JP2011245457A - Iron-oxides deposition inhibitor and blocking prevention method using the same - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide an iron-oxides deposition inhibitor which effectively prevents iron-oxides from being deposited on an instrument in contact with an iron-containing acidic water to block, and makes service life of the instrument greatly longer.SOLUTION: The iron-oxides deposition inhibitor is used for preventing iron hydroxide iron oxide or a mixture of both from depositing on the instrument in contact with the iron-containing acidic water, wherein the inhibitor consists of an iron oxidizing bacteria propagation inhibitor having a metallic aluminum as an effective component. The instrument in contact with the iron-containing acidic water is a closed conduit distributing pipe, a pump for pumping, etc.

Description

  The present invention relates to an iron oxide deposition inhibitor used to prevent iron hydroxide, iron oxide, or a mixture of both (hereinafter referred to as iron oxides) from depositing on equipment that comes into contact with iron-containing acidic water. . More specifically, the present invention relates to an inhibitor for preventing the deposition of iron oxides by suppressing the growth of iron-oxidizing bacteria.

  The effluent from the mine and the groundwater that permeates from the acidic soil are acidic and often dissolve iron as divalent ions. Such iron-containing acidic water is oxidized and deposited when exposed to air, and is deposited as trivalent iron oxide or iron hydroxide. This oxidation is known to be promoted by iron-oxidizing bacteria.

  In farmland with poor drainage of acidic soil widely distributed in Japan, iron-containing wastewater that has penetrated into dark drainage drained as drainage improvement deposits as iron oxides by iron-oxidizing bacteria in the dark drainage pipe, and dark drainage Patent Document 1 discloses a technique for preventing iron oxides from being deposited in a dark drainage pipe in order to reduce the water flow function by closing the pipe. That is, Patent Document 1 discloses the following.

  For agricultural lands with poor drainage, it is necessary to improve drainage with dark drainage to avoid moisture damage and ensure good crop growth. To drain the dark drainage, drill a ditch with a depth of 0.6m or less in the farmland with a gradient of 1/100 to 1/1000, bury the dark drainage pipe, and improve the water permeability. It is a method of burying to the bottom of the soil and directly under the soil. Among them, as a factor that reduces the effect of dark drainage, clogging of dark drainage pipes has been pointed out, especially for iron-containing acidic drainage. In-pipe cleaning technology has been proposed as a method for removing the occluding material, but it has not yet been used in practice. In addition, it has become clear that the dark drainage pipe plugging substance is mainly a reddish brown substance and is caused by the deposition of iron oxides. However, there is currently no method for preventing the deposition of iron oxides. Therefore, in Patent Document 1, in order to prevent the deposition of iron oxide, a blockage prevention material composed of granular rock wool, which is a high calcium silicate-containing material, and an inorganic hydraulic material is buried around a dark drainage pipe to prevent the blockage. It teaches the prevention of blockage in the dark by placing a hydrophobic material on top of the material.

  However, the problem that iron oxides are deposited on equipment that comes into contact with iron-containing acidic water is not limited to the dark drainage pipe, but also occurs, for example, in pumps that pump up ground water and equipment that is arranged in the vicinity thereof. Specifically, it also deposits on the impeller of the pump, the strainer arranged on the water absorption side of the pump, the piping in the vicinity thereof, the casing, and the like. In particular, when the material of the equipment that comes into contact with the iron-containing acidic water is an iron-based material, there arises a problem that the deposition of iron oxides proceeds rapidly and deposits firmly.

Patent Document 2 discloses a method for treating waste liquid using iron-oxidizing bacteria, which deals with iron-oxidizing bacteria that oxidize divalent iron ions in a waste liquid containing a plurality of metals such as pickling waste liquid and plating waste liquid. A method has been introduced in which, when an activity inhibitory substance is mixed, the inhibition of the activity of iron-oxidizing bacteria is detected at an early stage and the inhibition factor is released. Here, the activity inhibitors and their concentrations are Co ²⁺ (3 × 10 ⁻² M or more), Pb ²⁺ (10 ⁻⁴ M or more), Sn ²⁺ (10 ⁻³ M or more), Ag ⁺ ( Examples are metal ions such as 10 ⁻⁵ M or more), Hg ² (10 ⁻⁵ M or more), Ni ²⁺ (6 × 10 ⁻² M or more), and their concentrations.

