WO2013002542A2

WO2013002542A2 - Method for fixing carbon dioxide using waste

Info

Publication number: WO2013002542A2
Application number: PCT/KR2012/005060
Authority: WO
Inventors: 노열; 윤성준
Original assignee: 전남대학교산학협력단
Priority date: 2011-06-30
Filing date: 2012-06-27
Publication date: 2013-01-03
Also published as: WO2013002542A3; WO2013002542A9

Abstract

Provided is a method for fixing carbon dioxide using waste. First, it is possible to make a material containing asbestos to be harmless to improve the fixation efficiency of carbon dioxide and to generate a raw material for cement through carbonate mineralization by heat treating an material containing asbestos at 710-840 ℃, injecting a carrier solution, and injecting carbon dioxide. In addition, it is possible to fix carbon dioxide using the reaction of asbestos board waste and carbon dioxide and to employ calcium carbonate, a synthesized final product, as a raw material for cement by pulverizing an asbestos board, injecting the pulverized asbestos board into a carrier solution to prepare an asbestos board solution, injecting carbon dioxide into the asbestos board solution to fix carbon dioxide, and heat treating the same so as to make asbestos harmless. Furthermore, it is possible to fix carbon dioxide through the synthesis of calcium carbonate (calcite) using the reaction of asbestos board waste and carbon dioxide and to employ calcium carbonate, a synthesized final product, as a raw material for cement by injecting an asbestos board into a carrier solution to form slurry, injecting carbon dioxide into the slurry, and pressurizing and heating the same at 0.1-0.5 MPa and at 100-150 ℃, respectively.

Description

How to fix carbon dioxide using waste

The present invention relates to a method of fixing carbon dioxide using waste, and more particularly, to a method of fixing carbon dioxide using asbestos-containing waste or gypsum board waste.

Asbestos is the commercial term for naturally occurring fibrous silicate minerals, and the Occupational Safety and Health Administration (OSHA) defines asbestos as fibrous or acicular minerals with an aspect ratio of at least 3: 1 and at least 5 μm in length.

Asbestos is flexible and has a silky gloss. Asbestos can be divided into serpentine and hornblende crystals. The serpentine series basically has a crystal structure composed of a 1: 1 1: 1 (neutral) layer of a neutral charge, and the hornblende series has a double chain crystal structure in which SiO ₄ tetrahedra are bonded. Asbestos has been widely used industrially due to its high tensile strength, non-electricity, good resistance to heat and cold, and strong chemical corrosion. However, when exposed to asbestos, the thin, fibrous, mineralistic properties of asbestos are known to increase the risk of various lung-related diseases such as asbestos, lung cancer, and malignant species.

The slate is composed of 80% to 90% cement and 10% to 20% Chrysotile. The amount of slate used for the rural roof improvement project cannot be accurately determined, but according to the press release, 35 million sheets were sold annually from 1987 to 76, and gradually decreased to 32 million in 1977 and 30 million in 1978, and then in the 80s. 18 million were sold.

Even now, the slate used in houses, factories, houses, etc., is still aging. The slate is composed of cement and asbestos as mentioned above. Over time, the calcium hydroxide, a component of cement, dissolves in water, and asbestos is released into the environment.

In addition to the slats, asbestos-containing asbestos boards consist of limestone, gypsum and white asbestos. Therefore, as time goes by, asbestos boards are exposed to the atmosphere in the air by weathering, like slate.

Therefore, the problem of harming asbestos emitted to the surrounding environment has become a big social issue. Accordingly, studies on the problem of harming the waste containing asbestos have been actively conducted.

Currently, asbestos treatment is carried out by sealing in a polyethylene container and covering it with a designated waste landfill. A method of reclaiming asbestos waste by using a waste mine has also been proposed. In addition, many physical and chemical studies have been conducted to eliminate the harmfulness of asbestos. As an example, research has been conducted on a reaction mechanism capable of inducing mineral carbonation through dissociation of magnesium by chemically treating serpentine-based asbestos with sulfuric acid.

On the other hand, gypsum board refers to a sawdust, fiber, pearlite, etc. mixed with calcined gypsum as the main raw material, in some cases added with a blowing agent, kneaded with water and poured between two sheets to harden into a plate.

Gypsum board was invented in the United States in 1902 and is used for walls and ceilings in construction, and serves as a fire prevention material and at the same time as a interior material. Gypsum board has excellent fire resistance and plays a big role in the early fire prevention and combustion delay of building frame. In addition, the gypsum board can be shortened by the construction is easy, and the weight is light, the building structure cost can be reduced.

