JPH11156839A - Production of corrosion resistant hume pipe - Google Patents

Abstract

PROBLEM TO BE SOLVED: To produce Hume pipes resistant to concrete corrosion by sulfur oxidizing bacteria. SOLUTION: A corrosion resisting agent 1.2-2.5 in specific gravity which has growth inhibiting effects on sulfur oxidizing bacteria, especially one consisting of a phthalocyanine compound, is added into concrete, and the mixture is mold by centrifugal casting to produce a corrosion resistant Hume pipe. A Hume pipe in which the corrosion resisting agent is concentrated in the inner surface layer can be prepared easily by this method. In this way, sewerage system pipes can be kept sound efficiently over a long period.

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a method for producing a corrosion-resistant fume pipe by centrifugally molding concrete containing a corrosion inhibitor having a growth inhibiting effect on sulfur-oxidizing bacteria. More specifically, specific gravity 1.2
By centrifugal molding of concrete containing a corrosion inhibitor of ~ 2.5, anticorrosives with a specific gravity smaller than that of cement and aggregates are unevenly distributed on the inner peripheral surface of the fume pipe. A method for easily producing a more resistant fume tube.

[0002]

2. Description of the Related Art Fume pipes are reinforced concrete pipes formed by compacting concrete using centrifugal force and are most widely used as sewer pipes. Including propulsion pipes (reinforced concrete pipes for propulsion method) manufactured by the same centrifugal force molding, the order extension of sewer sewers by fume pipes exceeds 3,000 km every year.

In recent years, many cases of concrete corrosion have been reported in Japanese sewage facilities including fume pipes. Moreover, these corrosions are not limited to Japan, but have been reported in the United States, Egypt, South Africa, Australia and elsewhere. Since the construction of sewerage facilities is expensive, it is important to take appropriate measures to prevent concrete corrosion in order for these facilities to function effectively over the long term.

The concrete corrosion cycle involves two types of microorganisms: sulfate-reducing bacteria and Thiobacillus (Th).
It is known that sulfur oxidizing bacteria such as the genus iobacillus are involved. In the corrosion process of concrete by these microorganisms, first, sulfate present in sewage is reduced under anaerobic conditions by sulfate reducing bacteria to generate hydrogen sulfide. Next, the hydrogen sulfide is adsorbed by the water adhering to the concrete wall surface, and is oxidized by the sulfur-oxidizing bacteria under aerobic conditions to produce sulfuric acid. Calcium contained in the concrete is changed into calcium sulfate (gypsum) by the generated sulfuric acid, whereby the concrete expands and becomes brittle and corrodes.

[0005] Among the above two types of microorganisms, sulfur oxidizing bacteria are considered to be the main cause of corrosion of concrete structures such as sewage facilities. Several methods have been shown to prevent corrosion by preventing the change to. For example, it is known that the growth of sulfur-oxidizing bacteria is inhibited by various metal ions, and copper which is hardly soluble in water and soluble in sulfuric acid,
Japanese Patent Application Laid-Open No. 4-149053 discloses a method in which a metal such as nickel, tin, lead or the like or an oxide of these metals is contained in concrete to prevent corrosion of the concrete. In this method, metal ions are eluted from the metal and / or metal oxide by the sulfuric acid generated by the sulfur oxidizing bacteria, thereby preventing and / or sterilizing the sulfur oxidizing bacteria. However, since this method uses a metal and / or a metal oxide having high solubility in sulfuric acid, it has a drawback such as an increase in the amount of metal used to prevent corrosion of concrete for a long period of time. doing. In addition, since heavy metal ions such as nickel, tin, and lead elute in the sewage,
If a large amount of these metals and / or metal oxides is used, there is a possibility of water pollution.

[0006] JP-A-6-16460 and JP-A-6-16461 disclose a method of preventing concrete from corroding by adding metal complexes such as nickelocene and nickel dimethylglyoxime to concrete. However, these metal complexes have carcinogenicity and have a problem in safety.

Further, Japanese Patent Application Laid-Open No. 9-60768 discloses that
There is disclosed a method of obtaining a corrosion-resistant fume tube by incorporating an inorganic powder carrying antibacterial metal ions such as silver, copper, zinc, nickel, and cobalt.

