JP2005231927A - Fibrous basic magnesium sulfate massive material - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To provide a basic magnesium sulfate massive material which has high stability in water and whose particle shape and size can be easily controlled and a waste water treatment unit using the fibrous basic magnesium sulfate massive material as a waste water treating material. <P>SOLUTION: The fibrous basic magnesium sulfate massive material is formed by bonding a number of fibrous basic magnesium sulfate having 5-200 μm average length and 0.2-1.0 μm average diameter with a binder to expose at least a part of the fiber surface of the same. The waste water treatment unit is structured by filling the waste water treating material 3 comprising the fibrous basic magnesium sulfate massive material into a space between an outside cylindrical body 1 composed of a porous material and an inside cylindrical body 2 composed of the porous material which are concentrically assembled. <P>COPYRIGHT: (C)2005,JPO&NCIPI

Description

  The present invention relates to a fibrous basic magnesium sulfate lump that can be advantageously used as a wastewater treatment material, particularly an agglomerate of inorganic fine particles and emulsified oil fine particles in wastewater.

In general, inorganic fine particles and emulsified oil fine particles are mixed in the waste water of the grinding device and the polishing device. As a method for removing inorganic fine particles and oil fine particles from such waste water, the inorganic fine particles are brought into contact with the waste water by contacting a mass of fibrous basic magnesium sulfate [MgSO ₄ .5Mg (OH) ₂ .3H ₂ O]. There is known a method in which oil fine particles are each aggregated, inorganic aggregated particles are separated by a filter, and the oil aggregated particles are floated and separated.

Patent Document 1 discloses a liquid filtration device having a configuration in which a fibrous basic magnesium sulfate mass (adsorbent) is filled between a first filtration layer and a second filtration layer arranged concentrically. Has been. In the liquid filtration device disclosed in Patent Document 1, the wastewater comes into contact with the fibrous basic magnesium sulfate lump through the first filtration layer disposed on the outside. The agglomerated particles of the inorganic substance produced by contact with the porous magnesium sulfate lump can be separated by a second filtration layer disposed inside. This Patent Document 1 exemplifies a pill-like lump of about 250 μm formed by intertwining fibrous basic magnesium sulfate of about 30 μm as the basic magnesium sulfate lump.
Japanese Patent No. 264091

It is desired that the basic magnesium sulfate lump used as a wastewater treatment material is not easily disintegrated even in contact with wastewater, that is, has high stability in water.
Moreover, the basic magnesium sulfate lump used as a wastewater treatment material is preferable if the particle shape and the size thereof can be adjusted in consideration of the wastewater treatment amount and workability.
Accordingly, an object of the present invention is to provide basic sulfuric acid that has high stability in water, can easily adjust the particle shape and size, and exhibits an aggregating function such as inorganic fine particles that are effective for wastewater treatment. It is to provide a mass of magnesium.
Another object of the present invention is to provide a wastewater treatment material comprising the above fibrous basic magnesium sulfate lump.
Another object of the present invention is to provide a waste water treatment apparatus using the above waste water treatment material.

  In the present invention, a large number of fibrous basic magnesium sulfates having an average length of 5 to 200 μm and an average diameter of 0.2 to 1.0 μm have exposed at least a part of their fiber surfaces. In a fibrous basic magnesium sulfate lump formed by bonding with a binder.

Preferred embodiments of the fibrous basic magnesium sulfate lump of the present invention are as follows.
(1) The binder is insoluble in water.
(2) The binder is a fibrous inorganic compound other than fibrous basic magnesium sulfate, which is shorter than fibrous basic magnesium sulfate.
(3) The binder is zonotolite or sepiolite.
(4) The binder is made of a polymer material.
(5) The binder is fibrillated polytetrafluoroethylene.

  The present invention also resides in a wastewater treatment material comprising the fibrous basic magnesium sulfate lump of the present invention.