Since gypsum itself is a stable crystalline state, there is no stretch deformation due to temperature or humidity change, and thermal insulation is low, and thus excellent thermal insulation. In addition, the gypsum board has properties such as heat insulation, fire resistance, sound insulation, waterproof, light weight and workability, antibacterial, economical, shockproof.

In addition to the rapid economic growth, the domestic construction industry is becoming more diversified, larger, and higher. The domestic construction industry, which is constructing large-scale apartments nationwide, is making great efforts to maximize construction efficiency based on the smooth exchange of information on design, materials, and construction.

However, construction waste has increased significantly due to rapid economic growth over the past several years.

Among them, gypsum board is used in most construction works, and more than 300,000 tons of waste is generated annually. This is about 3% or more of the total amount of construction waste generated. However, as social infrastructure expansion projects, urban redevelopment projects, and reconstruction projects progress widely, the discharge of gypsum board waste is expected to increase steadily.

Therefore, there is an urgent need for efforts to reduce gypsum board waste generated during construction and the proper treatment of gypsum board waste. Although research on the treatment method of construction waste is underway, the research on the present condition and treatment of gypsum board waste is insufficient.

Gypsum board waste is reported to be recycled as a raw material of gypsum board through crushing and separation of paper by an intermediate processor. However, in reality, most of the gypsum board waste is disposed of in landfill due to difficulty in screening gypsum board waste and a lack of a recycling market for gypsum board.

Meanwhile, Korea's CO2 growth rate is the 1st among OECD countries, and it is the 10th carbon dioxide emitter in the world. Therefore, it is necessary to establish a reduction plan for this. As part of this, Carbon Capture and Storage (CCS) is being studied. Among the CCS technologies, various physical methods such as carbon dioxide deep sea storage, UGS (Underground Gas Storage), groundwater melting, and underground storage will be reviewed and attempted. However, these methods have the disadvantage of operating an expensive carbon dioxide monitoring system. In addition, there is a problem that there is not a lot of underground storage place in Korea due to the geological structure. Therefore, researches on carbonate mineralization, in which an alkaline earth metal component constituting a mineral is reacted with carbon dioxide and changed into a carbonate mineral in a thermodynamically stable state, are being actively conducted.

Jeon, Chi-Wan et al. (Reactivity Study on Mineral Carbonation of Pusan Gypsum and Ammonium Carbonate for Carbon Dioxide Capture, Chemistry, 2010, 14 (1), 81-84.) The mineral carbonation of ammonium carbonate and gypsum obtained from the reaction was studied. However, no research has been done on the recycling of products including carbon dioxide fixation using gypsum board waste directly.

The technical problem to be solved by the present invention is to provide a carbon dioxide fixing method using a waste that can harm the asbestos-containing slate by using heat treatment and carbon dioxide, and to fix the carbon dioxide, and to synthesize calcium carbonate, a raw material of cement. There is.

In addition, by using heat to harm the fibrous asbestos present in the asbestos board waste, and provides a method of fixing carbon dioxide using waste that can produce calcium carbonate, a raw material of cement using the interaction of asbestos board and carbon dioxide. There is.

In addition, the carbon dioxide immobilization is performed by using the reaction of the gypsum board and carbon dioxide, and to provide a method for fixing the carbon dioxide using waste that can produce calcium carbonate as a raw material of cement by recycling the gypsum board waste.

One aspect of the present invention to achieve the above technical problem provides a method for fixing the asbestos-containing material and carbon dioxide. The method includes heat treating the asbestos-containing material to a temperature of 710 ° C. to 840 ° C., and injecting the heat treated asbestos-containing material into a medium solution and injecting carbon dioxide into the medium solution.

After the step of injecting the carbon dioxide, the asbestos-containing material may further include the step of pressing at a temperature of 100 ℃ to 150 ℃ and a pressure of 0.1 MPa to 0.5 MPa.

Before the heat treatment of the asbestos-containing material, the method may further include the step of pulverizing the asbestos-containing material.

The grinding of the asbestos-containing material may include grinding the asbestos-containing material to 75 μm or less.

The asbestos-containing material may comprise a slate.

The mediator solution may be water or a basic solution. The basic solution may comprise NaCl and NaHCO ₃ .

In order to achieve the above technical problem, another aspect of the present invention provides a method of fixing asbestos board waste and carbon dioxide. The method includes the steps of crushing the asbestos board, adding the crushed asbestos board to the medium solution to form an asbestos board solution, injecting carbon dioxide into the asbestos board solution to fix the carbon dioxide and asbestos fixed carbon dioxide Heat-treating the board to harm the asbestos.

