KR20140137579A - Method for synthesizing high purity calcite from fgd gypsum with carbonation reaction using the intermediate product (ammonium carbamate) of captured co2 - Google Patents

Abstract

Disclosed is a method of synthesizing pure calcite from a carbonation reaction of desulfurization gypsum by using an intermediate product of captured CO2, and the method is characterized by including: (A) preparing an ammonia solution; (B) aerating carbon dioxide previously collected in the ammonia solution to form a first mixed solution; (C) putting desulfurization gypsum into the first mixed solution obtained from step (B) to from a second mixed solution; (D) filtering the second mixed solution; (E) a first separation step of separating pure calcite from the second mixed solution filtered in step (D); and (F) evaporating the second mixed solution to obtain ammonium sulfate.

Description

TECHNICAL FIELD The present invention relates to a method for synthesizing pure calcite from a carbonation reaction of desulfurized gypsum using a CO2 capture intermediate product. More particularly, the present invention relates to a method for synthesizing pure calcite from carbonation of a desulfurized gypsum using a carbon capture intermediate product.

The present invention relates to a process for the synthesis of pure calcite from the carbonation of gypsum, in particular desulfurized gypsum (CaSO ₄ .2H ₂ O), and more particularly to a process for the synthesis of pure calcite from carbon dioxide, ammonia and fertilizer plants (CaCO ₃ ) by reacting desulfurized gypsum discharged after the production of fertilizer in a coal-fired power plant or after flue gas desulfurization in a coal-fired power plant.

As a result of industrial activities, a large amount of carbon dioxide, which has a great influence on global warming, is being emitted.

In order to reduce the amount of discharged carbon dioxide, a method of reducing the amount of remaining in the atmosphere by a method of filling in a subterranean ground layer, a method of dissolving in seawater, or the like has been proposed.

Alternatively, the carbon dioxide leaching into the atmosphere can be converted into a useful mineral resource form by using the mineral carbonation reaction of carbon dioxide, specifically, the reaction between carbon dioxide and gypsum, thereby reducing the amount of carbon dioxide remaining in the atmosphere. There is also a way to prepare for even more stringent climate-related agreements.

Mineral carbonation is a reaction that collects carbon dioxide produced in large quantities as a result of industrial activities, reacts the captured carbon dioxide with ammonia aqueous solution (ammonia water) and gypsum, resulting in calcite and fertilizer.

At this time, since the carbon dioxide is fixed inside the calcite as a result of the mineral carbonation reaction, the outflow of carbon dioxide into the atmosphere can be drastically reduced.

On the other hand, gypsum is a sulphate mineral mainly composed of calcium sulfate (CaSO ₄ ), and usually the calcium sulfate (calcium sulfate) (CaSO ₄ .2H ₂ O) is referred to as gypsum.

Although gypsum is produced as natural gypsum, gypsum is produced through a flue gas desulfurization process as a result of various processes in a fertilizer factory or a coal-fired power plant, as described above.

The latter gypsum is an inevitably produced gypsum due to a larger range of industrial activities, and is excessively overproduced, so that these gypsum processing problems arise.

At present, gypsum, which is continuously produced in fertilizer factories or coal-fired power plants, has high purity, so it can be used as building materials, raw materials such as cement, gypsum board, plaster, etc., As a result, it is overproduced, and there is a high possibility of causing environmental pollution problem if it continues to be dark.

As a method capable of efficiently treating excessively produced gypsum, it is possible to consider a method of recycling the calcite and the waste from the gypsum by means of the mineral carbonation reaction and recycling the carbon dioxide causing global warming, as described above .

Here, the yuan represents (NH ₄ ) ₂ SO ₄ , that is, ammonium sulfate as a chemical formula, and is commonly referred to as Huang An. That is, the yuan may mean ammonium sulphate or sulfur. In addition, calcite can be represented by CaCO ₃ as a chemical formula.

As a method for producing sulfur oxide using gypsum and ammonia, there is a so-called Mersberg process, but the detailed contents thereof can be understood with reference to the patent literature introduced in the prior art in the prior art literature item And therefore, the description thereof will be omitted here.

Other methods include a method of producing calcite and oily by reacting ammonium carbonate ((NH ₄ ) ₂ CO ₃ ) with gypsum (CaSO ₄ · 2H ₂ O), a method of producing calcite and oily from gypsum using mineral carbonation, For the advantages and disadvantages of the method of manufacturing the oily solution using ammonium carbonate and gypsum, please refer to the description of the patent literature.

