JP2000140651A - Fixing method of carbon dioxide - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide fixing method of carbon dioxide capable of economically treating a large quantity of carbon dioxide using inorganic waste, which is industrial waste. SOLUTION: Waste mortal powder 4 and a cation exchange resin 5 are coexisted with the cation exchange resin 5 in a 1st reaction liquid 3 consisting essentially of water to adsorb Ca2+ of the waste mortal powder 4 on the cation exchange resin 5. Next, the cation exchange resin 5 is regenerated and CaCO3 in the 2nd reaction liquid 8 produced in the 2nd reaction liquid 8 to fix CO2 by existing the cation exchange resin 5 in a 2nd reaction liquid 8 consisting essentially of water and bubbling CO2 to separate and extract Ca2+ into the 2nd reaction liquid 8.

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

[0001] The present invention relates to a method for fixing carbon dioxide.

[0002]

2. Description of the Related Art In recent years, the concentration of carbon dioxide in the atmosphere has rapidly increased, and is considered to be a main cause of global warming. Carbon dioxide is generated from economic activities and daily life, and reducing emissions is urgently needed to maintain the global environment. That is, Japan's total carbon dioxide emission in 1994 was 340 million tons in carbon terms,
It is said that there is a tendency to increase by about 5%. Current,
Carbon dioxide separation technology and effective utilization technology are being actively studied.

On the other hand, in the construction and civil engineering industries, a large amount of cement-based construction waste is released due to demolition of buildings, and in the steel industry, slag from blast furnaces and converters is necessarily released. That is, it is said that the amount of inorganic waste generated in Japan is 48 million tons of cement-based construction waste and 215.6 million tons of slag annually. Conventionally, most of these inorganic waste materials have only been used for landfills.

[0004]

However, it is still difficult to treat a large amount of generated carbon dioxide economically and in a large amount with the conventional carbon dioxide separation technology and the like. Therefore, if carbon dioxide can be processed economically and in large quantities using inorganic waste material, which is industrial waste, the reduction of industrial waste by effective use of inorganic waste material and the reduction of carbon dioxide emitted into the atmosphere will be achieved. It is expected to be compatible.

The present invention has been made in view of the above-mentioned conventional situation, and provides a method of fixing carbon dioxide which can economically and massively treat carbon dioxide by using inorganic waste material as industrial waste. Is to be solved.

[0006]

Means for Solving the Problems The present inventors have conducted intensive studies to solve the above-mentioned problems, and since inorganic waste materials contain a large amount of CaO, alkaline earth metal ions such as Ca ²⁺ are separated therefrom. If possible, it was thought that the alkaline earth metal ion could generate an alkaline earth carbonate to immobilize carbon dioxide. The inventors have found that it is effective to use a cation exchange resin for that purpose, and have completed the present invention.

That is, according to the method for fixing carbon dioxide of the present invention, an inorganic waste material and an alkaline earth metal ion of the inorganic waste material can be adsorbed by ion exchange in a first reaction solution containing water as a main component. By coexisting with resin,
An ion exchange step of adsorbing the alkaline earth metal ion on the cation exchange resin; and causing the cation exchange resin after the ion exchange step to exist in a second reaction solution containing water as a main component. By bubbling carbon dioxide through the reaction solution, the alkaline earth metal ions are separated and extracted in the second reaction solution to regenerate the cation exchange resin, and at least the alkaline earth metal in the second reaction solution is regenerated. A bubbling step of fixing the carbon dioxide by generating an alkaline earth carbonate in which the metal ion and the CO ₃ ^2- have reacted.

According to the tests by the inventors, according to the method for fixing carbon dioxide of the present invention, since the cation exchange resin is used in the ion exchange step, the inorganic waste material can be rapidly removed regardless of the properties of the inorganic waste material. Dissolve in The mechanism of this dissolution is that ion exchange occurs between the cation exchange resin and the alkaline earth metal ion eluted in trace amounts from the inorganic waste material in the first reaction solution containing water as a main component, and the first reaction Since the equilibrium state in the solution is impaired, it is considered that alkaline earth metal ions are eluted into the first reaction solution to make up for it. The ion exchange in the first reaction solution is generally performed by separating hydrogen ions from the functional groups introduced into the resin substrate of the cation exchange resin, while adsorbing alkaline earth metal ions of the inorganic waste material there. It is believed to occur.