The fixing of the carbon dioxide may include a process of accelerating the fixing of the carbon dioxide by maintaining the asbestos board solution at a temperature of 100 ° C. to 150 ° C. and a pressure of 0.1 MPa to 0.5 MPa.

The assembling of the asbestos board may include grinding the asbestos board to 75 μm or less.

The heat treatment temperature may be 700 ℃ to 800 ℃.

Another aspect of the present invention to achieve the above technical problem provides a method for fixing the carbon dioxide and the synthesis of calcium carbonate using the gypsum board waste. The method comprises the steps of forming a slurry by injecting a gypsum board into the medium solution, injecting carbon dioxide into the slurry and the slurry injected with carbon dioxide at a pressure of 0.1 MPa to 0.5 MPa and a temperature of 100 ℃ to 150 ℃ Pressurizing and heating.

Before forming the slurry, the method may further include grinding the gypsum board. The grinding of the gypsum board may include grinding the gypsum board to 75 μm or less.

According to the present invention, the asbestos-containing material may be heat-treated at a temperature of 710 ° C. to 840 ° C. to make the asbestos-containing material harmless and improve the immobilization efficiency of carbon dioxide. In addition, it is possible to produce a raw material of cement through the carbonate mineralization action with the fixing of carbon dioxide. At this time, the carbonate mineralization action can be accelerated through the pressurization process under certain conditions.

In addition, by using the reaction of asbestos board waste and carbon dioxide, as well as fixing carbon dioxide, the final product of the synthesized calcium carbonate can be used as a raw material of cement. In addition, asbestos may be harmless through phase transition of minerals through heat treatment.

In addition, by using the reaction of the gypsum board waste and carbon dioxide, not only the fixation of carbon dioxide, but also the synthesized final product calcium carbonate can be used as a raw material of cement.

However, the effects of the present invention are not limited to the above-mentioned effects, and other effects not mentioned will be clearly understood by those skilled in the art from the following description.

1 is an XRD result analysis graph of particles formed through heat treatment and carbon dioxide injection of an asbestos-containing slate according to a first embodiment of the present invention.

2 is a SEM-EDX analysis image and graph of the asbestos-containing slate according to the first embodiment of the present invention.

FIG. 3 is an SEM-EDX analysis image and graph of particles formed by heat treatment and carbon dioxide injection of an asbestos-containing slate according to a first embodiment of the present invention.

4 is an XRD result analysis graph of a product formed using an autoclave sterilizer after injection of asbestos raw material and carbon dioxide according to a second embodiment of the present invention.

5 is an XRD result analysis graph of a product formed through asbestos raw material and heat treatment according to the second embodiment of the present invention.

6 is an SEM-EDS analysis image and graph of asbestos board raw material according to a second embodiment of the present invention.

FIG. 7 is an SEM-EDS analysis image and graph of a product formed using an autoclave sterilizer after injecting carbon dioxide according to a second embodiment of the present invention.

8 is a SEM-EDS analysis image and graph of the product formed through the heat treatment according to the second embodiment of the present invention.

9 is an XRD result analysis graph of particles produced according to the third embodiment of the present invention.

10 is a SEM-EDX analysis result image and graph of gypsum board waste according to a third embodiment of the present invention.

FIG. 11 is an SEM-EDX analysis image and graph of particles formed by injecting carbon dioxide into gypsum board waste according to a third embodiment of the present invention.

12 is a SEM-EDX analysis image and graph of particles formed through the pressurization and heating steps after carbon dioxide is injected into the waste of gypsum board according to the third embodiment of the present invention.

Hereinafter, exemplary embodiments of the present invention will be described in detail with reference to the accompanying drawings. However, the present invention is not limited to the embodiments described herein and may be embodied in other forms. Rather, the embodiments introduced herein are provided so that the disclosure may be made thorough and complete, and to fully convey the spirit of the present invention to those skilled in the art. In the drawings, the thicknesses of layers and regions are exaggerated for clarity. Like numbers refer to like elements throughout. In addition, in the following description of the present invention, if it is determined that a detailed description of a related known function or configuration may unnecessarily obscure the subject matter of the present invention, the detailed description thereof will be omitted.

First Embodiment: Asbestos-Containing Material

A method of fixing carbon dioxide of waste according to the first embodiment of the present invention will be described. The waste may be asbestos containing material. That is, the asbestos-containing material may be waste containing asbestos.

