JPH08205672A - Production of artificial soil - Google Patents

Abstract

PURPOSE: To obtain artificial soil, improved in pH, water holding properties and fertilizer holding power of soil and useful as a neutralizing agent, a soil improving material, etc., by mixing a used lime-based waste gas treating agent after use thereof as a desulfurizing or a denitrating agent with slaked lime, etc., and carrying out the hydrating treatment of the resultant mixture. CONSTITUTION: This artificial soil is obtained by mixing a used lime-based waste gas treating agent after use thereof as a desulfurizing or a denitrating agent with one or more selected from slaked lime, quick lime and gypsum, carrying out the hydrating treatment of the resultant mixture or further preferably treating the hydrated mixture with a gas containing SO2 , NOx and O2 . Furthermore, the treatment with the gas is preferably carried out by using a gas containing 100ppm to 1vol.% each of SO2 and NOx and 5-21vol.% O2 at 80-200 deg.C temperature and 5-50000 hr<-1> space velocity (SV) for a time sufficient to bring >=1mol SO2 and NOX based on 1kg dry weight of the hydrated mixture into contact therewith.

Description

Detailed Description of the Invention

[0001]

FIELD OF THE INVENTION The present invention relates to a method for producing artificial soil.

[0002]

[Prior Art] Japanese soil is often acidic, so soil p
It is necessary to adjust H, and pH is 6 in general plants.
In the case of cultivating plants extremely sensitive to acidity such as spinach and lettuce, the soil was mixed with calcium carbonate or calcium magnesium carbonate to neutralize the pH to about 7. Further, in order to improve the water retention and fertilizing power of the soil, soil-modifying materials such as corrosive acid materials, zeolite, perlite and vermiculite have been mixed with the soil. However, since the neutralizer and the soil modifier itself do not contain nutrients, it was necessary to add fertilizer.

[0003]

In view of the above-mentioned conventional state of the art, the present invention is for producing an artificial soil which not only functions as a neutralizing agent and a soil modifier, but also as a fertilizer when cultivating a plant. It is intended to provide a method.

[0004]

[Means for Solving the Problems] The present invention uses slaked lime as a used lime-based exhaust gas treatment agent after being used as a desulfurization / denitration agent.
Mix at least one selected from quicklime and gypsum,
A method for producing an artificial soil characterized by hydration treatment and at least one selected from coal ash and a used lime-based exhaust gas treatment agent are mixed with at least one selected from slaked lime, quick lime and gypsum, and water is added. After the sum treatment, SO ₂ , NOx
And a method for producing an artificial soil characterized by treating with a gas containing O ₂ , wherein the artificial soil can be adjusted to an appropriate state when the plant is cultivated by mixing with the soil. Becomes

Here, the coal ash as a raw material is pulverized coal combustion
The average particle size discharged from the boiler is 20-30 microns
What is called fly ash and falls to the bottom of the furnace
There is something called clinker ash that both
It can be used, but the particle size is fine from the viewpoint of hydration reactivity.
I prefer fly ash. Also, as plaster
Examples include anhydrous gypsum, hemihydrate gypsum, and dihydrate gypsum. plaster
As a substance containing, the in-furnace desulfurization agent such as fluidized bed combustion ash and
Examples include used lime-based exhaust gas treatment agents. here
Used lime-based exhaust gas treatment agents are CaO, Ca (O
H)₂, CaCO ₃Calci produced from such ingredients
Used um-based desulfurizing agent and JP-A-61-209
No. 038, JP-A-63-283745, etc.
CaO ・ Al₂O₃・ SiO₂・ CaSO_FourSystem
It refers to a used desulfurizing agent composed of a product.

[0006]

In the present invention, the hydrate obtained by mixing these raw materials and hydrating them and treating the hydrate with a gas containing SO ₂ , NOx and O ₂ has a complex composition and is analyzed. The above component ratios are as shown in Table 1 below as weight% of the anhydride.

[Table 1] Here, Ca (NO ₃ ) ₂ is generated by absorbing NOx during gas treatment.

