KR20190088926A - Method for recovering carbonate from slag and system therefor - Google Patents

Abstract

The present invention relates to a method for recovering carbonate using steelmaking slag and a system thereof. More specifically, the present invention relates to the method and the system for recovering extracted metal ions as carbonate by extracting metal ions contained in steelmaking slag. According to the present invention, by using a gaseous buffer as a means for controlling a carbonation reaction, it is possible to minimize change in a concentration of metal ions in a solution, at the same time, to control the pH in a basic atmosphere, thereby being able to increase a recovery rate of carbonate from steelmaking slag.

Description

[0001] METHOD FOR RECOVERING CARBONATE FROM SLAG AND SYSTEM THEREFOR [0002]

The present invention relates to a method and system for recovering carbonates using steelmaking slag, and more particularly, to a method and a system for recovering metal ions extracted as carbonates from metal ions contained in steelmaking slag.

Recently, the implementation of the Convention on Climate Change related to global warming has become a social and economic problem in the treatment of large amounts of steel slag, quicklime dust and various harmful gases generated in steelworks. In particular, it is imperative to solve the carbon dioxide emissions as one of the byproducts of the steelworks.

The slag is inevitably produced by the gangue component of iron ore or coke in the steelmaking process, the oxide produced in the oxidation or deoxidation of molten iron or molten steel during the steelmaking process, or the additive added for refining purposes. SiO ₂ and CaO Al ₂ O ₃ , FeO, MgO, P ₂ O ₅ and CaS depending on the type of refining reaction. The annual amount of blast furnace slag and steel slag is increasing year by year, but efforts to develop and apply these byproducts are insufficient compared to the amount generated. Most of these are buried or left in the site of the plant separately, and environmental problems are seriously highlighted. Various techniques for utilizing such steelmaking slag are being developed.

Korean Patent No. 10-1487977 discloses a method for recovering Fe in steelmaking slag, and Japanese Patent No. 10-1175422 describes a method for recovering valuable metals in slag. However, this is merely about recovery of Fe components in steelmaking slag Do.

Korean Patent Laid-Open No. 10-2004-26383 discloses a method for pulverizing steel making slag into a steel slag having a diameter of 45 μm or less and using water as a raw material to obtain a calcium ion eluate having a pH of 12 or more, And a method of producing calcium carbonate by reacting the carbon dioxide or carbon dioxide-containing flue gas so as to maintain the pH at 7 or more has been proposed. However, since the slag, which is a raw material having a particle size of about 45 탆, has to be processed through separate pulverization and sieving, and since only water is used as a solvent for elution of calcium ions, the above-mentioned technology has a very low calcium ion content There is a problem that it takes a long time to separate the filtration of the residual slag and the effluent.

Korean Patent Laid-Open No. 10-2006-0070017 discloses a method for producing ultra-fine calcium carbonate of high purity from a calcium compound in order to more efficiently recycle by-products of a steel mill, which comprises reacting a calcium compound with a strong acid such as nitric acid or hydrochloric acid, To prepare a calcium ion solution, to prepare calcium hydroxide by adjusting pH, and to produce calcium carbonate by reacting the produced calcium hydroxide with carbon dioxide gas. However, since this technique utilizes a high concentration of strong acid as a solvent, separation of calcium ions may be easier than using only water. However, in order to adjust the pH, an expensive solvent such as an aqueous solution of sodium hydroxide (NaOH) And precipitation of calcium carbonate can proceed very slowly at low pH values, resulting in very low production efficiency.

In addition, in the case of the prior art in which sodium hydroxide is used as a buffer to adjust the pH, it is added in the form of a solution. In this case, unnecessary cations are accumulated in the reaction solution to increase the concentration of the remaining salt (Na +) The concentration of the metal ion is relatively decreased, and such a concentration change eventually causes a problem of reducing the carbonation reaction efficiency. Further, when ammonium chloride and ammonium carbonate of weak bases are used as a buffer, it is difficult to control the pH to a basic atmosphere and improvement of the carbonate recovery rate is impossible.

Accordingly, there is a need to develop a technique for recovering an extractable metal component from steelmaking slag, in addition to Fe, and a recovery method having excellent carbonate recovery.