[0008] Separately, Japanese Unexamined Patent Publication No.
No. 42 discloses a method of preventing the deterioration of the inner peripheral surface of the fume tube by removing the surface layer of the inner peripheral surface having a large amount of easily degraded fine particles during molding and / or after curing of the fume tube. Is

[0009]

SUMMARY OF THE INVENTION An object of the present invention is to provide a method for producing a corrosion-resistant fume pipe by centrifugally molding concrete containing a corrosion inhibitor.

The present inventors have conducted intensive studies to develop a method for inhibiting the growth of sulfur-oxidizing bacteria, which is the main cause of the corrosion of fume pipes for sewer pipes, and as a result, the phthalocyanine compound was converted to sulfur-oxidizing bacteria. Was found to have the effect of inhibiting the growth of. It was also found that concrete mixed with a phthalocyanine compound had strong resistance to corrosion by sulfur-oxidizing bacteria. Furthermore, when concrete containing a corrosion inhibitor having a specific gravity of 1.2 to 2.5, such as a phthalocyanine compound, is formed by centrifugal force molding, the anticorrosive agent is unevenly distributed on the inner peripheral surface of the fume pipe, but the excess water and cement The present invention was found to be hardly contained in a waste liquid composed of fine particles and mud in the aggregate, which is usually called "Noro" or "Toro", and has led to the present invention.

[0011]

That is, the present invention provides a composition comprising a concrete and a corrosion inhibitor having a specific gravity of 1.2 to 2.5 and having a growth inhibiting effect on sulfur-oxidizing bacteria. The present invention provides a method for manufacturing a corrosion-resistant fume tube, characterized in that the mold is rotated and the mold is rotated to perform centrifugal molding.

Further, the present invention provides a method for producing the above corrosion-resistant fume tube, wherein the corrosion inhibitor is a phthalocyanine compound.

Further, the present invention provides the above-mentioned method for producing a corrosion-resistant fume tube, wherein the phthalocyanine compound is a metal phthalocyanine or a derivative thereof.

Further, the present invention provides a method for producing a metal phthalocyanine or a derivative thereof, wherein the metal atom is chromium, iron, cobalt, nickel, molybdenum, palladium, tin, tungsten,
And at least one selected from the group consisting of platinum and platinum.

Further, the present invention provides a method for producing the above corrosion-resistant fume tube, wherein the phthalocyanine compound is a metal phthalocyanine represented by the following general formula (1) or a derivative thereof. MX _n Pc (1) (wherein, M is a metal atom, X is an oxygen atom, a halogen atom or a hydroxyl group, Pc is a phthalocyanine skeleton, n represents 1 to 5
Are respectively shown. )

Further, the present invention provides the above-mentioned method for producing a corrosion-resistant fume tube, wherein the phthalocyanine compound is a metal-free phthalocyanine or a derivative thereof.

According to the method for producing a corrosion-resistant fume tube of the present invention, a fume tube in which a corrosion inhibitor that inhibits the growth of sulfur-oxidizing bacteria is unevenly distributed on the inner peripheral surface of the fume tube can be easily obtained. Corrosion of fume pipes by sulfur oxidizing bacteria is remarkable on the inner peripheral surface, so the obtained fume pipes show high corrosion resistance and can keep the sewer sewers sound effectively and for a long time .

[0018]

BEST MODE FOR CARRYING OUT THE INVENTION The corrosion inhibitor used in the present invention inhibits the growth of sulfur oxidizing bacteria and has a specific gravity of 1.2 to 1.2.
Any kind may be used as long as it is in the range of 2.5, but in consideration of its effect and stability under acidic conditions, a phthalocyanine compound is preferable.

The phthalocyanine compound used in the present invention refers to a compound having a phthalocyanine skeleton. The metal phthalocyanine used in the present invention is a compound in which a metal atom is coordinated to an unsubstituted phthalocyanine skeleton, and its derivative is a substituent atom other than a hydrogen atom on a benzene ring in a metal phthalocyanine molecule. Alternatively, it is a compound having a substituent. Further, the metal-free phthalocyanine used in the present invention is a compound in which two hydrogen atoms are coordinated at the center of a phthalocyanine skeleton having no substituent, and a derivative thereof refers to a compound in the metal-free phthalocyanine molecule. A compound having a substituent or a substituent other than a hydrogen atom on a benzene ring. In the present invention, it is desirable to use a metal phthalocyanine or a derivative thereof that does not dissolve in water.

