TW201927696A - Method for preparing calcium carbonate particles - Google Patents

Abstract

Provided is a method for preparing calcium carbonate particles, including passing a calcium source and a carbon source into a high-gravity spinning disk reactor having a spinning disk, wherein the concentration of the calcium source is between 0.00015 mol/L to 0.1 mol/L, allowing the calcium source and the carbon source to be mixed at a rotation speed of 1,000 rpm to 5,000 rpm and formed a calcium carbonate slurry; and performing a solid-liquid separation to obtain calcium carbonate particles with different crystalline forms such as petaloid form, chain form or cube form.

Description

Method for preparing calcium carbonate particles

The disclosure relates to a method for preparing calcium carbonate particles, in particular to a method for preparing different crystalline calcium carbonate particles.

Different crystal forms of calcium carbonate have different uses and are applied to different industries. For example, the petal-like rose petal-like calcium carbonate can be used in the paper industry and the rubber, plastics and coatings industries, where it provides whiteness, brightness, opacity, bulkiness and ink absorption in the paper industry. In the rubber, plastics and coatings industries, it provides applications such as improving coating porosity, oil absorption hydrophilicity, water retention and comprehensive physical and mechanical properties. Prismatic calcium carbonate can be used in the paper industry and provides opacity, strength and volume. Ordinary use; needle-like calcium carbonate can be used in the magazine paper and rubber and plastic industries, among which, in magazine paper applications, it has the purpose of improving paper gloss and fiber coverage; in the rubber and plastics industry, it has the effect of enhancing rubber reinforcement. And improve the impact resistance and bending strength of plastics; ultra-fine chain calcium carbonate can be used in rubber, plastics, paper and coating industries, to improve the dispersion of rubber, plastic, paper and paint, improve the break point of natural rubber Its activity makes it better to bond with the matrix and enhance the reinforcing effect of synthetic rubber. Reinforcing filler Materials, and partially replace carbon black or white carbon black, thereby reducing production costs and other uses; spherical calcium carbonate can be used in rubber, paper, ink and plastic industries, with improved dispersion, specific surface area, coating and filling properties, To improve gloss, whiteness, fluidity and printability; and flaky calcium carbonate can be used in paper and coating industries, with improved ink absorption, whiteness, printability, smoothness, smoothness and gloss. Degree, resistivity and elastic modulus.

As described above, calcium carbonate based on different crystal forms can be applied to different industries. Therefore, in the industry, the demand for calcium carbonate is very large. For example, the demand for plastic calcium carbonate in China is more than 1 million tons per year, and in the paper industry, the demand for calcium carbonate is more than 3 million tons per year; Taiwan’s Formosa Plastics has a capacity of about 250,000 per year in calcium carbonate. Tons; and Specialty Minerals of the United States has a capacity of 40 million tons per year in calcium carbonate.

From the above, it is known that the preparation of different crystalline calcium carbonate is very important in the industry. The prior art uses different methods to control the crystal appearance of calcium carbonate, for example, increasing the reaction temperature for producing calcium carbonate, adding an additive to the reaction solution, using a non-aqueous solvent such as methanol or a reverse micro-emulsion method using a surfactant; However, these methods have some disadvantages, for example, heating increases the manufacturing cost of calcium carbonate; residues of additives affect the purity and mechanical properties of calcium carbonate products; and the use of non-aqueous solvents and surfactants enhances the manufacture of calcium carbonate. Cost, reduce reaction speed, and cause environmental pollution.

Therefore, the development of a low-cost preparation method for improving the purity of the prepared calcium carbonate particles without using an additive such as a crystal modifier is a problem to be solved in the art.

A method for preparing calcium carbonate particles, comprising: feeding a calcium source and a carbon source having a concentration of 0.00015 m/liter to 0.1 m/liter into a supergravity rotating disk reactor having a rotating disk at 1,000 rpm to 5,000 rpm The rotation speed causes the calcium source and the carbon source to be mixed to form a calcium carbonate slurry; and the liquid and calcium carbonate particles are separated from the calcium carbonate slurry, wherein the crystal morphology of the calcium carbonate particles comprises a petal shape, a chain shape or a cubic shape .