SUMMARY OF THE INVENTION The present invention has been made to solve the above-mentioned problems, and it is an object of the present invention to provide a method and system for recovering carbonate from steelmaking slag using steelmaking slag having excellent carbonate recovery.

In order to achieve the above object, the present invention provides a method for producing a steel slag, comprising: 1) mixing a steelmaking slag and an acidic solvent to prepare a first mixed solution; 2) separating the first mixed solution into a second mixed solution and a filtrate through a first filter; 3) preparing a third mixed solution by adding a ligand to the second mixed solution, wherein the third mixed solution contains a complex formed by a reaction between a metal ion and a ligand in a second mixed solution; 4) separating only the solution containing the complex compound from the third mixed solution by electrochemical means, to obtain a fourth mixed solution; 5) hydrating a gaseous buffer in the fourth mixed solution, and then injecting carbon dioxide to form a carbonate; 6) separating the formed fourth mixture liquid containing the formed carbonate into a carbonate and a residual liquid; And 7) air stripping the remaining liquid to recover the buffer, then injecting the buffer into the third mixed liquid and circulating the recovered liquid so as to be reusable, and a method for recovering the carbonate using the slag.

The present invention also relates to a metal ion extraction unit for mixing a steelmaking slag and an acidic solvent to produce a first mixed solution containing metal ions; A first separator for separating the first mixed solution into a second mixed solution containing a metal ion and a filtrate; Mixing a ligand with the separated second mixed solution to produce a third mixed solution containing a complex formed by a reaction between a metal ion and a ligand; A complex separation unit for separating only the solution containing the complex compound from the third mixture solution to obtain a fourth mixture solution; A first gas injection unit injecting a gaseous buffer into the fourth mixed solution; A carbonation unit for forming carbonates by injecting carbon dioxide into the fourth mixed solution in which the buffer is hydrated; A carbonate separator for separating the formed fourth mixture liquid containing the formed carbonate into a carbonate and a residual liquid; And a gas circulation unit for recovering and reusing the buffer from the residual liquid, wherein the gas circulation unit comprises: a gas recovery unit for air stripping and recovering the buffer present in the residual liquid; And a second gas injection unit for re-injecting the recovered buffer into the carbonization process unit. The present invention also provides a system for recovering carbonates using steelmaking slag.

According to the method and system for recovering carbonate using the steelmaking slag of the present invention, by using a gaseous buffer as a pH control means for carbonation, the concentration of metal ions in the solution is minimized and the pH is changed to a basic atmosphere It is easy to control so that the recovery rate of carbonate from steelmaking slag can be increased.

In addition, the injected buffer can be recovered by air stripping in a gaseous state again, and the recovered buffer can be reused by injecting it into a carbonation reactor to replace the expensive solvent, thereby reducing the production cost.

1 is a flowchart showing a method for recovering carbonate using steelmaking slag according to an embodiment of the present invention.
2 is a schematic view showing a system for recovering carbonate using steelmaking slag according to an embodiment of the present invention.
3 is a schematic view illustrating a process of forming a carbonate according to an embodiment of the present invention.

The embodiments of the present invention are described in order to more fully explain the present invention to those skilled in the art, and the following embodiments may be modified in various other forms, The present invention is not limited to the embodiment. Rather, these embodiments are provided so that this disclosure will be more faithful and complete, and will fully convey the scope of the invention to those skilled in the art.

In the drawings, the thickness and the size of each layer are assumed for convenience and clarity of description, and the same reference numerals denote the same elements in the drawings. As used herein, the term "and / or" includes any and all combinations of one or more of the listed items.

The terminology used herein is for the purpose of describing particular embodiments only and is not intended to be limiting of the invention. As used herein, the singular forms "a," "an," and "the" include singular forms unless the context clearly dictates otherwise. Also, " comprise "and / or" comprising "when used herein should be interpreted as specifying the presence of stated shapes, numbers, steps, operations, elements, elements, and / And does not preclude the presence or addition of one or more other features, integers, operations, elements, elements, and / or groups.

All technical terms used in the present invention are used in the sense that they are generally understood by those of ordinary skill in the relevant field of the present invention unless otherwise defined. Also, preferred methods or samples are described in this specification, but similar or equivalent ones are also included in the scope of the present invention. The contents of all publications referred to herein are incorporated herein by reference.