First, an asbestos-containing material is prepared. As an example, the asbestos-containing material may be a slate containing asbestos.

The asbestos-containing material may be ground. This is to promote the reaction with carbon dioxide by increasing the surface area of the asbestos-containing material. At this time, it is preferable to grind the length of the asbestos-containing material to 75 μm or less. However, the grinding process may be omitted.

The ground asbestos-containing material is heat treated. The phase change of the asbestos-containing material may be changed through the heat treatment process. Carbon dioxide may be easily injected into the asbestos-containing material heat-treated in the steps to be described later through the phase change.

In the case of slate, it is preferable to heat-treat at a temperature of, for example, 710 ° C to 840 ° C. When the heat treatment temperature is less than 710 ° C., the white asbestos contained in the slate may not change in phase transition to gore olivine (Forsterite). In addition, when the heat treatment temperature is higher than 840 ℃, gory olivine formed by heat-treating the white asbestos contained in the slate may not react with carbon dioxide and bicarbonate to form a carbonate mineral, the cost of the high temperature heat treatment increases There is.

The heat treated asbestos-containing material is added to a carrier solution. The mediator solution may be a basic solution containing water or bicarbonate (HCO ₃ ⁻ ) ions. In this case, problems such as scattering of asbestos can be prevented through a wet process.

For example, the basic solution may include NaCl and NaHCO ₃ . However, the present invention is not limited thereto.

By injecting the heat-treated asbestos-containing material into the medium solution, gosterite produced by heat-treating the asbestos-containing material may react with carbon dioxide in the medium solution. In this case, the formation of the carbonate mineral is promoted so that the carbon dioxide can be easily fixed.

Carbon dioxide is injected into the medium solution containing the heat treated asbestos-containing material to fix the carbon dioxide, and the carbonate mineralization reaction is performed.

Carbonate mineralization reaction (Mineral carbonation) is a reaction in which the alkaline earth metal component constituting the mineral reacts with carbon dioxide and mimics the weathering action of the natural system to change into a carbonate mineral in a thermodynamically stable state.

The carbonate mineralization reaction is exothermic, and the product of the carbonate mineralization reaction has an energy level of 60 to 180 kJ / mol, which is lower than that of carbon dioxide. When the carbon dioxide is fixed in the form of carbonate mineral when viewed in the energy level, it is possible to fix the carbon dioxide for a long time in a state of a stable energy level. Therefore, since carbon dioxide is fixed to a stable energy level, a separate monitoring system for additionally managing the fixed state of carbon dioxide is unnecessary.

For example, carbon dioxide may be injected into the medium solution containing asbestos-containing slate at a pressure of 0.2 MPa. In this case, while the injected carbon dioxide is fixed, carbonate mineralization takes place at the same time to produce calcium carbonate.

After the step of injecting carbon dioxide, the asbestos-containing material may be pressed to accelerate the carbonate mineralization.

The pressurization process may be performed using an autoclave.

The pressurization is preferably carried out at a temperature of 100 ℃ to 150 ℃ and a pressure of 0.1 MPa to 0.5 MPa. The temperature and pressure range is a mild condition that can sterilize microorganisms.

Moreover, it is preferable to hold the said press process for 20 minutes or more. If the holding time of the pressing process is less than 20 minutes, there is a fear that it is insufficient to accelerate the carbonate mineralization action.

Hereinafter, preferred examples are provided to aid the understanding of the present invention. However, the following experimental examples are only for helping understanding of the present invention, and the present invention is not limited to the following experimental examples.

Experimental Example

Asbestos-containing materials were prepared asbestos-containing materials. In order to increase the surface area of the slate was made into a powder using a pulverizer (Pulverizer), it was filtered to 75㎛ (200 Mesh). Thereafter, the filtered powder was heat-treated for about 2 hours at a temperature of about 750 ° C. using a laboratory electric furnace.

The heat treated slate was added to a basic solution to prepare a slurry. The basic solution included NaCl and NaHCO ₃ . Carbon dioxide (CO ₂ ) was injected into the slurry at a pressure of about 0.2 MPa to asbestos-free and fix carbon dioxide. In addition, as the carbon dioxide immobilization proceeded, carbonate mineralization proceeded, and calcium carbonate was synthesized.

Thereafter, an autoclave was used for about 20 minutes at a temperature of about 120 ° C. and a pressure of about 0.25 MPa. Carbonate mineralization was accelerated through the pressing process.

The main component of the product synthesized through the experiment is calcium carbonate, the diameter of the product is 10㎛ to 20㎛, the product is a raw material of cement which is a calcite of round shape.