The metal atoms of the above metal phthalocyanine include lithium, magnesium, aluminum, silicon, calcium, chromium, manganese, iron, cobalt, nickel, copper, zinc, gallium, germanium, zirconium, molybdenum, palladium, silver, and cadmium. , Indium, tin, tungsten, platinum, mercury, lead, and rare earth elements, among which chromium,
Desirably, at least one selected from the group consisting of iron, cobalt, nickel, molybdenum, palladium, tin, tungsten, and platinum.

In the present invention, a metal phthalocyanine represented by the following general formula (1) can be used. MX _n Pc (1) (wherein, M is a metal atom, X is an oxygen atom, a halogen atom or a hydroxyl group, Pc is a phthalocyanine skeleton, n represents 1 to 5
Are respectively shown. The metal phthalocyanine represented by the general formula (1) is obtained by coordinating a metal atom represented by M to an unsubstituted phthalocyanine skeleton Pc, and further comprising an oxygen atom represented by X in the axial direction, fluorine, and chlorine. ,bromine,
A compound in which 1 to 5 halogen atoms or hydroxyl groups such as iodine are coordinated.

In the present invention, in order for the metal phthalocyanine to have the structure represented by the general formula (1), it is necessary that the valence of the metal atom is 3 to 7. In the present invention, any metal atom can be used as long as it is a metal atom capable of taking such a valence, but in particular, titanium, vanadium, chromium, molybdenum, tungsten,
Desirably, it is at least one of gallium, indium, silicon, and germanium.

Specific examples of the substituent or substituent other than the hydrogen atom in the metal phthalocyanine derivative and the metal-free phthalocyanine derivative include the following. That is, fluorine, chlorine, bromine, halogen atoms such as iodine, methyl group, ethyl group, propyl group, butyl group,
sec-butyl group, tert-butyl group, pentyl group,
Hexyl group, heptyl group, octyl group, stearyl group,
Substituted or unsubstituted trichloromethyl group, trifluoromethyl group, cyclopropyl group, cyclohexyl group, 1,3-cyclohexadienyl group, 2-cyclopenten-1-yl group, 2,4-cyclopentadiene-1-ylenyl group, etc. Substituted alkyl, methoxy, ethoxy, propoxy, n-butoxy, sec-butoxy, ter
Substituted or unsubstituted alkoxy groups such as t-butoxy group, pentyloxy group, hexyloxy group, stearyloxy group, trifluoromethoxy group, etc., methylthio group, ethylthio group, propylthio group, butylthio group, sec-butylthio group, tert- Substituted or unsubstituted thioalkoxy groups such as butylthio group, pentylthio group, hexylthio group, heptylthio group, octylthio group, nitro group, cyano group, carbonyl group, carboxyl group, ester group, hydroxyl group, sulfonic acid group, vinyl group, methyl group Alkyl-substituted amino groups such as amino group, dimethylamino group, ethylamino group, diethylamino group, dipropylamino group and dibutylamino group; carbocyclic aromatic amino groups such as diphenylamino group and ditolylamino group; Methyl) amino group, bi (Aceto oxyethyl) amino group, bis (aceto oxy propyl) amino group, bis (aceto oxy butyl) amino group, mono- or di-substituted amino group such as a dibenzylamino group, a phenoxy group, p-t
substituted or unsubstituted aryloxy groups such as tert-butylphenoxy group and 3-fluorophenoxy group, substituted or unsubstituted arylthio groups such as phenylthio group and 3-fluorophenylthio group, phenyl group, biphenyl group and triphenyl group , Tetraphenyl group, 3-nitrophenyl group, 4-methylthiophenyl group, 3,5-dicyanophenyl group, o-, m-, and p-tolyl group, xylyl group, o-, m-, and p-cumenyl Group, mesityl group,
Pentalenyl group, indenyl group, naphthyl group, azulenyl group, heptalenyl group, acenaphthylenyl group, phenalenyl group, fluorenyl group, anthryl group, anthraquinonyl group, 3-methylanthryl group, phenanthryl group,
Triphenylene group, pyrenyl group, chrysenyl group, 2-ethyl-1-chrysenyl group, picenyl group, perylenyl group,
Substituted or unsubstituted 6-chloroperylenyl group, pentaphenyl group, pentacenyl group, tetraphenylene group, hexaphenyl group, hexacenyl group, rubicenyl group, coronenyl group, trinaphthylenyl group, heptaphenyl group, heptacenyl group, pyranthrenyl group, ovarenyl group, etc. And the like.