Hereinafter, a method of recovering a carbonate using the steel making slag of the present invention and a system thereof will be described in detail with reference to the drawings.

FIG. 1 is a flowchart illustrating a method for recovering a carbonate using steelmaking slag according to an embodiment of the present invention. Referring to FIG. 1, a first mixed solution is prepared by mixing a steelmaking slag and an acidic solvent (S100). 2) separating the first mixed solution into a second mixed solution and a filtrate through a first filter (S200); 3) adding a ligand to the second mixed solution to prepare a third mixed solution, wherein the third mixed solution contains a complex formed by a reaction between a metal ion and a ligand in a second mixed solution; 4) separating only the solution containing the complex compound from the third mixed solution by electrochemical method to obtain the fourth mixed solution (S400); 5) a step S500 of hydrating a gaseous buffer in the fourth mixed solution and then injecting carbon dioxide to form a carbonate; 6) separating the formed fourth mixture liquid containing the formed carbonate into a carbonate and a residual liquid (S600); And 7) air stripping the residual liquid to recover the buffer, then injecting the buffer into the third mixed liquid and circulating the buffer liquid for reuse (S700).

Hereinafter, the method for recovering the carbonate will be described step by step.

The step 1) is a step (S100) of mixing a steelmaking slag and an acidic solvent to produce a first mixed solution. More specifically, in order to recover the steelmaking slag and facilitate the reaction with the acidic solvent, a primary crushing operation is carried out using a jaw crusher, and a secondary sieve is sieved to a diameter of less than 1000 μm . In other words, if the particle size is reduced, the steel sheet can be finely divided into a primary crushing operation and a secondary crushing operation in order to increase the contact area with the acidic solvent.

The obtained steelmaking slag having a fine particle size is mixed with an acidic solvent and reacted. Wherein the acidic solvent is nitric acid (HNO _3), hydrochloric acid (HCl), sulfuric acid (H ₂ SO _4), bromide acid (HBr), iodine hydrofluoric acid (HI), perchloric acid (HClO ₄₎ and phosphoric acid (H ₃ PO ₄ ), And preferably a nitric acid (HNO ₃ ) solvent of 1.0, 1.5, and 2.5 M, but is not limited to the examples.

When the steelmaking slag and the acidic solvent are mixed, the metal components in the steelmaking slag are present in the form of metal ions in the acidic solvent. Therefore, the first mixed solution is present in a state where the steel making slag, the acidic solvent, and the metal ions are mixed. In order to allow the metal component of the steelmaking slag to react with the acidic solvent to exist as a metal ion, stirring can be performed using a magnetic bar.

The step 2) is a step (S200) of separating the first mixture into a second mixture and a residue. More specifically, the first mixed solution exists in a state where the steel making slag, the acidic solvent, and the metal ions are mixed and is separated using the first filter. Only the metal ions which have passed through the first filter and have reacted with the acidic solvent can be classified into the second mixed solution and the acidic solvent that has not passed through the first filter and the unreacted steel making slag as the residue.

In the case of the first mixed liquor, steel-making slag and an acidic solvent are reacted to extract metal ions, but steel-making slag not reacting with an acidic solvent and components other than metal components are mixed. . The first filter includes pores having a diameter of 30 to 50 mu m so that components other than the large unreacted steel making slag and the metallic component can not be passed through the first filter and can be classified into a residue. The second mixed solution may include a metal ion and an acidic solvent because the particles pass through the first filter because they are acidic solvent and metal ion components having a small particle size.

In step S300, a ligand is added to a second mixed solution containing a metal ion and an acidic solvent to prepare a metal ion and a ligand. To form a complex, whereby a third mixed solution containing the complex can be prepared.

The ligand means a molecule or ion bonded around the central metal ion of the coordinating compound and is characterized in that it has a non-covalent electron pair in order to coordinate bond with the metal ion. The ligand selectively reacts with the metal ion. Therefore, the calcium ion (Ca ²⁺ ) can be selectively extracted from various metal ions of the second mixture. That is, the metal ions can be selectively extracted by using the property that the ligand binds to a specific metal ion.