1 is an XRD result analysis graph of particles formed by heat treatment and carbon dioxide injection of asbestos-containing slate according to the first embodiment of the present invention. For ease of analysis, the particles formed through the experiment were repeated three times using a centrifuge to remove NaCl, and then dried naturally.

Referring to FIG. 1, X-ray diffraction analysis (XRD) of asbestos-containing slate (raw sample) pulverized to 75 μm or less without heat treatment and asbestos-containing slate particles formed by heat-treating the raw material and injecting carbon dioxide ).

According to the analysis results, the slate ground to 75 μm or less without heat treatment mainly consisted of chrysotile (Ch) and calcium hydroxide (Calcium hydroxide, Ca).

Asbestos-containing slate particles formed by heat-treating the raw material and injecting carbon dioxide were tested with and without an autoclave at the temperature and pressure shown above after injecting carbon dioxide.

As a result, regardless of the use of the intruder, it was confirmed that the phase transition of minerals to calcite (C), which is both cement raw materials, occurred. However, it was confirmed that the crystallinity of the calcium carbonate was high in the case of using an intruder. This means that a greater amount of calcium carbonate was formed. Thus, it can be seen that the addition of the pressurization process can accelerate the carbonate mineralization reaction.

3 is an SEM-EDX analysis image and graph of a product formed by heat treatment and carbon dioxide injection of an asbestos-containing slate according to a first embodiment of the present invention.

2 and 3, scanning electron microscopy (SEM-EDX) was performed to confirm the size, shape and composition of the minerals. In slates (raw sample) ground to 75 μm or less without heat treatment, thin and long fiber-like white asbestos (Chrysotile, Mg ₃ (OH) ₄ Si ₂ O ₅ ) and rounded calcium hydroxides having a diameter of 5 μm or less (Calcium hydroxide, Ca (OH) ₂ ) was confirmed. On the other hand, in the asbestos-containing slate particles formed through heat treatment and carbon dioxide injection, thin and long fibrous asbestos was not identified, and calcium carbonate (calcite), which is a raw material of a round cement having a diameter of 10 μm to 20 μm, was confirmed. It became.

Therefore, it was confirmed that the hazard of fibrous asbestos was removed through heat treatment and injection of carbon dioxide, carbon dioxide was fixed, and calcium carbonate (calcite), which is a raw material of cement, was synthesized.

Second Embodiment: Asbestos Board

A method of fixing carbon dioxide using waste according to a second embodiment of the present invention will be described. The waste may be asbestos board.

First, the asbestos board can be ground. This is to increase the surface area of the asbestos board to promote the reaction with carbon dioxide. The asbestos board is preferably pulverized to 75㎛ or less.

The crushed asbestos board is introduced into a carrier solution to form an asbestos board solution. The asbestos board solution may have a slurry (Slurry) form. The mediator solution may be water or a basic solution. For example, when fixing the carbon dioxide on the asbestos board, by adjusting the pH of the asbestos board solution to 7 or more using water or a basic solution, it is possible to promote the fixed reaction of carbon dioxide. The basic solution may include distilled water, NaCl and NaHCO ₃ .

Injecting carbon dioxide into the asbestos board solution to fix the carbon dioxide. In this case, carbon dioxide is fixed and carbonate mineralization reaction (Mineral carbonation) may proceed. Therefore, the gypsum (CaSO ₄ ) of the asbestos board may be calcium carbonate (CaCO ₃ ) through a carbonate mineralization reaction.

Carbonate mineralization reaction (Mineral carbonation) is a reaction in which the alkaline earth metal component constituting the mineral reacts with carbon dioxide and mimics the weathering action of the natural system to change into a carbonate mineral in a thermodynamically stable state. The carbonate mineralization reaction is exothermic, and the product of the carbonate mineralization reaction has an energy level of 60 to 180 kJ / mol, which is lower than that of carbon dioxide. Therefore, fixing carbon dioxide in the form of a carbonate mineral is in a stable energy state, and thus there is an advantage of fixing carbon dioxide for a long time.

After injecting the carbon dioxide, it is possible to accelerate the carbonate mineralization action by maintaining a constant temperature and pressure. For example, autoclave can be used to maintain constant temperature and pressure conditions.

Preferably, the asbestos board solution may be maintained at a temperature of 100 ° C to 150 ° C and a pressure of 0.1 MPa to 0.5 MPa to accelerate carbon dioxide fixation. When the temperature of the accelerated process is less than 100 ° C., the time for fixing the carbon dioxide becomes long, and when the temperature of the accelerated process exceeds 150 ° C., there is a problem that the cost due to the high temperature heat treatment increases.