In the present invention, as the metal phthalocyanine derivative and the metal-free phthalocyanine derivative, 1 to 8 hydrogen atoms of the benzene ring in the above-mentioned metal phthalocyanine and metal-free phthalocyanine molecule are a halogen atom and a carbon atom having 1 to 6 carbon atoms. Is preferably a derivative substituted with an alkyl group, a nitro group, a cyano group, a hydroxyl group, or a sulfonic acid group. These phthalocyanine compounds may be used alone or in combination of two or more.

In the present invention, the corrosion inhibitor having a specific gravity of 1.2 to 2.5 is added when kneading cement, aggregate, water, etc., and the corrosion inhibitor and the cement are mixed in advance. You can use something. Also, at the time of fume tube production, admixing agents such as AE agents, water reducing agents, AE water reducing agents, thickeners, etc., which are added for the purpose of reducing unit water volume, increasing durability and strength, etc., and corrosion inhibitors in advance. It is also possible to use one that has been done.

In the present invention, it is desirable to add the corrosion inhibitor in an amount of 0.001 to 30 parts by weight, more preferably 0.01 to 5 parts by weight, based on 100 parts by weight of the cement component. When the amount of the corrosion inhibitor added to the cement component is less than 0.001 part by weight, it is difficult to maintain the growth inhibitory effect on sulfur oxidizing bacteria for a long time. On the other hand, even if the addition amount exceeds 30 parts by weight, further improvement of the growth inhibitory effect on sulfur oxidizing bacteria cannot be expected,
It is not preferable because the cost increases. Furthermore, the strength of the resulting fume tube is significantly reduced. In the present invention,
When the corrosion inhibitor is previously mixed with the above admixture,
Although it depends on the amount of the admixture, the corrosion inhibitor is preferably from 5 to 500 parts by weight, more preferably from 10 to 100 parts by weight, per 100 parts by weight of the admixture.

In the present invention, when the corrosion inhibitor is preliminarily mixed with the admixture, it is desirable that the corrosion inhibitor is uniformly dispersed in the admixture. In order to uniformly disperse the corrosion inhibitor in the admixture, various known pulverizers or dispersers can be used. Specifically, a three-roll mill, a two-roll mill, a ball mill, an attritor, a sand mill, a co-ball mill, a basket mill, and a ball mill, which are dispersed by an impact force due to collision with media such as glass beads, zirconia beads, and menor balls, are used. A vibrating mill, a paint conditioner, and a device such as a disperser, a homogenizer, and Clearmix (R) that disperse by a rotating blade that generates shear stress, cavitation, collision force, potential core, and the like can be used. Further, a kneader, an extruder, a jet mill, an ultrasonic disperser, and the like can be used.

In the present invention, the corrosion inhibitor is preferably in the form of a fine powder so that it can be easily and uniformly mixed with the fume tube, particularly the cement component in the fume tube.
The average particle size of the fine powder of the corrosion inhibitor in the present invention is preferably 0.001 μm to 1 mm,
More preferably, the thickness is from 0.1 μm to 0.1 mm.

In the present invention, centrifugal force molding can be performed by a conventional method. The centrifugal molding is generally performed by putting concrete into a cylindrical form, rotating the form on a wheel of a centrifuge, and gradually increasing the number of revolutions. When manufacturing a large-sized fume tube, a method is used in which concrete is mechanically put into a mold while rotating only the cylindrical mold. The concrete inside the form is pressed against the form surface by centrifugal force, and water is squeezed inward to obtain a centrifugal molded body. Thereafter, this is cured, and normal pressure steam curing or high-temperature high-pressure steam curing is performed as necessary.

In the centrifugal molding, the initial speed is generally about 3 G and the medium speed is about 15 G to shift to a high speed, but each speed is performed in a short time within several minutes. In particular, at high speeds, the speed does not exceed 30G, preferably 25 to 30G.
It is necessary to perform the process while keeping the range of G. If it exceeds 30 G, the amount of the waste liquid referred to as “NORO” or “TORO” rapidly increases, and the amount of the added corrosion inhibitor discharged into the waste liquid also increases. Further, the finish of the product itself deteriorates, and the strength of the product also decreases.

