JP3338828B2 - Method for solidifying CaCO3 and / or MgCO3 - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

The present invention relates to CaCO ₃ and / or M
It relates to a method of solidifying GCO _3, in particular, to a method of solidifying CaCO ₃ and / or MgCO _3, or these are mainly substances at mild process conditions.

[0002]

2. Description of the Related Art C in exhaust gas discharged in various industrial fields
Since there is a concern about the influence of O ₂ on the global warming phenomenon, studies are underway on reducing CO _{2 in} the atmosphere.

Conventionally, as a technology for reducing atmospheric CO ₂ ,
Absorbing gas containing ₂ such as combustion exhaust gas into seawater,
₂ is immobilized as CaCO ₃ and / or MgCO ₃ . Thus, immobilized CaCO ₃ or Mg
Attempts have been made to solidify CO ₃ and use it effectively for construction and civil engineering materials.

Conventionally, as a method for solidifying CaCO ₃ , a hot press method or a hydrothermal hot press method has been proposed.

[0005]

[SUMMARY OF THE INVENTION However, since the method of solidifying conventional CaCO ₃ in need of treatment conditions both conforming to generate conditions of marble and limestone is CaCO ₃ solidification of natural, processing conditions Due to the severe conditions of high temperature and high pressure and the complicated equipment, there are drawbacks that they are not suitable for mass processing, consume large amounts of energy, and require high processing costs.

The present invention solves the above-mentioned conventional problems, and provides
It is an object of the present invention to provide a method capable of solidifying CO ₃ and / or MgCO ₃ or a substance containing these as a main component under mild conditions.

[0007]

According to a first aspect of the present invention, there is provided a method for solidifying CaCO ₃ and / or MgCO ₃ , wherein CaCO ₃ and / or MgCO ₃ or a material containing these as a main component contains
O, Ca (OH) ₂ , MgO, Mg (OH) ₂ , one or more Ca and / or Mg-based materials selected from the group consisting of slag and concrete waste, silica-based materials , CaCO ₃ and / Or MgCO ₃ or silica based
Substances that increase the solubility of a substance (hereinafter “solubility enhancing substances”)
There is that. ) Is mixed, and then CaCO ₃ and / or Mg is added using an autoclave reaction under a saturated vapor pressure.
The dissolution and reprecipitation reaction of CO ₃ proceed, and (CaO and / or
Or MgO) to the generation of -SiO ₂ -H ₂ O-based solid material
Ri, characterized in that solidified.

[0008] CaCO ₃ of 請 Motomeko 2 and / or MgCO
₃ The method of solidification, in the method of claim 1, solubility enhancing _{substance, LiOH, NaOH, KOH, NH} 4 OH, L
i ₂ CO ₃ , Na ₂ CO ₃ , K ₂ CO ₃ , (NH ₄ ) ₂
CO ₃ , LiHCO ₃ , NaHCO ₃ , KHCO ₃ , N
H ₄ HCO ₃ , LiNO ₃ , NaNO ₃ , KNO ₃ , N
H ₄ NO ₃ , Ca (NO ₃ ) ₂ , LiF, NaF, K
F, NH ₄ F, LiCl, NaCl, KCl, NH ₄ C
1, LiBr, NaBr, KBr, and NH ₄ Br, or one or more selected from the group consisting of NH ₄ Br.

Hereinafter, the present invention will be described in detail.

The CaCO ₃ and / or MgCO _{3 of the} present invention
In the solidification method, as the raw material CaCO ₃ and / or MgCO ₃ or a substance containing these as a main component (hereinafter referred to as “raw material”), for example, CO ₂ in the combustion exhaust gas is absorbed into seawater or the like. Let CaCO ₃ and / or
Or a substance obtained by immobilization as MgCO ₃ , but is not limited to these substances.
The present invention relates to CaCO ₃ and / or MgCO ₃ , or C
If the ACO ₃ and / or MgCO ₃ substances which mainly can be effectively applied. This material may be dolomite, basic MgCO ₃ .