In addition, it is preferable to maintain the said temperature and pressure for 20 minutes or more. If the holding time is less than 20 minutes, it may be insufficient to accelerate the carbonate mineralization action.

Asbestos is harmless by heat treatment of the asbestos board to which carbon dioxide is fixed. When heat treatment without fixing carbon dioxide on the asbestos board, sulfur dioxide (SO ₂ ) may be generated from the gypsum (CaSO ₄ ) of the asbestos board, thereby forming an unwanted product. Through the heat treatment process, the phase change of the asbestos contained in the asbestos board is changed.

The heat treatment temperature may be 700 ℃ to 800 ℃. When the heat treatment temperature is less than 700 ° C, the white asbestos contained in the asbestos board may not change in phase transition to goto olivine (Forsterite). If the heat treatment temperature is higher than 800 ℃, there is a problem that the cost due to high temperature heat treatment increases.

In addition, the heat treatment process is preferably performed for 1 to 3 hours at a temperature of 700 ℃ to 800 ℃. Therefore, through the heat treatment process, calcite having a diameter of about 20 μm and having a round shape can be obtained, and the asbestos can be made harmless.

Experimental Example

In order to increase the surface area of the asbestos board, the asbestos board was formed into a powder form by using a pulverizer, and then it was filtered to 75 μm (200 Mesh). Asbestos crushed asbestos board was added to the basic solution for carbonate mineralization to prepare an asbestos board solution. The asbestos board solution consisted of 60 ml tertiary distilled water, 9 g pulverized asbestos board up to 75 μm (15% solids in total solution), 1.7535 g NaCl (1M) and 1.6129 g NaHCO ₃ (0.64M).

Carbon dioxide (99.999%) gas was injected into the asbestos board solution at 0.2 MPa pressure to fix the carbon dioxide. Thereafter, using a autoclave sterilizer, the temperature was maintained at 120 ° C. and 0.25 MPa pressure for 20 minutes to promote carbon dioxide fixation. The carbon dioxide-fixed asbestos board was heat-treated at about 700 ° C. for 2 hours using a laboratory electric furnace to make asbestos harmless.

For ease of analysis, 10 ml of distilled water was added and repeated three times using a centrifuge, followed by air drying to remove NaCl. Asbestos-board raw material pulverized to 75㎛ or less, the product formed after the carbon dioxide injection and the product through heat treatment were compared by X-ray diffraction analysis (XRD).

Referring to FIG. 4, the asbestos board (raw sample) pulverized to 75 μm or less is mainly composed of white asbestos (Chrysotile, Ch), limestone (Calcite, C), and gypsum (Gypsum, G). In addition, it can be confirmed that the particles formed by maintaining the above-described temperature and pressure by using an autoclave sterilizer after carbon dioxide injection were composed of limestone (Calcite, C) and white stone (Chrysotile, Ch). That is, it can be seen that carbon dioxide is fixed to gypsum and the carbonate mineralization reaction has occurred.

Referring to FIG. 5, the particles formed by heat treatment again after carbon dioxide injection were found to have calcite (C), calcium oxide (Calcium Oxide, Ca), and quartz (Quartz, Q), which are cement raw materials. That is, it can be confirmed that the phase transition of the mineral occurs.

Referring to FIG. 6, as a result of conducting scanning electron microscopy (SEM-EDS) to confirm the size, shape, and composition of minerals, asbestos board raw materials pulverized to 75 μm or less are rounded to 3 μm or less in diameter. Gypsum (Figs. 6 (b) and 6 (c)) and long and thin fibrous asbestos (Chrysotile) (Figs. 6 (d) and 6 (e)) were confirmed.

Referring to FIG. 7, the particles formed after the carbon dioxide injection were found to have a rounded calcite bonded to the elongated, fibrous asbestos (FIGS. 7A and 7B). In addition, round aggregates of calcite were also present (Figs. 7 (c) and 7 (d)). That is, it can be seen that carbon dioxide is fixed to gypsum to form calcium carbonate (CaCO ₃ ).

Referring to FIG. 8, no fibrous asbestos was observed in the particles formed after the heat treatment, and an aggregate of calcite, which is a raw material of a round cement having a diameter of 10 μm to 20 μm, was confirmed (FIG. 8 ( a) to 8 (d)).

Therefore, through the above results, it was confirmed that the cement raw material was synthesized using asbestos elimination, carbon dioxide fixation, and calcium carbonate formed as a product.