When performing centrifugal molding, in addition to cement, aggregate, water and a corrosion inhibitor having a specific gravity of 1.2 to 2.5,
If necessary, other known additives such as a swelling agent, a curing accelerator, and other auxiliary components can be appropriately added. The fume tube molded by centrifugal force may include a reinforcing bar inside for reinforcement.

[0032]

EXAMPLES Hereinafter, the present invention will be described in more detail with reference to Examples and Comparative Examples, but the present invention is not limited thereto.

(Examples 1 to 14) Cement 16.45K
g, expansive material 1.65 Kg, slag 5.5 kg, fine aggregate 4
7.65 Kg was stirred with a mixer, and coarse aggregate was added thereto.
9 kg was added and the mixture was further stirred. Separately, 23.5 g of a solution obtained by adding 235 g of a water reducing agent to 8.8 kg of water as a corrosion inhibitor and 23.5 g corresponding to 0.1% by weight of the total amount of cement + expanding material + slag are shown in Table 1. The phthalocyanine compound was added and mixed well, and the mixture was put into the above mixer and kneaded. 15.5 kg of the obtained concrete was placed in a cylindrical mold and subjected to centrifugal molding. The condition of centrifugal force molding is 3.6 G × 4 minutes → 15
G × 3 minutes → 25 G × 10 minutes. After the completion of the centrifugal molding, the mold was subjected to normal-pressure steam curing at 72 ° C. overnight. After steam curing, the fume tube was removed from the mold, and further subjected to standard curing for 28 days to obtain a fume tube containing a corrosion inhibitor. The size of the obtained fume tube was 20 cm in outer diameter, 12 cm in inner diameter, and 30 cm in length. Table 1 shows the specific gravities of the phthalocyanine compounds used, all of which were in the range of 1.2 to 2.5.

(Comparative Examples 1 to 14) Using the concrete prepared in Examples 1 to 14, according to the method of preparing a concrete strength test specimen (JIS A 1132), a cylindrical specimen having a diameter of 10 cm and a length of 20 cm was obtained. Was.

(Comparative Example 15) 16.45 kg of cement
In addition, metal nickel which is considered to have a growth inhibitory effect on sulfur oxidizing bacteria (Japanese Patent Application Laid-Open No. 4-149053, and T. Maeda et al .: Biosci. Biotech. Biochem., 60,
626, 1996), 23.5 g, and stirred well to mix. The specific gravity of metallic nickel was 8.9. In addition to this, 1.65 kg of expanding material, 5.5 kg of slag, and 47.6 fine aggregate
5 kg was added, and the mixture was stirred with a mixer.
9 kg was added and stirred. Separately, water reducing agent 23
A solution in which 5 g was added to 8.8 kg of water was prepared, and the mixture was charged into the above mixer and kneaded. 15.5 kg of the obtained concrete was placed in a cylindrical mold and subjected to centrifugal molding. The conditions for centrifugal force molding are 3.6 G × 4 minutes → 15 G ×
3 minutes → 25 G × 10 minutes. After the completion of the centrifugal molding, the mold was subjected to normal-pressure steam curing at 72 ° C. overnight. After steam curing, the fume tube was removed from the mold, and further subjected to standard curing for 28 days to obtain a fume tube containing a corrosion inhibitor.
The size of the obtained fume tube is 20 cm in outer diameter and 12 in inner diameter.
cm and a length of 30 cm.

(Comparative Example 16) The concrete prepared in Comparative Example 15 was used, and the diameter was set to 10c in accordance with the method of preparing a concrete strength test specimen (JIS A 1132).
A cylindrical specimen having a length of 20 cm and a length of 20 cm was obtained.