1‧‧‧Super Gravity Rotating Disk Reactor

10‧‧‧shell

11‧‧‧ rotating disk

12‧‧‧ shaft

13‧‧‧Infusion tube

13a, 13b‧‧‧ sub-management

14‧‧‧ gas inlet

15‧‧‧ gas export

16‧‧‧ Fluid outlet

1 is a schematic cross-sectional view of a supergravity rotating disk reactor; FIG. 2 is a petaloid calcium carbonate particle obtained by the embodiment of the present disclosure; and FIG. 3 is a view of the embodiment of the present disclosure. The chain-like calcium carbonate particles; the fourth figure is the cubic calcium carbonate particles obtained in the examples of the present disclosure; and the fifth figure is the nano calcium carbonate particles obtained in the comparative example of the present disclosure.

The embodiments of the present disclosure are described by way of specific examples, and those skilled in the art can understand the advantages and advantages of the disclosure. The present disclosure may also be implemented or applied by other different embodiments. The details of the present specification can also be modified and changed without departing from the spirit and scope of the present invention.

The singular <RTI ID=0.0>"1" </ RTI> </ RTI> and <RTIgt;

The term "or" as used in the specification and the appended claims is intended to include the meaning of "and/or".

As used herein, the term "crystallinity" refers to the appearance of a particle arrangement; the crystalline form is a chain-like system in which nanoparticles having a major axis of about 30 nanometers (nm) to 99 nm are interconnected to form a chain state; The petal-like shape refers to a petal state sample having a length of about 0.5 μm to 5 μm; and the crystal appearance is a cubic shape with a cube shape having a side length of about 0.5 μm to 5 μm.

The term "nanoparticle" as used herein refers to a particle having a size between 1 nm and 100 nm.

The present disclosure provides a method for preparing calcium carbonate particles, comprising: feeding a calcium source and a carbon source having a concentration of 0.00015 mol/liter to 0.1 mol/liter into a supergravity rotating disk reactor having a rotating disk at 1,000 rpm. The calcium source and the carbon source are mixed at a speed of 5,000 rpm to form a calcium carbonate slurry; and the liquid and calcium carbonate particles are separated from the calcium carbonate slurry, wherein the crystal morphology of the calcium carbonate particles includes a petal shape, a chain shape Or cube shape.

Referring to Figure 1, there is shown a schematic cross-sectional view of a supergravity rotating disk reactor, which is not intended to limit the supergravity rotating disk reactor aspect or structure used in the present disclosure.

The supergravity rotating disk reactor 1 has a casing 10; a rotating disk 11 disposed in the casing 10, wherein the rotating disk 11 has a radius of 5 cm to 80 cm; a rotating shaft 12 connecting the rotating disk 11; The infusion tube 13 to the rotating disk 11; the gas inlet 14, the gas outlet 15, and the fluid outlet 16 provided in the casing 10, wherein the infusion tube 13 may include two sub-tubes 13a, 13b. The method for preparing calcium carbonate particles provided by the present disclosure is to feed a calcium source having a concentration of 0.00015 mol/liter to 0.1 mol/liter through the infusion tube 13 to the rotating disk 11, and rotate the shaft of the disk reactor 1 by the supergravity. 12, at 1,000 rpm to The rotating disk 11 is rotated at a rotational speed of 5,000 rpm so that the calcium source is formed on the rotating disk 11 to form a liquid film having an average thickness of 0.005 cm to 0.1 cm; further, the carbon source is fed into the rotating disk 11 via the infusion tube 13 or the gas inlet 14 The calcium source and the carbon source are mixed to form a calcium carbonate slurry.