In the bubbling step, since the alkaline earth metal ions can be separated and extracted in the second reaction solution, the cation exchange resin can be regenerated. Further, calcium carbonate (CaC) in which at least alkaline earth metal ions and CO ₃ ^2- have reacted in the second reaction solution.
O ₃₎ alkaline earth carbonates such as may be generated.

Therefore, according to the method for fixing carbon dioxide of the present invention, carbon dioxide can be economically and massively treated using inorganic waste material, which is industrial waste. The inorganic waste material is preferably in a powder form. Powdered inorganic waste materials are
This is because, during the ion exchange step, the alkaline earth metal ion is easily eluted and easily dissolved as a whole because the contact area with the first reaction solution is large. Also, the cation exchange resin is preferably in the form of powder or granules. The powdery or granular cation exchange resin is used in the first step during the ion exchange step.
This is because the contact area with the reaction solution is large, so that the alkaline earth metal ions are easily adsorbed and the reaction efficiency is high. Further, the powdery or granular cation exchange resin is easy to regenerate in the bubbling step and has excellent workability. In addition, in the ion exchange step, it is preferable that the first reaction solution is stirred or vibrated. It is considered that the agitation or vibration promotes the elution of alkaline earth metal ions from the inorganic waste material, or promotes the contact between the cation and the cation exchange resin, and facilitates ion exchange in the entire first reaction solution. It is. Similarly, at the time of the bubbling step, it is preferable to stir or vibrate the second reaction solution. This is because the stirring and vibration promote the separation and extraction of the alkaline earth metal ion from the cation exchange resin, and can improve the fixed amount of carbon dioxide.

In the bubbling step, it is preferable that a base is present in the second reaction solution. This is because the reaction of immobilizing carbon dioxide easily proceeds under basicity of about pH 10. As the base, ammonia water, NaOH aqueous solution, diethylamine, diethylenetriamine, ethylenediamine, trimethanolamine, and the like can be used, but ammonia water is preferably used. This is because ammonia water can improve the fixed amount of carbon dioxide.

The first reaction tank in the ion exchange step can be used as it is in the second reaction tank in the bubbling step. In this case, the reactor becomes a single tank type,
Since the ion exchange step and the bubbling step can be performed without changing the reaction tank accommodating the reaction solution, good workability can be obtained. On the other hand, in the case of a single-tank type, continuous reaction is difficult to perform, so that the reaction efficiency deteriorates. For this reason,
The reactor is mainly composed of a two-tank type, a first reaction tank for performing an ion exchange step and a second reaction tank for performing a bubbling step, and the inorganic waste material and the cation exchange resin can be smoothly moved. Is preferred.

[0013]

DESCRIPTION OF THE PREFERRED EMBODIMENTS Embodiments 1 and 2 embodying the present invention will be described below with reference to the drawings. (Embodiment 1) In Embodiment 1, the following ion exchange step and bubbling step are executed according to the flowchart of FIG.

Mortar waste was used as the inorganic waste. After coarsely crushing this mortar waste with a jaw crusher, etc.
The mixture was wet-ground with a mill for 24 hours, and dried for one week with a drier at 90 ° C. to obtain mortar waste material powder 4. The average particle size of the obtained mortar waste material powder 4 is 6.55 μm. According to the XRD chart, the constituent phases of the mortar waste material powder 4 are quartz (quartz), albite (albite),
Calcite, chlorite (clinochl)
ore) and muscovite. The chemical composition (% by mass) of the mortar waste material powder 4 is as follows:
According to the XRF analysis, it was as shown in Table 1.

[0015]

[Table 1] However, this mortar waste material powder 4 contains C together with CaO.
aCO _{3 is} also included, and the content of CO ₂ in CaCO ₃ is 4.08% by mass according to the JIS method (R9011).
From the mortar waste material powder 4
CaO capable of fixing ₂ is estimated to be 11.8% by mass.