Hereinafter, the mineral carbonation reaction in which ammonium carbonate is obtained by reacting ammonia with water and carbon dioxide, and gypsum is added thereto to obtain calcite and oil, will be briefly described with reference to Formulas (1) and (2).

[Chemical Formula 1]

2 NH ₃ + H ₂ O + CO ₂ → (NH ₄ ) ₂ CO ₃

(2)

_{(NH 4) 2 CO 3 +} CaSO 4 · 2H 2 O → CaCO 3 + (NH 4) 2 SO 4

In the mineral carbonation reaction, ammonium carbonate ((NH ₄ ) ₂ CO ₃ ) can be obtained by reacting ammonia (2NH ₃ ) with water (H ₂ O) and carbon dioxide (CO ₂ ) (CaSO ₄ .2H ₂ O) is added to the ammonium carbonate ((NH ₄ ) ₂ CO ₃ ) obtained in the above formula (1) and finally calcite (CaCO ₃ ) and yuan sulfate, (NH ₄₎ it can be seen that ₂ SO ₄₎ to be obtained.

On the other hand, in the synthesis of calcite in this conventional technique, ammonia water and carbon dioxide are used, and CO ₂ and NH ₃ not participating in the reaction can all be recovered and reused.

Particularly, in the mineral carbonation reaction described above, since the intermediate product is used for the carbonation reaction, it is possible to reduce the CO ₂ recovery cost, and it is considered to be a considerable advantage.

In such a mineral carbonation reaction, NH ₄ HCO ₃ (ammonium bicarbonate) is mainly used as a CO ₂ trap intermediate.

For reference, the CO ₂ capture intermediate product can be prepared from ammonium carbamate, ammonium carbonate, ammonium bicarbonate or the like depending on the stoichiometric ratio of NH ₃ and CO ₂ and the time required for the collection. .

As described above, the simple mineral carbonation reaction using gypsum has been briefly described. According to the conventional simple mineral carbonation reaction according to the conventional method as described above, the theoretical mixing ratio is used, and the economical efficiency is lowered.

As a related art related to the present invention, there is Korean Patent Laid-Open Publication No. 10-2013-0009705 (published on Jan. 23, 2013) entitled "Method of producing high-purity yellow amorphous and calcite using gypsum ".

DISCLOSURE OF THE INVENTION Accordingly, the present invention has been made to solve the above-mentioned problems, and it is an object of the present invention to provide a new method for easily synthesizing white pure calcite by delaying the precipitation of calcium carbonate, that is, calcite during carbonation of desulfurized gypsum using CO ₂ trapping intermediate product The present invention has been made in view of the above problems.

According to another aspect of the present invention, there is provided a CCMS (carbon capture and storage by mineralization) method using the carbonation reaction. The mineral carbonation reaction has already been described.

It is to be understood that the subject matter of the present invention is not limited to the above-mentioned subject (s), and those skilled in the art will understand clearly the other subject (s) not mentioned in the following description It will be possible.

In order to solve the above problems, a method for synthesizing pure calcite from carbonation of a desulfurized gypsum using a CO ₂ trapping intermediate product according to a preferred embodiment of the present invention comprises the steps of: (A) preparing ammonia water; (B) forming a first mixed solution by aerating the carbon dioxide that has been previously collected in the ammonia water; (C) adding a desulfurizing gypsum to the first mixed solution obtained in the step (B) to form a second mixed solution; (D) filtering the second mixed solution; And (E) separating the pure calcite from the filtered second mixed solution in the step (D).

Here, in the step (B), it is preferable to add 2 equivalents of ammonia to carbon dioxide.

Further, in the step (C), it is more preferable that the second mixed solution is stirred.

On the other hand, in the step (D), it is preferable that the solid impurities and unreacted desulfurized gypsum are filtered out in the second mixed solution, and the solid impurities may be solid impurities existing in the desulfurized gypsum.

It is preferable that the step (E) is repeated until the pH of the second mixed solution reaches 9.3.

According to the present invention, after the step (F), a second separation step of separating the calcite can be further included.

In addition, the calcite obtained in the second separation step may contain impurities.