The ligand is _{CH 3 COOH, C 6 H 9} NO 6, C 6 H 5 NO 2, HN (CH 2 CO 2 H) 2 and at least one selected from the group consisting of C ₂ H ₂ O _4, preferably C ₂ H ₂ O _4, but any ligands capable of selectively coordinating to the calcium ion (Ca ²⁺ ) can be used and are not limited to the examples. Accordingly, the third mixed solution may contain an acidic solvent, a complex compound, unreacted ligand and unreacted metal ion.

The step 4) is a step (S400) of separating the complex compound contained in the third mixed solution of step 3) (S400), and more specifically, a step of mixing the acidic solvent, the complex compound, Is a step for sorting only the solution containing the complex in the third mixed liquid.

In order to obtain the fourth mixed solution, the fourth mixed solution classified by the electrochemical method may be composed of an acidic solvent and a complex compound.

Step 5) is a step S500 of forming a carbonate by injecting carbon dioxide after hydrating the buffer solution into the obtained fourth mixture solution. More specifically, the step 5) is a step of reacting CO ₂ with the complex compound contained in the fourth mixture solution, . Reaction of the complex with CO ₂ will be referred to as carbonation process. That is, when the complex is reacted with CO ₂ , the metal ion (Ca ^{2 +} ) of the complex having the ligand coordinated around the metal ion is more reactive with CO ₂ than the ligand, and when it comes to carbon dioxide, it reacts with CO ₂ to form carbonate , The ligand breaks the coordination bond and is present in the solution. That is, a carbonate can be formed by utilizing high reactivity between metal ions and CO ₂ .

However, this carbonation process will have to base the solution to increase the reactivity of metal ions and CO ₂ . Since the fourth mixed solution obtained in the step 4) is a mixture of the acidic solvent and the complex compound, the solution will be said to be acidic. When the solution is acidic, even if CO ₂ is added, the reactivity of the carbonate is deteriorated. To prevent this problem, a strong base may be added to the fourth mixed liquid obtained in step 4), and the fourth mixed liquid may exhibit basicity.

The buffer enhances the basic environment of the fourth mixed solution to increase the reactivity with carbon dioxide, thereby promoting the carbonation reaction. Conventionally, strong bases such as sodium hydroxide and calcium hydroxide have been used as buffering agents. However, the use of these bases makes it impossible to reuse the remaining solution in the remaining solution after separating the carbonate, and since the wastewater after the carbonate separation is strongly basic, As shown in FIG.

According to the present invention, a gaseous buffer can be injected in place of the buffer in the solution state. The gaseous buffer may be representative of ammonia (NH ₃ ), but is not limited to examples. The ammonia is injected into the reactor in the gaseous state, is hydrated in the reaction solution, and is ionized with ammonium ions (NH ^{4 +} ) and hydroxide ions (OH ^- ), whereby the pH atmosphere can be controlled with a strong base.

That is, 4) the pH of the fourth mixed solution obtained in step S400 may be 1 to 3, preferably 2, and a strong base as a buffer is added to the fourth mixed solution to adjust the pH to 8 to 10, preferably 9 or more Can be controlled. The base which can be added is a strong base in a gaseous state such as ammonia (NH ₃ ), but it is not limited to the base type in the above-mentioned examples and can be used.

As described above, carbonate can be formed by utilizing high reactivity of metal ions (Ca ^{2 +} ) and CO ₂ .

The step 6) separates the formed carbonate-containing fourth mixture into a carbonate and a residual solution (S600). In this step, only the carbonate to be recovered can be separated and recovered.

More specifically, a second filter including micro-sized pores may be used to recover only the carbonate from the fourth mixed solution containing carbonates after the carbonation step. And the second filter includes a plurality of pores having a diameter of 30 to 40 mu m. Since the size of the carbonate to be recovered is more than 40 mu m, if the fourth mixed liquid containing carbonate is flowed through the second filter, it can be separated into the carbonate that has not passed through the second filter and the remaining liquid that has passed through the second filter have.

In the step 7), the remaining liquid is deaerated to recover the buffer, and then the liquid is injected into the third mixed liquid and circulated so as to be reusable (S700). More specifically, there is no carbonate in the remnant passing through the second filter, but there is a ligand separated from a complex compound, metal ion (Ca ^{2 +} ), which has not reacted with carbon dioxide. Therefore, the solution having passed through the second filter can be recovered separately and can be reused by moving it to a reactor for producing the third mixed solution in the step 3).