Further, as the cation exchange resin 5, a gel type strongly acidic cation exchange resin (Diaion SK; manufactured by Mitsubishi Chemical Corporation, granular having a diameter of about 0.2 mm, specific gravity 1.1)
Was prepared. After washing this cation exchange resin 5 with a large amount of distilled water, it was filtered under reduced pressure to obtain a wet state. "Ion exchange step" First, in step S1, the first
A washing basket 2 having an opening of 149 μm is housed in the reaction tank 1.
Further, a first reaction liquid 3 consisting of 300 ml of distilled water in the first reaction tank 1, 4.0 g of mortar waste material powder 4, and 5.0.
0 g of the cation exchange resin 5 are introduced. Then, the mixture is stirred by the stirrer 6 for 15 minutes. Thereby, the Ca ²⁺ removed from the mortar waste material powder 4 was added to the cation exchange resin 5.
Is adsorbed.

Thereafter, in step S2, the first reaction
Lift the washing basket 2 from the tank 1 and ²⁺Cation adsorbed
Exchange resin 5 with remaining mortar waste powder 4 and first reaction
Separate from liquid 3. Then, in step S3, the remaining
Mortar waste powder 4 and first reaction liquid 3 by filtration
To separate. The first reaction liquid 3 is the first reaction tank 1 in step S1.
Put back inside. In step S4, distilled water 7 is used.
To wash the cation exchange resin 5
Of mortar waste powder 4 after treatment adhering to the surface of
You. "Bubbling process" Then, in step S5, 3
A second reaction liquid 8 containing 00 ml of distilled water is contained.
Prepare two reaction tanks 9 and wash basket 2 in second reaction tank 9
The cation exchange resin 5 is stored in the container. And stirrer
While stirring at 10, CO_TwoGas (CO_Two100%)
Bubble at 0.15 ml / min for 10 minutes. Thus,
2 CO in reaction liquid 8_TwoAfter making the concentration constant, pipette 1
Ammonia water with a concentration of 29% is used as base substance 12 according to 1.
Added to the second reaction solution 8 and kept at pH 10 for another 10 minutes
CO_TwoThe gas is bubbled at a flow rate of 0.15 ml / min. What
The second reaction tank 9 is also provided with a pH meter 13. This
Thus, the second reaction liquid 8 (base substance)
12 inclusive. )²⁺Cation exchange
While regenerating the exchange resin 5, the second reaction liquid 8 (basic substance 1
2 inclusive. ) In at least Ca²⁺And CO_Three ^2-React with
(Carbonation), Ca as alkaline earth carbonate 14
CO_ThreeAnd precipitate.

Thereafter, in step S6, the second reaction
Lift the washing basket 2 from the tank 9 and remove Ca ²⁺Extracted and extracted
The ion exchange resin 5 is mixed with the alkaline earth carbonate 14 and the second
Separate from the reaction solution 8 (including the base substance 12). And
In step S7, the alkaline earth carbonate 14 and the second
The reaction solution 8 (including the base substance 12) is separated by filtration.
You. Alkaline earth carbonate 14 is dried in an 80 ° C.
After drying for days, it was weighed and identified as calcite by XRD. other
On the other hand, the second reaction liquid 8 (including the base substance 12) is prepared in Step S
5 is returned to the second reaction tank 9. Also, in step S8
Then, the cation exchange resin 5 is washed using distilled water 15,
Alkaline earth carbonic acid attached to the surface of the cation exchange resin 5
The salt 14 is removed.

Next, in step S9, the cation exchange resin 5 is placed in a third reaction solution 16 comprising hydrochloric acid and distilled water.
And the cation exchange resin 5 is almost completely regenerated.
This cation exchange resin 5 is used in the first reaction tank 1 in step S1.
Put back inside. Thus, in the first embodiment, by using the mortar waste material powder 4 as the industrial waste, it can be understood that CO ₂ , which has recently been required to be reduced from the viewpoint of maintaining the global environment, can be economically and massively fixed. "Evaluation 1" As the base 12, an aqueous NaOH solution, diethylamine, diethylenetriamine, ethylenediamine or trimethanolamine was used in place of the above-mentioned ammonia water.
4 was examined.

