KR100659330B1 - Manufacturing method of high purity calcium carbonate by the crystallization method - Google Patents

Abstract

The present invention relates to a method for producing high purity water-soluble calcium using a crystallization method, the composition of which is 30-50 ml / l of ammonia water (NH ₄ OH) or 40-ammonia gas (NH ₃ ) while stirring the calcium chloride aqueous solution from which suspended matter is removed. Adding 60 ml / l to remove impurities of Sr, K and Na; Heating the aqueous solution from which the impurities are removed to produce a concentrated solution, and growing the single crystal by the slow cooling method and the temperature difference method; Producing a calcium carbonate slurry of high purity by gas blowing the grown crystals; Filtering and drying the resulting calcium carbonate slurry.

    Calcium chloride, crystallization method, calcium carbonate powder, organic acid solvent

Description

    Manufacturing method of high purity calcium carbonate by the crystallization method

1 is a view showing the results of X-ray diffraction analysis of the high purity calcium carbonate powder on the calsite prepared from calcium chloride according to Example 1 of the present invention,

FIG. 2 is a diagram showing the results of X-ray diffraction analysis of an amorphous neutral high purity water soluble calcium powder prepared from high purity calcium carbonate according to Example 2 of the present invention.

The present invention relates to a high-purity calcium production method using a crystallization method, and more particularly, by producing a high-purity calcium carbonate using calcium chloride, to facilitate the development of cutting-edge industrial fields such as electronics, information and communication At the same time using the prepared high purity calcium carbonate powder to prepare a neutral water-soluble calcium powder dissolved in 100% water and having an amorphous phase precursor precursor for the shape control of calcium carbonate and food additives, health supplements, high quality It is intended to be used in a wide range of applications.

In general, the synthesis of high purity calcium carbonate of more than 99% is prepared by the wet method and solid phase method, after dissolving calcium chloride, calcium oxide or calcium hydroxide in hydrochloric acid, nitric acid, and then obtaining an aqueous solution through repeated filtering and purification It is obtained by neutralization with strong alkalis such as sodium bicarbonate and ammonium carbonate.

However, since calcium carbonate synthesized by the conventional technology uses strong acidic materials such as hydrochloric acid and nitric acid, it causes serious problems such as harmful gas generation and water pollution due to wastewater generation, as well as large-scale industries. In terms of strong acidity and strong alkaline solutions, corrosion of the reactor, resulting in lowering of production rate, lowering of yield, etc., and a serious problem in the reproducibility of the purity.

In addition, the impurity elements strontium (Sr), sodium (Na), and potassium (K), which directly affect the purity of calcium carbonate, cannot be removed by the wet method and the solid phase method. Is extremely difficult. Therefore, an efficient removal method for these problems is one of the main technologies to be solved in the preparation of stable and formulated high purity calcium carbonate, and particularly the removal of strontium contained as impurities is higher than 99.9%. It is a technical problem to be solved in the manufacture of purity calcium carbonate.

In addition, when looking at the manufacturing method of the high purity calcium carbonate in the prior art, the purity of the calcium carbonate prepared in the prior patents of the Republic of Korea Patent No. 14682, 19482, 99296 and 45270 are all 96-97% or less Since it requires a heat treatment step at 300 to 400 ° C, purity of 97% or more cannot be expected.

In general, the properties of the powder, depending on the purity, shape, particle size, etc., in particular, in the case of calcium carbonate, the particle size and purity is very important. Therefore, calcium carbonate powder prepared from the prior patent is mostly used for the production of calcium phosphate-based compounds, such as lime fertilizer.

Calcium carbonate, on the other hand, is a water-insoluble (1.5 mg / 100 g, 25 ° C.) material that is insoluble in water regardless of purity. Moreover, with the development of well-being culture and the desire of modern people to pursue quality life, the number of modern people who refrain from instant food and pursue natural foods such as organic food is increasing, and in this context, it is most necessary to maintain the health of modern people. Increasingly important are calcium-based supplements such as calcium carbonate.

Conventional supplements for health supplements and food additives for calcium supplementation prepared using shell calcium (milk) prepared from egg shells (Korea Patent No. 0232567, 148886) egg shells obtained by washing and grinding shells containing calcium carbonate as a main ingredient Whey calcium, and the like, algae, calcium lactate, calcium acetate. If they are largely classified, they can be classified into water-soluble calcium and water-insoluble calcium. Examples of water-soluble calcium include shell calcium and eggshell calcium, and water-soluble calcium includes calcium lactate and calcium acetate.

