calcium hydroxide suspension obtained after digestion is refined and matured and then pumped into the carbonization section. The calcium hydroxide slurry and the purified kiln gas are sequentially contacted and reacted in the primary and secondary high-gravity reactors filled with modified nickel foam fillers, so that the reaction pH drops and stabilizes in different high-gravity reactors. Carry out, prepare the nano-calcium carbonate slurry, and then obtain the nano-calcium carbonate powder product after surface treatment, filtration, drying, crushing and classification.

The high-gravity reactor used in the embodiments of the present invention can be, for example, the high-gravity rotating packed bed of the conventional structure disclosed in the Chinese invention patent application with the publication number CN2221437A, and the one disclosed in the Chinese invention patent application with the publication number CN104511235A Rotating packed bed device with self-pressurization function. And the filler layer of the hypergravity reactor of the present invention is filled with modified nickel foam filler.

Example 1

The preparation of modified nickel foam filler, the steps are as follows:

(1) Immerse the foamed nickel filler in a 1.0mol L ^-1 sodium hydroxide solution, heat it to 60°C in a water bath, keep it warm for 45 minutes, take out the foamed nickel filler and rinse it with deionized water three times;

(2) Air-dry the rinsed nickel foam filler, immerse it in dilute H ₂ SO ₄ solution, heat it to 60°C in a water bath, keep it warm for 25 minutes, take out the foam nickel filler and rinse it with deionized water three times;

(3) After air-drying the foamed nickel filler after washing, put it into anhydrous ethanol solution, and utilize an ultrasonic instrument to sonicate it for 15 minutes;

(4) After taking out the nickel foam filler, put it directly into the absolute ethanol solution of 1-tetradecylphosphoric acid with a concentration of 0.03mol L ^- 1 and soak it for 45 hours, and keep it at 50°C by heating it with a water bath;

(5) Take out the processed nickel foam filler, wash it with absolute ethanol solution, and then dry it naturally in the air to obtain the modified nickel foam filler.

It has been determined that the contact angle between the surface of the nickel foam filler and water before modification is 108.5°, while the contact angle between the surface of the modified nickel foam filler and water after modification can be expanded to about 150°.

In some embodiments of the present invention, the concentration of the above-mentioned sodium hydroxide solution can be, for example, 0.5 mol·L ^-1 , 0.8 mol·L ^-1 , 1.2 mol·L ^-1 , 1.5 mol·L ^-1 , resulting in The performance of the modified nickel foam filler is similar to that of the modified nickel foam filler obtained above.

In some embodiments of the present invention, the temperature of the water bath in the above step (1) and step (2), for example, can be 40°C, 50°C, and 60°C independently, and the performance of the modified nickel foam filler obtained is the same as that obtained above The performance of modified nickel foam filler is similar.

Example 2

A production method of cubic nano-calcium carbonate, the steps are as follows:

1) Calcination: Limestone and coke are calcined at high temperature in a shaft kiln at a mass ratio of 9.8:1 to obtain calcium oxide and kiln gas;

2) Kiln gas purification, digestion and refining:

Cool down, remove dust and desulfurize the kiln gas to obtain purified kiln gas with a carbon dioxide concentration of 35%;

The obtained calcium oxide, after removing impurities, is digested with 5 times its mass of hot water at 70°C, and then aged for 6 hours after screening and removing impurities, and then separated by a suspension separator to remove slag and dilute with water to obtain the concentration Be the calcium hydroxide suspension of 7wt%;