In the present invention, the hydration treatment means a treatment necessary for adding water to a raw material mixture to form a hydration reaction product, and includes, for example, hot water curing, steam curing, etc. It is classified into hydration treatment and non-caking hydration treatment.

The curable hydration treatment means that the weight mixing ratio (solid-liquid ratio) of the raw materials and water at the time of treatment is made small, for example, 1: 0.2.
It is a hydration treatment in which the bond between the material particles is promoted to obtain a cured product by setting the ratio to ˜1: 0.99, and this treatment method includes steam curing. It is preferable that steam curing be carried out by mixing and kneading the above-mentioned raw materials with water at a temperature of 60 to 180 ° C. and a saturated moisture of 100% relative humidity for several minutes to several days.

The non-consolidating hydration treatment refers to hot water curing in which the solid-liquid ratio at the start of treatment is set to a large value, for example, 1: 1 to 1:20, and the treatment is carried out with hot water. Is 60 ~
This is a method in which the raw material is dispersed in water at 180 ° C., and the raw material is treated for a few minutes to a dozen hours while stirring so that the raw material does not settle down and harden.

The hydrate obtained by the above treatment had a large specific surface area of 40 to 80 m ² / g, and it was confirmed by X-ray diffraction that it was a substance containing amorphous calcium silicate and ettringite. This hydrate has an alkaline neutralizing power as it is, and has a large specific surface area, so that it has water retention and fertilizing power. However, it can be treated with a gas containing SO ₂ , NOx and O ₂ . It can be added as a fertilizer. In this case CaO and Ca
The ratio of SO ₄ and Ca (NO ₃ ) ₂ naturally changes, but of these, Ca (NO ₃ ) ₂ generated by absorption of NOx is a substance that is easily dissolved in water, and NO ₃ ions eluted from this are sufficiently nitrogenous. (N) It can be a fertilizer and can further improve the fertilization effect.

The method of gas treatment containing SO ₂ , NOx and O ₂ depends on the form of the hydrate obtained.
O _2, NOx and includes each 100ppm~1vol%, dry weight of the hydrate at a temperature 80 to 200 ° C. of the gas in the SV 5～50000H ^-1 containing O ₂ 5~21vol% 1
The treatment may be performed for a sufficient time so that at least 1 mol of SO ₂ and NOx per kg are contacted. In the gas treatment, SO ₂ , NOx and O ₂ are hydrates of NOx.
Is a component necessary for absorbing and fixing as Ca (NO ₃ ) ₂ . In the reaction between SO ₂ and hydrate, when the temperature is 80 ° C. or lower, NOx and O ₂ do not participate so much, but the N content that absorbs SO ₂ and NOx and becomes a fertilizer component is Ca (NO ₃ ) ₂ To fix as SO ₂ and O
_It is unlikely to occur without the coexistence of ₂ . Therefore, the content of N content fixed in the hydrate is small and the utilization effect as artificial soil is weakened.

The mechanism of this reaction is considered as follows. That is, the above hydrate is converted into SO ₂ , NOx
Since the exhaust gas is desulfurized and denitrified when it is treated with the exhaust gas containing O ₂ and O ₂ , it can be used as a desulfurization / denitration agent first, and then the hydrate after the treatment can be used as artificial soil. Thus, in the method of the present invention, when the gas treatment is carried out using the exhaust gas containing SO ₂ , NOx, O _2, etc., the desulfurization and denitration of the exhaust gas are carried out at the same time, which makes the production of artificial soil extremely economical. It can be carried out. The following chemical reactions are considered to occur here.

[Chemical Formula 1] NO + 1 / 2O ₂ → NO ₂ NO ₂ + SO ₂ → SO ₃ + NO Ca (OH) ₂ + SO ₃ + H ₂ O → CaSO ₄ + 2H ₂
O Ca (OH) ₂ + NO ₂ + 1 / 2O ₂ → Ca (NO ₃ )
₂ + 2H ₂ O However, in these reactions, the hydrate constituents are expediently Ca
(OH) ₂ . Further, when the used agent after being used as a desulfurizing / denitrifying agent is used as a raw material for producing a hydrate, for example, a gypsum source, it is intentionally treated with SO ₂ and NOx because it contains N as a fertilizer component. Even if it is not used, it can be sufficiently applied as artificial soil.