In one embodiment, examples of the calcium source include a calcium hydroxide slurry or an aqueous calcium chloride solution, and the flow rate of the calcium source fed to the supergravity rotary disk reactor 1 is from 0.1 liter/minute to 1.0 liter/minute. More specifically, in a specific embodiment, the method for preparing the calcium carbonate particles further comprises: adding calcium source and the carbon source to the super gravity rotating disk reactor 1 having the rotating disk 11 to make calcium oxide A hydration reaction with water is performed to obtain the calcium hydroxide slurry as a calcium source fed to the supergravity rotating disk reactor having a rotating disk. In a specific embodiment of the calcium source calcium hydroxide slurry, a calcium hydroxide slurry having a concentration of 0.00015 mol/L to 0.1 mol/L and a flow rate of 0.1 L/min to 0.35 L/min is fed Rotating the disk 11 in the supergravity rotating disk reactor 1 and feeding the rotating disk 11 to a carbon source concentration of 0.005 m/liter to 0.05 m/liter, a carbonate aqueous solution having a pH of 3 to 5, and The aqueous solution of carbonic acid is fed into the supergravity rotating disk reactor 1 at a flow rate of 0.5 liter/min to 1.2 liter/min, and the calcium hydroxide slurry and the aqueous solution of carbonic acid are mixed at a speed of 1,000 rpm to 5,000 rpm to form calcium carbonate. The slurry finally obtains cubic calcium carbonate particles. In this embodiment, the calcium source and the carbon source can be mixed into each other via the sub-tubes 13a, 13b, respectively, and then mixed with each other to form a calcium carbonate slurry. Liquid film.

In addition, in order to obtain an aqueous solution of carbonic acid, the preparation method of the calcium carbonate particles of the present disclosure may include feeding the calcium source and the carbon source into the rotating disk 11 Before the supergravity rotating disk reactor 1, carbon dioxide gas was dissolved in water by bubbling to obtain the aqueous solution of carbonic acid.

In the method for preparing the calcium carbonate particles of the present disclosure, in addition to using an aqueous solution of carbonic acid as a carbon source, the carbon source may be carbon dioxide, a mixed gas containing carbon dioxide, or an aqueous carbonate solution. In addition, the crystal morphology of the resulting calcium carbonate particles can be altered by controlling the phase or flow rate of the supplied carbon source.

In one embodiment, the carbon source is carbon dioxide, and the carbon dioxide is fed into the supergravity rotating disk reactor 1 via a gas inlet 14, and the residual gas is discharged from the gas outlet 15, wherein the carbon dioxide flow rate is 0.2 liter. /min to 3.0 l/min. If the carbon source is a mixed gas containing carbon dioxide, the concentration of the carbon dioxide is 10% to less than 100% based on the total volume in the mixed gas, and the mixed gas is fed into the flow rate of the supergravity rotating disk reactor 1 It is from 0.2 liters / minute to 50 liters / minute.

In a specific embodiment using carbon dioxide or a mixed gas containing carbon dioxide as a carbon source, the flow rate of the carbon dioxide may be from 0.2 liter/min to 1.2 liter/min to obtain a calcium carbonate particle having a long diameter of from 30 nm to 99 nes. Rice nanoparticles, which are arranged in a chain. If the flow rate of the carbon dioxide is adjusted to 1.3 liter/min to 3.0 liter/min, petaloid calcium carbonate particles can be obtained.

According to the method for preparing calcium carbonate particles according to the present disclosure, the calcium source and the carbon source are mixed at various concentrations and flow rates at normal temperature, for example, 15 ° C to 35 ° C to form a calcium carbonate slurry, and thereafter, the calcium carbonate slurry. Flowing through the fluid outlet 16, separating the liquid and calcium carbonate particles from the calcium carbonate slurry by filtration or centrifugation to obtain calcium carbonate particles of different crystal appearance, and the disclosure is not used. The crystallographic control agent does not contain a crystallographic control agent in the calcium carbonate slurry. Therefore, the preparation method of the calcium carbonate particles can save energy cost, avoid the residue of the additive, and affect the purity of the calcium carbonate particles and the mechanical properties thereof. Furthermore, according to the preparation method of the calcium carbonate particles of the present disclosure, the problem that the nucleation speed caused by the supergravity rotating disk reactor is too fast and the crystal shape cannot be controlled can be avoided.

Example 1: Preparation of petaloid calcium carbonate particles

Put 0.0146 moles of calcium oxide into 1 liter of deionized water, stir and mix to form a calcium hydroxide slurry; the calcium hydroxide slurry and carbon dioxide gas at a flow rate of 0.25 liter / minute and 2 liter / minute, respectively, please enter the speed of 2,000 rpm In the supergravity rotary disk reactor with a rotating disk, the calcium hydroxide slurry is formed on the rotating disk to form a liquid film having an average thickness of 0.03 cm, and the carbon dioxide gas is mixed with the calcium hydroxide slurry on the rotating disk to form a calcium carbonate slurry. . The calcium carbonate slurry was filtered to separate the solid and liquid to obtain petal-like calcium carbonate particles as shown in Fig. 2. The purity of the obtained petaloid calcium carbonate particles was about 95.3% as measured by a thermogravimetric analyzer, and was observed by an electron microscope to have a length of about 0.5 μm to 5 μm.