3) Two-stage carbonization: pump the above-mentioned calcium hydroxide suspension into the first stirred tank matched with the first-level supergravity reactor through the feed pump after passing through the heat exchanger. When the material in the first stirred tank reaches the predetermined Stop the feed pump after the volume, then the material in the first stirred tank is pumped into the first-stage high-gravity rotating packed bed filled with the modified nickel foam filler prepared in Example 1, and from the primary high-gravity rotating packed bed The purified kiln gas passed through the air inlet of the gas inlet is in parallel contact and carbonization reaction, the temperature in the packed bed is controlled at 10°C, the supergravity level is 150, and the pH of the slurry in the packed bed is 8 after circulation to the packed bed. After that, the above-mentioned one The first-stage carbonization section (including the first-stage high-gravity rotating packed bed and the supporting first stirred tank) began to enter the continuous operation state, and the feed pump was restarted, and the slurry in the first-stage high-gravity rotating packed bed was mixed with the feed pump The same flow is pumped into the secondary high-gravity rotating packed bed filled with the modified nickel foam filler prepared in Example 1, and is in parallel contact with the purified kiln gas from the primary high-gravity rotating packed bed and reacts, and then the slurry The material leaves the secondary high-gravity rotating packed bed and flows into the supporting second stirred tank. When the material in the second stirred tank reaches the preset volume, the circulation pump starts to circulate, and the circulating slurry and the slurry from the first-level high-gravity rotating packed bed Mix the materials and continue the carbonization reaction in the secondary high-gravity rotating packed bed. Control the temperature in the high-gravity rotating packed bed to 10°C and the super-gravity level to 150. The pH control is 6.8, and when the slurry in the stirred tank reaches a predetermined volume, part of the slurry in the secondary supergravity reactor is sent to the aging tank according to the same amount as the input amount for aging, and the aforementioned secondary carbonization section ( Including the secondary high-gravity rotating packed bed and the supporting second stirred tank) began to enter the continuous operation state;

4) Modification: pump the aged slurry into a modification tank, raise the temperature to 80°C, add a surfactant stearic acid with a mass percentage of 4% of the slurry, stir and keep warm for 2 hours, and then let it stand for 2 hours. Obtain the modified slurry;

5) The modified slurry is filtered, dried, pulverized and classified, and packaged to obtain nanometer calcium carbonate powder.

After 12 hours of continuous feeding in step 3), through analysis, the utilization rate of carbon dioxide reaches 78%. Through transmission electron microscope analysis, it can be seen that the size of the nano-calcium carbonate powder obtained at this time is about 9～10nm, and the obtained nano-calcium carbonate crystal form is cubic.

After 72 hours of continuous feeding in step 3), the utilization rate of carbon dioxide was still maintained at 78% through analysis. As shown in Figure 2, it can be known through transmission electron microscope TEM analysis that the crystal form of the obtained nano-calcium carbonate is cubic, and the size of the obtained nano-calcium carbonate powder is about 10 nm, and the size distribution is shown in Figure 3.

Example 3

Repeat Example 2, the difference is that in step 3), the temperature of the first-level high-gravity rotating packed bed and the second-level high-gravity rotating packed bed are both 25 ° C, and the high-gravity level is 100. In the first-level high-gravity rotating packed bed The pH value of the slurry is 11 and then enters the continuous operation state, and the pH value of the slurry in the secondary high-gravity rotating packed bed is controlled to be 6.9. Among them, the gas-liquid contact in the two high-gravity rotating packed beds is countercurrent contact, and the rest Conditions remain the same. After 12 hours of continuous feeding and 72 hours of continuous feeding, the utilization rate of carbon dioxide is 85%. Through transmission electron microscopy analysis, the crystal form of the obtained nano-calcium carbonate powder is cubic, and the size is about 40nm.

Example 4

Repeat Example 3, the difference is that in step 2), the carbon dioxide concentration in the purified kiln gas is 30%; the concentration of calcium hydroxide suspension is 15wt%; in step 3), the gas-liquid contact The contact is countercurrent, the gas-liquid contact in the two-stage high-gravity rotating packed bed is cocurrent contact, and other conditions remain unchanged. After 12 hours of continuous feeding and 72 hours of continuous feeding, the utilization rate of carbon dioxide is 82%. Through transmission electron microscopy analysis, the crystal form of the obtained nano-calcium carbonate powder is cubic, and the size is about 55nm.