The artificial soil is used in a granular or powdery form depending on whether the hydrate obtained is a hardened product or a slurry-like product. In the case of the curable hydration treatment, the raw material and water are mixed and kneaded, and then extrusion molding is carried out with a pelletizer or the like, and steam curing is performed to obtain granules sized to an arbitrary size. On the other hand, in the case of non-consolidating hydration treatment, a powdery hydrate is obtained by drying the hydrate slurry. Each hydrate obtained here was treated with SO ₂ , NOx
And a method of treating with an exhaust gas containing O _2, for the granular material can be achieved by passing the exhaust gas to be charged into the reactor of a fixed bed or a fluidized bed type, also ducts of the exhaust gas for the powdery substance This can be achieved by spraying into the inside and then collecting with a dust collector, for example, a filter cloth of a bag filter. The artificial soil of the present invention adjusts the pH of the soil by mixing it with acidic soil, and since it has a large specific surface area and is porous, it is possible to store air and water in the soil and improve water retention and fertilizing power. Can be planned. Furthermore, the components include N, P, K, Ca, Mg, Fe, etc., and these components also function as fertilizers by being eluted into the soil.

The preferred embodiments of the present invention are summarized below. (1) The method for producing artificial soil according to claim 2, wherein the coal ash is fly ash having an average particle size of 20 to 30 μm or clinker ash that drops to the bottom of the furnace. (2) The method for producing artificial soil according to claim 1 or 2, wherein the gypsum is at least one selected from anhydrous gypsum, hemihydrate gypsum, and gypsum dihydrate. (3) The method for producing artificial soil according to (2) above, wherein the gypsum is a substance containing gypsum selected from in-furnace desulfurization agents such as fluidized bed combustion ash and used lime-based exhaust gas treatment agents. (4) The method for producing artificial soil according to claim 1 or 2, wherein the hydration treatment is a hardening hydration treatment or a non-consolidating hydration treatment. (5) The method for producing artificial soil as described in (4) above, wherein the hardening hydration treatment is by steam curing. (6) Curable hydration treatment mixed ratio of raw material and water (solid-liquid ratio)
The method for producing an artificial soil as described in (4) or (5) above, wherein the ratio is 1: 0.2 to 1: 0.99.

(7) The method for producing an artificial soil as described in (5) above, wherein steam curing is carried out at a temperature of 60 to 180 ° C. and a saturated water content of 100% relative humidity for several minutes to several days. (8) The method for producing an artificial soil as described in (4) above, wherein the non-consolidating hydration treatment is by hot water curing. (9) The non-consolidating hydration treatment was performed at a solid-liquid ratio of 1: 1 to 1:20
The method for producing an artificial soil as described in (4) or (8) above, which is performed so as to fall within the range. (10) The method according to (8) above, wherein hot water curing is performed by dispersing the raw material in water at a temperature of 60 to 180 ° C. and treating it for several minutes to several tens of hours while stirring so that the raw material does not settle and harden in the lower part. Method for producing artificial soil. (11) The treatment with a gas containing SO ₂ , NOx and O ₂ includes SO ₂ and NOx in an amount of 100 ppm to 1 vol% and O ₂ in an amount of ₅ to 21 vol% at a temperature of 80 to 200 ° C. and an SV of 5 to 50000 h ^{−. 1} in 1 dry weight of hydrate
The method for producing an artificial soil according to claim 2 or any one of (1) to (10) above, which is carried out by treating for a time sufficient to bring at least 1 mol of SO ₂ and NOx per kg.