Example 2: Preparation of calcium carbonate particles arranged in chains

0.0446 mol of calcium oxide was placed in 1 liter of deionized water and stirred to form a calcium hydroxide slurry; the calcium hydroxide slurry and carbon dioxide gas were fed at a flow rate of 2,000 rpm at a flow rate of 0.25 liter/min and 1 liter/min, respectively. In the supergravity rotary disk reactor with a rotating disk, the calcium hydroxide slurry is formed on the rotating disk to form a liquid film having an average thickness of 0.03 cm, and the carbon dioxide gas is mixed with the calcium hydroxide slurry on the rotating disk to form a calcium carbonate slurry. . The calcium carbonate slurry is filtered to separate the solid and liquid to obtain a chain as shown in Fig. 3. Calcium carbonate particles arranged in a shape. The obtained chain-like calcium carbonate particles have a purity of about 96.7% and have nanoparticle having a long diameter of about 30 nm to 99 nm.

Example 3: Preparation of cubic calcium carbonate particles

0.0446 moles of calcium oxide was placed in 1 liter of deionized water and stirred to form a calcium hydroxide slurry; and an aeration device was used to inject carbon dioxide into the water to form an aqueous solution of pH 3.8. The calcium hydroxide slurry and the aqueous solution of carbonic acid were fed into a super-gravity rotating disk reactor with a rotating disk at a flow rate of 2,000 rpm at a flow rate of 0.25 liter / minute and 0.75 liter / minute, respectively, so that the calcium hydroxide slurry and the aqueous solution of carbonic acid were After mixing on a rotating disk, a calcium carbonate slurry is formed. The calcium carbonate slurry was filtered to obtain cubic calcium carbonate particles as shown in Fig. 4. The obtained cubic calcium carbonate particles have a purity of about 97.7% and have a side length of about 0.5 to 5 μm.

Comparative Example 1: Preparation of nano calcium carbonate particles

0.178 mol of calcium oxide was placed in 1 liter of deionized water and stirred to form a calcium hydroxide slurry; the calcium hydroxide slurry and carbon dioxide gas were fed at a flow rate of 2,000 rpm at a flow rate of 1.1 liter/min and 2 liter/min, respectively. In the supergravity rotary disk reactor with a rotating disk, the calcium hydroxide slurry is formed on the rotating disk to form a liquid film having an average thickness of 0.055 cm to 0.067 cm, and the carbon dioxide gas is mixed with the calcium hydroxide slurry on the rotating disk to form Calcium carbonate slurry. The calcium carbonate slurry was filtered to separate solid and liquid to obtain nano calcium carbonate particles as shown in Fig. 5.

Comparing the above Examples 1 to 3 and Comparative Example 1, the preparation method of the different crystalline calcium carbonate particles of the present disclosure is at room temperature, for example, 15 ° C to 35 ° C, The calcium hydroxide slurry obtained by hydration reaction with a low concentration of calcium source is mixed with a carbon source through a supergravity rotating disk reactor, and by adjusting the flow rate of the calcium source and the carbon source, and the rotation speed of the rotating disk, Calcium carbonate particles of different crystallinity, chain shape or cube shape, such as a high-purity petal, chain or cube, are obtained in a continuous production condition by adding any additive such as a crystal grain controlling agent, an unsaturated fatty acid or a dispersing agent. In addition, in the preparation method of the different crystalline calcium carbonate particles of the present disclosure, the calcium oxide used in the calcium source can be obtained from the product obtained after the limestone is calcined, and the carbon dioxide used in the carbon source can be recovered from the air, therefore, the disclosure It not only provides a low-cost preparation method, but also achieves the effect of protecting the earth's resources and reducing environmental pollution by recycling and recycling waste. Moreover, the present disclosure avoids the influence of additive residues, affecting the purity of the calcium carbonate particles and their mechanical properties.