As a result, CaCO ₃ cannot be generated for the bases 12 other than ammonia water and diethylamine,
When an aqueous NaOH solution was used, Na ₂ CO ₃ was mainly produced as alkaline earth carbonate 14. The reason is that NaOH
The aqueous solution is a strong base having a high ionization degree, and the high concentration of Na ⁺ in the second reaction liquid 8 makes it easy to react with CO ₃ ²⁻ , whereas the aqueous ammonia is a weak base having a low ionization degree. And the concentration of NH ₄ ⁺ in the second reaction liquid 8 is low,
O ₃ ² - reaction with are presumed to be less likely to occur. On the other hand, with respect to diethylenetriamine, ethylenediamine and trimethanolamine, although the carbonation reaction was expected to be accelerated, black tar-like organic substances which could not be identified by XRD were generated as alkaline earth carbonates 14. pH
It is considered that these were added in large amounts in order to adjust. In addition, calcite and aragonite (a
ragonites), but mainly aragonite could be formed with diethylamine.

Therefore, it is understood that it is preferable to use diethylamine as the chloride 12 in producing aragonite. The recovery rate (%) of CaCO ₃ is 21.0% when ammonia water is used, and 7.4% when dieteramine is used. A higher recovery rate can be secured when ammonia water is used. I understand.

Therefore, it can be seen that the use of ammonia water as the chloride 12 is preferable from the viewpoint of improving the fixed amount of CO ₂ . "Evaluation 2" The reaction time for bubbling CO ₂ gas was 5
８０80 minutes, and the relationship between the reaction time (minutes), the recovery rate (%) of CaCO ₃ , and the effect on the alkaline earth carbonate 14 was examined.

FIG. 2 shows the relationship between the reaction time and the recovery rate.
FIG. 2 shows that the longer the reaction time is, the higher the recovery is, and the amount of fixed CO ₂ can be improved. "Evaluation 3" Further, the amount of the mortar waste material powder 4 was set to 0.5 to
8.0 g, Ca ²⁺ adsorption rate (%) on cation exchange resin 5, CaCO ₃ generation amount (g) and recovery rate (%)
And sought a relationship. The results are shown in FIG.

From FIG. 3, it can be seen that, with the improvement of the adsorption rate, the production amount is large and the recovery rate is high, but when the adsorption rate is about 50%, the production amount and the recovery rate are saturated. In addition, when the cation exchange resin 5 before and after the bubbling step was compared by line analysis of the cross section and surface analysis of the cross section, it was found that Ca ²⁺ was uniformly adsorbed to the inside before the bubbling step, and that after the bubbling step, The concentration of Ca ²⁺ decreases, and Ca near the surface decreases.
It was confirmed that the concentration of ²⁺ was lowered. For this reason,
The generation of CaCO ₃ does not occur inside the cation exchange resin 5, but Ca ²⁺ elutes from the surface of the cation exchange resin 5 into the second reaction solution 8 (including the base substance 12), 2
In the reaction solution 8 (including the base substance 12), the Ca ²⁺
And CO ₃ ^2- react with each other. Then, Ca which is insufficient on the surface of the cation exchange resin 5
It is assumed that Ca ²⁺ diffuses from inside the cation exchange resin 5 so as to supplement ²⁺ . Therefore, when the adsorption rate is about 50%, the amount of production and the recovery rate are saturated because the reaction time is less than 10%.
And the adsorption rate is about 50%, the diffusion rate of Ca ²⁺ or the dissolution rate of CO ₂ in the second reaction liquid 8 (including the base substance 12) is rate-limiting, and the cation exchange resin 5
The total amount of adsorbed Ca ²⁺ is not consumed in the CaCO ₃ produced is estimated that the amount of CaCO ₃ is because reach an equilibrium value at 10 min reaction time.

Therefore, it can be seen that, if the amount of the mortar waste material powder 4 is increased, the adsorption rate of Ca ²⁺ to the cation exchange resin 5 can be increased, thereby improving the amount of fixed CO _2. . "Evaluation 4" Also, the pH of the second reaction liquid 8 (including the base substance 12) was changed to 9, 9.5, 1 by changing the amount of aqueous ammonia as the base substance 12 added to the second reaction liquid 8.
The level was changed to four levels of 0 and 10.5, and the relationship between the pH of the second reaction liquid 8 (including the base substance 12) and the recovery rate (%) of CaCO ₃ was determined. FIG. 4 shows the results.

