JP3733921B2 - Dephosphorization material - Google Patents

Description

[0001]
BACKGROUND OF THE INVENTION
The present invention relates to a dephosphorizing material for removing phosphoric acid and phosphate (hereinafter abbreviated as “phosphorus”) from lakes, swamps, reservoirs, river water, domestic wastewater, livestock wastewater, and sewage.
[0002]
[Prior art]
For example, measures to prevent eutrophication in reservoirs are broadly divided into measures for inflowing rivers and measures in reservoirs. Reservoir measures include aeration circulation, fountains and selective discharge. However, these are not measures to actively remove nutrients. Inflow river countermeasures include channel change and inflow water treatment. Channel switching also does not actively remove nutrients. Influent treatment is a method aimed at actively removing nutrients. This removes phosphorus in the water by contact between gravel, coagulation sedimentation separation, phosphorus adsorbent and the like.
[0003]
In particular, dephosphorization treatment with a phosphorus adsorbent is considered to be an effective means. This is because a sludge recovery process such as coagulation sedimentation separation is unnecessary. As the phosphorus adsorbing material (phosphor removing material), those described in Japanese Patent Application Laid-Open No. 62-183898 are conventionally known. This is a porous treatment material having closed cells whose main mineral is tobermorite hydrate. In this dephosphorizing material, voids are made using a foaming agent such as aluminum powder. Therefore, the bubble which is a space | gap is a closed cell on the manufacturing method.
[0004]
As a result of examining the dephosphorization effect using the above dephosphorization material, it was found that phosphorus was fixed in the form of apatite (apatite) using tobermorite hydrate grown inside the bubbles as a precipitation site. Further, the precipitation of apatite was active only in the vicinity of the surface of the cured body in direct contact with the phosphorus solution, and no apatite deposition was observed in the bubbles inside the cured body. This is due to the fact that the bubbles must be independent bubbles in the manufacturing process of the cured body.
[0005]
[Problems to be solved by the invention]
Thus, since the conventional phosphorus removal material has closed cells, the phosphorus removal effect is insufficient. In particular, apatite could not be adsorbed inside. Therefore, the phosphorus removal material has a problem that it is large and bulky, and its volumetric efficiency is low.
[0006]
OBJECT OF THE INVENTION
Therefore, an object of the present invention is to dramatically increase the volumetric efficiency as a phosphorus removal material. The purpose is to significantly reduce the amount of waste and disposal costs. Furthermore, the object of the present invention is to make the hardness of the dephosphorizing material relatively uniform.
[0007]
[Means for Solving the Problems]
The invention according to claim 1 is a dephosphorization material mainly composed of calcium silicate hydrate, which is formed in a substantially spherical shape or a hollow pipe shape, and is formed in the shape of a card house on its surface. Is a dephosphorized material .
The method for forming the dephosphorizing material into a substantially spherical shape is not limited.
The method for forming the dephosphorizing material into a hollow pipe shape is not limited. The hollow pipe shape is not limited to a circular shape with a circular cross section, and each cross section may be an elliptical shape, a polygonal shape such as a triangle, a quadrangle, a pentagon, or an arbitrary shape.
[0008]
The invention according to claim 2 is the dephosphorization material according to claim 1, wherein the card house-like calcium silicate hydrate is deposited on the entire surface thereof.
[0009]
The invention according to claim 3 is produced by rolling granulation using a powder made of a siliceous raw material and a powder made of a calcareous raw material, and after the granulation, this is produced by curing at high temperature and high pressure. It is a dephosphorization material in which calcium hydrate is the main constituent, and has a substantially spherical shape, and calcium silicate hydrate grows in the shape of a card house on its surface.
As this siliceous raw material and calcareous raw material, silica stone, diatomaceous earth, silicate white clay, blast furnace slag, fly ash, cement, gypsum, quick lime and the like are suitable.
[0010]
Invention of Claim 4 softens the mixed material which mixed the powder consisting of the siliceous raw material, and the powder consisting of the calcareous raw material, this softened mixed material is extruded into a hollow pipe shape, and after extrusion molding, This is a dephosphorized material produced by curing this at high temperature and high pressure, with calcium silicate hydrate as the main constituent, and in the form of a hollow pipe and calcium silicate hydrate grown in the shape of a card house on its surface.
In the production of the dephosphorizing material, the extruded dephosphorizing material is cured at room temperature, and then autoclave curing can be performed.
