KR101157909B1 - Methods of forming carbonate using steel slags - Google Patents

Abstract

PURPOSE: A carbonate manufacturing method using steel slag is provided to increase elution of calcium composition from steel slag by using materials containing boron oxide. CONSTITUTION: A carbonate manufacturing method using steel slag comprises the following steps: providing materials containing steel slag and boron oxide to a reaction solution(s110); separating the steel slag from the reaction solution(s120); providing carbon dioxide to the reaction solution which steel slag is separated(s130); and separating carbonate from the reaction solution(s140). The carbonate is formed by a reaction of carbonate ion and calcium ion. The boron oxide contains trioxide lice boron(B2O3).

Description

Carbonate manufacturing method using steel slag {METHODS OF FORMING CARBONATE USING STEEL SLAGS}

The present invention relates to a method for producing a carbonate using steel slag. More specifically, the present invention relates to a method for preparing carbonates by reacting metal ions eluted from steel slag with carbonate ions formed from carbon dioxide.

Recently, as environmental issues such as global warming due to carbon dioxide have been raised, a lot of research has been conducted on the method of fixing carbon dioxide through mineral carbonation.

Mineral carbonation requires a raw material that provides metal ions that can react with carbonic acid ions derived from carbon dioxide. Natural minerals and industrial wastes are generally used as such raw materials. Initially, research on carbonation using natural minerals has been mainly conducted, but research on carbonation using industrial waste has been actively conducted in Japan and Europe.

Steelmaking slag among industrial wastes is difficult to handle because of its low industrial utilization and environmental problems. The industrial utilization and environmental problems of steelmaking slag are mainly caused by the calcium oxide (CaO) component in steelmaking slag. If the steelmaking slag is used as a raw material for mineral carbonation, the effects of carbon dioxide immobilization and waste treatment can be achieved simultaneously. will be. In Korea, steelmaking slag, which is a vast amount of industrial waste, is produced every year from POSCO and Hyundai Steel. Therefore, there is an urgent need for mineral carbonation technology using the same.

For mineral carbonation using such steelmaking slag, it is necessary to develop a technology capable of performing mineral carbonation at high speed.

It is an object of the present invention to provide a method for producing a carbonate in which the elution of calcium components from steel slag is increased by using a boron oxide containing material.

In order to achieve the above object of the present invention, a method for producing a carbonate according to an embodiment of the present invention comprises the steps of supplying a steel slag and boron oxide containing material to the reaction solution; Separating the steel slag from the reaction solution; Supplying carbon dioxide to the reaction solution in which the steel slag is separated; And separating carbonates formed by the reaction of calcium ions eluted from the steel slag with carbonate ions formed by the carbon dioxide.

The boron oxide-containing material may include diboron trioxide (B ₂ O ₃ ).

In one embodiment of the present invention, the steel slag and the boron oxide containing material may further comprise the step of stirring the reaction solution supplied. For example, the reaction solution supplied with the steel slag and the boron oxide-containing material may be stirred for at least 9 hours. Preferably, the reaction solution supplied with the steel slag and the boron oxide-containing material may be stirred for at least 65 hours. The steel slag may be steelmaking slag.

In the method for preparing carbonate according to the embodiment of the present invention, by supplying a boron oxide-containing material together with the steel slag to the reaction solution, the amount of calcium component eluted from the steel slag can be increased by inducing a reaction between the steel slag and boron oxide. As a result, it is possible to increase the production efficiency and speed of calcium carbonate, which is a carbonate.

1 is a flowchart illustrating a method of forming a carbonate according to an embodiment of the present invention.
2 is a graph showing the results in Tables 2 and 3.

Hereinafter, exemplary embodiments of the present invention will be described in detail with reference to the accompanying drawings. As the inventive concept allows for various changes and numerous embodiments, particular embodiments will be illustrated in the drawings and described in detail in the text. However, this is not intended to limit the present invention to a specific disclosed form, it should be understood to include all modifications, equivalents, and substitutes included in the spirit and scope of the present invention. In the accompanying drawings, the size and amount of the objects are shown to be enlarged or reduced than actual for clarity of the invention.

The terms first, second, etc. may be used to describe various components, but the components should not be limited by the terms. The terms are used only for the purpose of distinguishing one component from another. For example, without departing from the scope of the present invention, the first component may be referred to as a second component, and similarly, the second component may also be referred to as a first component.