As the silica-based material, amorphous SiO ₂ ,
Other crystalline SiO _2, silica sand, Kira fine sand, diatomaceous earth, clay, silica fume, white carbon, tile waste, glass waste, brick waste, slag, cement and concrete waste, coal ash, sludge,釉汚mud, Industrial waste after extracting sludge incineration ash and Ca (eg, cement and concrete waste,
Slag, glaze sludge, coal ash, sludge incineration ash, glass waste Ca
Extracted) can be used. By these silica-based material as the Ca and / or Mg based material reacts, (CaO and / or MgO) -SiO ₂ -H ₂ O-based solid material in a solidified body obtained is efficiently generated In addition, the strength of the solidified body can be increased.

If the proportion of the silica-based material is too large, the proportion of the raw material is relatively reduced, and the efficiency in terms of effective utilization by solidification of CaCO ₃ and / or MgCO ₃ is reduced. The amount of the system material used is preferably such that the proportion of the mixed material in the raw material is 50% by weight or less, particularly 10 to 30% by weight in terms of SiO ₂ .

As the Ca and / or Mg-based substance, Ca
One or more of O, Ca (OH) ₂ , MgO, Mg (OH) ₂ , slag, and concrete waste are used. Among them, CaO and / or Ca (OH) ₂ or those containing Ca (OH) ₂ as a main component are preferable.
Is preferably digested before molding. In addition,
Slag and concrete waste also act as silica-based materials.

The proportion of the Ca and / or Mg-based material in the raw material after mixing is calculated as CaO and / or
It is preferable that the content be 50% by weight or less, especially 10 to 30% by weight in terms of O.

The total amount of the silica-based material and the Ca and / or Mg-based material is such that the proportion occupied in the mixed raw material is SiO
50% by weight in ₂ conversion and CaO conversion and / or MgO conversion
It is preferable that the ratio is less than the above without reducing the ratio of the raw material.

LiOH, Na
OH, KOH, NH ₄ OH, Li ₂ CO ₃ , Na ₂ CO
₃ , K ₂ CO ₃ , (NH ₄ ) ₂ CO ₃ , LiHCO ₃ ,
NaHCO ₃ , KHCO ₃ , NH ₄ HCO ₃ , LiNO
₃ , NaNO ₃ , KNO ₃ , NH ₄ NO ₃ , Ca (NO
₃ ) ₂ , LiF, NaF, KF, NH ₄ F, LiCl,
NaCl, KCl, NH ₄ Cl, LiBr, NaBr,
Alkaline substances such as alkali hydroxides such as KBr and NH ₄ Br, alkali salts, alkali carbonates, alkali hydrogen carbonates and alkali halides; and ammonium substances,
Substances containing these are preferred. Further, a substance containing alkali oxide (eg, glass, mineral, or the like) is also suitable.
Preferably, this solubility enhancing substance utilizes industrial waste. Note that these solubility enhancing substances are CaC
It has the effect of increasing the solubility of O ₃ , MgCO ₃ and / or silica-based substances. A plurality of such solubility enhancing substances may be mixed at the same time.

It is preferable that the content of the alkali metal ion or ammonium ion in the raw material after mixing is 10 wt% or less, particularly 0.1 to 5 wt%. .

The raw material is a Ca and / or Mg-based material,
The solidified raw material obtained by mixing the silica-based substance and the solubility-enhancing substance is molded into a desired shape by a molding method such as press molding, cast molding, extrusion molding, or casting, and then subjected to an autoclave treatment. Incidentally, the solidified material is not particularly perform molding, after it was autoclaved processed, molded, may be further autoclaving.

In the present invention, the autoclave treatment liquid may be water or a solution of the above-mentioned alkaline substance.

The solution of an alkaline substance contains 5 mol of an alkali metal ion or ammonium ion contained therein.
It is preferable that the concentration be 1 / l or less, especially 0.01 to 1 mol / l.

The autoclave treatment is performed at 100 to 300
° C, especially a saturated vapor pressure of about 150 to 250 ° C (40 kg
(f / cm ² or less), and the treatment time is usually about 2 to 20 hours, particularly about 5 to 10 hours.

The obtained solid is dried under appropriate conditions as needed, and then used as various construction and civil engineering materials.

In the present invention, the raw material may be surface-treated by acid treatment, treatment with an ion exchange resin, or the like.

In the present invention, BaCO ₃ or SrCO ₃
Application to solidification can also be expected.

