KR20060023206A - Method for fixing of carbon dioxide - Google Patents

Abstract

The present invention relates to a method of immobilizing carbon dioxide using slag, in particular, slag having a water content of 5 to 35% and having a particle size of 1 mm or less by reacting carbon dioxide gas for at least 3 hours to absorb and fix carbon dioxide on the surface of slag with high efficiency. Not only can carbon dioxide, which is the main cause of warming, be efficiently reduced, but also it is useful as a civil engineering aggregate by preventing generation of highly alkaline effluent water, colored water, cloudy water and cloudy precipitates from the slag fixed with carbon dioxide. It relates to a method of immobilizing carbon dioxide using slag that can be used easily.

Carbon dioxide, immobilized

Description

Immobilization Method of Carbon Dioxide {METHOD FOR FIXING OF CARBON DIOXIDE}

The present invention relates to a method of immobilizing carbon dioxide using slag, and more specifically, by absorbing and immobilizing carbon dioxide on the surface of slag with high efficiency, carbon dioxide, which is a major factor of global warming, can be efficiently reduced, and at the same time, the carbon dioxide is fixed. The present invention relates to a method of immobilizing carbon dioxide using slag, which can be usefully used as aggregate for civil engineering by preventing generation of highly alkaline eluate, colored water, white turbidity and white sedimentation.

Carbon dioxide began to increase gradually with the birth of human beings and the increase of population, and recently began to increase rapidly due to the large consumption of fossil fuels. As a result, abnormal climate symptoms such as floods and cold drops are becoming a real problem. In other words, carbon dioxide is the main cause of global warming, and the concentration of carbon dioxide in the air is increasing by 1.3 to 1.5 ppm per year, and the concentration of carbon dioxide in the atmosphere is now about 330 ppm.

In general, there are two methods of suppressing the emission of carbon dioxide: a method of reducing the use of fossil fuels, and a method of separating, recovering and fixing carbon dioxide. The former method is related to sex energy and clean energy, and the latter method is a method of separating and recovering carbon dioxide and using it as a raw material for methanol synthesis, or fixing and discharging by ocean dumping or carbonate after separation and recovery of carbon dioxide.

The method of immobilization includes a method of dumping and storing carbon dioxide, a method of storing as carbonate, a method of reusing carbon dioxide as a carbonic acid resource, and the method of dumping and storing carbon dioxide as a method of dumping in the ocean and the ground ( Mol, 28, 51, 1990) and carbonate or hydro tarcite (Mg4.5Al (OH) 13CO33.5H2O).

In particular, the dumping method to the ocean is a method of isolating and recovering carbon dioxide from large-scale process sources such as thermal power plants, steel mills, cement plants, etc. and injected into a deep sea of 500 m or more is the most useful method of carbon dioxide immobilization method.

In addition, the immobilization of carbon dioxide by the carbonate is well known as the urey reaction as in Scheme 1 or 2.

Scheme 1

Scheme 2

However, in general, calcium or silicate has a slow dissolution rate, and in order to solve this problem, it is necessary to crush it into sub-micron submicron particles to increase the surface area, and studies for this continue.

In order to solve the problems of the prior art as described above, an object of the present invention is to provide a method for immobilizing carbon dioxide using slag that can efficiently reduce carbon dioxide, which is a major factor of global warming, by absorbing and immobilizing carbon dioxide on the surface of slag with high efficiency. It is done.

Another object of the present invention is to fix the carbon dioxide on the surface by the above method to efficiently reduce the carbon dioxide, and at the same time to prevent the production of highly alkaline effluent from the slag, the production of colored water, the production of cloudy and cloudy precipitates It is to provide a slag that can be useful as a civil engineering aggregate.

In order to achieve the above object, the present invention is a method for immobilizing carbon dioxide using slag, the reaction of slag having a water content of 5 to 35% and a particle size of 1 mm or less by reacting carbon dioxide gas for at least 3 hours to fix the carbon dioxide on the surface of the slag It provides a method of immobilizing carbon dioxide using a slag comprising the step.

In another aspect, the present invention provides a slag having a carbonation layer is fixed to the surface of the carbon dioxide.

Hereinafter, the present invention will be described in detail.

The present inventors confirmed that carbon dioxide can be immobilized by carbonate using slag generated in a large amount in a steel mill, and thus the present invention has been completed.                     

The present invention is characterized by forming a carbonation layer (CaCO ₃ layer) by immobilizing carbon dioxide on the surface of the slag by reacting slag having a water content of 5 to 35% and having a particle size of 1 mm or less for at least 3 hours.

Of course, the slag used in the present invention can use all the slag generated in the steel mill, and in particular, it is better to use the slag having a particle size of 1 mm or less for immobilization of carbon dioxide. When the particle size of the slag exceeds 1 mm, the specific surface area is small, the reactivity is small, the area in contact with the gas carbon dioxide is small, the reaction rate is lowered, there is a problem that the absorption amount and fixed amount of carbon dioxide is lowered.