This method is advantageous in that it is possible to recycle the resources in that the ligand used in the carbonate recovery method can be reused because the necessity of constantly purchasing and introducing the ligand is reduced in order to produce the third mixed solution in the step 3) The effect of saving is excellent. Further, a solution for recovery and recycling has a complex compound. By reacting the complex again with CO ₂ , the recovery rate of the carbonate can be improved.

2 to 3 are schematic views showing a system for recovering carbonate using steelmaking slag according to an embodiment of the present invention.

2, the system for recovering carbonate using steelmaking slag according to an embodiment of the present invention includes a metal ion extraction unit 100, a separation unit 200, a complex compound production unit 300, a complex compound separation unit 400, A carbonic acid separation unit 600 and a gas circulation unit 700, and further may further include a recovery unit 800.

More specifically, the metal ion extraction unit 100 relates to mixing a steelmaking slag and an acidic solvent to produce a first mixed solution containing metal ions. The metal components contained in the steel making slag are extracted with metal ions, and the metal ions are extracted by reacting with an acidic solvent. According to one embodiment of the present invention, a first mixed solution is prepared by mixing a steelmaking slag and an acidic solvent, and the first mixed solution may include unreacted steel slag, an acidic solvent, and a metal ion.

The separation unit 200 separates the first mixed solution generated in the metal ion extraction unit 100 into a second mixed solution containing metal ions and a filtrate, and the first mixed solution is an unreacted Steelmaking slag, acidic solvent and metal ion, it is possible to separate unnecessary unreacted steel making slag from the carbonate recovery system of the present invention and recover it as a filtrate to obtain a second mixed solution containing an acidic solvent and a metal ion.

The complex compound-producing part 300 is prepared by adding a ligand to a second mixed solution separated from the separating part 200 and mixing the mixed solution to react the metal ion and the ligand to form a complex mixture. The ligand, as mentioned above, can coordinate with a specific metal ion to form a complex. That is, a ligand capable of selectively reacting only calcium ions (Ca ^< ^{2 + &} gt ^; ) among a plurality of metal ions contained in the second mixed solution to form a complex is included in the second mixed solution, ^{2 &lt}; ^{+ &} gt ^; ) to form a complex.

The complex separation unit 400 separates the third mixed solution produced in the complex-compound production unit 300 to obtain a fourth mixed solution of a solution containing only a complex, and more specifically, And separating into metal ions which have not reacted with the ligand. The complex separation unit 400 can efficiently separate the fourth mixed solution using the property that the complex is not charged and the ligand and unreacted metal ions are charged.

The carbonated crystal unit 500 forms a carbonate by reacting the complex compound separated in the complex compound separation unit 400 with carbon dioxide. The ligand selectively reacts with the metal ion to form a complex. When the complex is reacted with CO ₂ , the metal ion (Ca ^{2 +} ) of the complex is highly reactive with CO ₂ than the ligand. When the carbon dioxide is encountered, CO ₂ To form a carbonate. ≪ RTI ID = 0.0 > [0040] < / RTI >

However, even if CO ₂ is reacted in the case of a solution having an acidity, the solution flowing into the carbonation unit 500 is acidic, and because of the characteristic that the carbonation does not occur, a buffer solution for increasing the pH of the acid solution A strong base such as NH ₄ OH, NaOH or KOH may be used instead of the buffer solution. However, in the present invention, by increasing the pH by injecting a gaseous buffer such as ammonia (NH 3) You can give.

More specifically, the gaseous buffer agent, that is, the ammonia, is injected into the reactor in a gaseous state, and then hydrated in the reaction solution to facilitate control of the pH atmosphere with a strong base. In addition, it is possible to solve the problem of decreasing the carbonation reaction efficiency by preventing the concentration of the metal ions in the solution by accumulating unnecessary cations in the reaction solution, which is generated when the solution is added in the state of the conventional solution.

The fourth mixture liquid separated from the complex compound separating unit 400 and flowing into the carbonizing unit 500 has an acidity of 1 to 3, preferably 2, and the environment of the carbonation unit 500 is acidic , Even if CO ₂ is reacted, the carbonation reaction does not easily occur. However, in the present invention, the environment of the carbonation unit 500 is adjusted to a pH of 8 to 10, preferably, a pH of 8 to 10 by using a gaseous buffering agent, that is, ammonia, as described above. 9 or more. It is possible to prevent the concentration change of the metal ion in the reaction solution, which has an effect on the recovery efficiency, compared with the case of using a buffer solution such as sodium hydroxide or potassium hydroxide in the past, and to reduce the amount of expensive solvent, And the cost savings are excellent.