According to the present invention, it is preferable that ammonium carbamate (NH ₂ COONH ₄ ) is formed in the first mixed solution in the step (B). The above ammonium carbamate exhibits a delayed precipitation effect of calcium carbonate, i.e., calcite, during the mineral carbonation reaction.

Here, the ammonium carbamate can be obtained by the following formula (3).

(3)

2NH ₃ + CO _{2 -} > NH ₂ COONH ₄

In addition, the ammonium carbamate and the desulfurized gypsum can be precipitated into calcite by the following chemical formula (4).

[Chemical Formula 4]

NH ₂ COONH ₄ + CaSO ₄揃 2H ₂ O → CaCO ₃ + (NH ₄ ) ₂ SO ₄ + H ₂ O

The details of other embodiments are included in the detailed description and the accompanying drawings.

BRIEF DESCRIPTION OF THE DRAWINGS The advantages and / or features of the present invention and the manner of achieving them will be apparent from and elucidated with reference to the embodiments described hereinafter in conjunction with the accompanying drawings. However, it is to be understood that the present invention is not limited to the disclosed embodiments, but may be embodied in many different forms and should not be construed as limited to the exemplary embodiments set forth herein, Are provided to fully disclose the scope of the present invention, and the present invention is only defined by the scope of the claims.

It is to be understood that the same reference numerals refer to the same components throughout the specification and that the size, position, coupling relationship, etc. of each component constituting the invention may be exaggerated for clarity of description.

According to the method of synthesizing pure calcite from carbonation of desulfurized gypsum using the CO ₂ trapping intermediate product according to the preferred embodiment of the present invention, it is possible to efficiently fix carbon dioxide in useful minerals, that is, calcite.

It is also expected that the calcite with carbon dioxide is highly purity and rich in economic value.

1 is a flowchart showing a schematic flow of a method of synthesizing pure calcite from a carbonation reaction of desulfurization gypsum using a CO ₂ trapping intermediate product according to a preferred embodiment of the present invention.

Hereinafter, embodiments of the present invention will be described in detail with reference to the accompanying drawings.

1 is a flowchart showing a schematic flow of a method of synthesizing pure calcite from a carbonation reaction of desulfurization gypsum using a CO ₂ trapping intermediate product according to a preferred embodiment of the present invention.

According to a preferred embodiment of the present invention, a method of synthesizing pure calcite from a carbonation reaction of desulfurized gypsum using a CO ₂ trapping intermediate product comprises the steps of preparing ammonia water (S100), adding carbon dioxide (S110) forming a first mixed solution (S110), forming a second mixed solution by injecting desulfurized gypsum (S120), starting stirring (S130), separating solid impurities and unreacted desulfurized gypsum A step S160 of filtering out the pure calcite and filtering and separating it, a step S160 of checking whether the pH exceeds 9.3, a stirring end step S170, filtering and separating remaining calcite S180, And separating the oily solution by evaporating the second mixed solution (S190).

Hereinafter, each step will be described in order.

Steps to prepare ammonia water

A step of preparing an aqueous ammonia (S100) is a step to prepare the required ammonia water (NH ₄ OH ·) in the mineral carbonation reaction is the basic idea of the invention.

At this time, the concentration of the prepared ammonia water was 8%.

Here, with respect to 100 parts by weight of the desulfurized gypsum, the concentration range of the ammonia water is preferably about 5% to 8%. Ammonia water at a concentration of less than 5% is disadvantageous to the production of ammonium carbamate chemically, and is unfavorable because it may not react with ammonia water at a concentration exceeding 8% and excess ammonia may be present.

A step of aerating the carbon dioxide that has been captured in advance to form a first mixed solution

The carbon dioxide previously captured in the prepared ammonia water is aerated to form a first mixed solution.

At this time, carbon dioxide captured in advance means carbon dioxide which is a main cause of global warming that has been collected in advance, and it is preferable to collect carbon dioxide produced in large quantities in a fertilizer factory or coal thermal power plant as a result of industrial activities Do.

Carbon dioxide that has been captured in advance may be carbon dioxide that has been collected in a fertilizer factory or a coal-fired power plant in advance, or it may be carbon dioxide that has been collected in advance from other carbon dioxide emission plants.

It is particularly preferable to add 2 equivalents of ammonia to carbon dioxide when carbon dioxide is aerated in this step S110.

Wherein the two equivalents may be determined from Formula (3) wherein two moles of ammonia react with one mole of CO ₂ , as will be appreciated by one of ordinary skill in the art.