  The present invention further includes a wastewater treatment in which the wastewater treatment material of the present invention is filled between an outer cylindrical body made of porous materials and an inner cylindrical body made of a porous material combined concentrically with each other. Also in the device.

  In the fibrous basic magnesium sulfate lump of the present invention, since a large number of fibrous basic magnesium sulfates are bonded together by a binder, the particle shape and the size thereof can be easily adjusted. In addition, since many fibrous basic magnesium sulfates forming a lump are exposed on the fiber surface, they exhibit the ability to aggregate inorganic fine particles and oil fine particles. Therefore, the waste water treatment material comprising the above fibrous basic magnesium sulfate lump and the waste water treatment apparatus using the waste water treatment material can be advantageously used for treatment of waste water containing inorganic fine particles and oil fine particles.

The fibrous basic magnesium sulfate lump of the present invention has an average length of 5 to 200 μm and a large number of fibrous basic magnesium sulfate in the range of 0.2 to 1.0 μm. It is bonded by a bonding material with at least part of the surface exposed.
The average length of the fibrous basic magnesium sulfate is preferably in the range of 5 to 100 μm, and more preferably in the range of 5 to 35 μm. The average diameter is preferably in the range of 0.3 to 1.0 μm. Here, the average length and the average diameter are values obtained by measuring the length and diameter of individual primary particles from a photographed image of an electron microscope and calculating the average value.

The binder is preferably water insoluble. Here, water-insoluble means that the solubility in water at 20 ° C. is 0.03 g / L or less.
The binder may be an inorganic compound (excluding basic magnesium sulfate) or a polymer material.

The binder made of an inorganic compound is preferably fibrous. The fibrous inorganic compound is preferably present in the fibrous basic magnesium sulfate mass in a state where an aggregate is formed between the fibrous basic magnesium sulfate and the fibrous basic magnesium sulfate. The average length of the fibrous inorganic compound is preferably shorter than the average length of the fibrous basic magnesium sulfate.
It is more desirable that the fibrous inorganic compound is fibrillated under shearing conditions such as kneading and changes into fine fibers. Examples of such fibrous inorganic compounds include zonotlite [6CaO · 6SiO ₂ · H ₂ O] and sepiolite [Mg ₈ Si ₁₂ O ₃₀ (OH) ₄ (OH ₂ ) ₄ · 8H ₂ O].

  The binder made of a polymer material is also preferably fibrous. The fibrous polymer material is preferably present in the fibrous basic magnesium sulfate mass in a state where a large number of fibrous basic magnesium sulfates are entangled. Fibrilized polytetrafluoroethylene (PTFE) can be used as the fibrous polymer material.

  The binder content of the fibrous basic magnesium sulfate lump can not be uniformly determined because the optimum range differs depending on the material of the binder, but when the binder is an inorganic compound, It is preferably in the range of 1 to 40% by mass, more preferably in the range of 5 to 30% by mass. When the binder is a polymer material, it is preferably in the range of 0.05 to 5% by mass and more preferably in the range of 0.1 to 5% by mass with respect to the total mass of the block.

  The fibrous basic magnesium sulfate lump of the present invention can be produced, for example, by mixing or kneading fibrous basic magnesium sulfate and a binder in the presence of water and then granulating the lump. When fibrillated PTFE is used as a binder, fibrous basic magnesium sulfate and PTFE powder or dispersion are kneaded in the presence of water under the conditions for PTFE fibrillation, and then granulated in a lump. It is preferable to manufacture by this.

  The particle shape of the fibrous basic magnesium sulfate lump is preferably spherical, flat (flakes), or cylindrical. The average particle size of the spherical and flat fibrous basic magnesium sulfate agglomerates is preferably in the range of 0.3 to 5.0 mm. Moreover, it is preferable that a columnar fibrous basic magnesium sulfate lump has an average diameter in the range of 1.0 to 5.0 mm and an average length in the range of 1.0 to 10.0 mm.