However, shells and eggshell calcium have a disadvantage in that the absorption rate of the human body is low because of non-water solubility, thereby lowering the efficiency of calcium supplementation. In addition, there is a problem in that it is easy to incorporate impurities harmful to the human body because it is manufactured only by the washing-grinding process without performing the purification process.

In the case of water-soluble calcium, which is represented by calcium acetate, calcium lactate, etc., since the calcium content is low (less than 20%) and the acidic compound (pH = 4-5), the off-flavor is already severe, and thus the inherent characteristics of the applied product. In addition, since the calcium content is small, it has a problem of ingesting and adding a large amount.

Therefore, in order to supplement the problems of the calcium-based additives, the development of a purification technology for removing impurities is a problem to be solved first, and a new production of calcium, which is water soluble and high in calcium content, and exhibits neutrality. Technology development is desperately needed, but there are no reports on this until now.

The present invention has been invented to solve this problem in view of the above, the first object is to produce an aqueous solution through the purification process using calcium chloride as a starting material, and then grow the crystals by slow cooling method and temperature difference method It is dissolved again to neutralize the mixed gas of ammonia gas and carbon dioxide gas by gas blowing method to produce high purity calcium carbonate of 99.9% or more,

The second object is to produce an amorphous water-soluble calcium powder that is neutral and soluble in 100% water by treating the above-described high purity calcium carbonate as a starting material and reacting with an organic acid solvent in a continuous process of dissolution-filtration-recrystallization.

In order to achieve the above object, a characteristic technical composition of the method for producing high purity calcium using the crystallization method of the present invention is 30-50 ml / l of ammonia water (NH ₄ OH) or ammonia while stirring the calcium chloride aqueous solution from which the suspended matter is removed. Removing impurities of Sr (strontium) and K (potassium) Na (sodium) by adding 40 to 60 ml / l of gas (NH ₃ ); Heating the aqueous solution from which the impurities are removed to produce a concentrated solution, and growing the single crystal by the slow cooling method and the temperature difference method; Producing a calcium carbonate slurry of high purity by gas blowing the grown crystals; Filtering and drying the resulting calcium carbonate slurry; Is done.

Then, the heat treatment of the aqueous solution is concentrated for 4 to 6 hours at a temperature of 90 ~ 110 ℃, the crystal growth by the slow cooling method is to precipitate the crystal while the concentrated solution is 0.5 to 3 ℃ / min slow cooling, The crystal growth by the temperature difference method is carried out in a water bath maintained at 20 to 35 ℃, the gas blowing method for producing the calcium carbonate slurry, the grown crystals are put in a reaction tank and 1000ml / L injection of carbon dioxide gas It is dissolved by adding ammonia gas to the 100ml / L reaction tank to adjust the pH to 8 ~ 10 and synthesized, the particle size of the pulverized calcium carbonate slurry is 10 ~ 20㎛.
In addition, the step of wet-reacting the prepared calcium carbonate powder with an organic acid solvent to produce an aqueous solution; Heating the wet-reacted aqueous solution to produce a concentrate and growing crystals from the concentrate; Heat-treating the crystals thus produced to produce an amorphous neutral water soluble calcium powder; to further prepare an amorphous neutral water soluble calcium.
In addition, the wet reaction is to completely dissolve the high-purity natural calcium and organic acid solvents such as acetic acid, lactic acid, citric acid and so on at high speed of 0.5 to 1.5 hours at 250 to 350 rpm at 30 ° C. to completely dissolve the aqueous solution. The heat treatment is 4 to 6 hours at 90 to 110 ° C., and the crystals of the concentrate are grown while cooling at a rate of 0.5 to 3 ° C./min, and the high temperature treatment of the produced crystals is 230 to 250 ° C. 2 to 4 hours at.
The method for preparing high purity water-soluble calcium using the crystallization method of the present invention having the above characteristics will be described by dividing each step as follows.

delete

delete

delete

<Step 1>

The first step of the present invention is a step of removing impurities by adding ammonia water or ammonia gas while stirring the calcium chloride aqueous solution from which the suspended solids are removed, wherein the aqueous calcium chloride solution is dissolved in water using calcium chloride as a starting material and filtered. It was removed.