It should be noted that in this step (S110), ammonium carbamate is used instead of NH ₄ HCO _{3, which} has been conventionally used as a CO ₂ trapping intermediate in the description related to the mineral carbonation reaction described above.

The formation of the ammonium carbamate (NH ₂ COONH ₄ ) is represented by the following chemical formula 5.

[Chemical Formula 5]

2 NH ₃ + CO ₂ ^- > NH ₂ COO ^- + NH ₄ ⁺

From the above formula (5), the present invention is characterized in that NH ₂ COONH ₄ (ammonium carbamate) is used as a CO ₂ trapping intermediate product generated due to aeration of carbon dioxide, and in particular, carbamate in NH ₂ COONH ₄ Is used as the starting material for the carbonate reaction.

The reason why the ammonium carbamic acid is used as a starting material will be described.

Carbamates (NH ₂ COONH ₄ ) are ultimately converted to carbonates (CO ₃ ), but since the reaction takes a considerable amount of time compared to the conversion of bicarbonate (HCO ₃ ) to carbonates, the overall carbonation process itself is relatively It proceeds very slowly. Specifically, it is preferable to understand that the carbonation process at this time is carried out by two steps of the following formulas (6) and (7).

[Chemical Formula 6]

NH ₂ CO ₂ ^- + CO ₂ + 2H ₂ O ^- > 2 HCO 3 ^- + NH ₄ ⁺

When the reaction of the above formula (6) proceeds, the calcium dissolved in the desulfurized gypsum is present in a dissolved form of Ca ²⁺ for a certain period of time before being precipitated as calcite.

(7)

HCO ₃ ^- & gt ^; CO ₃ ^2- + H ⁺

When the reaction of the above formula (7) is started in earnest, the dissolution rate of the gypsum is remarkably accelerated and the carbonation reaction is accelerated, and the induction time for crystallization, that is, the delay time, is virtually disappeared and calcite (CaCO ₃ ) And subsequently precipitated.

Therefore, it is preferable to separate the solution near pH 9.3 in order to prevent the reaction of formula (7) from starting. For this purpose, it is preferable to check the pH of the solution using a pH meter or the like.

The pH check of the solution will be described in more detail in the step of checking whether the pH described later exceeds 9.3 (S160).

Therefore, in the present invention, the reaction induction time until the calcium carbonate to be finally obtained, that is, the calcite is precipitated is increased so that the calcium carbonate is dissolved in the solution for a relatively long time in the solution have.

Such a reaction will be described in more detail in the following subsequent steps.

A step of adding a desulfurized gypsum to form a second mixed solution

The step S120 of forming the second mixed solution by introducing the desulfurized gypsum is performed by injecting a desulfurizing gypsum (FGD gypsum), which is a core material in the mineral carbonation reaction, into the first mixed solution formed of the carbon dioxide- 2 mixed solution.

The desulfurization gypsum supplied in this step S120 contains a considerable amount of solid impurities. Most impurities are insoluble minerals such as muscovite, dolomite, iron (Fe), unburned carbon, And the like.

Therefore, these impurities are known to exist in a mostly solid state at pH (> 7) at which mineral carbonation occurs.

It should be noted that in this step S120, the desulfurized gypsum to be introduced need not be crushed or crushed.

This is because the desulfurized gypsum itself is composed of fine particles, that is, particles having 80% or more of 74 탆 or less.

Therefore, when the desulfurization gypsum is used for the carbonation reaction in terms of the process, it is expected that the crushing or grinding process is reduced, and that the increase in the economic cost due to the reduction can be suppressed.

Starting Stage of Stirring

The stirring start step (S130) is a step of stirring the second mixed solution.

At this time, stirring is performed to uniformly mix the ammonium carbamic acid (NH ₂ COONH ₄ ) formed in the second mixed solution and the desulfurized gypsum added in the step of forming the second mixed solution (S 120).

As a result of the reaction between the ammonium carbamic acid and the desulfurized gypsum by stirring, the precipitation of the pure calcite, which is the object of the present invention, can be promoted.

At this time, stirring of about 150 rpm had no significant effect on precipitation of pure calcite, and significant stirring effect was observed at about 300 rpm.

Here, according to a preferred embodiment of the present invention, the present step is preferably carried out at room temperature, for example, at about 20 캜. The reaction in Formulas (6) and (7) proceeds too quickly, so that the induction time for crystallization, that is, the delay time, disappears and calcium carbonate of high purity can not be easily obtained.