As shown in FIG. 4, the highest recovery rate can be obtained when the pH of the second reaction liquid 8 (including the base substance 12) is about 10, but the recovery is performed depending on the pH of the second reaction liquid 8 (including the base substance 12). It can be seen that the rate hardly changes. One of the causes, due to the relatively short reaction times, not promoted dissolution of CO _2, CO ₃ ^{2-concentration} second reaction liquid 8
It is thought that this is because it did not significantly contribute to the pH of the base (including the base 12). In addition, the amount of aqueous ammonia increases to maintain the pH at a predetermined value.
(Including base 12), the amount of CO ₃
It is also considered that the reason is that the contact between ^2- and Ca2 ^{+ -adsorbed} cation exchange resin 5 is hindered.

According to the XRD chart of the alkaline earth carbonate 14, no difference in the formation phase due to pH was recognized. Therefore, it is understood that the pH of the second reaction liquid 8 (including the base substance 12) is preferably about 10. "Evaluation 5" It is expected that exhaust gas from factories and the like will be used as a CO ₂ supply source. Because of this, CO
_{2 The} concentration (%) was changed. The balance of the gas except for CO ₂ is N ₂ . In this way, the relationship between the CO ₂ concentration and the recovery rate (%) of CaCO ₃ was determined under the reaction time of 10 to 40 minutes. FIG. 5 shows the results.

FIG. 5 shows that as the CO ₂ concentration decreases, the recovery rate decreases accordingly. The behavior of the recovery rate with the change in the CO ₂ concentration was as follows:
Although there is no significant difference in the reaction time, the reaction time of 40 minutes is less than that of the reaction time of 20 minutes at the same CO ₂ concentration.
It can be seen that the recovery rate is about twice as high. This is because the CO ₂ concentration decreases and the second reaction solution 8 (including the base 12).
CO ₂ ^2- and C ₃
Since the chance of contact with the cation exchange resin 5 to which a ²⁺ has been adsorbed decreases, the recovery rate of CaCO ₃ decreases, while the reaction time is lengthened to increase the second reaction liquid 8 (including the base substance 12). This is presumed to be because the concentration of CO ₃ ^{2- in} ) is secured and the fixed amount of CO ₂ is improved.

According to the XRD chart of the alkaline earth carbonate 14, when the CO ₂ concentration was low and the reaction time was short, the amount of CaCO ₃ produced was low. In particular, when the CO ₂ concentration was 5% and the reaction time was 10 minutes, the amount of generated CaCO ₃ was lower and the amount of fixed CO ₂ was lower as the XRD analysis became more difficult. Therefore, it is understood that it is preferable to use a gas having a high CO ₂ concentration. In addition, CO ₂ such as exhaust gas
When using a low concentration gas bubbling step, the reaction time is prolonged, increasing the stirring speed, vibrating, CO ₂
Increasing the flow rate of the gas, etc finer bubbles CO ₂ gas, a means of increasing the frequency of contact with the cation exchange resin 5 with adsorbed CO ₃ ^2- and Ca ²⁺ to promote the dissolution of CO ₂ It may be necessary. "Evaluation 6" is changed in the second reaction solution 8 (containing the nucleotide product 12.) The stirring speed of 100 to 400 (rpm), to determine the relationship between the recovery rate of the stirring speed and CaCO ₃ (%). FIG. 6 shows the results.

FIG. 6 shows that as the stirring speed increases, C
It can be seen that the recovery rate of aCO ₃ is improved and the fixed amount of CO ₂ is also improved. By increasing the stirring speed, the frequency of contact with CO ₃ ^2- and dissolved and Ca ²⁺ of CO ₂ it is believed to be due to enhanced. Further, according to the XRD chart of the alkaline earth carbonate 14, it was confirmed that there was no difference in the generated phase due to the difference in the stirring speed.

Therefore, when a gas having a low CO ₂ concentration such as exhaust gas is used in the bubbling step, it is considered that increasing the stirring speed is effective. "Evaluation 7": The second reaction liquid 8 (base substance 12) in the second reaction tank 9
including. In order to oscillate (2), an ultrasonic transmitter was provided in the second reaction tank 9, and the frequency was changed at three levels of 28 kHz, 45 kHz, and 100 kHz. At this time, stirring was not performed. Thus, the relationship between the ultrasonic frequency and the recovery rate (%) of CaCO ₃ was obtained. FIG. 7 shows the results.