(Comparative Example 17) 16.45 kg of cement,
Expanding material 1.65 kg, slag 5.5 kg, fine aggregate 47.
65Kg was stirred with a mixer, and 39.9K of coarse aggregate was added here.
g was added and further stirred. Separately, water reducing agent 2
A solution in which 35 g was added to 8.8 kg of water was prepared, and charged into the above mixer and kneaded. 15.5 kg of the obtained concrete was placed in a cylindrical mold and subjected to centrifugal molding. The condition of centrifugal force molding is 3.6G x 4 minutes → 15G
× 3 minutes → 25G × 10 minutes. After the completion of the centrifugal molding, the mold was subjected to normal-pressure steam curing at 72 ° C. overnight. After steam curing, the fume tube was removed from the mold, and further subjected to standard curing for 28 days to obtain a fume tube containing a corrosion inhibitor.
The size of the obtained fume tube is 20 cm in outer diameter and 12 in inner diameter.
cm and a length of 30 cm.

(Comparative Example 18) Using the concrete prepared in Comparative Example 17, according to the method of preparing a specimen for strength test of concrete (JIS A 1132), diameter 10c.
A cylindrical specimen having a length of 20 cm and a length of 20 cm was obtained.

Table 1 Example and Comparative Example Phthalocyanine Compound Specific Gravity ─────────────────────────────── Example 1, Comparative Example 1 CrPc 1.55 Example 2, Comparative Example 2 CoPc 1.64 Example 3, Comparative Example 3 NiPc 1.74 Example 4, Comparative Example 4 MoPc 1.70 Example 5, Comparative Example 5 PdPc 1.54 Example 6, Comparative Example 6 SnPc 1.66 Example 7 Comparative example 7 WPc 1.54 Example 8, Comparative example 8 PtPc 1.66 Example 9, Comparative example 9 NiPc / WPc (weight ratio 8: 2) 1.70 Example 10, Comparative example 10 NiPc-Cl ₄ 1.69 Example 11, Comparative Example 11 MoOPc 1.53 Example 12, Comparative Example 12 WOPc 1 73 Example 13, Comparative Example 13 Al (OH) Pc 2.01 Example 14, Comparative Example 14 H ₂ Pc 1.50 ───────────────────── ───────────── * CrPc, CoP in phthalocyanine compounds
c, NiPc, MoPc, PdPc, SnPc, WP
c and PtPc represent metal phthalocyanines whose metal atoms are chromium, cobalt, nickel, molybdenum, palladium, tin, tungsten, and platinum, respectively, and H ₂ Pc represents metal-free phthalocyanine. Also, M
oOPc, WOPc, and Al (OH) Pc represent a metal phthalocyanine in which the metal atom M is molybdenum, tungsten, or aluminum and X is an oxygen atom or a hydroxyl group in the general formula (1). Further, Cl represents that the substitution atom is a chlorine atom.

A portion having a thickness of 1.0 cm from the inner peripheral surface of the fume tube obtained in each of Examples 1 to 13 and Comparative Example 15 and the surface of the cylindrical specimen obtained in each of Comparative Examples 1 to 13 and 16. Of concrete was collected. This was pulverized and then thermally decomposed with concentrated nitric acid and concentrated hydrochloric acid. The concentrations of the central metal of the phthalocyanine compound used in the preparation of the fume tube and the cylindrical specimen and the added nickel in the decomposition solution were measured by atomic absorption spectrometry and inductively coupled plasma (ICP) emission spectrometry. The concentration of the phthalocyanine compound and metallic nickel (= corrosion inhibitor) on the inner peripheral surface of the fume tube and the surface of the cylindrical specimen were determined from the above. The results are shown in Table 2.

The fume tube and the cylindrical specimen obtained in the examples and the comparative examples were exposed to the inside of a wall of a sludge facility of a sewage treatment plant.
The exposure test was performed for 9 months. After the exposure test, the state of adhesion of sulfur-oxidizing bacteria and the state of gypsum formation on the inner peripheral surface of the fume tube and the surface of the cylindrical specimen were evaluated as follows. The result is
The results are shown in Table 2.

(Adhesion of Sulfur-Oxidizing Bacteria) The inner peripheral surface of the fume tube and the surface of the cylindrical specimen were washed with 50 ml of sterilized tap water (sterilized in an autoclave for 20 minutes) using a tooth brush. The washings were sonicated and then diluted. This was cultured for 11 days at a culture temperature of 30 ° C. using a solid ONM medium (Imai, Kazumi, Katagiri: Fermentation Engineering, Vol. 42, p. 762, 1964) to which yeast extract was added and solidified with gellan gum. Colonies were counted. From this value, the number of sulfur-oxidizing bacteria per 1 ml of the washing solution (cell / ml) was determined, and the adhesion of the sulfur-oxidizing bacteria was evaluated based on the following evaluation criteria.