The terminology used herein is for the purpose of describing particular example embodiments only and is not intended to be limiting of the present invention. Singular expressions include plural expressions unless the context clearly indicates otherwise. In this application, the terms "comprise" or "include" are intended to indicate that there is a feature, step, function, component, or combination thereof described on the specification, and other features, steps, functions, components Or it does not exclude in advance the possibility of the presence or addition of them in combination.

On the other hand, unless otherwise defined, all terms used herein, including technical or scientific terms, have the same meaning as commonly understood by one of ordinary skill in the art to which this invention belongs. Terms such as those defined in commonly used dictionaries are to be interpreted as having a meaning consistent with the contextual meaning of the related art and are to be interpreted as either ideal or overly formal in the sense of the present application Do not.

1 is a flow chart illustrating a method of forming a carbonate in accordance with an embodiment of the present invention.

Referring to FIG. 1, in order to form a carbonate according to an embodiment of the present invention, first, steel slag and a boron oxide-containing material may be supplied to a reaction solution.

The reaction solution may be an aqueous solution. In one example, the reaction solution may be an alkaline aqueous solution. Specifically, the reaction solution may be an aqueous solution adjusted so that the pH is in the range of about 8 to 13 with ammonia or sodium hydroxide.

Steel slag is used as a raw material to provide metal components in the final product of carbonate. For example, in the present invention, the carbonate may be calcium carbonate (CaCO ₃ ), and the steel slag may be used as a raw material for providing a calcium (Ca) component. Steel slag can generally be divided into blast furnace slag produced in pig iron manufacturing process and steelmaking slag generated in steelmaking process. In the present invention, both blast furnace slag and steelmaking slag may be used as a raw material for providing a metal component, but steelmaking slag is preferably used. Steelmaking slag has a higher content of calcium oxide than blast furnace slag, which leads to low industrial utilization and high environmental problems. Steelmaking slag is mainly composed of calcium oxide (CaO), iron oxide (T-Fe: FeO, Fe ₂ O ₃ , Fe ₃ O _4, etc.), silicon dioxide (SiO ₂ ). Table 1 below is a result of analyzing the chemical components of 'sample 1' and 'sample 2' of steelmaking slag. The main mineral phases of steelmaking slag are C ₂ S (dicalciumsilicate, Ca ₂ SiO ₄ ), C ₃ S (tricalciumsilicate, Ca ₃ SiO ₅ ), wustite {(Fe, Mg, Ca, Mn) O}, C ₂ F ( dicalcium ferrite, Ca ₂ Fe ₂ O ₅ ), lime {(Ca, Mg, Mn, Fe) O} and the like.

T-Fe CaO SiO ₂ Al ₂ O ₃ MnO MgO TiO ₂ P ₂ O ₅ Sample 1 33.22 22.61 19.61 13.06 6.34 6.12 0.77 0.31 Sample 2 23.83 23.81 21.76 14.42 6.54 6.47 0.81 0.321

[Unit: wt.%]

The boron oxide containing material may contain diboron trioxide (B ₂ O ₃ ). The boron oxide containing material may increase the amount of calcium (Ca) component eluted from the steel slag. When the boron oxide-containing material and the steel slag are supplied to the reaction solution, the boron trioxide (B ₂ O ₃ ) of the boron oxide-containing material and the components constituting the steel slag react with each other, and in this process, the reaction solution among the components of the steel slag. The amount of calcium oxide (CaO) in contact with the increase. The calcium oxide (CaO) component in contact with the reaction solution can be easily ionized according to the following 'Scheme 1', and as a result, the amount of the calcium component eluted from the steel slag can be increased. By supplying diboron trioxide (B ₂ O ₃ ) to the molten steel slag, it can be seen that the viscosity of the molten slag is lowered, in view of the above, the boron trioxide (B ₂ O ₃ ) of the boron oxide-containing material constitutes the steel slag Bonds between the components, specifically 'bonding between the calcium oxide component (CaO) and silicon dioxide (SiO ₂ ) components' and 'bonding between the calcium oxide (CaO) component and the iron oxide (T-Fe) component' It can be weakened or destroyed. As a result, it is determined that the boron oxide-containing material can increase the amount of calcium oxide eluted from the steel slag by increasing the amount of calcium oxide (CaO) in contact with the reaction solution.

[Reaction Scheme 1]

_{CaO (s) + H 2 O} -> Ca 2+ (aq) + 2OH - (aq)

The steel slag and boron oxide containing material can be supplied to the reaction solution at the same time. Alternatively, it is also possible to dissolve the boron oxide containing material in the reaction solution first and then supply the steel slag to the reaction solution.