FIG. 7 shows that the lower the frequency, the more CaCO ₃
It can be seen that the recovery rate is increased, a fixed amount of CO ₂ can be improved. However, the higher the frequency, the lower the amount of generated CaCO _{3 and} the lower the amount of fixed CO ₂ . Due to the effect of cavitation generated by using ultrasonic waves, a frictional force is generated between the second reaction liquid 8 (including the base substance 12) and the cation exchange resin 5 adsorbing Ca ²⁺ , whereby Ca 2 + It is presumed that the bond of the cation exchange resin 5 having adsorbed ²⁺ is broken.

According to the XRD chart of the alkaline earth carbonate 14, the formation of aragonite was confirmed when the frequency was low. Therefore, the second reaction solution 8 is
When vibrating (including the base substance 12), it is understood that a relatively low frequency is more suitable for fixing CO ₂ . "Evaluation 8" Similarly to the evaluation 7, the second reaction tank 9 is shaken to vibrate the second reaction liquid 8 (including the base substance 12) in the second reaction tank 9.
Was provided with an ultrasonic transmitter, and the output was changed at three levels. At this time, stirring was not performed. Thus, the relationship between the intensity of the ultrasonic wave and the recovery rate (%) of CaCO ₃ was obtained. The amount of ammonia water (l) used to maintain the second reaction solution 8 (including the base substance 12) at pH 10 and CaCO ₃
The relationship with the recovery rate (%) was determined. FIG. 8 shows the results.

From FIG. 8, the magnitude of the output of the ultrasonic wave is CaCO
_It can be seen that the recovery rate of No. ₃ and thus the fixed amount of CO ₂ are not so affected, and the amount of fixed CO ₂ is improved by not vibrating by ultrasonic waves. On the other hand, it can be seen that the amount of ammonia water used is lower when not vibrating by ultrasonic waves. This is due to cavitation when using ultrasonic waves.
This is because the temperature of the reaction solution 8 (including the base substance 12) increases, and the pH decreases due to the ionic product. For this reason, when vibrating with ultrasonic waves, the amount of ammonia water used to maintain pH 10 increases, and the proportion of Ca ²⁺ in the second reaction liquid 8 (including the base 12) is considered to decrease. . Further, the second reaction liquid 8 is vibrated by ultrasonic vibration.
When the temperature of the base (including the base 12) increases, C
It is considered that the solubility of O ₂ decreases and the frequency of contact between CO ₂ and Ca ²⁺ decreases.

Further, according to the XRD chart of the alkaline earth carbonate 14, there was no difference in the generated phases at all three levels.
Therefore, the second reaction liquid 8 (basic substance 12
Is vibrated, it is assumed that it is necessary to take another means for maintaining the temperature of the second reaction liquid 8 (including the base substance 12). "Evaluation 9" 0~15l the flow rate of the second reaction solution 8 (containing the nucleotide product 12.) CO ₂ gas supplied into the (CO ₂ 100%)
/ Min, and the relationship between the CO ₂ gas flow rate and the recovery rate (%) of CaCO ₃ was determined. FIG. 9 shows the results.

FIG. 9 shows that the smaller the flow rate, the lower the recovery rate and the lower the fixed amount of CO ₂ . However, even if the flow rate is increased, the recovery rate is saturated, and the fixed amount of CO ₂ reaches a plateau. It is assumed that the concentration of CO ₃ ^2- in the second reaction liquid 8 (including the base substance 12) is saturated. Further, according to the XRD chart of the alkaline earth carbonate 14, there was no difference in the generated phase due to the difference in the flow rate of the CO ₂ gas.