Autoclave curing is a curing method mainly used for secondary concrete products, and is a curing method that combines the action of saturated steam pressure and heat.
A known extrusion molding machine can be used for the extrusion molding of the powder.
[0011]
In the invention described in claim 5, the calcium silicate hydrate is one kind or a combination of two or more kinds of tobermorite, zonotrite, hireblandite and wollastonite. The dephosphorizing material according to claim 1.
[0012]
[0013]
[0014]
[Action]
In the dephosphorizing material according to the first to fifth aspects of the present invention , the dephosphorizing material is accommodated in a container such as a column, for example, and this container is put into sewage containing phosphorus. This dephosphorizing material has a substantially spherical shape or a hollow pipe shape, and calcium silicate hydrate which is apatite precipitation site grows on the entire surface. For this reason, the contact area between calcium silicate hydrate, which is the precipitation site of apatite, and phosphorus-containing water is increased, and the phosphorus adsorption efficiency is extremely high. Moreover, when it is set as a substantially spherical shape, the handleability as a phosphorus removal material is excellent. This dephosphorizing material can also be used as a packed bed.
[0015]
In the production of the phosphorus removal material , rolling granulation or extrusion molding is performed using a siliceous raw material powder and a calcareous raw material powder. In the case of rolling granulation, for example, a sphere having a diameter of about 1 to 15 mm is used. In the case of extrusion molding, for example, a hollow pipe having an outer diameter of 3 to 20 mm, an inner diameter of 1 to 15 mm, and a length of about 0.3 to 2 m is used. Then, this granulated body or molded body is cured in a humid air or at room temperature. Further, this is cured at high temperature and high pressure. For example, it is cured at 180 ° C. and 10 atm in an autoclave. As a result, a substantially spherical calcium silicate hydrate dephosphorizing material is produced. And this dephosphorization material is accommodated and used in containers, such as a column.
In addition, when rolling granulation of a substantially spherical dephosphorization material, the surface portion is inevitably weaker than the center portion, and the hardness of the dephosphorization material as a whole tends to be uneven. In contrast, when extruding the dephosphorizing material into a hollow pipe shape, the molding is stable, so this situation hardly occurs and the entire dephosphorizing material should have a uniform hardness. Can do.
[0016]
DETAILED DESCRIPTION OF THE INVENTION
The first embodiment of the dephosphorizing material according to the present invention will be described below with reference to FIGS.
The following are prepared as raw materials for the phosphorus removal material.
Silica powder is used as the siliceous material.
Ordinary Portland cement is used as the calcareous material.
The fineness of these powders is 5000 cm ² / g and 3200 cm ² / g, respectively. The ratio is mixed at a weight ratio of 43:57.
And the raw material which mixed these was rolling granulated using the bread | pan type | mold pelletizer of diameter (phi) 1.5m. While putting the raw material into the bread, it was granulated by spraying water at the same time. The number of rotations of the bread and the amount of watering during granulation were adjusted while observing the granulation status.
[0017]
As a result, the following curing was applied to the obtained granulated body having a diameter of 1 to 5 mm. That is, it was cured at a temperature of 40 ° C. and a humidity of 100% for 10 hours.
Next, this was put in a stainless steel container, immersed in water, and cured for 8 hours in an autoclave at a pressure of 10 atm and 180 ° C.
After curing, this was observed with an electron microscope. As a result, it was confirmed that tobermorite grown in a card house shape or a plate shape was deposited on the surface.
FIG. 1A shows a dephosphorization material 1. The entire surface serves as an adsorption site for phosphorus. On the other hand, in the conventional phosphorous removal material 2 shown in (B), the bubble portion only becomes an adsorption site.
[0018]
And the performance of this dephosphorization material 1 was investigated with the apparatus shown in FIG. The dephosphorizing material 1 was housed in an acrylic column. As a comparative example, the column described in JP-A-62-183898 was packed in the column, and its dephosphorization performance was examined. An artificial phosphorus solution (KH ₂ PO ₄ , 10 mg · P / liter) was passed through the apparatus. The artificial phosphorus solution was flowed at a rate of 392 ml / hour with respect to the column volume of 392 ml. The results of measuring the phosphorus concentration in the solution are shown in FIG.
As a result, according to this invention, the dephosphorization performance more excellent with respect to the comparative example was able to be confirmed.
[0019]
Next, a dephosphorizing material according to a second embodiment of the present invention will be described with reference to FIGS.