Example 5

Repeat Example 2, the difference is that in step 3), the temperature in the first-stage supergravity rotating packed bed is 35 ° C, the supergravity level is 80, and the pH value of the slurry is 9 before entering the continuous operation state, the second stage The temperature in the high-gravity rotating packed bed is 35°C, the high-gravity level is 80, and the pH value of the slurry is controlled to be 6.9. Among them, the gas-liquid contact in the first-stage high-gravity rotating packed bed is co-current contact, and the first-stage ultra-gravity The gas-liquid contact in the gravity rotating packed bed is countercurrent contact, and other conditions remain unchanged. After 12 hours of continuous feeding and 72 hours of continuous feeding, the utilization rate of carbon dioxide is 80%. Through transmission electron microscope analysis, the crystal form of the obtained nano-calcium carbonate powder is cubic, and the size is about 60nm.

Example 6

Repeat embodiment 3, difference is, step 2) in, carbon dioxide concentration is 33% in the purification kiln gas; The concentration of calcium hydroxide suspension is 12wt%; Step 3) in, the temperature in the one-stage supergravity rotating packed bed is 38°C, the pH value of the slurry is controlled to be 9, the temperature in the secondary high-gravity rotating packed bed is 38°C, and other conditions remain unchanged. After 12 hours of continuous feeding and 72 hours of continuous feeding, the utilization rate of carbon dioxide is 82%. Through transmission electron microscope analysis, the crystal form of the obtained nano-calcium carbonate powder is cubic, and the size is about 80nm.

Comparative example 1

Repeat Example 2, the difference is that in step 3), the fillers in the first-level high-gravity rotating packed bed and the second-level high-gravity rotating packed bed are unmodified foamed nickel fillers, and all the other conditions are constant, and feed continuously for 12 hours , The generated nano-calcium carbonate slurry scales on the filler, the equipment needs to be cleaned, and the utilization rate of carbon dioxide is only 65%.

Comparative example 2

Repeat Example 2, the difference is that the modified nickel foam filler of the first-stage high-gravity rotating packed bed is changed to unmodified nickel foam filler. The rest of the conditions remain the same. When feeding continuously for 15 hours, the generated nano-calcium carbonate slurry will scale on the filler, and the equipment needs to be cleaned. The utilization rate of carbon dioxide is low, below 70%.

Apparently, the above-mentioned embodiments of the present invention are only examples for clearly illustrating the present invention, and are not intended to limit the implementation of the present invention. Those of ordinary skill in the art can also make It is impossible to exhaustively list all the implementation modes here, and any obvious changes or changes derived from the technical solutions of the present invention are still within the scope of protection of the present invention.

Claims (9)