Separating solid impurities and unreacted desulfurized gypsum

Next, separating the solid impurities and the unreacted desulfurized gypsum (S140) comprises filtering and separating solid impurities and unreacted desulfurized gypsum and the like from the second mixed solution under stirring in step S130 to be.

Examples of the solid impurities include muscovite, dolomite, iron (Fe), and unburned carbon, which are insoluble minerals, as described above.

In this step S140, solid impurities and unreacted desulfurization gypsum which are filtered and separated are preferably filtered and separated by a mesh having a size of 0.45 mu m.

The 0.45 탆 sized mesh is a commonly used mesh at the laboratory level, and is not limited to such a mesh, so other appropriate sized meshes may be used if desired.

The reason why the solid impurities and the unreacted desulfurized gypsum are separated by filtering in this step S140 is that the calcium carbonate in a dissolved state in the second mixed solution is isolated from the solid impurities and the unreacted desulfurized gypsum , And to induce crystallization of calcite, that is, precipitation.

In this case, the calcium carbonate is present in a dissolved state in the second mixed solution. Further, since the solubility of the solid impurities and the unreacted desulfurized gypsum is relatively low, the solid impurities, unreacted desulfurized gypsum, There is no need to worry about the calcium reaction.

Precipitation of pure calcite and filtering and separating it

Next, in step S150 of filtering and separating the pure calcite, the solid impurities and the unreacted desulfurized gypsum and the like are separated by filtration in the step S140 and then crystallized, that is, precipitated And the pure calcite is precipitated and formed, and the precipitated calcite is filtered and separated.

It should be noted that in this step (S150), the precipitation of the calcite precipitated and separated is further promoted by stirring.

The stirring condition at this time was 300 rpm. When stirring for at least 3 minutes, it was possible to visually observe the separation of calcite, that is, formation of calcite precipitate.

It should be noted that the stirring is a conventional laboratory stirring condition and, if implemented on an industrial scale, the stirring rpm may be faster or slower than the 300 rpm mentioned above.

It should be noted that the calcite precipitated in this step S150 is a pure calcite having a purity of 100 white.

At this time, the meaning of "purity of 100%" means that an attempt was made to detect other metal components such as impurities in the calcite finally precipitated, for example, Fe and Mn, but the detection ratio was 0.1 ppm (mg / That is, it is detected below the detection limit of the ICP equipment, so the purity is 100%.

At this time, the precipitated calcite may be in the form of a white powder.

Here, it is expected that the greater the amount of calcium carbonate dissolved in the second mixed solution, the greater the precipitation amount of calcite from these calcium carbonates.

For this purpose, it is preferable that the solid impurities and the unreacted desulfurized gypsum are separated in advance in the step (S140).

Further, it is more preferable that the pure calcite that has already been precipitated and produced is separated by filtration in this step (S150).

At this time, as a result of the reaction between the ammonium carbamate and the desulfurized gypsum, the chemical reaction formula in which calcite is formed is represented by the following chemical formula (8).

[Chemical Formula 8]

Ca (aq) ²⁺ + CO ₃ (aq) ^2- ? CaCO ₃ (aq) ⁰ ? Calcite (CaCO ₃ (s)

From the formula (8), the components excluding the unreacted gas desulfurization gypsum and impurities, i.e., _{^{Ca 2+, HCO 3 -, CO}} 3 2-, NH 4 +, SO 4 2-, NH 3 (aq), CO 2 (aq) , NH ₂ COO ^- are all present in the aqueous state before leaching into calcite and precipitated, and the mechanism by which calcite (CaCO ₃ ) (s) is formed in the filtered solution can be known.

Checking whether the pH exceeds 9.3

Next, in step S160 of checking whether the pH exceeds 9.3, in order to continuously repeat the precipitation, filtering and separation step (S160) of the pure calcite, the pKa of the ammonia and the pH conversion value become 9.3 Filtering and separation step (S160) of the calcite is repeatedly performed. When the pH reaches 9.3, the process proceeds to the next step (S170). have.

Confirmation of the pH value can be performed by a pH meter.

When the pH value exceeds 9.3, the solid impurities and the unreacted desulfurized gypsum separated in step S140 are re-introduced into the second mixed solution and the precipitation, filtering, and separation step (S160) of the calcite are repeated .