The method of dissolving the calcium chloride in water is performed by high speed stirring at 1900 to 2100 rpm for 0.5 to 2 hours, and the filtration is preferably filtered using a pressure filtration filter equipped with a housing filter and a membrane filter.

As described above, the filtered aqueous solution is added with ammonia water or ammonia gas to remove Sr, Na, and K impurities. In this case, the filtered aqueous solution is stirred at 1900 to 2100 rpm at high speed with 30 to 50 ml / l of ammonia water having a purity of 99.9%, and ammonia. The reaction may be performed by adding 40 to 60 ml / l of gas, followed by filtration using the filtration method, that is, a pressure filtration filter equipped with a housing filter and a membrane filter.

The impurity removal method is divided into 1st and 2nd order, because in general purification, impurities reacting with acid and impurities reacting with alkali are present separately so that they are divided into 1st and 2nd removal to remove them.

The reason for using ammonia water and ammonia gas when removing the above impurity is, in general, sodium hydroxide, potassium hydroxide, ammonia and the like in the case of alkali ions reacting in an aqueous solution. Among them, sodium hydroxide and potassium hydroxide are difficult to remove due to the incorporation of impurities when used in this process. However, ammonia does not exist as an impurity because of its high volatility. When this is lowered, when used over 50ml / min, chloride is easily formed, thereby causing agglomeration. In addition, when the ammonia gas is used 40ml / min or less, the reactivity is lowered, the yield is lowered, and when 60ml / min or more is used chloride is likely to form easily due to the aggregation phenomenon occurs.

On the other hand, in the case of the ammonia gas, the same result as when a small amount of ammonia water (30ml / min or less) and a large amount (50ml / min or more) is obtained, and the amount of ammonia increased because the ammonia gas is relatively unstable.

<Step 2>

The second step of the present invention is a step of heating the aqueous solution from which impurities are removed by the first step to produce a concentrated solution and growing the crystals by slow cooling method and temperature difference method, wherein the concentrated solution is grown. The heat treatment is preferably performed at a temperature of 90 to 110 ° C. for 4 to 6 hours, and the crystal growth precipitates crystals while slowly cooling the concentrated solution obtained above at 0.5 to 3 ° C./min, or 20 to 35 ° C. It is preferable to grow by using a temperature difference method in a water base maintained at.

The aqueous solution from which impurities are removed The reason for the heat treatment at 90-110 ° C. is that the heat treatment generally uses a cut point (110 ° C.), but when the temperature is higher than this, unstable axial growth occurs during crystallization and impurities are mixed. In addition, growth of the concentrated solution is not performed at 90 ° C or lower. Therefore, in order to grow the aqueous solution from which impurities were removed, it is preferable to heat-process at 90-110 degreeC.

The reason why the heat treatment time of the aqueous solution is 4 to 6 hours is because the amount of water added during the heat treatment at 90 to 110 ° C. and the state in which crystallization can occur most best are the time.

Further, the conditions for growing the crystals by the slow cooling method and the temperature difference method is that the crystals are precipitated while the concentrated solution is slowly cooled to 0.5 to 3 ° C / min, and the slow solution is 0.5 to 3 ° C / min. The reason is that slow cooling at a temperature of 0.5 ° C./min or less is not applicable to the field due to poor productivity, and when it is 3 ° C./min or more, the growth rate is so fast that axial growth is facilitated, and consequently, impurities are mixed. It becomes easy. Therefore, it is preferable to slowly cool the concentrated solution at 0.5 to 3 ° C / min.

In addition, crystal growth by the temperature difference method is performed in a water bath maintained at 20 to 35 DEG C. The reason is that, in general, the temperature difference method makes the temperature difference between the solution inside and the outside somewhat constant and Whether it can be reduced is an important factor. Therefore, in the water bath maintained at 20 to 35 ℃ relatively easy to operate, it is possible to make the temperature difference constant, it is because the external influence can be reduced.

<Step 3>

The third step of the present invention is to produce a high purity calcium carbonate slurry by gas blowing the crystals grown in the second step, the gas blowing method is performed by the second step After the grown crystals are put in a reaction tank, it is preferable to synthesize by adjusting the pH to 8 to 10 by injecting carbon dioxide gas into 900 ~ 1100ml / L to dissolve and blown ammonia gas into the 90 ~ 110ml / L reaction tank.