Therefore, it is necessary to determine the flow rate of the CO ₂ gas in consideration of the reaction efficiency in relation to the amount of the second reaction solution 8 (including the base substance 12), the reaction time, and the like. it is conceivable that. Embodiment 2 In Embodiment 2, the reaction apparatus shown in FIG. 10 is used. In this reaction apparatus, a first reaction tank 21 and a second reaction tank 22 are provided in a processing chamber 20. A washing basket 23 having an opening of 177 μm is stored in the first reaction tank 21, and a washing basket 2 having an opening of 177 μm is also stored in the second reaction tank 22.
4 are stored. In addition, an electric conductivity meter 25 and a variable output stirrer 26 are provided in the first reaction tank 21 and the washing basket 23. On the other hand, a pH meter 27 and a variable output stirrer 2 are provided in the second reaction tank 22 and the washing basket 24.
8 and a nozzle 31 connected via a pump 30 to a cylinder 29 containing ammonia water.
Is provided. In addition, C
Nozzle 33 connected to cylinder 32 containing O ₂ gas
And an ultrasonic transmitter 34 is provided on the inner bottom surface of the second reaction tank 22.

A pipe 36 is connected to the bottom of the first reaction tank 21 via a valve 35. A filtrate receiving tank 38 is provided with the dewatering basket 37 having a large filter paper of 5B facing upward. A forked pipe 40 is connected to the bottom of the filtrate receiving tank 38 via a pump 39. One end of the pipe 40 is located inside the first reaction tank 21 via a valve 41, and the other end of the pipe 40 is located outside via a valve 42.

Further, a valve 43 is provided at the bottom of the second reaction tank 22.
The pipe 44 is connected via a pipe No. A filtrate receiving tank 46 is provided with the dewatering basket 45 having a large filter paper of 5B facing upward. A forked pipe 48 is connected to the bottom of the filtrate receiving tank 46 via a pump 47. One end of the pipe 48 is located inside the second reaction tank 22 via a valve 49, and the other end of the pipe 48 is located outside via a valve 50.

An exhaust pipe 52 connected to the outside via an exhaust fan 51 is provided above the processing chamber 20. Also,
A control panel 53 is provided outside the processing chamber 20, and an electric conductivity meter 25, stirrers 26 and 28, a pH meter 27, a pump 3
0, 39, 47, ultrasonic transmitter 34 and exhaust fan 51
Are connected to the control panel 53. The ion exchange step and the bubbling step are performed by such a reaction apparatus as in the first embodiment. However, in consideration of workability, the ion exchange step is performed in the first reaction tank 21 and the bubbling step is performed in the second reaction tank 22. “Ion exchange step”, that is, a first reaction solution composed of a fixed amount of distilled water, an inorganic waste material such as the mortar waste material powder, and a cation exchange resin are charged into the first reaction tank 21, and the electric conductivity is measured. Stirrer 26 while checking with a total of 25
For a certain period of time.

Then, the valve 35 is opened, the cation exchange resin adsorbing Ca ²⁺ is left in the washing basket 23, and the remaining inorganic waste material and the first reaction solution are passed through the dewatering basket 37 to the filtrate receiving tank 38.
Receive at At this time, the inorganic waste material after the treatment is left on the filter paper of the dewatering basket 37, so that the first reaction liquid is stored in the filtrate receiving tank 38. This first reaction solution is circulated into the first reaction tank 21 via the pump 39 and the valve 41 via the pump 39 and the valve 41 if reusable, and the pipe 40 via the pump 39 and the valve 42 if not reusable. Is discharged to the outside. The treated inorganic waste material remaining on the filter paper of the dewatering basket 37 can be dewatered and returned to the first reaction tank 21 again, or can be reused elsewhere. “Bubbling step” The cation exchange resin left on the washing basket 23 after the ion exchange step is transferred into the washing basket 24. Here, the cation exchange resin can be dehydrated and then transferred. In the second reaction tank 24, distilled water and cylinder 2
A fixed amount of each of the ammonia water added from 9 through the pump 30 and the nozzle 31 is stored, and these constitute a second reaction liquid. And pH meter 2
While confirming in step 7 and stirring with the stirrer 28, CO ₂ gas is bubbled through the cylinder 32 and the nozzle 33 at a constant flow rate and for a fixed time.

