KR20190050236A - Method for extracting calcium ions from inorganic materials containing alkaline ions for indirect carbonation process - Google Patents

Abstract

Disclosed is a method for extracting calcium ions from inorganic materials containing alkaline ions such as steel-making slag for an indirect carbonation process. According to an embodiment, the method for extracting calcium ions comprises the following steps of: dissolving ions contained in the inorganic materials containing alkaline ions in an eluting agent such as a hydrogen chloride solution; immersing and separating a foreign substance except for calcium ions by adjusting pH concentration by adding a basic solution to the eluting agent containing the ions; and immersing and separating calcium hydroxide by inputting sodium hydroxide (NaOH) to the basic solution in which the calcium ions are dissolved.

Description

[0001] The present invention relates to a method for extracting calcium ions from an alkaline ion-containing inorganic material for an indirect carbonation process,

The present invention relates to a technique for extracting high-purity calcium ions by extracting alkaline ions from industrial by-products or industrial wastes such as steel slag and the like, and separating tions from the extracted alkali ions for the indirect carbonation process.

The recent rapid increase in carbon dioxide emissions has resulted in rapid global warming. As a countermeasure against this, a carbon dioxide removal and / or recycling method is suggested, which is called a carbon capture and storage (CCS) technique. CCS technology collects carbon dioxide (CO2) at high concentration before it is discharged to the atmosphere, and collectively refers to the technology of compressing and transporting it. One of the CCS technologies is the recycling of carbon dioxide, which refers to the conversion of carbon dioxide into other forms of material and utilization of it as a resource. For example, the carbonation process converts carbon dioxide into calcium carbonate, and the calcium carbonate obtained through the carbonation process is being used for various industrial activities such as building materials.

In order to convert carbon dioxide to calcium carbonate, calcium or calcium ions (hereinafter referred to as " calcium ions ") are required. Also, as one of the sources of calcium ions, it is helpful in terms of resource recycling when utilizing industrial by-products or wastes such as steel slag and the like. Thus, the production of calcium carbonate by utilizing calcium ions separated from industrial by-products or wastes is referred to as an indirect carbonation process. However, in this case, the efficiency of the indirect carbonation process may decrease as the amount of the impurity (hereinafter referred to as "tion") contained in the calcium ion is increased. This is because, when the tion is extracted together with the extraction of calcium ions, the purity of the final product, calcium ion, is lowered and the efficiency of the carbonation reaction is lowered by the content of tion. Therefore, in order to improve the efficiency of the indirect carbonation process, a tie separation method is needed to minimize the amount of tie (impurity) contained in the calcium ion.

Korean Patent Publication No. 10-2014-0095194 Korean Patent No. 10-1549980

One of the problems to be solved by the present invention is to provide a method for extracting calcium ions from an alkali ion-containing inorganic material capable of extracting calcium ions whose content of impurities is minimized by effectively separating tions from alkaline ion-containing inorganic substances such as steel- will be.

According to an aspect of the present invention, there is provided a method for extracting calcium ions from an alkali ion-containing inorganic material, comprising the steps of: (a) dissolving and dissolving ions contained in an alkali ion- b) precipitating tions other than calcium ions by adjusting the pH concentration by adding a basic solution to the solution containing the ion containing ions, and (c) adding sodium hydroxide (NaOH ) Is added to precipitate and separate calcium hydroxide.

According to an aspect of the embodiment, in step (b), the pH concentration may be adjusted to 9.5 or more.

According to another aspect of the embodiment, in the step (b), the basic solution may include ammonium hydroxide (NH4OH) or sodium hydroxide (NaOH).

According to another aspect of the embodiment, the tantalum other than calcium may include at least one of magnesium (Mg), silicon (Si), and aluminum (Al).

According to still another aspect of the present invention, in step (c), sodium hydroxide may be added so that the pH is 13 or higher.

According to another aspect of the embodiment, the calcium ion extraction method further comprises the step of (d) electrolyzing the separated solution of calcium hydroxide to obtain sodium hydroxide, and the sodium hydroxide obtained in step (d) (C) or (b) and (c) in a calcium ion extraction process.

According to the embodiment of the present invention described above, since the calcium ion and the tion are separated using the difference in solubility between calcium ion and tions, particularly, the solubility difference property at pH 9.5 or more, the calcium obtained by efficiently removing tion The purity of the ions can be increased. These high-purity calcium ions can be used in the indirect carbonation process to increase the efficiency of the indirect carbonation process. In addition, the sodium hydroxide can be recovered from the remaining solution by separating the calcium hydroxide and can be recycled to the subsequent extraction process of calcium ions, so that the entire process cost can be lowered.

