JP2003112044A - In-water dephosphorizing agent, dephosphorizing method using the same and method of manufacturing fertilizer - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide a dephosphorizing agent which can efficiently dephosphorize in water, is easily dispersible in water when the agent is charged into rivers, lakes, ponds or impounding reservoirs, is easily recoverable and recyclable after phosphorus adsorption, and a dephosphorizing method using the same. SOLUTION: This underwater dephosphorizing material is formed by providing the surface of a ligneous base material with a coating layer of a dephosphorizable composition prepared by compounding (B) 2 to 150 parts by mass hydraulic binder and (C) a calcium feeding material of an amount not exceeding 150 parts by mass as desired with (A) 100 parts apatite formable material. This underwater dephosphorizing material is charged into a phosphorus-containing aqueous solution and after the phosphorus is sufficiently adsorbed thereto, the phosphorus is separated and recovered from the inside of the aqueous solution.

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to an underwater dephosphorization material for efficiently removing and purifying phosphorus contained in rivers, lakes, seawater, domestic wastewater, and industrial wastewater, which causes environmental pollution. The present invention relates to a dephosphorization method using the same and a method for effectively using used underwater dephosphorization material as a fertilizer raw material.

[0002]

2. Description of the Related Art Phosphorus contained in wastewater discharged from factories and households causes eutrophication of rivers, lakes and seawater and causes environmental damage. Therefore, removal and recovery of phosphorus becomes a major social problem. ing. In addition, the treatment of waste wood from parks, forests, houses and construction sites has become a social issue.

Therefore, various kinds of underwater dephosphorizing agents and underwater dephosphorizing methods have been proposed so far. That is, as the dephosphorizing agent in water, for example, a dephosphorizing agent composed of a reaction product of a calcareous raw material, a siliceous raw material, and zeolite (Japanese Patent Application Laid-Open No. 20-200200).
No. 01-9470), a removal material formed by molding a substance containing allophane as a main component, and firing it at 300 to 600 ° C. (JP-A-3-68445), and slag obtained by melting industrial waste. Is finely pulverized, and calcium oxide therein is treated with an alkali to remove it, and a porous inorganic adsorbent for phosphorus removal (Japanese Patent Laid-Open No. 63-39632) and ash discharged from a fluidized-bed boiler are main components. And a dephosphorizing material (Japanese Patent Application Laid-Open No. 5-261378) for example, and as a dephosphorizing method in water, for example, dephosphorizing seawater by contacting seawater with activated alumina containing aluminum oxide and sodium oxide. Method (Japanese Patent Laid-Open No. 6-328067), magnesium ions are added to phosphate wastewater containing ammonium ions, and then the pH value is adjusted to 8 or more, and then phosphate A method in which phosphorus in wastewater is deposited as magnesium ammonium phosphate particles on the surface layer of the above-mentioned granules by passing through a packed bed of the nesium-ammonium-containing granules (JP-A-63-200888), an aqueous solution containing phosphorus is calcium ion. In the presence of the above, when contacting with a granular material having a phosphorus removing ability, a salt solution is added to this aqueous solution to adjust the electric conductivity of the solution to 2000 i □ / cm or more and catalytic dephosphorization is performed. Kaihei 3-2074
No. 89) is known.

However, these dephosphorizing agents and dephosphorizing methods have problems that secondary pollution occurs, it is necessary to use a substance with a small production amount, special equipment is required, and the removal efficiency is low. Therefore, it is not yet sufficiently satisfactory to treat a large amount of phosphorus-containing aqueous solution.

In order to improve the disadvantages of such conventional dephosphorizing agents and dephosphorizing methods, the present inventors have first (A) 100 parts by mass of an apatite-forming substance, and (B) a hydraulic binder 3 to 3. In-water dephosphorization composition containing 100 parts by mass and (C) 2 to 50 parts by mass of aqueous resin emulsion and optionally (D) calcium-providing substance in an amount not exceeding 150 parts by mass, and in-water dephosphorization method using the same Proposed. However, this dephosphorizing agent in water is difficult to collect after it is put into rivers, lakes and marshes to remove phosphorus, and it must be thrown away. I cannot escape.