In one embodiment of the present invention, in order to dissolve the boron oxide-containing material and promote the calcium elution reaction described above, the reaction solution supplied with the steel slag and the boron oxide-containing material may be stirred. In order to increase the elution amount of the calcium component, it is preferable to supply the steel slag to the reaction solution and then stir the reaction solution for about 9 hours or more, preferably about 65 hours or more. In another embodiment of the present invention, in order to dissolve the boron oxide-containing material and promote the calcium elution reaction described above, in addition to stirring the reaction solution supplied with the steel slag and the boron oxide-containing material, heat energy may be additionally applied to the reaction solution. It may be.

Subsequently, the steel slag can be separated from the reaction solution containing calcium ions (Ca ²⁺ ) eluted from the steel slag. (S120) Separation of the steel slag from the reaction solution permeates the reaction solution but not the steel slag. Can be performed using a filter. This is a step for industrially utilizing the final product carbonate, if the carbonate is formed in the reaction solution in which the steel slag is present, it is not easy to separate the steel slag and carbonate. Therefore, by separating the steel slag before the carbonate is formed, it is possible to facilitate the industrial use of the carbonate.

Subsequently, carbon dioxide may be supplied to the reaction solution containing calcium ions (Ca ²⁺ ) eluted from the steel slag and the steel slag is removed. (S130) Carbon dioxide may be supplied alone or in combination with other gases. The type of carbon dioxide supplied to the reaction solution is not limited. In one embodiment of the present invention, carbon dioxide may be supplied to the reaction solution in the form of micro bubbles. Such carbon dioxide micro bubbles may be formed according to known methods, and may have a size of about 50 μm or less.

Carbon dioxide supplied to the reaction solution may be ionized according to the following 'Scheme 2' to generate carbonate ions (CO ₃ ^2- ). The carbonate ions (CO ₃ ^2- ) thus formed may react with calcium ions (Ca ²⁺ ) present in the reaction solution to form calcium carbonate (CaCO ₃ ) according to Scheme 3 below.

Scheme 2

^{_{CO 2 (aq) + 2OH -}} (aq) -> CO 3 2- (aq) + H 2 O

Scheme 3

Ca ²⁺ (aq) + CO ₃ ^2- (aq)-> CaCO ₃ (s)

Subsequently, the produced calcium carbonate (CaCO ₃ ) may be separated from the reaction solution. (S140) The calcium carbonate thus separated may be used as various industrial raw materials.

The present inventors conducted the following experiments to grasp the degree of contribution of the boron oxide-containing material in eluting the calcium component from the steel slag. In the following description, 'Experimental Example' relates to the elution of calcium components in the case of supplying steel slag to water in which diboron trioxide (B ₂ O ₃ ) is dissolved, and the 'Comparative Experimental Example' refers to diboron trioxide (B ₂ O). ₃ ) is related to the elution of calcium components in the case of supplying steel slag to water that does not exist.

[Experimental Example]

1 L of water (H ₂ O) and 20 g of diboron trioxide (B ₂ O ₃ ) were added to each of the first to fifth containers, and stirred for a predetermined time at a speed of 300 rpm to dissolve all diboron trioxide (B ₂ O ₃ ). Thereafter, 50 g of steel slag was put into each of the first to fifth containers. The samples in the first to fifth vessels were then stirred for different times at a rate of 300 rpm. Specifically, the samples B1, B2, B3, B4 and B5 of the first to fifth containers were stirred for 6 hours, 9 hours, 65 hours, 89 hours and 117 hours, respectively. Thereafter, the concentrations of calcium ions (Ca ²⁺ ), iron ions (Fe ²⁺ , Fe ³⁺ ) and silicon ions (Si ⁴⁺ ) eluted in each sample were measured, and the results are shown in Table 2. .

sample Stirring time (h) Calcium ion concentration
(mg / L) Iron ion concentration
(mg / L) Silicon ion concentration
(mg / L) B1 6 426 29.6 45.4 B2 9 447 17.2 40.5 B3 65 485 1.01 27.9 B4 89 481 0.71 29.2 B5 117 498 0.26 28.4