The reason why the carbon dioxide gas is injected is 900 to 1100 ml / min. Since the carbon dioxide gas has little solubility in solution, preliminary experiments were conducted to provide a sufficient reaction state. As a result, the flow rate was optimal, and impurities were minimized. And used to easily dissolve the grown crystals.

In addition, the reason why the ammonia gas is blown into the reaction vessel of 90 to 110 ml / min is that when the ammonia gas is injected at the maximum time in a short time, the phase change during powder synthesis is likely to be present in a mixed phase, and the flowability of the powder is high. This is because it must fall considerably and perform expensive grinding.

<Step 4>

The fourth step of the present invention is a step of filtering and drying the calcium carbonate slurry produced by the third step, the drying is carried out for 4 to 6 hours at a temperature of 90 ~ 110 ℃, the particle size is 10 ~ 20 micrometers.

The particle size of the pulverized calcium carbonate slurry is 10 ~ 20㎛, which is a high purity calcium carbonate powder obtained by this process has a size of 10 ~ 20㎛ in the as-grown state without a separate grinding process, Is formed.

The first to fourth steps described above will produce 99.9% ultra high purity calcium carbonate powder.

In addition, the present invention by further performing the process described below for the prepared 99.9% ultra-high purity calcium carbonate powder, to prepare a neutral water-soluble calcium powder 100% soluble in water, the addition for preparing the The process comprises the steps of wet-reacting the calcium carbonate powder prepared by the first step to the fourth step with an organic acid solvent to produce an aqueous solution; Heating the wet-reacted aqueous solution to produce a concentrate and growing crystals from the concentrate; High temperature treatment of the resulting crystals to produce an amorphous neutral water-soluble calcium powder;

At this time, the wet reaction is preferably completely dissolved by high-speed reaction of 99.9% calcium carbonate and organic acid solvents such as acetic acid, lactic acid and citric acid at a rate of 250 to 350 rpm at 0.5 ° C. for 0.5 to 1.5 hours. Go The reason for using pure natural calcium and organic acid solvents such as acetic acid, lactic acid, citric acid, etc. is required to generate a change in mechanism of chemical bonding structure in order to produce water-soluble calcium. That is, in order to prepare water-soluble calcium primarily, an ionization process is required, and at this time, it is difficult to use the inorganic acid because it is difficult to decompose.

The reason why the high-purity natural calcium and organic acid solvents such as acetic acid, lactic acid and citric acid are reacted at a high speed at 250 ° C. for 0.5 to 1.5 hours at 250 to 350 rpm is high. It becomes a state and cannot obtain a desired solution. On the contrary, if it is fast, problems such as production cost and field application may occur.

The heat treatment for concentrating the aqueous solution is preferably performed at 90 to 110 ° C. for 4 to 5 hours, and the crystals of the concentrate are grown by cooling at a rate of 0.5 to 3 ° C./min by a slow cooling method. It is preferable to grow by a temperature difference method in a water bath maintained at 20 to 35 ° C. The reason for setting the heating temperature to 90 to 110 ° C. is that the heat treatment generally uses a break point (110 ° C.). At high temperatures, unstable axial growth occurs during crystallization, resulting in the mixing of impurities. In addition, growth of the concentrated solution is not performed at 90 ° C or lower. Therefore, in order to grow the aqueous solution from which impurities were removed, it is preferable to heat-process at 90-110 degreeC.

The reason why the heat treatment time of the aqueous solution is 4 to 6 hours is because the amount of water added during the heat treatment at 90 to 110 ° C. and the state in which crystallization can occur most best are the time.

The crystals of the concentrate are grown while cooling at a rate of 0.5 to 3 ° C./min. The reason for cooling at the rate of 0.5 to 3 ° C./min is that the slow cooling at a temperature of 0.5 ° C. or less is more productive. This is because it can not be applied to the site, and when the temperature is 3 ° C./min or more, the growth rate is so fast that axial growth is facilitated, thereby facilitating the incorporation of impurities.