In this case, step S140 and step S150 may be performed successively.

Stirring termination step

The stirring termination step (S170) is a step of terminating the stirring when the pH reaches 9.3 in the step (S160).

Filtering and separating the remaining calcite

Next, the step of filtering and separating the remaining calcite (S180) is a step of filtering and separating the calcite remaining in the second mixed solution in the step (S170).

Since the calcite in this step S180 may contain impurities, the pure calcite obtained in the above step S150 may be white calcite, which is somewhat yellowish.

Since the purity of the calcite obtained in this step S180 is not high, the industrial availability may be lowered unlike the calcite obtained in the step S150. Therefore, the calcite obtained in this step S180 may need further processing.

In this step S180, the filter used for filtering the calcite containing impurities is preferably a mesh of 0.45 mu m.

Separating the oily solution by evaporating the second mixed solution

Finally, the step (S190) of separating the oily solution by evaporating the second mixed solution is a byproduct of the separation of pure calcite according to the present invention, and is a step to obtain the solution.

The remaining oily solution ((NH ₄ ) ₂ SO ₄ ) can be obtained by evaporating the second mixed solution after stirring. In this case, since the impurities and the calcite are all filtered and separated in the step S180, the purity is high.

In this step (S190), ammonia remaining in the second mixed solution is preferably recovered and recycled in the step (S100) of preparing the above-mentioned ammonia water.

Example

Ammonia water (NH ₄ OH) was prepared, and the carbon dioxide previously collected was aerated to form a first mixed solution in which ammonium carbamate (NH ₂ COONH ₄ ) was produced.

At this time, the concentration of ammonia water is preferably about 5% to 8% with respect to 100 parts by weight of the desulfurized gypsum. The effect of such a concentration range has already been described.

Further, it is preferable to add 2 equivalents of ammonia to carbon dioxide.

150 g of FGD gypsum was introduced into the first mixed solution thus obtained under the condition of 0.2 g / 100 mL to form a second mixed solution while allowing the mineral carbonation to proceed.

The desulfurized gypsum to be introduced into the second mixed solution need not be separately pulverized as described above.

It is further preferable that the second mixed solution is continuously stirred.

At this time, the impurities composed of the insoluble minerals contained in the desulfurization gypsum and the unreacted desulfurized gypsum are preferably separated from the second mixed solution by filtration.

In the second mixed solution, oily ((NH ₄ ) ₂ SO ₄ , ammonium sulfate) is dissolved.

Since the solubility of the oily solution is very high, a highly purified oily solution can be obtained by filtering and separating all the impurities remaining in the second mixed solution and then evaporating the second mixed solution.

In the second mixed solution, calcium carbonate in a dissolved state exists not only in the form of oily components but also in dissolved form.

The oil is preferably dissolved in an amount of 74 g / 100 mL, and the calcium carbonate may preferably be dissolved in an amount of 0.15 g / 100 mL.

As described above, in the calcium carbonate, due to the precipitation delay effect of calcium carbonate, that is, calcite during the mineral carbonation reaction by ammonium carbamate (NH ₂ COONH ₄ ) as a CO ₂ trapping intermediate product, And may be present in a dissolved form in the second mixed solution.

Therefore, when the calcium carbonate is present in a form dissolved in the second mixed solution for a long time, the amount of the calcium carbonate in the second mixed solution is relatively increased when the solid impurities and the unreacted desulfurized gypsum are separated, The higher the purity of the calcite precipitated as a result.

Finally, by filtering and separating the crystallized calcite in the second mixed solution, a pure calcite with a purity of 100% can be obtained.

The reason why the purity is 100% is that the metal ion was not detected in the calcite obtained according to the preferred embodiment of the present invention as a result of the ICP (Inductively Coupled Plasma) analysis.

A small amount of HCO ₃ ^- , CO ₃ ^2- , NH ₄ ⁺ , SO ₄ ^2- , NH ₃ (aq), CO ₂ (aq) and NH ₂ COO ^- , which may be attached to the surface of precipitated calcite, And then washing with a small amount of water to remove it.

These components are sufficiently removed with a small amount of water because of their high solubility in water. Therefore, it is preferable to understand that the purity of the calcite is 100%.