Comparative Experimental Example

Only 1L of water (H ₂ O) was put in each of the sixth to tenth containers, and stirred for the same time as the above experimental example at a speed of 300 rpm. Thereafter, 50 g of steel slag was put into each of the sixth to tenth containers. Subsequently, the samples in the sixth to tenth vessels were stirred at different speeds at 300 rpm. Specifically, the samples (H1, H2, H3, H4, H5) of the sixth to tenth containers were stirred for 6 hours, 9 hours, 65 hours, 89 hours, and 117 hours, respectively. Thereafter, the concentrations of calcium ions (Ca ²⁺ ), iron ions (Fe ²⁺ , Fe ³⁺ ) and silicon ions (Si ⁴⁺ ) eluted in each sample were measured, and the results are shown in Table 3. .

sample Stirring time (h) Calcium ion concentration
(mg / L) Iron ion concentration
(mg / L) Silicon ion concentration
(mg / L) H1 6 34.6 <0.02 8.48 H2 9 34.3 <0.02 9.19 H3 65 25.9 <0.02 27.9 H4 89 44.4 <0.02 35.1 H5 117 48.8 <0.02 36.4

[Effect Analysis of Diboron Trioxide]

2 is a graph showing the results in Tables 2 and 3. In Fig. 2, the 'X-axis' represents the stirring time (h), and the 'Y-axis' represents the concentration (mg / L) of each ion.

2, Table 2 and Table 3, in the case of the samples (B1, B2, B3, B4, B5) in which diboron trioxide is dissolved (H1, H2, H3, H4, H5) It can be seen that it has a significantly higher calcium ion (Ca ²⁺ ) concentration than). In other words, when the boron trioxide is supplied to the reaction solution together with the steel slag, a significantly increased amount of calcium components can be eluted from the steel slag as compared with the case where the boron trioxide is not supplied.

And it can be seen that the concentration of each ion changes with the stirring time of the sample. For example, it can be seen that the concentration of calcium ions (Ca ²⁺ ) increases as the stirring time increases in the sample in which diboron trioxide is dissolved. Specifically, it can be seen that the concentration of calcium ions rapidly increases until the stirring time of the sample dissolved in diboron trioxide reaches 9 hours, and the rate of change of the calcium ion concentration decreases rapidly when the stirring time exceeds 65 hours. It can be seen. In contrast, it can be seen that the concentration of iron ions (Fe ²⁺ , Fe ³⁺ ) and silicon ions (Si ⁴⁺ ) decreases as the stirring time increases in the sample in which diboron trioxide is dissolved. Specifically, the concentrations of iron ions (Fe ²⁺ , Fe ³⁺ ) and silicon ions (Si ⁴⁺ ) rapidly decrease until the stirring time reaches 9 hours, and when the stirring time reaches 65 hours, the minimum is almost minimum. It can be seen that concentration is reached. In particular, it can be seen that in the case of iron ions (Fe ²⁺ , Fe ³⁺ ) when the stirring time exceeds 65 hours, the concentration is reduced to a level that can be almost negligible.

In view of these matters, in order to improve the production efficiency of calcium carbonate, it is preferable to supply steel slag to the reaction solution and then stir for about 9 hours or more. More preferably, the steel slag is supplied to the reaction solution, and then stirred for about 65 hours or more.

According to the present invention described above, by supplying a boron oxide-containing material with the steel slag to the reaction solution to induce a reaction between the steel slag and boron oxide to increase the amount of calcium components eluted from the steel slag, as a result carbonate It is possible to increase the production efficiency and rate of phosphorus calcium carbonate.

While the foregoing has been described with reference to preferred embodiments of the present invention, those skilled in the art will be able to variously modify and change the present invention without departing from the spirit and scope of the invention as set forth in the claims below. It will be appreciated.

Claims (6)

Supplying steel slag and boron oxide-containing material to the reaction solution;
Separating the steel slag from the reaction solution;
Supplying carbon dioxide to the reaction solution in which the steel slag is separated; And
Separating the carbonate formed by the reaction of calcium ions eluted from the steel slag and the carbonate ions formed by the carbon dioxide. The method of claim 1, wherein the boron oxide-containing material comprises diboron trioxide (B ₂ O ₃ ). The method of claim 1, further comprising stirring the reaction solution supplied with the steel slag and the boron oxide-containing material. 4. The method according to claim 3, wherein the reaction solution supplied with the steel slag and the boron oxide-containing material is stirred for at least 9 hours. 4. The method according to claim 3, wherein the reaction solution supplied with the steel slag and the boron oxide-containing material is stirred for at least 65 hours. The method according to claim 1, wherein the steel slag is steelmaking slag.

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