The fibrous basic magnesium sulfate lump of the present invention can be advantageously used as a wastewater treatment material, particularly as a wastewater treatment material for a grinding device or a polishing device. That is, by bringing the fibrous basic magnesium sulfate lump of the present invention into contact with waste water, inorganic fine particles (for example, silica fine particles) and emulsified oil fine particles in the waste water can be aggregated. Further, heavy metal ions (for example, lead ions) in the waste water can be reacted with a hydroxyl group of basic magnesium sulfate to be precipitated as hydroxide particles.
The produced inorganic aggregated particles (including hydroxide particles) can be separated from the waste water using a known filtration device such as a filter or a sand filtration device. The oil agglomerated particles can be separated from the waste water using a known device such as a flotation device.

Next, an example of the waste water treatment apparatus using the waste water treatment material comprising the fibrous basic magnesium sulfate lump of the present invention will be described with reference to FIG.
FIG. 1 is a cross-sectional view of an example of a wastewater treatment apparatus according to the present invention.
In FIG. 1, the waste water treatment apparatus includes the above-described fibrous basic magnesium sulfate between an outer cylindrical body 1 made of a porous material and an inner cylindrical body 2 made of a porous material that are concentrically combined with each other. The waste water treatment material 3 made of a lump is filled.
The outer cylindrical body 1 is made of, for example, a resin such as polypropylene, and is attached to the first cylindrical body 1a formed in a porous body or a mesh body, and the first cylindrical body 1a. And a first porous material 1b made of synthetic paper or the like. The inner cylindrical body 2 is installed concentrically with the outer cylindrical body 1, is made of, for example, a resin such as polypropylene, is formed in a porous body or a mesh body, and has a diameter larger than that of the first cylindrical body 1a. The second cylindrical body 2a is composed of a small second cylindrical body 2a and a second porous material 2b made of, for example, synthetic paper, attached to the second cylindrical body 2a. For example, a blind portion 2c made of a plate-like body is provided at the upper end of 2a.

  The filter 4 is, for example, a cylindrical body, is installed in the hollow portion of the inner cylindrical body 2 so as to be replaceable, and is in contact with the inner peripheral surface of the inner cylindrical body 2 to reinforce the strength of the inner cylindrical body 2. To do. The support body 6 is made of, for example, an insulating material, and integrally supports the outer cylindrical body 1, the inner cylindrical body 2, and the filter 4. The pressing plate 7 presses and supports the outer cylindrical body 1, the inner cylindrical body 2, and the filter 4 integrally on the support body 6. The spring receiver 8 is installed in the hollow shaft core portion of the filter 4 and closes the upper opening of the hollow portion of the filter 4. The spring 9 is installed on the spring receiver 8, and presses the spring receiver 8 against the upper end surface of the filter 4 by the pressing plate 7.

  The container 10 includes a container portion 10c having an inlet 10a and an outlet 10b, and a lid portion 10e having an air vent 10d. A support plate 10f that supports the support 6 is attached to the outlet 10b. Yes. The spring 11 is installed in the spring receiving portion 7 a of the pressing plate 7 and is pressed by the lid portion 10 e to press the pressing plate 7.

  The wastewater that flows into the container 10 from the inlet 10 a passes through the outer cylindrical body 1 and reaches the wastewater treatment material 3. When the wastewater passes through the wastewater treatment material 3, the inorganic particles and oil fine particles in the wastewater are aggregated. Moreover, heavy metal ions in the wastewater are precipitated as hydroxide particles. The inorganic agglomerated particles and hydroxide particles are filtered off on the outer peripheral surface of the filter 4. On the other hand, the aggregated oil particles pass through the filter 4 together with the waste water. The oil agglomerated particles in the waste water can be separated and recovered from the waste water by a floating separator (not shown).