[0006]

DISCLOSURE OF THE INVENTION The present invention is capable of efficiently dephosphorizing in water, and can be used in rivers, lakes and marshes.
The purpose of the present invention is to provide a dephosphorization material and a dephosphorization method using the same that can be easily dispersed over the entire surface when it is put into a reservoir, etc., and can be easily recovered and reused after phosphorus adsorption. is there.

[0007]

DISCLOSURE OF THE INVENTION The inventors of the present invention have conducted extensive studies to develop a dephosphorizing agent which can efficiently remove phosphorus in water and can be handled safely. As a result, calcium phosphate-based ceramics have been obtained. Focusing on the phenomenon that hydroxyapatite crystallizes above, we proposed a new dephosphorizer with a mechanism of action completely different from that of conventional dephosphorizers. By loading it on the surface of the base material, it can be easily distributed when it is thrown into rivers, lakes, reservoirs, etc., and can be easily recovered after phosphorus adsorption, and the dephosphorized material after this recovery is easily fertilizer. The present invention has been completed based on this finding.

That is, the present invention relates to (A) 100 parts by mass of an apatite-forming substance, (B) 2 to 150 parts by mass of a hydraulic binder, and optionally (C) a calcium supplying substance in an amount not exceeding 150 parts by mass. A coating layer of a dephosphorizing composition containing a water-based dephosphorizing material, characterized in that it is provided on the surface of a wood base material, this in-water dephosphorizing material is put into a phosphorus-containing aqueous solution to sufficiently adsorb phosphorus. After that, the present invention provides an underwater dephosphorization method for separating and recovering from an aqueous solution, and a method for producing a fertilizer for treating the recovered underwater dephosphorization material as it is or by pulverizing it.

[0009]

DETAILED DESCRIPTION OF THE INVENTION The present invention will be described below with reference to the accompanying drawings. FIG. 1 is a cross-sectional view showing the structure of the underwater dephosphorization material of the present invention, which comprises a wood base material 1 and a coating layer 2 of the dephosphorization composition provided on the surface thereof.
As the wood-based material 1, wood powder such as wood chips, sawdust, and wood powder produced by cutting or crushing wastes such as large and small branches and construction waste generated by pruning and felling of trees is hardened with a binder. Molded granules prepared by the above method are used. These wood base materials 1 are 5 to 100 m in length and width in consideration of spraying on the water surface and easy handling of recovery after phosphorus adsorption.
m, preferably 10 to 50 mm, thickness 0.5 to 20 m
It is preferable to process to a size of m, preferably 2 to 5 mm.

Next, the dephosphorization composition for forming the coating 2 on the surface of the wooden base material is (A) an apatite-forming substance, (B) a hydraulic binder, and (C) calcium supply optionally used. Composed of substances.

As the apatite-forming substance of the component (A), a substance mainly composed of an insoluble phosphoric acid compound such as Ca ₃ (PO ₄ ) ₂ is used, but it is discarded as unused pottery clay without being used. It is better to use abandoned bone ash or abandoned bone china. Examples of the apatite-forming substance include α-calcium phosphate, β-tricalcium phosphate, tetracalcium phosphate Ca ₄ (PO ₄ ) ₂ , calcium hydrogen phosphate dihydrate CaHPO ₄ .2H ₂ O, and phosphorus. It is possible to use those mainly containing calcium hydrogen hydride anhydrous CaHPO ₄ , calcium dihydrogen phosphate hydrate Ca (H ₂ PO ₄ ) H ₂ O, and the like. Usually, as the apatite-forming substance, it is preferable to use bone china, which is at least 10% by mass, preferably 30 to 30% by mass.
It contains an insoluble phosphate compound at a phosphorus concentration of 60% by weight. This apatite-forming substance usually has an average particle size of 5 to 1
It is used as a powder of 00 μm, preferably 10 to 50 μm.