Then, the valve 43 is opened, and the cation exchange resin from which Ca ²⁺ has been separated and extracted is left in the washing basket 24 and CaCO 2 ⁺
_{The third} and second reaction solutions are passed through a dewatering basket 45 to a filtrate receiving tank 46.
Receive at At this time, since CaCO ₃ remains on the filter paper of the dewatering basket 45, the second reaction liquid is stored in the filtrate receiving tank 46. If the second reaction solution can be reused, the second reaction tank 22 is connected to the second reaction tank 22 by a pipe 48 via a pump 47 and a valve 49.
If it cannot be reused, the pump 47 and the valve 5
The gas is discharged to the outside through the pipe 48 through the pipe 0. here,
The cation exchange resin remaining on the washing basket 24 is dehydrated, washed with hydrochloric acid or the like, returned to the first reaction tank 21 again, and reused. Further, CaCO ₃ remaining on the filter paper of the dewatering basket 45 can be dewatered and reused for other purposes.

Thus, in the second embodiment, it is possible to secure both CaCO ₃ and immobilize CO ₂ under excellent workability.

[Brief description of the drawings]

FIG. 1 is a flowchart of a first embodiment.

FIG. 2 is a graph showing a relationship between a reaction time and a recovery rate in Evaluation 2 of Embodiment 1.

FIG. 3 is a graph showing a relationship between a Ca ²⁺ adsorption rate, a CaCO ₃ generation amount, and a recovery rate according to Evaluation 3 of the first embodiment.

FIG. 4 is a graph showing the relationship between the pH of a second reaction solution (including a base substance) and the recovery rate of CaCO _{3 according to} Evaluation 4 of Embodiment 1.

FIG. 5 shows CO ₂ concentration and Ca
Is a graph showing the relationship between the recovery rate of the CO _3.

FIG. 6 shows stirring speed and CaC in connection with Evaluation 6 of Embodiment 1.
O is a graph showing the relationship between the recovery rate of _3.

FIG. 7 is a graph showing a relationship between an ultrasonic frequency and a recovery rate of CaCO _{3 according} to Evaluation 7 of the first embodiment.

FIG. 8 is a graph showing the relationship between the strength of ultrasonic output, the amount of used ammonia water, and the recovery rate of CaCO _{3 according to} Evaluation 8 of Embodiment 1.

FIG. 9 relates to the flow rate of CO ₂ and C
is a graph showing the relationship between the recovery rate of the ACO _3.

FIG. 10 is a schematic configuration diagram of a reaction apparatus according to a second embodiment.

[Explanation of symbols]

 3 ... First reaction liquid 4 ... Inorganic waste material (mortar waste material powder) 5 ... Cation exchange resin 8 ... Second reaction liquid 14 ... Alkaline earth carbonate 12 ... Base

 ──────────────────────────────────────────────────続 き Continuing from the front page (72) Inventor Hiroki Manami 5-1-1 Koie Honcho, Tokoname-shi, Aichi Pref. Inside Inax (72) Inventor Hiroaki Kuno 5-1-1 Koiehonmachi, Tokoname-shi, Aichi Inax Corporation (72) Inventor Tadashi Nishino 694 Hirokamocho, Machida-shi, Tokyo F-term (reference) 4G046 JB08 JC06 4G075 AA04 AA37 BB03 BB04 BB05 BB10 BD27 CA51 CA55 4G076 AA16 AB28 BA34 BE04

Claims (3)

[Claims] 1. A method according to claim 1, wherein said inorganic waste material and a cation exchange resin capable of adsorbing an alkaline earth metal ion of said inorganic waste material by ion exchange coexist in a first reaction solution containing water as a main component. An ion exchange step of adsorbing an earth metal ion to the cation exchange resin; and causing the cation exchange resin after the ion exchange step to exist in a second reaction liquid containing water as a main component. Bubbling carbon dioxide into the second reaction solution to separate and extract the alkaline earth metal ions in the second reaction solution to regenerate the cation exchange resin, and at least the alkaline earth metal in the second reaction solution. A method for fixing carbon dioxide, comprising: a bubbling step of fixing an carbon dioxide by generating an alkaline earth carbonate in which ions and CO ₃ ^2- have reacted. 2. The method according to claim 1, wherein a base is present in the second reaction solution. 3. The method according to claim 1, wherein the first reaction solution after the ion exchange step is a second reaction solution before the bubbling step.
Or the method for fixing carbon dioxide according to 2 above