The carbonate separator 600 separates carbonates produced in the carbonation unit 500 and includes a filter including a plurality of pores having a diameter of 30 to 40 탆. Since the diameter of the pores in the filter of the carbonate separator 600 is at most 40 탆, the carbonate having a diameter exceeding 40 탆 can not pass through the carbonate separator 600, Can be separated.

The gas circulating unit 700 separates the carbonates from the carbonate separator 600 and recovers the buffer remaining in the remaining liquid by air stripping and then discharges the recovered buffer to the complex compound production unit 300 The buffer can be circulated to be reusable by injection.

More specifically, the gas circulating unit 700 includes a gas recovery unit for recovering gas in a gas state by air stripping the buffer remaining in the remnant remaining after the carbonate is separated; And a second gas injection unit for re-injecting the recovered gaseous buffer into the carbonization process unit. The gas recovery unit may degas the buffering agent remaining in the residual liquid, for example, ammonium ions (NH ⁴⁺ ) and hydroxide ions (OH ^- ) and may be recovered again as gaseous ammonia (NH ₃ ). The ammonia thus recovered can be injected into the reaction solution in the carbonation unit 500 through the second gas injection unit and hydrated, thereby controlling the pH atmosphere with a strong base.

The use of such gaseous buffering agents can be reused in a system where a continuous carbonation process is carried out after separating the carbonates, and since the remaining liquid after separation of the carbonate is not basic, there is no need to perform wastewater treatment in a separate process.

The system for recovering carbonates using steelmaking slag according to the present invention may further include a recovery unit 800. The carbonate solution separator 600 separates the mixed solution from the carbonic acid separator 600 into a solution of micro size The recovered carbonates may be passed through a filter including pores to recover the carbonate that has not passed through the filter. In this case, the recovery unit 800 may further include a recovery unit 800 for recovering the mixed solution having passed through the filter. Since the complex did not react with the collection unit 800, the mixed solution was passed through a filter recovered in the carbon dioxide and metal ions the ligand isolated from the (Ca ^{2 +)} is present, to recover them from the recovery unit (800), It is possible to reuse the ligand used in the carbonate recovery method, and it is possible to recycle the resources, and the cost can be reduced. The effect of Further, a solution for recovery and recycling has a complex compound. By reacting the complex again with CO ₂ , the recovery rate of the carbonate can be improved.

100: Metal ion extraction unit
200:
300:
400: Complex separation unit
500: Carbonation core
600: carbonate separator
700: gas circulation part
800:

Claims (23)