In addition, the high temperature treatment of the produced crystals is preferably performed for 2 to 4 hours at a temperature of 230 to 250 ° C. to produce an amorphous neutral water-soluble calcium powder, but the treatment temperature of the generated crystals is 230 to 250 ° C. The reason for 2 to 4 hours is that when the heat treatment is performed at a temperature of 230 to 250 ° C, deoxidation can be carried out and a neutral and amorphous powder can be produced.

When the preparation of the neutral neutral water-soluble calcium powder 100% soluble in water by the above method, it can be applied as food additives and health supplements.

Hereinafter, the present invention will be described in detail with reference to the following Examples.

(Example 1)

This Example 1 shows an example of producing a high purity calcium carbonate powder of 99.9% or more from calcium chloride, which was dissolved in a high speed stirring at 2000 rpm by adding calcium chloride powder to a dissolving tank. The obtained calcium chloride aqueous solution was first filtered and purified by a pressure filtration filter system equipped with a housing filter and a membrane filter to remove suspended matter.

Thereafter, in order to remove Sr, Na, and K impurities in the purified aqueous solution, one of 30-50 ml / l of ammonia water (purity 99.9%) and 40-60 ml / l of ammonia gas was added while stirring at high speed at 2000 rpm. The reaction was carried out for 1 hour, and the pH was maintained at 11 or more. After the reaction was completed, impurities were purified and filtered by a pressure filtration filter.

The aqueous solution thus purified was concentrated while heating for 4-6 hours at a temperature of 90 ~ 110 ℃. The concentrated solution was slowly cooled to 0.5 to 3 ° C./min, or crystals having a size of 3 to 5 cm were grown using a temperature difference method in a water base maintained at 20 to 35 ° C.

The crystals thus obtained were dissolved in tertiary distilled water and blown with carbon dioxide gas at 1000 ml / l for 3 hours to dissolve it, and 100ml / l of ammonia gas (purity 99.9%) was added thereto while the pH was adjusted to 8-10 to 99.9%. A high purity calcium carbonate slurry was produced, and dried at 100 ° C. for 5 hours to prepare at least 99.9% of ultra high purity calcium carbonate having a particle size of 10 to 20 μm, as shown in FIG. 1. Had a structure.

On the other hand, for the 99.9% high purity calcium carbonate slurry and powder prepared according to the above example, the detection test for the hazardous metals and the strontium, sodium, potassium by using inductively coupled plasma atomic emission spectroscopy (ICP) The impurities were analyzed for impurities, and the results are shown in Table 1 below.

Samples for analysis were synthesized and measured five times by the method described above for reproducibility analysis.

Table 1

 ICP Analysis

Item Sample A B C D E     CaO 99.95 99.90 99.91 99.96 99.95     SrO ND ND ND ND ND     MgO Tr Tr Tr Tr Tr SiO ₂ ND ND ND ND ND Fe ₂ O ₃ Tr Tr Tr Tr Tr TiO ₂ Tr Tr Tr Tr Tr Na ₂ O Tr Tr Tr Tr Tr K ₂ O Tr Tr Tr Tr Tr MnO ₂ ND ND ND ND ND     Pb ND ND ND ND ND     Cu ND ND ND ND ND     CD ND ND ND ND ND     Hg ND ND ND ND ND

Tr: Trace (no quantitative analysis), ND: No Detect

(Example 2)

Example 2 shows an example of preparing an amorphous neutral water-soluble calcium powder that is soluble in 100% water using a high purity calcium carbonate powder of 99.9% or more, which is 99.9% high purity prepared in Example 1 The calcium carbonate powder was wet-reacted with an organic acid solvent and then rapidly stirred (300 rpm) to completely dissolve it, and then concentrated at a temperature of 90 to 110 ° C. for 4 to 6 hours.

The crystals were grown by slow cooling at a rate of 0.5 to 3 ° C./min or in a water bath maintained at 20 to 35 ° C. using a temperature difference method. Did. The size of the grown crystals was 0.5-1cm, which was subjected to high temperature treatment at a temperature of 230-250 ° C. for 4-6 hours to produce a water-soluble calcium powder that was neutral and dissolved in 100% water. The resulting neutral water-soluble calcium powder had a pH of 7 to 8 and had an amorphous crystal structure as shown in FIG.