The above embodiments are merely illustrative of the method of the present disclosure and are not intended to limit the disclosure. Any of the above-described embodiments may be modified and altered by those skilled in the art without departing from the spirit and scope of the disclosure. Therefore, the scope of protection of the present disclosure should be as set forth in the scope of the patent application described below.

Claims (16)

A method for preparing calcium carbonate particles, comprising: feeding a calcium source and a carbon source having a concentration of 0.00015 m/liter to 0.1 m/liter into a supergravity rotating disk reactor having a rotating disk at 1,000 rpm to 5,000 rpm The rotation speed causes the calcium source and the carbon source to be mixed to form a calcium carbonate slurry; and the liquid and calcium carbonate particles are separated from the calcium carbonate slurry, wherein the crystal morphology of the calcium carbonate particles comprises a petal shape, a chain shape or a cubic shape . The method for preparing calcium carbonate particles according to claim 1, wherein the calcium source is fed to the rotating disk, and the average liquid film thickness is 0.005 cm to 0.1 cm. The method for preparing calcium carbonate particles according to claim 1, wherein the calcium source comprises a calcium hydroxide slurry or an aqueous calcium chloride solution, and the flow rate of the calcium source fed to the supergravity rotating disk reactor is 0.1. l / min to 1.0 l / min. The method for preparing calcium carbonate particles according to claim 3, further comprising hydrating calcium oxide and water before feeding the calcium source and the carbon source to the supergravity rotating disk reactor having a rotating disk. The reaction is carried out to obtain the calcium hydroxide slurry as a calcium source fed to the supergravity rotating disk reactor having a rotating disk. The method for producing calcium carbonate particles according to claim 1, wherein the carbon source comprises carbon dioxide, a mixed gas containing carbon dioxide, an aqueous solution of carbonic acid or an aqueous solution of carbonate. A method for preparing calcium carbonate particles according to claim 5, Wherein, the carbon source is carbon dioxide, and the flow rate of the carbon dioxide fed to the supergravity rotating disk reactor is from 0.2 liter/min to 3.0 liter/min. The method for preparing calcium carbonate particles according to claim 5, wherein the carbon source is a mixed gas containing carbon dioxide, and the concentration of the carbon dioxide is 10% to less than 100% based on the total volume of the mixed gas. And the mixed gas is fed into the supergravity rotating disk reactor at a flow rate of 0.2 liter / minute to 50 liter / minute. The method for preparing calcium carbonate particles according to claim 6 or 7, wherein the flow rate is from 0.2 liter/min to 1.2 liter/min, and the obtained calcium carbonate particles have a long diameter of 30 nm to 99 nm nanoparticle, which is arranged in a chain. The method for producing calcium carbonate particles according to claim 6 or 7, wherein the flow rate is from 1.3 liters/min to 3.0 liters/min, and the calcium carbonate particles obtained are in the form of petals. The method for preparing calcium carbonate particles according to claim 5, wherein the carbon source has a concentration of 0.005 mol/liter to 0.05 mol/liter, a carbonate aqueous solution having a pH of 3 to 5, and the carbonic acid The flow rate of the aqueous solution fed to the supergravity rotating disk reactor is from 0.5 liter/minute to 1.2 liter/minute. The method for preparing calcium carbonate particles according to claim 10, wherein the calcium source is fed into the supergravity rotating disk reactor at a flow rate of 0.1 liter/min to 0.35 liter/min, and the obtained carbonic acid is obtained. The calcium particles are in the shape of a cube. The method for preparing calcium carbonate particles according to claim 10 or 11, further comprising feeding the calcium source and the carbon source to the rotating disk Before the supergravity rotating disk reactor, carbon dioxide gas is dissolved in water by bubbling to obtain the aqueous solution of carbonic acid. The method for preparing calcium carbonate particles according to claim 1, wherein the calcium source and the carbon source are mixed at 15 ° C to 35 ° C. The method for preparing calcium carbonate particles according to claim 1, wherein the calcium carbonate slurry does not contain a crystallographic control agent. The method for producing calcium carbonate particles according to claim 1, wherein the rotating disk has a radius of 5 cm to 80 cm. The method for preparing calcium carbonate particles according to claim 1, wherein the liquid and calcium carbonate particles are separated from the calcium carbonate slurry by filtration or centrifugation.