1 is a flowchart showing a method of extracting calcium ions from a steel slag for an indirect carbonation process according to an embodiment of the present invention.
FIG. 2 is a graph showing ion extraction amounts of the hydrogen chloride solution of Table 3 according to concentration. FIG.
FIG. 3 is a graph (pC-pH diagram) showing the solubility of calcium and tion with changes in pH.
FIG. 4 is a graph showing experimental results when an ammonium hydroxide solution is added for pH control in step S20. FIG.
FIG. 5 is a graph showing experimental results when sodium hydroxide solution is added for pH control in step S20. FIG.
6 is a graph showing an XRD pattern analysis result for a sample.
FIG. 7 is a flow chart illustrating the process of confirming that sodium chloride is present in the residual solution by evaporating the residual solution after performing the calcium ion extraction method up to step S30 according to the embodiment of the present invention described above with reference to FIG. It is an example.
8 is an example of a configuration diagram of the electrolysis process performed in step S40 of Fig.
FIG. 9 is an example of a flowchart illustrating a process of performing the calcium ion extraction method up to step S40 according to the embodiment of the present invention described above with reference to FIG.

Hereinafter, embodiments of the present invention will be described in detail with reference to the accompanying drawings. The terms and words used in the present specification are selected in consideration of the functions in the embodiments, and the meaning of the terms may vary depending on the intention or custom of the invention. Therefore, the terms used in the following embodiments are defined according to their definitions when they are specifically defined in this specification, and unless otherwise specified, they should be construed in a sense generally recognized by those skilled in the art.

1 is a flowchart showing a method of extracting calcium ions from a steel slag for an indirect carbonation process according to an embodiment of the present invention.

Referring to FIG. 1, first, ions contained in a steel slag are dissolved and extracted using a hydrogen chloride (HCl) solution (S10). For example, 100 ml of 2M HCl solution can be used to extract 10 g of calcium ions and tions in the steel slag (25 ° C). As a result of extraction, various alkali ions and the like contained in the iron slag exist in the solution and other substances (solid matter) forming the iron slag are filtered and filtered as a precipitate.

The steel slag in step S10 in the embodiment of the present invention is an example of industrial by-products or industrial waste, and refers to a substance that can be applied to the indirect mineral carbonation process among the CCS techniques. Therefore, the steel-making slag in step S10 corresponds to at least one example of an " alkaline ion-containing inorganic material " containing alkaline ions such as calcium (Ca), magnesium (Mg) do. Examples of the alkali ion-containing inorganic material include waste cement, slag, fly ash, Feldspar (CaAl2Si2O8), Forsterite (Mg2SiO4), Glauconite, Ilmenite (FeTiO3) (Mg, Fe) 2SiO4), Opoka, Serpentine, Serpentinite, talc (Mg3Si4Si10), talc (OH) 2), wollastonite (CaSiO3), or a combination of two or more thereof.

Table 1 and Table 2 below show the amounts of calcium ions contained in steel slag, which is a kind of alkali ion-containing inorganic material containing calcium ions. Table 1 shows the results of EDS analysis. Table 2 shows IC / ICP The results of the analysis. In the experimental example of the present invention to be described later, the experiment was conducted using steel slag 1.

The hydrogen chloride (HCl) used as the solvent in step S10 is an example of an extraction agent capable of extracting alkali ions and the like, including calcium ions. Therefore, the solubilizing agent is not limited to the hydrogen chloride solution, and the same function, that is, a solution capable of dissolving at least calcium ion and extracting from the steel slag can be used irrespective of the kind thereof.

As a result of performing Step S10, aluminum ions, silicon ions, and magnesium ions (hereinafter, referred to as "tions"), which are other main components of the steel slag, were also extracted together with calcium ions in the hydrogen chloride solution. One experimental example of this extraction result is shown in Table 3, which discloses the extraction amounts of each of the calcium ions and tions at various concentrations of the hydrogen chloride solution. And FIG. 2 is a graph showing the ion extraction amount by the concentration of the hydrogen chloride solution of Table 3.

Subsequently, referring to FIG. 1, the pH of a solution in which calcium ions and tions are dissolved is adjusted to precipitate tions except calcium ions (S20). This step separates tions other than calcium ions that are dissolved in the eluent by utilizing the difference in solubility between the calcium ions and the tions according to their pH. For the adjustment of pH, ammonium hydroxide (NH4OH) solution or sodium hydroxide (NaOH) solution may be used in the embodiment of the present invention, and the pH can be adjusted to be about 9.5 or more.

FIG. 3 is a graph (pC-pH diagram) showing the solubility of calcium ions and tions with changes in pH. Referring to FIG. 3, it can be seen that as the pH is higher than 9 and the pH is higher than 9, the tions are precipitated earlier than the calcium ions as the pH is increased, and the calcium ions are also precipitated when the pH is 13 or higher.

And Table 4 shows the extraction of tions in the range of pH 9 and 10 in the graph of FIG. As shown in Table 4, since the extraction amount of tion is the lowest in the pH range of 9.5? 0.1, it is judged that it is the optimum condition for selectively extracting calcium ions.