In addition, the moisture contained in the slag serves as a catalyst for promoting the reaction of the slag as a solid and the carbon dioxide gas as a gas to play an important role in immobilizing the carbon dioxide in the form of CaCO ₃ . That is, the moisture serves to promote the dissolution of calcium ions in the solid slag and the dissolution of carbonate ions in carbon dioxide gas.

Therefore, the preferable slag water content is 5 to 35%, and if the water content is less than 5%, the surface of all solid slag cannot be involved in the reaction with carbon dioxide gas, and thus there is a problem in that the fixed amount of carbon dioxide and the improvement of the reaction rate cannot be expected. In case of exceeding 35%, the diffusion rate of carbon dioxide gas in the water is lowered and the reaction of calcium ions eluted from the slag may be slowed, and the reaction of slag and carbon dioxide gas proceeds very quickly at the initial stage to determine the CaCO ₃ crystal. Since this is achieved quickly, the carbonation layer (CaCO ₃ layer) formed on the surface of the slag in the reaction vessel is not easy to dissolve calcium ions from the slag in the subsequent reaction step, so that the immobilization reaction of carbon dioxide is not continuously performed. have.

The carbon dioxide gas used in the present invention is a conventional industrial furnace such as a hot stove, a lime kiln, a coke oven, an industrial furnace such as sintering, hot rolling, or the like, a carbon dioxide gas produced by an ironworks, or an industrially produced carbon dioxide gas. Of course, all carbon dioxide gas can be used, and it is advantageous to use a gas having a high carbon dioxide content in terms of reaction rate, reaction time, and treatment effect when reacting with slag.

It is preferable to use a saturated steam vaporized gas as described above, and the saturated steam vaporization of the carbon dioxide gas is performed by adding or passing carbon dioxide into water or passing the carbon dioxide gas through a scrubber. Can be.

The reaction of the slag and carbon dioxide gas as described above is preferably carried out for more than 3 hours, if the reaction time is within the above range, the fixed amount of carbon dioxide per unit weight of slag by the reaction of all the calcium ions in the slag that can react with carbon dioxide It is increased and better in terms of efficiency of reduction of carbon dioxide.

In addition, the present invention provides a slag having a carbonation layer formed by fixing the carbon dioxide on the surface in the same manner as described above, the slag can efficiently absorb and immobilize the carbon dioxide on the surface to effectively reduce the carbon dioxide which is the main factor of global warming. In addition, there is an advantage that can be usefully used as aggregate for civil engineering by preventing the generation of highly alkaline effluent water, the generation of colored water, the production of turbid water and turbid sediment from the slag at the same time.

Hereinafter, preferred examples are provided to help understanding of the present invention, but the following examples are merely to illustrate the present invention, and the scope of the present invention is not limited to the following examples.

EXAMPLE

Example 1

1,640 g of tap water was added to 32.8 kg of the steelmaking slag having a particle size of 1 mm or less discharged from the steelmaking process to adjust the water content to 5%, and the reactor was filled with a packing density of 2.4 g / cm 3. Thereafter, a gas having a carbon dioxide concentration of 20% was passed through a scrubber to saturated steam, and the saturated steamed carbon dioxide gas was blown into the reactor at a flow rate of 20 L / min. At this time, the temperature of the carbon dioxide gas blown was 23 ° C, and the reaction was terminated when the concentration of carbon dioxide at the entrance and exit was the same (after 3 hours).

Examples 2-4 and Comparative Examples 1-2

In Example 1, the reaction was carried out in the same manner as in Example 1, except that the water content of the slag was adjusted by varying the amount of tap water as shown in Table 1 below.

Comparative Examples 3 to 5

In the same manner as in Example 1 except that the slag water content was adjusted to 15% and the particle size was adjusted to 1 to 20 mm, 20 to 40 mm, and 40 to 70 mm in Example 1, respectively. Reacted.

Using the reaction samples of Examples 1 to 4 and Comparative Examples 1 to 5, the carbon content of the sample was quantitatively analyzed by a carbon analyzer, and the fixed amount of carbon dioxide, the absorption amount, and the effective reaction rate were represented by Equations 1 to 3 below. Calculated according to the results shown in Table 1 below.

[Equation 1]

[Equation 2]

[Equation 3]

(At this time, the theoretical CO2 fixed amount is

TABLE 1

division Reaction condition Carbon dioxide absorption characteristics Particle size (mm) Input amount (g) Water content (%) Response time (min) CO ₂ fixed amount (g-CO ₂ / ㎏-slag) Absorption amount (g-CO ₂ / ㎏-slag) Effective response rate (%) Before reaction After reaction Example One 1 or less 1,640 5 180 51.7 64.7 13 5.8 2 1 or less 4,920 15 180 51.7 75.9 24.2 10.7 3 1 or less 7,200 25 180 51.7 67.8 16.1 7.13 4 1 or less 11.480 35 180 51.7 65.6 13.9 6.2 Comparative Example One 1 or less 0 0 180 51.7 52.1 0.4 0.18 2 1 or less 13,120 40 180 51.7 55.7 4 1.8 3 1 to 20 4,920 15 180 1.2 3.5 2.3 0.65 4 20-40 4,920 15 180 0.7 2.0 1.3 0.37 5 40-70 4,920 15 180 0.7 1.5 0.8 0.23 [Note] CaO content of slag with particle size of 1 mm or less: 35.3 wt% CaO content of slag with particle size of 1-20 mm, 20-40 mm, 40-70 mm: 45.0 wt%