Mixing a steelmaking slag and an acidic solvent, and adding a ligand to a metal ion-containing mixed solution having passed through the filter to prepare a mixed solution containing a complex; And
And injecting a gaseous buffer into the complex-containing acidic solution separated from the complex-containing mixed solution to hydrate the carbonic acid-containing acidic solution, and then separating the formed carbonate by reacting with carbon dioxide.
1) mixing a steelmaking slag and an acidic solvent to prepare a first mixed solution;
2) separating the first mixed solution into a second mixed solution and a filtrate through a first filter;
3) adding a ligand to the second mixed solution to prepare a third mixed solution, wherein the third mixed solution contains a complex formed by a reaction between a metal ion and a ligand in the second mixed solution;
4) separating only the solution containing the complex compound from the third mixed solution by electrochemical means, to obtain a fourth mixed solution;
5) hydrating a gaseous buffer in the fourth mixed solution, and then injecting carbon dioxide to form a carbonate;
6) A method for recovering a carbonate using a steelmaking slag, comprising: separating a fourth mixed liquid containing the formed carbonate into a carbonate and a residual liquid.
3. The method of claim 2,
The pH of the fourth mixed solution in step 4) is 1 to 3,
Wherein the pH of the fourth mixed solution in which the gaseous buffer in step 5) is hydrated is adjusted to be in the range of 8 to 10. The method for recovering carbonate by using the steel making slag.
3. The method of claim 2,
Wherein the buffer is ammonia (NH ₃ ) gas.
3. The method of claim 2,
The method of claim 6, wherein the carbonate is separated using a second filter including micro-sized pores.
6. The method of claim 5,
Wherein the diameter of the pores of the second filter is 30 to 40 占 퐉.
6. The method of claim 5,
And recovering the remaining liquid in the step 6) and supplying the recovered carbonate to the reaction vessel for producing the third mixed liquid in step 3).
3. The method of claim 2,
The acidic solvent in step 1) may be at least one selected from the group consisting of nitric acid (HNO ₃ ), hydrochloric acid (HCl), sulfuric acid (H ₂ SO ₄ ), hydrobromic acid (HBr), hydroiodic acid (HI), perchloric acid (HClO ₄ ) H ₃ PO ₄ ). The method for recovering carbonates using steelmaking slag according to claim 1,
3. The method of claim 2,
^Wherein the metal ion in the step 3) is Ca ²⁺ , and recovering the carbonate using the steel making slag.
3. The method of claim 2,
Wherein the ligand in step 3) is at least one selected from the group consisting of CH ₃ COOH, C ₆ H ₉ NO ₆ , C ₆ H ₅ NO ₂ , HN (CH ₂ CO ₂ H) ₂ and C ₂ H ₂ O ₄ , A method of recovering carbonate using steelmaking slag.
3. The method of claim 2,
Wherein the carbonate is CaCO ₃ , and recovering the carbonate using the steelmaking slag.
3. The method of claim 2,
Wherein the diameter of the pores of the first filter is 30 to 50 占 퐉.
A metal ion extracting unit for mixing a steelmaking slag and an acidic solvent to produce a first mixed solution containing metal ions;
A first separator for separating the first mixed solution into a second mixed solution containing a metal ion and a filtrate;
Mixing a ligand with the separated second mixed solution to produce a third mixed solution containing a complex formed by a reaction between a metal ion and a ligand;
A complex separation unit for separating only the solution containing the complex compound from the third mixture solution to obtain a fourth mixture solution;
A first gas injection unit injecting a gaseous buffer into the fourth mixed solution;
A carbonation unit for forming carbonates by injecting carbon dioxide into the fourth mixed solution in which the buffer is hydrated; And
And a carbonate separator for separating the formed fourth mixture liquid containing the formed carbonate into a carbonate and a residual liquid.
14. The method of claim 13,
Further comprising a gas circulation unit for recovering and reusing the buffer from the residual liquid,
Wherein the gas circulation unit includes a gas recovery unit for recovering air by stripping a buffer present in the residual liquid.
14. The method of claim 13,
The pH of the fourth mixed solution separated in the complex separation unit is 1 to 3,
Wherein the pH of the fourth mixed solution into which the buffering agent is injected in the carbonation well is in the range of 8 to 10, and the carbonate recovery method using the steel making slag.
14. The method of claim 13,
Wherein the buffer is ammonia (NH ₃ ) gas.
14. The method of claim 13,
Wherein the carbonate separator separates the carbonate using a second filter including micro-sized pores.
18. The method of claim 17,
Wherein the diameter of the pores of the second filter is 30 to 40 占 퐉.
14. The method of claim 13,
And recovering the remaining liquid and supplying the recovered liquid to the complex compound production section.
14. The method of claim 13,
Wherein the acidic solvent is nitric acid (HNO _3), hydrochloric acid (HCl), sulfuric acid (H ₂ SO _4), bromide acid (HBr), iodine hydrofluoric acid (HI), perchloric acid (HClO ₄₎ and phosphoric acid (H ₃ PO ₄ ), Wherein the carbonates are recovered from the slag.
14. The method of claim 13,
^Wherein the metal ion is Ca < ^{2 + &} gt ;.
14. The method of claim 13,
Wherein the ligand is at least one selected from the group consisting of CH ₃ COOH, C ₆ H ₉ NO ₆ , C ₆ H ₅ NO ₂ , HN (CH ₂ CO ₂ H) ₂ and C ₂ H ₂ O ₄ , Carbonate recovery system.
14. The method of claim 13,
Wherein the carbonate is CaCO ₃ , and the carbonate recovery system using steelmaking slag.

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