  Patent Document 3 discloses an antibacterial agent for preventing sulfur oxidizing bacteria and sulfur iron oxide oxidizing bacteria that cause deterioration of concrete in sewage treatment facilities and the like. Here, examples of the antibacterial material powder include metals such as nickel, tin, and copper, metal oxides such as nickel oxide, tin oxide, cobalt oxide, and cuprous oxide, and mixtures thereof. These are blended at a desired position in the concrete when the concrete is formed.

JP 2004-270161 A JP 2008-264654 A JP-A-8-268823

  However, according to the above prior art, the effect is insufficient, the processing is complicated, or it is harmful. Therefore, an object of the present invention is to provide an iron oxide deposition preventive agent that can be easily prepared or processed using a safe material and an iron oxide deposit preventive method using the same.

  The present invention is an iron oxide deposition inhibitor used to prevent iron oxides from being deposited on equipment that comes into contact with iron-containing acidic water, and comprises an iron-oxidizing bacterial growth inhibitor containing metal aluminum as an active ingredient. This is an iron oxide deposition inhibitor. Here, the iron oxides refer to trivalent iron oxide, iron hydroxide, or a mixture thereof.

  As the iron-oxidizing bacteria propagation inhibitor, a coating containing a plated or sprayed metallic aluminum or metallic aluminum powder is preferable. Further, as the equipment that comes into contact with the iron-containing acid water, a dark drainage pipe, an impeller of a pump for pumping water, or a pipe or strainer arranged around the pump is suitable.

  The present invention is also a method for preventing blockage of a dark drainage pipe, which comprises plating, spraying, or applying the iron oxide deposition inhibitor at or near an opening of the dark drainage pipe. Furthermore, the present invention provides a method for preventing clogging of a pump for pumping, characterized by plating, spraying, or applying the iron oxide deposition preventive agent on a pump impeller for pumping water or a pipe or strainer arranged around the pump. It is.

  The iron oxides deposition inhibitor of the present invention can effectively prevent the deposition of iron oxides on the equipment that comes into contact with the iron-containing acidic water, so that the service life of the equipment can be greatly extended. In addition, since the iron oxide deposition preventive agent of the present invention has no toxicity, it can be safely used for drainage pipes, drainage pumps, and the like used for discharging iron-containing acidic water into rivers and the like.

  The iron oxides deposition inhibitor of the present invention comprises an iron-oxidizing bacteria propagation inhibitor containing metallic aluminum as an active ingredient. Previously, certain heavy metals were known to inhibit the growth of iron-oxidizing bacteria, but metal aluminum that is harmless to many organisms was not known to inhibit the growth of iron-oxidizing bacteria. Met.

  The iron-oxidizing bacteria propagation inhibitor may be metallic aluminum itself, but it is effective to adhere to the surface of equipment that comes into contact with iron-containing acidic water, and for that purpose, it is used as plated or sprayed metallic aluminum. Or it is preferable to disperse metal aluminum powder and use it as a paint. In addition, pipe manufacturing with aluminum itself, aluminum spraying on synthetic resin pipes, vapor deposition, metal foil sticking, laminating (or double pipe), painting of aluminum-containing paint, etc. can be considered, but in terms of durability and cost Laminate or paint is practically superior. When the pipe is composed of a plurality of pipes, it is also effective to use an aluminum material at the joint location so that the pipe contacts the iron-containing acidic water.

  Since metallic aluminum is easily attacked by acidic water, it is disadvantageous to make the main body of the equipment that comes into contact with iron-containing acidic water made of aluminum, and anticorrosion-coated iron-based materials, acid-resistant stainless steel, and the like are often used.

  Therefore, aluminum is used for such material as plating or spraying, or metallic aluminum powder is dispersed and used as a paint. In the case of plating, since it is a thin film, the acidity of the iron-containing acidic water is not high and is effective when the amount of water is small. In the case of thermal spraying, since a relatively thick film can be formed, it is effective when the acidity is high and the amount of water is large. When used as a paint, a part of the aluminum metal is exposed and a part of the resin component in the paint protects the surface of the aluminum metal, so that even if the effect is somewhat inferior, it can be used for a long time. However, in any case, since aluminum gradually dissolves, it is necessary to add, replace, or apply an iron-oxidizing bacterial growth inhibitor at appropriate intervals, but iron oxides are deposited on equipment that comes into contact with iron-containing acidic water. The blockage due to this can be greatly delayed, and the period for repair or replacement can be extended.