1. a production method of cubic nano-calcium carbonate, is characterized in that, comprises the steps: 1) Limestone and coke are calcined in a vertical kiln to produce calcium oxide and kiln gas; 2) cooling, dedusting and desulfurizing the above kiln gas to obtain purified kiln gas with a carbon dioxide concentration of 15-40%; using the above-mentioned calcium oxide as a raw material, preparing a calcium hydroxide suspension with a concentration of 5-15 wt%; 3) Carbonization section: in the start-up stage of the equipment, firstly, the calcium hydroxide suspension obtained in step 2) is pumped into the first stirred tank matched with the first-level supergravity reactor through the heat exchanger through the heat exchanger, when the second After the material in the first stirred tank reaches the predetermined volume, the feed pump is stopped, and then the material in the first stirred tank is pumped into the first-level supergravity reactor to contact with the purified kiln gas and undergo carbonization reaction, and then circulate to the first-level supergravity reactor. The pH of the slurry in the reactor is 8 to 12. After that, the aforementioned first-stage carbonization section enters a continuous operation state, and the feed pump is restarted, and the slurry in the first-stage high-gravity reactor is discharged at the same flow rate as the feed pump. It is pumped into the secondary high-gravity reactor, and contacts and reacts with the purified kiln gas from the primary high-gravity reactor, and the slurry leaving the secondary high-gravity reactor flows into the matching second stirred tank. After the slurry in the kettle reaches the preset volume, it starts to circulate. The circulating slurry is mixed with the slurry from the first-level high-gravity reactor and continues to undergo carbonization reaction in the second-level high-gravity reactor. The slurry in the second-level high-gravity reactor The pH is controlled at 6.8-7. When the slurry in the second stirred tank reaches a predetermined volume, the slurry in the secondary high-gravity reactor is sent to the aging tank according to the same amount as the input amount for aging. The aforementioned secondary The carbonization section began to enter a continuous operation state, in which the temperature of the first-level high-gravity reactor and the second-level high-gravity reactor were both controlled at 10-50°C; 4) Pump the aged slurry into the modification tank, and modify it at a temperature of 40-80°C; 5) Filtering, drying, crushing and grading the modified slurry to obtain a cubic nano calcium carbonate product. 2. The production method according to claim 1, characterized in that, in step 2), the preparation method of the calcium hydroxide suspension is: adding 40-70°C hot water to digest the calcium oxide obtained in step 1) after removing impurities , wherein the mass ratio of calcium oxide to hot water is 1:4 to 7, and then aged for 6 to 12 hours after screening and removing impurities, and then the slag is removed after the suspension separator and diluted with water to obtain a concentration of 5 to 15 wt%. calcium hydroxide suspension. 3. production method according to claim 1, it is characterized in that, step 3) in, the slurry that is pumped into one-level supergravity reactor and pumped into two-stage supergravity reactor and/or material and purification kiln The gases are independently contacted in parallel or in countercurrent, preferably all in countercurrent. 4. production method according to claim 1, is characterized in that, step 3) in, described one-stage high-gravity reactor and secondary high-gravity reactor are respectively independently selected from high-gravity rotating packed bed or have self-increasing A high-pressure high-gravity reactor; preferably, the high-gravity levels of the first-stage high-gravity reactor and the secondary high-gravity reactor are respectively 30-500, more preferably 50-150. 5. production method according to claim 1, is characterized in that, step 3) in, the filler in the packing layer of described one-level supergravity reactor and secondary supergravity reactor is modified nickel foam filler, so The treatment process of the modified nickel foam filler includes: soaking the nickel foam filler in sodium hydroxide solution and dilute sulfuric acid solution at 40-70°C in sequence, and ultrasonic cleaning in absolute ethanol solution, then placing the nickel foam filler in Soak in an absolute ethanol solution of 1-tetradecylphosphoric acid with a concentration of 0.01 to 0.05mol L ^-1 for 40 to 60 hours, wherein the soaking temperature is 50°C, then take it out and dry it to obtain the modified nickel foam filler . 6. The production method according to claim 1, characterized in that, in step 4), the modification step comprises: pumping the aged slurry into a modification tank, and raising the temperature to 40-80°C Finally, add a surfactant, stir and keep warm for 1 to 3 hours, and then let it stand for 1 to 3 hours; preferably, the addition of the surfactant is 2 to 6% of the mass of the aged slurry; more preferably Preferably, the surfactant is selected from one of stearic acid, sodium stearate, dioctyl phthalate, palmitic acid, glyceride, silane coupling agent, titanate coupling agent or in any Mixed in several proportions. 7. The production method according to claim 1, characterized in that, in step 5), said filtering refers to pressure filtration or centrifugal filtration to obtain a filter product with a water content of 40 to 50 wt%; said drying includes filtering The product is subjected to primary drying and secondary drying, so that the water content of the press-filtered product is reduced to below 0.5 wt%. 8. the cubic nano calcium carbonate that production method as claimed in claim 1 obtains. 9. cubic nano calcium carbonate according to claim 8, is characterized in that, the particle size of described nano calcium carbonate is 10～80nm.