Next, as the hydraulic binder of the component (B), an inorganic binder containing silicon and calcium, such as Portland cement, alumina cement, special cement, blast furnace slag cement and fly ash cement, which can be hardened by water, is used. To be As the hydraulic binder, one having a low pH value is particularly preferable. This hydraulic binder is usually used as a powder having an average particle size of 5 to 50 μm, preferably 10 to 30 μm. The pH of the molded product is 7.5 to 10, preferably 7.8 to
A range of 9.5 is good. This (B) component is (A) component 1
2 to 150 parts by mass, preferably 5 to 50 parts by mass per 00 parts by mass
It is used in a proportion of parts by mass.

In addition, the dephosphorizing composition used in the present invention may contain an aqueous resin emulsion in the hydraulic binder, if desired, in order to enhance the moldability by cement and impart alkali resistance and water resistance as a binder. be able to. As this aqueous resin emulsion, aqueous latex, acrylic emulsion, ethylene-vinyl acetate emulsion, vinyl acetate-acrylic emulsion,
A polyurethane emulsion, an epoxy emulsion, a silicone emulsion, a powder emulsion, etc. may be used alone or in admixture of two or more. All of these are well known and can be easily obtained as commercial products. This water-based resin emulsion includes anionic and cationic ones.
It is preferably 60% by mass.

The use of this aqueous resin emulsion is
In addition to having little effect on the water content of the wood-based material, using an organic solvent-based emulsion adversely affects the environment and hygiene, and without solvent, mixing is poor, while workability is good, This is because mixing is easy. It is preferable that this emulsion does not need to use an organic solvent or a plasticizer, has a large molecular weight, and exhibits water resistance. Formability and strength can be improved by adding this, but if too much is added, the phosphoric acid component and the alkaline component will be formed into a film and sealed, and the desired effect will not be achieved. 2 to 2 parts by mass
It should be 50 parts by mass (solid content conversion). The preferred ratio is 4 to 20 parts by mass, but when used, it may be appropriately diluted if necessary.

In the dephosphorizing composition used in the present invention, in order to supplement the insufficient amount of calcium component, (C)
As a component, it is necessary to incorporate a calcium supplying substance such as calcium carbonate, calcium oxide, calcium hydroxide, calcium sulfate. As the calcium supplying substance, coral and shellfish of aquatic wastes can be crushed and used. If the amount of this calcium component is too small, the dephosphorization effect will be insufficient, and if it is too much, it will cause secondary pollution, so that it is 5 to 100 parts by mass of the component (A).
It is necessary to use it in the range of 150 parts by mass.

The dephosphorizing composition of the present invention is preferably prepared so that the phosphorus concentration therein is at least 10% by mass, preferably 30-60% by mass. In this dephosphorization composition, the specific gravity of the coating after drying is 1.1 to 2.
It is preferable to adjust it to 3, preferably 1.5 to 2.0.

The dephosphorizing composition of the present invention comprises (A),
The component (B) and the component (C) that is used as desired are mixed in a predetermined ratio, water is added and the mixture is kneaded, and the mixture is applied to the surface of the wooden base material. This coating method can be arbitrarily selected from the methods usually used for forming a coating film on a solid surface, such as dipping, brush coating, roller coating, and spraying.

The thickness of the coating layer of the underwater dephosphorizing material of the present invention is usually 20 μm to 5.0 mm, preferably 200 μm.
It is selected in the range of m to 2.0 mm. This thickness does not necessarily have to be uniform throughout. Then, by adjusting the thickness of this coating layer, the specific gravity of the entire underwater dephosphorization material is controlled to be 1.00 or less, preferably within the range of 0.95 to 1.00, depending on the usage mode. It can be floated up to the surface or can be made larger than 1.00 and settled in water.