  The form of the coating can be a method of dispersing metal aluminum powder in a normal anticorrosion coating. As a particle size of metal aluminum powder, 0.005-0.2 mm is desirable. As a compounding quantity in a coating material, 10-80 wt% of the total solid content, Preferably the range of 20-60 wt% is good.

  In the case of plating, plating methods such as electrolytic plating and electroless plating can be appropriately selected. In the case of thermal spraying, plating methods such as flame spraying and electric spraying can be selected as appropriate. In the case of a paint, a coating method such as spraying or brushing can be appropriately selected. These thicknesses are advantageous because the thicker the function as an iron-oxidizing bacteria propagation inhibitor lasts longer, but the thickness does not hinder the function of the equipment that comes into contact with the iron-containing acidic water.

  Examples of the equipment that comes into contact with the iron-containing acidic water include, but are not limited to, a dark drainage pipe, a pump impeller for pumping water, a pipe or a strainer disposed around the pump, and the like. Hereinafter, although the example which applies the iron oxidation bacteria reproduction inhibitor of this invention to a dark drainage pipe and a pump for pumping is shown, it can carry out according to this also about the equipment which touches other iron-containing acidic water.

  In the dark drainage pipe located in the farmland, surplus water permeates the soil and subsoil, leaching the water-soluble divalent iron, and the water containing the iron-containing drainage mainly passes through the hydrophobic material. Then flow into. A clogging prevention material made of rock wool or the like is laid around the opening of the dark drainage pipe to prevent mud and dirt from entering.

  In the dark drainage pipe, iron oxides are easily deposited around the opening through which the iron-containing acidic water flows, and the vicinity of the opening is easily blocked. Therefore, it is preferable to apply the iron-oxidizing bacteria propagation inhibitor mainly in the vicinity of the opening of the dark drainage pipe. For example, it is advantageous to apply a thick iron-oxidizing bacteria growth inhibitor in the vicinity of the opening and apply it thinly or not to other contact surfaces. If the dark drainage pipe is made of metal such as iron, it can be plated, sprayed or painted as a paint. If it is made of non-metal, coating as a paint is advantageous.

  The iron-containing acidic water that has reached the opening in the dark drainage pipe is brought into contact with the iron-oxidizing bacteria growth inhibitor of the present invention, thereby suppressing the activity of iron-oxidizing bacteria. Therefore, it is possible to prevent clogging with iron oxides that have conventionally occurred in the opening of a dark drainage pipe or in the vicinity of the opening.

  Pumps for pumping are used for pumping water for the purpose of using groundwater and improving the ground, etc., but iron-containing acidic water contacts the inside of the pump and the strainer attached to the pump to deposit iron oxides. Occurs, causing pump efficiency to drop and stop. The iron-oxidizing bacteria propagation inhibitor of the present invention can be applied to pumps other than those described above, and is also suitable for sewage pumps, industrial acid water pumps, mining wastewater pumps, and the like.

  Therefore, the iron-oxidizing bacteria propagation inhibitor of the present invention is applied to a location where iron oxides are deposited in the pump. In places where the water flow is not intense, such as a strainer or casing, plating, thermal spraying, or painting as a paint is possible. However, if it is an impeller or the like, plating or thermal spraying is preferable.

Example 1
In a test field in a volcanic mudflow area where it has been confirmed that the dark drainage pipe is blocked in a short period of 1 to 2 years, 2 mm of metal aluminum is placed around the opening in the dark drainage groove with an average gradient of 1/100. A dark drainage pipe made of hard vinyl chloride resin with an inner diameter of 90 mm sprayed to a thickness was installed. Excavation of the dark drainage at the center of the dark drainage after 6 months has passed since construction, and the situation of the blocking prevention material and the vertical drainage pipe were opened in the vertical direction, and the blockage inside the pipe was investigated. There was no deposition of iron oxides and no blockage of the dark drainage was observed. Furthermore, as a result of observing the attached white crystals with an optical microscope and an electron microscope, iron-oxidizing bacteria were not confirmed.