Third Embodiment: Gypsum Board

A method of fixing carbon dioxide using waste according to a third embodiment of the present invention will be described. The waste may be gypsum board.

First, the gypsum board can be pulverized. This is to increase the surface area of the gypsum board to promote the reaction with carbon dioxide. At this time, it is preferable to grind the length of the gypsum board to 75㎛ or less. However, the grinding process of the gypsum board may be omitted. If the grinding process of the gypsum board is omitted, there is an advantage that can prevent the scattering of the gypsum board generated during the grinding process.

The gypsum board is added to a carrier solution to form a slurry.

The mediator solution may be water or a basic solution. The basic solution may include bicarbonate ions (HCO ₃ ⁻ ). The basic solution including the bicarbonate (HCO ₃ ⁻ ) allows the carbon dioxide to be easily fixed when the gypsum board and the carbon dioxide react. For example, the basic solution may include NaCl and NaHCO ₃ . However, the present invention is not limited thereto.

Inject carbon dioxide into the slurry. When injecting carbon dioxide into the slurry, it may be injected using a predetermined pressure.

Pressurizing and heating the slurry in which the carbon dioxide is injected to proceed with the carbonate mineralization reaction (Mineral carbonation). That is, when a predetermined pressure and a certain temperature is applied to the slurry injecting carbon dioxide, the gypsum board and carbon dioxide react to form a carbonate mineral.

The carbonate mineralization reaction is exothermic, and the product of the carbonate mineralization reaction has an energy level of 60 to 180 kJ / mol, which is lower than that of carbon dioxide. In view of the energy level, when carbon dioxide is fixed in the form of carbonate mineral, carbon dioxide can be immobilized for a long time in a stable energy level. Therefore, since carbon dioxide is fixed to a stable energy level, a separate monitoring system for additionally managing the fixed state of carbon dioxide is unnecessary.

The pressurizing and heating process may be performed using an autoclave. The pressing and heating process is preferably carried out at a pressure of 0.1 MPa to 0.5 MPa and a temperature of 100 ℃ to 150 ℃. In the above pressure and temperature range, gypsum (CaSO ₄ ), which is a main component of gypsum board, may react with bicarbonate (HCO ₃ ⁻ ) in which carbon dioxide is dissolved in the slurry. By the reaction, calcium carbonate (CaCO ₃ ) may be synthesized in a short time (within 30 minutes). In addition, the pressure and temperature range may be pressure and temperature conditions capable of sterilizing microorganisms.

It is preferable to hold the pressurization and heating step for 20 minutes or more. If the holding time of the pressurizing and heating process is less than 20 minutes, there is a fear that the time is insufficient to perform the carbonate mineralization action. As such, when a predetermined pressure and temperature are applied to the slurry into which the carbon dioxide is injected, carbonate mineralization proceeds to fix carbon dioxide, and as a product, calcium carbonate (CaCO ₃ ), which is a cement raw material, may be synthesized.

Experimental Example

In order to increase the surface area of the gypsum board waste, it was made into powder by using a pulverizer and then placed in a thickness of 75 μm (200 Mesh). 30 ml of water, 4.5 g of plasterboard waste of less than 75 μm, 1.7535 g (1 M) of NaCl, 1.6129 g (0.64 M) of NaHCO ₃ were injected into a 120 ml media bottle to form a slurry. Carbon dioxide gas was injected into the slurry at 0.2 MPa pressure. Then, pressurization and heating were maintained at 120 ° C. and 0.25 MPa for 20 minutes using an autoclave to accelerate the carbonate mineralization. 10 ml of water was added for ease of analysis, repeated three times using a centrifuge, followed by air drying to remove NaCl.

Comparative example

Except for omitting the pressurization and heating step to accelerate the carbonate mineralization action was carried out in the same manner as in the experimental example.

The gypsum board waste (raw sample) pulverized to 75 μm or less and the particles formed by the experimental and comparative examples were compared by X-ray diffraction analysis (XRD).

Scanning electron microscopy (SEM-EDX) was performed to determine the size, shape and composition of the minerals of the gypsum board waste (raw sample) pulverized to 75 μm or less and the particles formed by the experimental and comparative examples.

9, the gypsum board waste (raw sample) pulverized to 75 μm or less mainly consisted of gypsum (Gypsum, G) and calcite (Calcite, C). On the other hand, the particles formed by the comparative example is a case that does not use an autoclave after the carbon dioxide injection, there was no phase transition of minerals. On the other hand, the particles formed by the experimental example is a case of using a autoclave after the injection of carbon dioxide, it can be seen that the phase transition of minerals to calcite (C), a cement raw material.