FIG. 4 is a graph showing experimental results when an ammonium hydroxide solution is added for pH control in step S20. FIG. At this time, the ammonium hydroxide solution was injected 1, 1.5, 2, and 4 times in proportion to the number of moles of calcium ions, and the pH of the solution was in the range of 9.6 to 10.5. Referring to FIG. 4, it can be confirmed that most of the tie is precipitated and the calcium ions are not precipitated in the range of the corresponding pH.

FIG. 5 is a graph showing experimental results when sodium hydroxide solution is added for pH control in step S20. FIG. At this time, the sodium hydroxide solution was also injected 1, 1.5, 2 and 4 times in proportion to the number of moles of calcium ions, and the pH was in the range of 8.75 to 13.05. Referring to FIG. 5, it can be confirmed that most of the tie is precipitated and the calcium ion is not precipitated in the pH range of 8.75 to 12.18, but when the pH is 13.05, it is confirmed that the calcium ion also precipitates. When pH is adjusted with NaOH solution, calcium ion can not be precipitated unless the pH is higher than 13.

Subsequently, referring to FIG. 1, sodium hydroxide (NaOH) is added to a solution in which calcium ions are dissolved as a result of step S20 to precipitate and separate calcium hydroxide (Ca (OH) 2) (S30). Sodium hydroxide is added to provide a hydroxyl group (OH ^- ) and also to bring the pH of the solution to 13 or higher. As a result, the calcium ion in the solution reacts with hydroxyl group to precipitate in the form of calcium hydroxide. By the process up to this step S30, calcium ions contained in the seasonal slag can be obtained.

The resultant solution of step S30 (however, the resultant solution was sodium hydroxide for pH adjustment in step S20) was confirmed. For this, a sample was prepared by evaporating the solution after calcium ion extraction to obtain a solid, and XRD pattern analysis was performed on the prepared sample. 6 is a graph showing the results of XRD pattern analysis for these samples. Referring to FIG. 6, sodium chloride (NaCl) is present in the remaining solution. In order to calculate the purity of sodium chloride (NaCl), the purity of 99.98557% was calculated using the mass balance of the precipitated material after excessive injection of sodium hydroxide (sodium hydroxide (NaOH) except).

FIG. 7 is a flow chart illustrating the process of confirming that sodium chloride is present in the residual solution by evaporating the residual solution after performing the calcium ion extraction method up to step S30 according to the embodiment of the present invention described above with reference to FIG. It is an example. Since the flowchart shown in FIG. 7 has been described in detail above, a description thereof will be omitted below.

Subsequently, referring to FIG. 1, as a result of the step S30, sodium hydroxide is obtained by electrolysis of a solution in which calcium hydroxide is precipitated and separated and the sodium chloride is confirmed to be dissolved as a remaining solution (S40). An example of a configuration diagram of the electrolysis process performed in step S40 is shown in FIG. 8, and a specific process thereof is disclosed in Korean Patent No. 10-1549980, " Method for producing carbonate of alkaline ion using electrolysis system & A detailed description thereof will be omitted in the following.

This step (S40) is for recycling the remaining solution after the separation and extraction of calcium ions to the process according to the embodiment of the present invention. This is because sodium hydroxide is a substance that can be utilized in step S30 of the calcium ion extraction method described above with reference to FIG. 1 and also in step S20 depending on the embodiment. According to this, since sodium hydroxide extracted as the result of step S40 can be utilized in step S30, step S20, and step S30 described above, a continuous process is possible without addition of additional chemicals (compounds).

FIG. 9 is an example of a flowchart illustrating a process of performing the calcium ion extraction method up to step S40 according to the embodiment of the present invention described above with reference to FIG. Since the flowchart shown in FIG. 9 has been described in detail above, a description thereof will be omitted below.

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 exemplary embodiments, but, on the contrary, It is possible.

Claims (6)

(a) dissolving and dissolving ions contained in an alkali ion-containing inorganic material in an eluent;
(b) precipitating tions other than calcium ions by separating the calcium ions by adjusting the pH concentration by adding a basic solution to the solution of the eluent containing the ions; And
(c) introducing sodium hydroxide (NaOH) into the basic solution in which calcium ions are dissolved to precipitate and separate calcium hydroxide. The method according to claim 1,
Wherein the pH is adjusted to 9.5 or more in the step (b). The method according to claim 1,
Wherein the basic solution in step (b) comprises ammonium hydroxide (NH4OH) or sodium hydroxide (NaOH). The method according to claim 1,
Wherein the tions other than calcium include at least one of magnesium (Mg) ions, silicon (Si) ions and aluminum (Al) ions. The method according to claim 1,
Wherein the sodium hydroxide is added so that the pH is 13 or more in the step (c). The method according to claim 1,
(d) electrolyzing the separated solution of calcium hydroxide to obtain sodium hydroxide,
Wherein the sodium hydroxide obtained in step (d) is used in step (c) or steps (b) and (c) in the subsequent step of extracting calcium ions.

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