In general, when a powder is synthesized by reacting organic acid solvents such as acetic acid, lactic acid and citric acid with calcium carbonate and calcium hydroxide, crystalline compounds such as calcium acetate, calcium lactate and calcium citrate are obtained, respectively. 4-5. In addition, even if the high temperature heat treatment is carried out as in the present embodiment, only the crystallinity is increased, not affecting the crystal structure at all, and the acidity (pH value) cannot be lowered.

However, when the crystal is grown and subjected to high temperature heat treatment as in the present embodiment, the form of the chemical bonding structure can be changed, so that a neutral amorphous water-soluble calcium powder having a pH of 7-8 can be prepared while being dissolved in 100% water.

On the other hand, since the state of the powder produced by such a process is agglomerated with each other, in order to use it as a food additive, a health supplement, etc., it is preferable to set it as 10 micrometers or less. Therefore, it was dispersed during the crystal formation, dried and heat-treated to obtain a fine powder.

As described above, the present invention easily removes Sr, K, Na and the like by the crystallization method using calcium chloride, and manufactures high purity calcium carbonate of 99.9%, thereby developing in advanced industrial fields such as the electronics industry and information and communication. In addition, the shape control of calcium carbonate can be promoted by developing a neutral water-soluble calcium powder having an amorphous phase while being dissolved in 100% water by a change in chemical bonding structure using the prepared high purity calcium carbonate powder. It is possible to contribute to the industrial development by enabling a wide range of precursor raw materials and food additives, dietary supplements, high-quality papermaking, cosmetic raw materials, and the like.

Claims (12)

Removing impurities of Sr, K and Na by adding 30 to 50 ml / l of ammonia water (NH ₄ OH) or 40 to 60 ml / l of ammonia gas (NH ₃ ) while stirring the aqueous calcium chloride solution from which the suspended matter is removed; Heating the aqueous solution from which the impurities are removed to produce a concentrated solution, and growing the single crystal by the slow cooling method and the temperature difference method; Producing a calcium carbonate slurry of high purity by gas blowing the grown crystals; Filtration and drying the resulting calcium carbonate slurry; Method for producing high purity water-soluble calcium using the crystallization method, characterized in that consisting of. delete The method of claim 1, wherein the heat treatment of the aqueous solution is concentrated at a temperature of 90 ° C. to 110 ° C. for 4 to 6 hours. The method of claim 1, wherein the crystal growth by the slow cooling method precipitates crystals while slowly cooling the concentrated solution at 0.5 to 3 ° C / min. The method for producing high purity water-soluble calcium using the crystallization method according to claim 1, wherein the crystal growth by the temperature difference method is performed in a water bath maintained at 20 to 35 ° C. According to claim 1, The gas blowing method for producing the calcium carbonate slurry, the grown crystals are put in a reaction tank and dissolved by injecting carbon dioxide gas 1000ml / ℓ and blowing ammonia gas into a 100ml / ℓ reaction tank pH Method for producing a high purity water-soluble calcium using a crystallization method characterized in that to be adjusted to 8 to 10 to synthesize. The method of claim 1, wherein the pulverized calcium carbonate slurry has a particle size of 10 μm to 20 μm.  The method of claim 1, further comprising: wetly reacting the prepared calcium carbonate powder with an organic acid solvent to produce an aqueous solution; Heating the wet-reacted aqueous solution to produce a concentrate and growing crystals from the concentrate; Heat-treating the crystals thus produced to produce an amorphous neutral water soluble calcium powder; and adding an amorphous neutral water soluble calcium to produce a high purity water soluble calcium using the crystallization method.  According to claim 8, The wet reaction is characterized in that the complete dissolution of a high-purity natural calcium and organic acid solvents such as acetic acid, lactic acid, citric acid and the like by high-speed reaction at a speed of 250 to 350rpm at 0.5 ℃ to 1.5 hours Method for producing high purity water soluble calcium using crystallization.  9. The method of claim 8, wherein the heat treatment for concentrating the aqueous solution is performed for 4 to 6 hours at 90 to 110 ° C. The method of claim 8, wherein the crystal of the concentrate is grown while cooling the crystal at a rate of 0.5 ~ 3 ℃ / min using a high purity water-soluble calcium using the crystallization method. The method for producing high purity water-soluble calcium using the crystallization method according to claim 8, wherein the high-temperature treatment of the produced crystals is carried out at 230 to 250 ° C for 2 to 4 hours.

Images