[0025]

In [act invention method, the autoclaving, lysis and re-precipitation reaction of CaCO ₃ and / or MgCO ₃ is advanced, solid particles such as CaCO ₃ and / or MgCO ₃ is attached. As a result, the temperature is lower than that of the conventional method,
Under mild conditions of low pressure, CaCO ₃ and / or MgCO _3
3 or a substance containing these as a main component can be solidified.

In particular, in the present invention, the starting material is Ca
And / or a mixture of a Mg-based material and a silica-based material for autoclaving, so that (CaO and / or MgO)-
Due to the generation of the SiO ₂ —H ₂ O-based solid substance, a high-strength solid can be obtained.

Furthermore, for use an alkaline substances which increase the solubility of CaCO ₃ and / or MgCO _3, it is possible to obtain even higher strength concrete substance.

[0028]

The present invention will be described more specifically with reference to the following Reference Examples, Examples and Comparative Examples . In addition, Reference Example, Example 及
CaCO ₃ , MgCO ₃ and S used in Comparative Examples
The iO ₂ raw material is as shown in Table 1 below. Reagents were used for other raw materials.

[0029]

[Table 1]

The bending strength of each sample was measured by measuring the distance between the spans of 30 mm and the crosshead speed of 0.5 mm / m.
The measurement was performed under the three-point bending strength measurement conditions of "in".

Reference Example 1, Comparative Example 1 The solidified raw materials were dry-mixed in a mortar with the composition shown in Table 2,
40 mm × 10 mm × subjected to pressure molding at 0 kgf / cm ²
A molded body having a thickness of about 10 mm was obtained. Table 2 shows the bending strength of the obtained molded body. Put each compact in an autoclave,
It was solidified by treatment under the conditions shown in Table 2. It should be noted that 29 liters of distilled water was placed in the autoclave container (capacity: 2000 cc).
The mixture was treated at a saturated vapor pressure by adding 0 cc.

After the obtained solid was dried at 60 ° C., the bending strength was measured. The results are shown in Table 2.

[0033]

[Table 2]

From Table 2, the following is clear. That is, by mixing Ca (OH) ₂ and a silica-based substance and performing autoclave treatment, the mixture can be easily solidified by a treatment at a saturated vapor pressure at a temperature of 280 ° C. or less, and a high-strength solidified body can be obtained. On the other hand, one containing only CaCO ₃ (No. 12) and one containing only SiO ₂ (No. 1)
3), only Ca (OH) ₂ added (No. 14)
Then, sufficient solidification strength cannot be obtained.

[0035] Using the Reference Example 2, MgCO ₃ instead of Comparative Example 2 CaCO _3, performing molding and autoclaved in the same manner as in Reference Example 1, to measure the flexural strength of the molded product and solidified, the results The results are shown in Table 3.

[0036]

[Table 3]

[0037] From Table 3, for the MgCO _3, CaC
It is clear that, similarly to O ₃ , by mixing Mg (OH) ₂ and a silica-based substance and performing autoclave treatment, the mixture can be easily solidified under mild conditions to obtain a high-strength solid.

[0038] Reference Example 3, in place of Comparative Example 3 CaCO ₃ with a mixture of CaCO ₃ and MgCO _3, performing molding and autoclaved in the same manner as in Reference Example 1, the flexural strength of the molded product and solidified Measure,
The results are shown in Table 4.

The autoclave conditions were all 2
It was 7 hours under a saturated vapor pressure of 30 ° C.

[0040]

[Table 4]

From Table 4, it can be seen that the mixed system of CaCO ₃ and MgCO ₃ also has Ca (OH) ₂ and / or Mg (O
H) By autoclaving the mixture of ₂ and the silica-based material, it is easily solidified under mild conditions,
It is clear that a high-strength solid can be obtained.

Example1 reference In Examples 1 to 3,Of solubility enhanceralkali
Molding and auto
Carry out the creep treatment to reduce the bending strength of the compact and solid
The measurement was performed and the results are shown in Tables 5 and 6.

The autoclave conditions were all 2
It was 7 hours under a saturated vapor pressure of 30 ° C.

[0044]

[Table 5]

[0045]

[Table 6]

From Tables 5 and 6, it is clear that a higher strength solidified product can be obtained by mixing an alkaline substance.

Example2  Crystalline SiO₂Was replaced with the one shown in Table 7.
Examples other than1No.36 (CaCO₃Use) or No.
41 (MgCO₃Molded and solidified in the same manner as
Was manufactured. Table 7 shows the strength measurement results.