Evaluation Criteria for Sulfur-Oxidizing Bacteria Adhesion Evaluation 1: 10 ⁶ cell / ml or more Evaluation 2: 10 ⁴ to 10 ⁶ cell / ml Evaluation 3: 10 ² to 10 ⁴ cell / ml Evaluation 4: 10 ² cell / ml Less than 5 ml Evaluation 5: No adhesion was observed at all

(Gypsum state) 10 g of the inner peripheral surface of the fume tube and the surface of the cylindrical specimen were sampled, and the amount of calcium sulfate was measured using an X-ray diffractometer. From this value,
The proportion (%) of calcium on the surface of the specimen that changed to calcium sulfate, which is a corrosion product due to sulfuric acid, was determined, and the gypsum state of the specimen was evaluated based on the following evaluation criteria.

Evaluation criteria for gypsum state of test specimen Evaluation 1: 80% or more Evaluation 2: 50 to 80% evaluation 3: 30 to 50% evaluation 4: 1 to 30% evaluation 5: No gypsum formation was observed.

Table 2 Example and Comparative Example Corrosion inhibitor concentration (weight %) Adhesion state Gypsum state ────────────────────────────────── Example 1 0.06 Evaluation 5 Evaluation 5 Example 2 0.05 Evaluation 5 Evaluation 5 Example 3 0.05 Evaluation 5 Evaluation 5 Example 4 0.05 Evaluation 5 Evaluation 5 Example 5 0.06 Evaluation 5 Evaluation 5 Example 6 0.05 Evaluation 5 Evaluation 5 Example 7 0.06 Evaluation 5 Evaluation 5 Example 8 0.05 Evaluation 5 Evaluation 5 Example 9 0.05 Evaluation 5 Evaluation 5 Example 10 0.05 Evaluation 5 Evaluation 5 Example 11 0.06 Evaluation 5 Evaluation 5 Example 12 0.05 Evaluation 5 Evaluation 5 Example 13 0.04 Evaluation 5 Evaluation 5 Example 14 Evaluation 5 Evaluation 5 Ratio Comparative Example 1 0.02 Evaluation 3 Evaluation 4 Comparative Example 2 0.02 Evaluation 4 Evaluation 4 Comparative Example 3 0.02 Evaluation 4 Evaluation 4 Comparative Example 4 0.02 Evaluation 4 Evaluation 4 Comparative Example 5 0.02 Evaluation 3 Evaluation 4 Comparative Example 6 0.02 Evaluation 3 Evaluation 4 Comparative Example 7 0.02 Evaluation 4 Evaluation 4 Comparative Example 8 0.02 Evaluation 3 Evaluation 4 Comparative Example 9 0.02 Evaluation 4 Evaluation 4 Comparative Example 10 0.02 Evaluation 4 Evaluation 4 Comparative Example 11 0.02 Evaluation 4 Evaluation 4 Comparative Example 12 0.02 Evaluation 4 Evaluation 4 Comparative Example 13 0.02 Evaluation 3 Evaluation 4 Comparative Example 14 Evaluation 3 Evaluation 4 Comparative Example 15 0.01 Evaluation 2 Evaluation 3 Comparative Example 16 0.02 Evaluation 3 Evaluation 4 Comparative Example 17 Evaluation 1 Evaluation 1 Comparative Example 18 Evaluation 1 Evaluation 1 ───────────────────────────── ─────