Example 2
An experiment was conducted to examine materials to prevent clogging by iron scales in underdrains and pumping wells.
As evaluation agents, a) Moldtech: MW500-FP (product compatible with iron bacteria), b) Ecowell: product compatible with iron bacteria AP, product compatible with iron bacteria, c) aluminum plate, and d) Nippon Steel & Sumikin Steel Company: Corrosion resistant Al-Zn alloy plated steel plate was used.
The test method was to immerse the specimen in iron-containing acidic river water in the Nishikawa Izumi area, hold it for a certain period, and then evaluate the deposition condition.

The measurement items and methods for water quality at the test site are as follows.
・ Temp, pH, electrical conductivity (EC), turbidity (TURB), dissolved oxygen (DO), total dissolved solids (TDS) …… Multi-water quality monitoring system ・ Total iron (T-Fe), Fe (II) …… Colorimetric measurement with 1,10 phenanthroline method · Anion… Anion chromatography · Cation… Capillary electrophoresis Table 1 shows the measurement results.

  To detect iron-oxidizing bacteria, add sediment at the bottom of the river in M-70 medium containing ferrous sulfate and incubate for 72 hours to confirm the state of inhabiting of iron-oxidizing bacteria Thiobacillus ferooxidans using a biological microscope did.

  Tables 2 to 6 show the test results obtained by immersing synthetic resin plate (PP), aluminum plate or corrosion-resistant Al-Zn alloy plated steel plate (plated steel plate) in iron-containing acidic river water in Nishikawa Izumi area. Table 4 shows the X-ray fluorescence (EDX) analysis result (%) of the deposit on the synthetic resin plate (no treatment). Table 5 shows a comparison between the aluminum plate and the Al-Zn alloy-plated steel plate (plated steel plate) (after 6 days immersion). Table 6 shows the data after immersion for 45 days in the aluminum plate.

From the results of the above-mentioned field evaluation test, it was confirmed that the effect of preventing adhesion of metal aluminum to iron scale was high. Also, commercially available antibacterial drugs have a low iron scale adhesion prevention effect. Furthermore, it was confirmed that the corrosion-resistant plated steel sheet has less iron scale adhesion than the synthetic resin board (PP board).
From the above, as a mechanism of iron scale generation by iron-oxidizing bacteria, reduction of divalent iron ions in water inhibits the oxidation reaction of divalent iron ions when oxidized by iron-oxidizing bacteria and precipitated as trivalent iron hydroxide. It has been confirmed that a substance that coexists with an oxidative substance and generates repellent ions of iron-oxidizing bacteria is effective in preventing the generation of iron scale. It was confirmed that metallic aluminum is effective as such a material.

  As a method of using metallic aluminum, manufacturing of pipes with aluminum itself, spraying of aluminum on synthetic resin pipes, vapor deposition, application of metal foil, lamination (or double pipes), painting of aluminum-containing paints, etc. can be considered. Lamination or painting is considered realistic and effective in terms of durability and cost.

Claims (7)

  Iron oxide bacteria deposition inhibitor used to prevent iron hydroxide, iron oxide, or a mixture of both from depositing on equipment that comes in contact with iron-containing acidic water, and suppresses the growth of iron-oxidizing bacteria that contain metallic aluminum as an active ingredient An iron oxide deposition inhibitor characterized by comprising an agent.   The iron oxide bacterial deposition inhibitor according to claim 1, wherein the iron-oxidizing bacteria growth inhibitor is plated or sprayed metallic aluminum.   The iron oxide bacteria deposition inhibitor according to claim 1, wherein the iron-oxidizing bacteria propagation inhibitor is a paint containing metallic aluminum powder.   The iron oxide deposition preventive agent according to any one of claims 1 to 3, wherein the equipment that contacts the iron-containing acidic water is a dark drainage pipe.   The iron oxide deposition preventive agent according to any one of claims 1 to 3, wherein the equipment that comes into contact with the iron-containing acidic water is an impeller of a pump for pumping water, a pipe or a strainer arranged around the pump.   A method for preventing blockage of a dark drainage pipe, comprising plating, spraying or applying the iron oxide deposition inhibitor according to any one of claims 1 to 3 at an opening of the dark drainage pipe or in the vicinity thereof.   A pump for pumping water characterized by plating, spraying, or applying the iron oxide deposition inhibitor according to any one of claims 1 to 3 to an impeller of a pump for pumping water or a pipe or strainer arranged around the pump. Blockage prevention method.