[0048]

[Table 7]

Example3  Ca (OH) as Ca and / or Mg based material₂Or M
g (OH)₂No. 81 and 82 in Table 8 instead of
Example except that2In the same manner as
A solid was produced. Table 8 shows the strength measurement results.

Example4  No. 83 and 84 in Table 8 as Ca and / or Mg-based substances
And NaOH is a solid material
As an autoclave solution (0.1 m
ol / l)2As well as
Thus, a compact and a solid were produced. Table 8 shows the strength measurement results.
Show.

[0051]

[Table 8]

[0052]

As described in detail above, the CaCO _{3 of} the present invention is used.
And / or according to the method of solidifying MgCO _3, CaCO only treatment in an autoclave which is a common device ₃ and / or MgCO _3, or a material mainly composed of these, relatively low temperature, low pressure mild conditions Solidification can be easily and efficiently performed under the above to obtain a high-strength solidified body.

According to the present invention, CO ₂ in the combustion exhaust gas is fixed as CaCO ₃ and / or MgCO ₃ and recovered and solidified at a low processing cost, so that it can be effectively used for construction and civil engineering materials. Can be planned .

────────────────────────────────────────────────── ─── Continued on the front page (51) Int.Cl. ⁷ Identification code FI C04B 28/18 B01D 53/34 135Z (72) Inventor Keiichi Inukai 1-1208 Mambayama, Midori-ku, Nagoya-shi, Aichi Fragrance, all-round Mountain A-202 (72) Inventor Makoto Kigami 1-28 Umegaoka, Chita City, Aichi Prefecture Royal Heights B-203 (72) Inventor Hideki Ishida 2-17 Horisakicho, Handa City, Aichi Prefecture Corp. Nomura Handa Building No. 604 (72) Inventor Yasuo Goto 1-38 Nakata-cho, Handa-shi, Aichi Prefecture (72) Inventor Tatsuya Nagata 1-29, Sunagawa, Taketoyo-cho, Chita-gun, Aichi Prefecture (72) Inventor Takeyuki Yamamoto 29-13, Tokoname-shi, Tokoname-shi, Aichi No. 29-13 7 Young Takedoryo (72) Inventor Hiroki Manami 1-29 Minatomachi, Tokoname City, Aichi Prefecture (56) References JP-A-51-202021 (JP, A) JP-A-3-252341 (JP, A) JP-A-7 −61842 (JP, A) Special Flat 7-267758 (JP, A) JP flat 7-267698 (JP, A) (58 ) investigated the field (Int.Cl. ^7, DB name) C04B 40/02 C04B 28/18 C04B 7/34

Claims (2)

(57) [Claims] 1. A method according to claim 1, wherein CaCO ₃ and / or MgCO ₃ or a substance containing these as main components is CaO, Ca (O
H) ₂ , MgO, Mg (OH) ₂ , slag, and one or more C selected from the group consisting of concrete waste
a and / or Mg-based material, silica-based material, and CaCO
₃ and / or solubility of MgCO ₃ or silica-based material
After mixing the material to improve the, the CaCO ₃ and / or MgCO ₃ utilizing Otokure <br/> over blanking the reaction with saturated vapor pressure
The dissolution and reprecipitation reaction proceed, and (CaO and / or Mg
O) —CaCO ₃ and / or MgCO solidified by the formation of a SiO ₂ —H ₂ O-based solid substance
_3. Solidification method. 2. The method of claim 1 , wherein the solubility enhancing substance is LiOH, NaOH, KOH, NH ₄ OH,
Li ₂ CO ₃ , Na ₂ CO ₃ , K ₂ CO ₃ , (NH ₄ )
₂ CO ₃ , LiHCO ₃ , NaHCO ₃ , KHCO ₃ ,
NH ₄ HCO ₃ , LiNO ₃ , NaNO ₃ , KNO ₃ ,
NH ₄ NO ₃ , Ca (NO ₃ ) ₂ , LiF, NaF, K
F, NH ₄ F, LiCl, NaCl, KCl, NH ₄ C
1, a method for solidifying CaCO ₃ and / or MgCO ₃ , wherein the compound is one or more selected from the group consisting of LiBr, NaBr, KBr and NH ₄ Br.