The following are prepared as raw materials for the phosphorus removal material.
Silica powder is used as the siliceous material.
Ordinary Portland cement is used as the calcareous material.
Methyl cellulose is used as the thickener.
The fineness of these quartzite powders and ordinary Portland cement is 5000 cm ² / g and 3200 cm ² / g, respectively. The ratio is mixed at a weight ratio of 43:57. And the thickener was mixed in the ratio of 1 weight part with respect to 100 weight part of these mixtures.
[0020]
After 22% by weight of water was added to the mixed raw material and kneaded, a hollow pipe-shaped formed body was obtained by a general extrusion molding machine as shown in FIG. 5 (outer diameter 5 mm, inner diameter 2 mm, length 1 m). The molded body was cured in a room at 20 ° C. for 24 hours, then placed in a stainless steel container and immersed in water, followed by autoclave curing at 10 atm and 180 ° C. for 8 hours. After curing, this was observed with an electron microscope, and tobermorite grown in a card house shape or a plate shape could be confirmed on the outer peripheral surface, inner peripheral surface and fracture surface.
FIG. 4 shows the hollow pipe-shaped dephosphorizing material 3. The entire surface serves as an adsorption site for phosphorus.
[0021]
Then, the performance of the dephosphorizing material 3 was examined in the same manner as in the first example by using the apparatus shown in FIG. The result of measuring the phosphorus concentration in the solution was substantially the same as in FIG.
In FIG. 5, 10 is an extrusion molding machine main body, 11 is a hopper for charging raw materials, 12 is a drive motor, 13 is a heater, 14 is a screw, 15 is a base, 16 is a forming die, 17 is a cooling tank, and 18 is A take-up machine, 19 is a fixed-size automatic cutter, and 20 is a molded hollow pipe-shaped body.
As shown in FIG. 5, the raw material charged into the extrusion molding machine main body 10 from the hopper 11 is melted by the heat of the heater 13 while being transferred to the outlet side of the molding machine main body 11 by the screw 14. And it is extruded from the nozzle | cap | die 15 with which this exit was mounted | worn in the shape of a hollow pipe. After that, this molded body is also helped by the pulling force of the take-up machine 18, forming the shape when passing through the forming die 16, and further cooled and cured to a predetermined temperature when passing through the cooling tank 17, and thereafter, It is cut into the predetermined length by the automatic sizing cutter 19.
[0022]
【The invention's effect】
According to the phosphorus removal material according to the present invention, the phosphorus removal effect can be enhanced. In particular, the volumetric efficiency can be increased .
Further, if a hollow pipe-shaped phosphorus removal material is manufactured by extrusion molding, a high quality product having a relatively uniform hardness can be obtained in the entire phosphorus removal material.
[Brief description of the drawings]
FIG. 1 is a conceptual diagram showing a dephosphorizing material according to the present invention.
FIG. 2 is a diagram showing an experimental apparatus according to the first embodiment of the present invention.
FIG. 3 is a graph showing experimental results according to the first embodiment of the present invention.
FIG. 4 is a conceptual diagram showing a dephosphorizing material according to a second embodiment of the present invention.
FIG. 5 is a perspective view showing a dephosphorizing material extruding machine according to a second embodiment of the present invention.
[Explanation of symbols]
1,3 Dephosphorizing material.

Claims (5)

A dephosphorization material mainly composed of calcium silicate hydrate, which is formed in a substantially spherical shape or a hollow pipe shape, and on which the calcium silicate hydrate grows in a card house shape. The dephosphorization material according to claim 1, wherein the card house-like calcium silicate hydrate is deposited on the entire surface. Rolled granulation using powder made of siliceous raw material and powder made of calcareous raw material, and after this granulation, it is manufactured by curing at high temperature and high pressure, and calcium silicate hydrate is the main constituent. A dephosphorized material in which calcium silicate hydrate is grown in the shape of a card house on the surface of a roughly spherical shape. Manufactured by softening a mixed material made by mixing powder made of siliceous raw material and powder made of calcareous raw material, extruding the softened mixed material into a hollow pipe shape, and extruding it, followed by curing at high temperature and pressure A dephosphorization material in which calcium silicate hydrate is the main constituent, is in the shape of a hollow pipe, and calcium silicate hydrate grows in the shape of a card house on its surface. The dephosphorization material according to any one of claims 1 to 4, wherein the calcium silicate hydrate is one or a combination of two or more of tobermorite, zonotrite, millebrandite, and wollastonite. .

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