From the results shown in Table 2, specific gravities of 1.2-2.
The fume tube obtained by compounding a corrosion inhibitor consisting of a phthalocyanine compound of No. 5 into concrete, and centrifugally molding is used. It was recognized that the concentration of the corrosion inhibitor was two to three times unevenly distributed. The uneven distribution of the phthalocyanine on the inner peripheral surface was confirmed by the naked eye from the marked coloring of the inner peripheral surface. In such a fume tube, it was shown that the adhesion state of the sulfur oxidizing bacteria and the gypsum state on the inner peripheral surface were both lower than that of the cylindrical specimen having the same composition. On the other hand, the specific gravity is 8.
In the case of a fume tube obtained by mixing metallic nickel of 9 with concrete as a corrosion inhibitor and centrifugally molding, the concentration of the corrosion inhibitor on the inner peripheral surface is lower than that of a cylindrical specimen obtained from the same concrete. On the contrary, it was found that the adhesion state of the sulfur-oxidizing bacteria and the gypsum formation state were higher than those of the cylindrical specimens. In addition, it was also shown that the state of adhesion of sulfur oxidizing bacteria and the state of gypsum formation on the inner peripheral surface of the fume tube were higher than that of a fume tube obtained by mixing a corrosion inhibitor having a specific gravity of 1.2 to 2.5. . In addition, in the fume tube and the cylindrical specimen which did not contain the corrosion inhibitor, adhesion of sulfur oxidizing bacteria was remarkable, and the surface became gypsum and corrosion proceeded.

[0048]

According to the present invention, there are several enzymes involved in sulfur redox such as sulfide oxidase and sulfadioxidase in the body of sulfur-oxidizing bacteria present in sewage and soil and causing concrete corrosion. Sulfuric acid is produced by these interactions (Koizumi: Water and wastewater, Vol. 31,
307, 1989). In addition, sulfur oxidizing bacteria have an ecological feature that solid substances such as sulfur particles can be used as a substrate. For this reason, the phthalocyanine compound contained in the concrete is also easily taken into the cells of the sulfur-oxidizing bacteria. These substances taken into the cells of the sulfur-oxidizing bacteria inhibit the enzyme reaction in the cells of the sulfur-oxidizing bacteria, thereby inhibiting the growth of the sulfur-oxidizing bacteria. Specific gravity 1.2 or more like phthalocyanine compound
When the corrosion inhibitor of 2.5 is mixed with concrete and formed by centrifugal force, the specific gravity of the corrosion inhibitor is smaller than that of the fine aggregate and coarse aggregate in the concrete. Conversely, the corrosion inhibitor is arranged inward, and the corrosion inhibitor is unevenly distributed on the inner peripheral surface of the fume tube. Further, since the specific gravity of the corrosion inhibitor is larger than that of water, it is hardly discharged into a waste liquid usually called "Noro" or "Toro" after centrifugal molding. Since the corrosion of the fume tube by the sulfur-oxidizing bacteria is remarkable on the inner peripheral surface through which the sewage passes, it is considered that the uneven distribution of the corrosion inhibitor on the inner peripheral surface is effective in preventing the corrosion by the sulfur-oxidizing bacteria. Thus, the method of the present invention makes it possible to easily produce fume pipes that are more resistant to corrosion by sulfur oxidizing bacteria, thereby making the sewage sewer effective and effective for a long time. Can be kept.

──────────────────────────────────────────────────続 き Continued on the front page (51) Int.Cl. ⁶ Identification code FI // C04B 103: 69 111: 20

Claims (6)

[Claims] 1. A composition comprising a concrete and a corrosion inhibitor having a specific gravity of 1.2 to 2.5, which has a growth inhibiting effect on sulfur oxidizing bacteria, is put into a concrete cylinder, and the mold is rotated. A method for producing a corrosion-resistant fume tube, characterized by performing centrifugal force molding. 2. The method for producing a corrosion-resistant fume tube according to claim 1, wherein the corrosion inhibitor is a phthalocyanine compound. 3. The method for producing a corrosion-resistant fume tube according to claim 2, wherein the phthalocyanine compound is a metal phthalocyanine or a derivative thereof. 4. The method according to claim 1, wherein the metal atom of the metal phthalocyanine or a derivative thereof is at least one selected from the group consisting of chromium, iron, cobalt, nickel, molybdenum, palladium, tin, tungsten, and platinum. Item 3. The method for producing a corrosion-resistant fume tube according to Item 3. 5. The method for producing a corrosion-resistant fume tube according to claim 3, wherein the phthalocyanine compound is a metal phthalocyanine represented by the following general formula (1) or a derivative thereof. MX _n Pc (1) (wherein, M is a metal atom, X is an oxygen atom, a halogen atom or a hydroxyl group, Pc is a phthalocyanine skeleton, n represents 1 to 5
Are respectively shown. ) 6. The method according to claim 2, wherein the phthalocyanine compound is a metal-free phthalocyanine or a derivative thereof.