Referring to FIG. 10, it was confirmed that the gypsum board waste (raw sample) is composed of a round shape having a diameter of 30 μm to 40 μm and a rectangular gypsum having a length of 30 μm to 35 μm.

Referring to FIG. 11, when a pressurizer was not used after injecting carbon dioxide, gypsum containing sulfur (S) such as a raw material was confirmed. Therefore, when a certain pressure and temperature are not applied after injecting carbon dioxide into the slurry containing the gypsum board waste, it can be confirmed that the phase transition of the mineral does not occur to the calcite which is a cement raw material.

Referring to FIG. 12, it was confirmed that the particles formed when a pressurizer was used after carbon dioxide injection had a diameter of 20 μm to 30 μm and were calcite, which is a raw material of a round cement.

Gypsum, a constituent mineral of gypsum board waste, is a phase transition to carbonate minerals. At this time, sulfur (S), which is a main component of gypsum, is present in the headspace of the media bottle as sulfur oxide (SO _x ) in a gaseous state. Thus, the gypsum board waste can be reacted with carbon dioxide using a pressurizer at the temperature and pressure conditions set forth above. This confirmed that the carbon dioxide was fixed and synthesized as a cement raw material using calcium carbonate formed product.

In the above, the present invention has been described in detail with reference to preferred embodiments, but the present invention is not limited to the above embodiments, and various modifications and changes by those skilled in the art within the spirit and scope of the present invention. Changes are possible.

Claims

Heat treating the asbestos-containing material to a temperature of 710 ° C. to 840 ° C .; And

Injecting the heat-treated asbestos-containing material into the mediator solution, and injecting carbon dioxide into the mediator solution.
The method of claim 1,

After injecting the carbon dioxide,

And assembling the asbestos-containing material at a temperature of 100 ° C. to 150 ° C. and a pressure of 0.1 MPa to 0.5 MPa.
The method of claim 1,

Before the heat treatment of the asbestos-containing material,

Method for fixing carbon dioxide using waste further comprising the step of pulverizing the asbestos-containing material.
The method of claim 3,

The assembling of the asbestos-containing material may include grinding the asbestos-containing material to 75 μm or less.
The method of claim 1,

The asbestos-containing material carbon dioxide fixing method using a waste containing a slate.
The method of claim 1,

The mediator solution is a carbon dioxide fixing method using waste water or basic solution.
The method of claim 6,

The basic solution is a method of fixing carbon dioxide using waste containing NaCl and NaHCO 3 .
Grinding the asbestos board;

Adding the crushed asbestos board to a medium solution to form an asbestos board solution;

Fixing carbon dioxide by injecting carbon dioxide into the asbestos solution; And

Method of fixing carbon dioxide using waste comprising the step of heat-treating the asbestos board is fixed carbon dioxide.
The method of claim 8,

Fixing the carbon dioxide,

Maintaining the asbestos board solution at a temperature of 100 ℃ to 150 ℃ and a pressure of 0.1 MPa to 0.5 MPa to accelerate the fixing of carbon dioxide comprising a process for fixing carbon dioxide.
The method of claim 8,

The assembling of the asbestos board, the carbon dioxide fixing method using the waste that is the step of grinding the asbestos board to 75㎛ or less.
The method of claim 8,

The mediator solution is a carbon dioxide fixing method using waste water or basic solution.
The method of claim 11,

The basic solution is a method of fixing carbon dioxide using waste containing NaCl and NaHCO 3 .
The method of claim 8,

The heat treatment temperature is carbon dioxide fixing method using a waste 700 ~ 800 ℃.
Putting a gypsum board into a medium solution to form a slurry;

Injecting carbon dioxide into the slurry; And

Pressurizing and heating the slurry injecting the carbon dioxide at a pressure of 0.1 MPa to 0.5 MPa and a temperature of 100 ° C to 150 ° C.
The method of claim 14,

Prior to forming the slurry,

Method of fixing carbon dioxide using waste further comprising the step of crushing the gypsum board.
The method of claim 15,

Grinding the gypsum board,

Carbon dioxide fixing method using a waste that is the step of grinding the gypsum board to 75㎛ or less.
The method of claim 14,

The mediator solution is a carbon dioxide fixing method using waste water or basic solution.
The method of claim 17,

The basic solution is a method of fixing carbon dioxide using waste containing NaCl and NaHCO 3 .