Through the above Table 1, the slag of Examples 1 to 4 in which the slag having a water content of 5 to 35% and the particle size of 1 mm or less was reacted with carbon dioxide gas according to the present invention, the CO ₂ fixed amount increased after the reaction than before the reaction, and the carbon dioxide absorption amount The silver slag was more than 10 g per kg, and the effective reaction rate was in the range of 6-11%. From this, the slag prepared according to the present invention can efficiently reduce carbon dioxide by absorbing and immobilizing a large amount of carbon dioxide. And it was found.

On the other hand, in Comparative Example 1, which contained no moisture (0% water content) and Comparative Example 2, which contained excess water (40% water content), the absorption of carbon dioxide was 4% or less, and the effective reaction rate was also 2% or less. Low value of.

In addition, in the case of Comparative Examples 3 to 5 in which the particle size of the slag was adjusted to 1 mm or more, the fixed amount of CO ₂ , the absorbed amount of carbon dioxide, and the effective reaction rate were all low.

From this, it can be seen that according to the present invention, when the slag having a water content of 5 to 35% and the particle size of 1 mm or less is reacted with carbon dioxide gas, carbon dioxide can be effectively reduced by efficiently absorbing and reacting carbon dioxide and immobilizing on the surface of the slag. Could.

Example 5

4,920 g of tap water was added to 32.8 kg of the steelmaking slag having a particle size of 1 mm or less discharged from the steelmaking process to adjust the water content to 15%, and the reactor was filled with a packing density of 2.4 g / cm 3. Thereafter, a gas having a carbon dioxide concentration of 20% was passed through a scrubber to saturate steam, and the saturated steamed carbon dioxide gas was blown to the lower end of the reactor at a flow rate of 20 L / min for 4 hours to complete the reaction. The temperature of the carbon dioxide gas blown was 23 ° C.

Example 6 and Comparative Examples 6-7

In Example 5, the reaction was carried out in the same manner as in Example 5, except that the reaction time was changed as shown in Table 2 below.

The fixed amount of carbon dioxide, the absorbed amount, and the effective reaction rate of the reaction samples of Example 5 or 6 and Comparative Examples 6 or 7 were measured in the same manner as above, and the results are shown in Table 2 below.

TABLE 2

division Reaction condition Carbon dioxide absorption characteristics Particle size (mm) Input amount (g) Water content (%) Response time (min) CO ₂ fixed amount (g-CO ₂ / ㎏-slag) Absorption amount (g-CO ₂ / ㎏-slag) Effective response rate (%) Before reaction After reaction Example 5 1 or less 1,640 5 180 51.7 64.7 13 5.8 6 1 or less 4,920 15 180 51.7 75.9 24.2 10.7 Comparative example 6 1 or less 0 0 180 51.7 52.1 0.4 0.18 7 1 or less 13,120 40 180 51.7 55.7 4 1.8

Through Table 2, in Examples 5 or 6 in which the slag having a water content of 5 to 35% and the particle size of 1 mm or less is reacted with carbon dioxide gas for 3 hours or more, the fixed amount, the absorption amount, and the effective reaction rate of carbon dioxide. It was confirmed that this appeared excellent.

On the other hand, in the case of Comparative Example 6 or 7 in which the slag and carbon dioxide gas was reacted for less than 3 hours, the absorption amount and the effective reaction rate of carbon dioxide were significantly lower than those of Example 5 or 6.

According to the present invention, by absorbing and immobilizing carbon dioxide on the surface of the slag with high efficiency to form a carbonation layer, not only can the carbon dioxide, which is a major factor of global warming, be efficiently reduced, but also the formation of highly alkaline effluent water and the generation of colored water from the slag. By preventing the formation of white turbid water and white sedimentation, there is an effect that can be usefully used as aggregate for civil engineering.                     

Although only described in detail with respect to the described embodiments of the present invention, it will be apparent to those skilled in the art that various modifications and variations are possible within the technical spirit of the present invention, it is natural that such variations and modifications belong to the appended claims. .

Claims (3)

A method of immobilizing carbon dioxide using slag, the method comprising: immobilizing carbon dioxide on the surface of the slag by reacting slag having a water content of 5 to 35% and having a particle size of 1 mm or less with carbon dioxide gas for at least three hours. Way. The method of claim 1, The carbon dioxide immobilization method using the slag, characterized in that the gas is saturated steam. A slag in which carbon dioxide is fixed to a surface to form a carbonation layer by the method of claim 1.