While the present invention has been particularly shown and described with reference to exemplary embodiments thereof, it is to be understood that the invention is not limited to the disclosed embodiments, but, on the contrary, You will know well. Accordingly, the spirit of the present invention should not be construed as being limited to the embodiments included in the above description, but should be determined only by the claims of the following claims, and all modifications equivalent or equivalent to the claims of the claims .

S100: Step for preparing ammonia water
S110: a step of aerating carbon dioxide that has been captured in advance to form a first mixed solution
S120: a step of adding a desulfurized gypsum to form a second mixed solution
S130: stirring start step
S140: Separation of solid impurities and unreacted desulfurized gypsum
S150: precipitation of pure calcite, filtering and separation thereof
S160: Checking whether the pH exceeds 9.3
S170: stirring end step
S180: Filtering and separating the remaining calcite
S190: separating the oily solution by evaporating the second mixed solution

Claims (12)

(A) preparing ammonia water;
(B) forming a first mixed solution by aerating the carbon dioxide that has been previously collected in the ammonia water;
(C) adding a desulfurizing gypsum to the first mixed solution obtained in the step (B) to form a second mixed solution;
(D) filtering the second mixed solution; And
(E) separating the pure calcite from the filtered second mixed solution in the step (D).
A Method for the Synthesis of Pure Calcite from Carbonation of Desulfurized Gypsum Using CO ₂ Collecting Intermediate.
The method according to claim 1,
Wherein in step (B), two equivalents of ammonia are added to carbon dioxide,
A Method for the Synthesis of Pure Calcite from Carbonation of Desulfurized Gypsum Using CO ₂ Collecting Intermediate.
The method according to claim 1,
Wherein in the step (C), the second mixed solution is stirred.
A Method for the Synthesis of Pure Calcite from Carbonation of Desulfurized Gypsum Using CO ₂ Collecting Intermediate.
The method according to claim 1,
Characterized in that, in the step (D), what is filtered out in the second mixed solution is solid impurities and unreacted desulfurization gypsum.
A Method for the Synthesis of Pure Calcite from Carbonation of Desulfurized Gypsum Using CO ₂ Collecting Intermediate.
5. The method of claim 4,
Characterized in that the solid impurities are solid impurities present in the desulfurized gypsum.
A Method for the Synthesis of Pure Calcite from Carbonation of Desulfurized Gypsum Using CO ₂ Collecting Intermediate.
The method according to claim 1,
Wherein the step (E) is repeated until the pH of the second mixed solution reaches 9.3.
A Method for the Synthesis of Pure Calcite from Carbonation of Desulfurized Gypsum Using CO ₂ Collecting Intermediate.
The method according to claim 1,
Further comprising a second separating step of separating the calcite after the step (F)
A Method for the Synthesis of Pure Calcite from Carbonation of Desulfurized Gypsum Using CO ₂ Collecting Intermediate.
8. The method of claim 7,
Characterized in that the calcite obtained in the second separation step contains an impurity.
A Method for the Synthesis of Pure Calcite from Carbonation of Desulfurized Gypsum Using CO ₂ Collecting Intermediate.
(A) preparing ammonia water;
(B) forming a first mixed solution containing ammonium carbamate (NH ₂ COONH ₄ ) by aerating the carbon dioxide that has been previously collected in the ammonia water;
(C) adding a desulfurizing gypsum to the first mixed solution obtained in the step (B) to form a second mixed solution;
(D) filtering the second mixed solution; And
(E) separating the pure calcite from the filtered second mixed solution in the step (D).
A Method for the Synthesis of Pure Calcite from Carbonation of Desulfurized Gypsum Using CO ₂ Collecting Intermediate.
10. The method of claim 9,
Characterized in that the ammonium carbamate is obtained by the following formula:
A Method for the Synthesis of Pure Calcite from Carbonation of Desulfurized Gypsum Using CO ₂ Collecting Intermediate.
2NH ₃ + CO _{2 -} > NH ₂ COONH ₄
10. The method of claim 9,
Characterized in that the ammonium carbamate and the desulfurized gypsum are precipitated into calcite according to the following formula:
A Method for the Synthesis of Pure Calcite from Carbonation of Desulfurized Gypsum Using CO ₂ Collecting Intermediate.
_{^{Ca (aq) 2+ + CO 3}} (aq) 2- → CaCO 3 (aq) 0 → calcite (CaCO ₃ (s))
A pure calcite having a purity of 100% obtained from a desulfurized gypsum by the method according to any one of claims 1 to 11.

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