According to the present invention, to perform dephosphorization in water,
For example, the above-mentioned underwater dephosphorization material is put into water in which phosphorus components are accumulated, such as lakes and reservoirs, and left for a time sufficient for the phosphorus concentration in the water to be substantially reduced. This time depends on the phosphorus concentration in the water, the flow state of the water, the overgrowth state of the underwater plants, the habitation state of the aquatic organisms, etc., but it is usually 1 to 150 hours. In this way, 1 / of the initial concentration
The phosphorus concentration can be reduced to about 5 to 1/20, or 1.0 ppm or less as an absolute concentration.

In this way, after the phosphorus in the water is sufficiently adsorbed, the underwater dephosphorization material is recovered. This recovery can be performed by, for example, using a mud collector or a wire net to scoop up from the water bottom or the water surface, or by previously connecting the underwater dephosphorization material with a metal wire or the like and then pulling it all at once. Since the recovered used dephosphorization material contains active ingredients such as phosphorus component, plant constituent component and calcium component, it can be applied as fertilizer for various agricultural products after being crushed as desired.

[0021]

EXAMPLES The present invention will be described in more detail with reference to examples.

Reference Example 1 100 parts by mass of bone ash, 30 parts by mass of low pH cement (manufactured by Ishikawa Sangyo Co., Ltd., trade name "Eco-cement", pH 8.2), acrylic emulsion (manufactured by BASF Dispersion, trade name "Acronal YJ") -1655D ", solid content concentration 55 mass%) 5 parts by mass and cellulose (Shin-Etsu Chemical Co., Ltd., trade name" Metroze ") 0.2 parts by mass are mixed, and Mechanomill (Okada Seiko Co., Ltd. trade name" Laboratory powder " Using a body treatment apparatus "), the mixture was mixed for 7 minutes under the condition of 450 rpm and then granulated to prepare a granular dephosphorization composition having a diameter of 13 to 17 mm. The phosphorus concentration of this product was 75% by mass in terms of calcium phosphate.

Phosphate buffer aqueous solution 1 having an initial concentration of 325 ppm
To 100 parts by mass, 10 parts by mass (● mark) and 20 parts by mass (▲ mark) of the granular dephosphorization composition obtained in Reference Example 1, respectively.
And 50 parts by mass (marked with ■) were added, and the relationship between the immersion time and the residual amount of phosphorus in the aqueous solution was investigated, and a graph shown in FIG.
Shown in. As is clear from this figure, the dephosphorizing composition used in the present invention exhibits a remarkable dephosphorizing effect on phosphorus in water.

Example 1 100 parts by mass of bone ash, 30 parts by mass of low pH cement (manufactured by Ishikawa Sangyo Co., Ltd., trade name "Eco-cement", pH 8.2), and cellulose (manufactured by Shin-Etsu Chemical Co., Ltd., trade name "Metroze") To the powder mixture consisting of 0.2 parts by mass, 15 parts by mass of water was added and kneaded to prepare a dephosphorizing composition coating liquid. Then, put wood chips 50 mm long and 50 mm wide and 5 mm thick into the mechanomill, and while rotating, on the surface,
The above-mentioned dephosphorizing composition coating solution was sprayed and blow-dried to form a coating having a thickness of about 0.5 mm, and an underwater dephosphorizing material having a specific gravity of about 0.90 and floating on the water surface was produced.
The phosphate concentration of this product is 75 in terms of calcium phosphate.
The mass ratio of the wood chips and the powder mixture was 1: 1.

Example 2 To 100 parts by mass of an aqueous phosphate buffer solution having an initial concentration of 300 ppm, the dephosphorizing agent in water obtained in Example 1 was added at a ratio of 10% by mass and left for 15 hours. Was taken out and the phosphorus concentration of the phosphate buffered aqueous solution was measured,
It was about 150 ppm. In addition, extend the leaving time to 1
After 20 hours, the phosphorus concentration became almost zero.