[Example 1]
(1) Production of basic magnesium sulfate slurry 9 kg of magnesium sulfate heptahydrate was dissolved in 120 L of water, and 2.25 kg of magnesium hydroxide and 0.4 kg of basic magnesium sulfate serving as seed crystals were dispersed in this solution. . This dispersion was put into a 170 L autoclave and reacted at 170 ° C. for 3 hours to obtain a basic magnesium sulfate slurry having a solid content concentration of 3 mass%. A part of the basic magnesium sulfate in the slurry was collected, dried, and observed with an electron microscope. The particle shape was fibrous, the average length was 28 μm, and the average diameter was 0.5 μm. .

(2) Production of fibrous basic magnesium sulfate lump The fibrous basic magnesium sulfate slurry produced as described above was vacuum filtered and pressure dehydrated to obtain a cake having a moisture content of 50% by mass. To this fibrous basic magnesium sulfate cake, fibrous zonotlite (average length: 3 μm, average diameter: 0.3 μm) was added and mixed so that the solid content was 20% by mass. This mixture was kneaded using an extrusion granulator (meet chopper, manufactured by Hiraga Kogyo Co., Ltd.) and extruded and granulated from an extrusion hole having a diameter of 2.3 mm to obtain a cylindrical hydrous mass. This water-containing lump was dried at a temperature of 120 ° C. for 24 hours.

  Observation of the shape of the cylindrical lump produced in this way with an electron microscope reveals that a large number of fibrous basic magnesium sulfates are partially bound by fine fibrous agglomerated zonotolite aggregates. It was confirmed that most of the fiber surface was exposed. The average length of fibrous basic magnesium sulfate was 8 μm, and the average diameter was 0.5 μm.

[Example 2]
In the same manner as in Example 1, except that the mixture of the fibrous basic magnesium sulfate cake and the fibrous zonotlite was granulated using a tumbling granulator (New Grumman, manufactured by Seishin Enterprise Co., Ltd.), A fibrous basic magnesium sulfate mass was produced.
The morphology of the mass produced in this way was observed with an electron microscope. As a result, a large number of fibrous basic magnesium sulfates were partially bound by agglomerated fine fibrous zonotolite, and the fiber surface It was confirmed that most were exposed. The average length of fibrous basic magnesium sulfate was 8 μm, and the average diameter was 0.5 μm.

[Example 3]
In the same manner as in Example 1, except that fibrous sepiolite (average length: 2 μm, average diameter: 0.2 μm) was added instead of fibrous zonotlite so that the solid content was 10% by mass, A columnar fibrous basic magnesium sulfate mass was produced.
When the morphology of the mass produced in this way was observed with an electron microscope, a large number of fibrous basic magnesium sulfates were partially bound by agglomerated fine fibrous sepiolite aggregates. It was confirmed that most were exposed. The average length of the fibrous basic magnesium sulfate was 7 μm, and the average diameter was 0.4 μm.

[Example 4]
Instead of fibrous zonotlite, polytetrafluoroethylene (PTFE) powder is added so that the solid content is 0.3% by mass, and the mixture is kneaded using an extrusion granulator while heating at 80 ° C., A cylindrical fibrous basic magnesium sulfate lump was produced in the same manner as in Example 1 except for granulation.
When the morphology of the mass produced in this way was observed with an electron microscope, a large number of fibrous basic magnesium sulfates were entangled and bonded to the fibrillated PTFE, and most of the fiber surface was exposed. Was confirmed. The average length of the fibrous basic magnesium sulfate was 8 μm and the average diameter was 0.4 μm. On the other hand, the diameter of fibrillated PTFE was about 0.05 μm.

[Example 5]
In the fibrous basic magnesium sulfate slurry produced in Example 1 (1), fibrous zonotolite (average length: 3 μm, average diameter: 0.3 μm) was added so that the solid content was 10% by mass. Added and mixed with stirring. The mixed slurry was vacuum-filtered with a honey screw filter and dehydrated with a dehydrator to obtain a cake having a moisture content of 50% by mass. This cake was dried at a temperature of 150 ° C. by a fluid bed dryer. The obtained dried product was crushed with a power mill having a mesh opening of 3 mm to produce a flat fibrous basic magnesium sulfate lump.
When the morphology of the mass produced in this way was observed with an electron microscope, a large number of fibrous basic magnesium sulfates were partially bound by aggregates of fibrous zonotlite, and most of the fiber surface was exposed. It was confirmed that The average length of the fibrous basic magnesium sulfate was 28 μm and the average diameter was 0.5 μm.