[0016]

The present invention will be described in more detail with reference to the following examples.
However, the present invention is not limited to this. Department in text and%
Is based on weight. (Example 1) Composition is SiO₂: 60%, Al₂O₃: 2
3%, CaO: 4.3%, Fe₂O ₃: 5.5%, Mg
O: 2.4%, Na₂O: 0.7%, K₂O: 1.3
%, TiO₂: 1.2%, S: 0.2%, C: 1.2%
And slaked lime 30 in 60 parts of coal ash with an average particle size of 23 microns
Parts and hemihydrate gypsum 10 parts (CaSO_Four(Converted) mixed, water
40 parts were added and kneaded. Next, a die with a hole diameter of 5 mm
Extruded and cured in steam at 95 ° C for 12 hours
And dried at 200 ° C. for 2 hours to obtain a hydrated cured product.
Was. Next, this cured product is₂1000ppm, NOx2
00ppm, CO ₂13vol%, O₂6vol%, H
₂O8vol% (the rest is N₂) Gas SV1000h
^-1And composition shown in Table 2 after treatment at 130 ° C for 100 hours
The artificial soil having the property was obtained. In this, apply as fertilizer component
The content concentration of the total N observed was 2.5%.

Spinach was cultivated using this artificial soil. Commercial field soil and vermiculite 1: 1
The mixture of 1) and the mixture of the commercially available field soil and the artificial soil of the present invention in a ratio of 1: 1 and 3: 1 were potted as soil and cultivated in a greenhouse for about 2 months. Table 3 shows the results. No topdressing was given in any case.

[0018]

[Table 2]

[0019]

[Table 3] As shown in Table 3, it can be seen that by mixing the artificial soil of the present invention with the soil, proper cultivation can be performed without applying fertilizer.

(Example 2) 20 parts of coal ash and 20 parts of slaked lime used as the raw material and water in Example 1 and a used lime type exhaust gas treating agent (composition: SiO ₂ : 25%, AlO ₃ : 9.
6%, CaO: 26%, Fe 2 O 3: 2.4%, Mg
O: 0.8%, Na ₂ O: 0.2%, K ₂ O: 0.6
%, S: 11.2%, C: 1.0%, TN: 1.9.
%) The artificial soil A was obtained by the same treatment as in Example 1 except that 60 parts and 45 parts of water were used. As a result of analyzing the total N content of this product, it was 2.3%. The water content was 33%.

(Example 3) 30 parts of quicklime was added to 500 parts of hot water at 75 ° C., and after stirring for 20 minutes, 50 parts of coal ash used in Example 1 and 20 parts of gypsum dihydrate (CaSO ₄
(Calculated) was added and the mixture was kept at a temperature of 95 ° C. for 12 hours, dehydrated and dried at 150 ° C. for 2 hours to obtain a powdery hydrate. Blowing this powder into a reactor equipped with a bag filter, SO
₂ 2000ppm, NOx 600ppm, CO ₂ 13v
ol%, O ₂ 10 vol%, H ₂ O 10 vol%, (remainder is N ₂ ) and contact with a gas at a temperature of 100 ° C. (SV in the bag filter layer is 20000 h ⁻¹ ) to obtain a powdery artificial soil B. It was As a result of analyzing the total N of this product, 1.2%
Met.

(Example 4) A part of the slurry obtained in Example 2 was dehydrated and then dried at 150 ° C to adjust the water content to 25%, and extrusion molding was carried out by a disc pelleter.
It was dried at 0 ° C. for 2 hours to obtain a pellet-shaped cured product. This cured product was gas-treated under the same conditions as in Example 1 except that the temperature was 100 ° C. and the SV was changed to 500 h ⁻¹ with the gas composition of Example 1 to obtain artificial soil C. The total N concentration of this product was 3%.

(Embodiment 5) Clinker ash (particle size 1.0 mm or less, composition Si
O ₂ : 63%, Al ₂ O ₃ : 18%, CaO: 5.6
%, MgO: 3.5%, Fe ₂ O ₃ : 6.2%, Na ₂
O: 0.3%, K ₂ O: 0.6%, S: 0.4%, C:
(0.6%) 60 parts were mixed with 20 parts of slaked lime and 20 parts of anhydrous gypsum and 40 parts of water was added and kneaded. This kneaded product is 5m
After extrusion molding with a die having a pore size of m, it was placed in an autoclave and cured in steam at 150 ° C. for 12 hours.
Next, this molded product was dried at 200 ° C. and gas-treated in the same manner as in Example 1 to obtain artificial soil D. The total N concentration of this product was 0.3%.