Example 3 Water in Gugagaike, Nagakute Town, Gifu Prefecture (pH 6.0, phosphorus concentration 1)
(2.7 ppm) 1000 g, 400 g of the dephosphorizing material in water obtained in Example 1 was charged and floated. When the phosphorus concentration was measured after standing for 7 days, it decreased to 0.3 ppm. Then, the dephosphorized material in water was recovered, air-dried, and then applied as a fertilizer to the roots of cedar saplings.

[0027]

EFFECTS OF THE INVENTION According to the present invention, it is possible to obtain a dephosphorization material which can be easily dispersed over the entire surface and efficiently dephosphorized when thrown into a river, a lake, a water reservoir, or the like. Has an advantage that it can be easily recovered after adsorption of phosphorus, and can be used as a fertilizer by crushing and drying after recovery. Further, as the wood base material of the raw material, the felled waste wood of the adjacent area can be used, which is also suitable from the viewpoint of effective utilization of forestry waste.

[Brief description of drawings]

FIG. 1 is a sectional view of an underwater dephosphorization material of the present invention.

FIG. 2 is a graph showing the dephosphorization effect of the dephosphorization composition used in the present invention.

[Explanation of symbols]

1 Wood base material 2 Dephosphorization composition coating

   ─────────────────────────────────────────────────── ─── Continued front page    (72) Inventor Naoyuki Kato             2717-4 Minamikomatsucho, Yokkaichi-shi, Mie Prefecture F-term (reference) 4D024 AA05 AB12 BA11 BB07                 4G066 AA17A AA47A AA49A AA66A                       AA73C AC07C AC12C AE20C                       BA20 BA38 CA41 DA07 DA08                       FA03 FA26 FA28 FA40                 4H061 AA01 CC02 CC03 CC04 CC05                       EE43 EE64 FF06 FF08 GG13                       LL07 LL26

Claims (10)

[Claims] 1. A coating layer of a dephosphorization composition containing (A) 100 parts by mass of an apatite-forming substance and (B) 2 to 150 parts by mass of a hydraulic binder is provided on the surface of a wood base material. Underwater dephosphorization material characterized by. 2. A dephosphorizing property in which (A) 100 parts by mass of an apatite-forming substance, (B) 2 to 150 parts by mass of a hydraulic binder and (C) 150 parts by mass of a calcium supplying substance are mixed. An underwater dephosphorization material, characterized in that a coating layer of the composition is provided on the surface of a wooden base material. 3. The underwater dephosphorization material according to claim 1, wherein the apatite-forming substance as the component (A) is at least one selected from bone ash and bone china. 4. The hydraulic binder as the component (B) is at least one selected from Portland cement, alumina cement, special cement, blast furnace slag cement and fly ash cement. Underwater dephosphorization material. 5. The water according to claim 2 or 3, wherein the component (C) that supplies calcium is at least one selected from calcium carbonate, calcium oxide, calcium hydroxide, calcium sulfate, shells and corals. Dephosphorization material. 6. The underwater dephosphorizing material according to claim 1, wherein the wood base material is at least one selected from wood chips and wood powder molded granules. 7. The specific gravity is changed to 1.00 by changing the thickness of the coating layer.
The underwater dephosphorization material according to any one of claims 1 to 6, which is adjusted as follows. 8. A wood base material having a length of 5 to 100 mm and a width of 5 to 1
The underwater dephosphorization material according to any one of claims 1 to 7, which has a size within a range of 00 mm and a thickness of 0.5 to 20 mm. 9. An in-water dephosphorization method in which the underwater dephosphorizing material according to any one of claims 1 to 8 is added to a phosphorus-containing aqueous solution to sufficiently adsorb phosphorus, and then separated and recovered from the aqueous solution. . 10. The method for producing a fertilizer according to claim 9, wherein the recovered underwater dephosphorizing material is used as it is or is pulverized to be fertilized.