Example 6 Coal ash 20 used in Example 1
10 parts of slaked lime and 70 parts of spent desulfurization agent in fluidized bed furnace (composition: SiO ₂ : 15%, Al ₂ O ₃ : 5.2%, F
e ₂ O ₃ : 4.6%, CaO: 22%, MgO: 2.3
%, Na ₂ O: 0.5%, K ₂ O: 0.6%, S: 3.
1%, C: 2.1%), and 50 parts of water were added and treated in the same manner as in Example 1 to obtain artificial soil E. All N of this thing
The concentration was 1.2%.

(Reference Example) Spinach cultivation was carried out in the same manner as in Example 1 except that the artificial soils A to E obtained in Examples 2 to 6 were mixed with the soil of the field in a ratio of 1: 1. It was The results are shown in Table 4.

[Table 4] (Soil mixing ratio is 1: 1)

(Example 7) The artificial soil A obtained in Example 2 was added to the field soil in an amount of 10% by weight, and a cultivation test was carried out using baron potatoes and radish radish. The results are shown in Table 5.

(Comparative Example 1) As a comparative example of the effect of the soil improver, the same cultivation test as in Example 7 was conducted using 10% by weight of compost as soil. Table 5 shows the cultivation test results of Comparative Example 1.
Shown in

(Comparative Example 2) As a comparative example of the effect of the soil improver, the same cultivation test as in Example 7 was carried out on fertilizer-free soil. Table 5 shows the results of the cultivation test of Comparative Example 2.

[0029]

[Table 5]

[0030]

Industrial Applicability As described above, the artificial soil of the present invention is easily produced by using relatively inexpensive raw materials or what was conventionally considered as waste, and the soil pH and water retention at the time of plant cultivation are maintained. The industrial value of the present invention is very great because it can improve the fertilizing ability and can itself serve as a fertilizer.

─────────────────────────────────────────────────── ─── Continuation of the front page (51) Int.Cl. ⁶ Identification number Reference number within the agency FI Technical indication location B01D 53/74 B01J 20/04 C (72) Inventor Kunihiro Mori 4 Mihogaoka, Toyohira-ku, Sapporo, Hokkaido 4-9 2-2-1 Hokkaido Electric Power Co., Inc. Research Center (72) Inventor Tsutomu Ueno 4-9-1, Migamioka, Toyohira-ku, Sapporo-shi, Hokkaido Hokkaido Electric Power Co. Research Center (72) Inventor Kazutoshi Saito Hokkaido Sapporo 1-14 Shimonoboro Techno Park, Atsubetsu-ku, Yokohama-shi Econics Co., Ltd. (72) Inventor, Fumiyuki Nakadate 1-2-14 Shimotono-Poro Techno Park, Atsubetsu-ku, Sapporo-shi, Hokkaido (72) Inventor Atsushi Taya, Chiyoda, Tokyo 2-5-1 Marunouchi Ward Sanryo Heavy Industries Co., Ltd. (72) Inventor Hiroshi Fujita Hiroshima Hiroshima 4-6-22 Kannon-Shinmachi, Nishi-ku, Hiroshima Research Institute, Mitsubishi Heavy Industries, Ltd. (72) Inventor, Yasuyuki Kogushi, 4-6-22, Kannon-Shinmachi, Nishi-ku, Hiroshima, Hiroshima (72) Inventor, Tatsu Kinoshita 4-6-22 Kannon-shinmachi, Nishi-ku, Hiroshima-shi, Hiroshima Prefecture Mitsubishi Heavy Industries Ltd. Hiroshima Research Institute

Claims (2)

[Claims] 1. An artificial soil characterized by mixing at least one selected from slaked lime / quick lime and gypsum with a used lime-based exhaust gas treating agent after being used as a desulfurizing / denitrifying agent and hydrating the mixture. Production method. 2. At least one selected from coal ash and a used lime-based exhaust gas treating agent is mixed with at least one selected from slaked lime / quick lime and gypsum, and after hydration treatment, SO ₂ , NOx and O are mixed. _A method for producing an artificial soil, which comprises treating with a gas containing ₂ .