[Comparative Example 1]
A cylindrical fibrous basic magnesium sulfate lump was produced in the same manner as in Example 1 except that no fibrous zonotlite was added. Observation of the morphology of the mass thus produced with an electron microscope confirmed that only fibrous basic magnesium sulfate was entangled.

[Evaluation]
(1) Average particle size, (2) Loose apparent density, (3) Residual rate after contact with running water, (4) Bulk shape of fibrous basic magnesium sulfate blocks produced in Examples 1 to 5 and Comparative Example 1 The turbidity of water after contact with an object, (5) silica removal rate, and (6) lead removal rate were measured by the following methods. The results are shown in Table 1.

(1) Average particle size: For a cylindrical lump (Example 1, Example 3, Example 4, Comparative Example 1), the length and diameter were measured using calipers, and the average value was calculated. did. The spherical mass (Example 2) and the flat mass (Example 5) were measured for particle size distribution using a standard sieve defined in JIS-J-8801, and the average particle size (D ₅₀ ) was calculated.
(2) Loose apparent density: Measured using a powder tester manufactured by Hosokawa Micron Corporation.

(3) Residual rate after contact with running water: 50 cm ³ of lumps are packed into a 3.5 mm diameter glass column and backwashed with 150% expansion condition for 1 hour, and then the lumps remain in the column. The rate was calculated. The higher the residual rate, the better the stability in water.
(4) Water turbidity after contact with the lump: The lump 50 cm ³ was filled into a 3.5 mm diameter glass column, and the clean water was passed under the condition of SV = 50. The white turbidity of water after contact with the lump was visually observed and evaluated in the following four stages.
A: No cloudiness is observed immediately after the start of water flow.
B: Cloudiness is recognized up to a water flow rate of 2 BV (100 cm ³ ).
C: Cloudiness is recognized up to a water flow rate of 10 BV (500 cm ³ ).
D: White turbidity continues even if the water flow rate exceeds 10 BV (500 cm ³ ).

(5) Removal rate of colloidal silica: After packing 50 cm ³ of a lump into a 3.5 mm diameter column and backwashing, a suspension (concentration: 800 ppm) of colloidal silica (average particle size: 80 nm) Water was passed under 50 conditions. The water after contact with the lump was filtered using a membrane filter having an opening of 15 μm. And the silica density | concentration in a filtrate was quantified with the ICP spectrometer, and the silica removal rate was computed by the following formula. The higher the silica removal rate, the higher the lump's silica aggregation ability.
Silica removal rate (mass%) = [silica concentration of colloidal silica suspension (800 ppm) −silica concentration in filtrate (unit: ppm)] / silica concentration of colloidal silica suspension (800 ppm) × 100

(6) Lead removal ratio: bulk was filled with 50 cm ³ in the column of 3.5mm diameter, after backwash, lead nitrate solution (concentration: 10 ppm) were passed through under the conditions of SV = 50. The water after contact with the lump was filtered using a membrane filter having an opening of 15 μm. The amount of lead in the filtrate was quantified with an ICP spectrometer, and the lead removal rate was calculated according to the following formula. The higher the lead purification rate, the higher the ability to precipitate heavy metal ions in the lump as hydroxide particles.
Lead removal rate (mass%) = [lead concentration of lead nitrate aqueous solution (10 ppm) −lead concentration in filtrate (unit: ppm)] / lead concentration of lead nitrate aqueous solution (10 ppm) × 100

（＊）通水後、繊維状塩基性硫酸マグネシウム塊状物が直ちに崩壊したため測定できず。

(*) After passing water, the fibrous basic magnesium sulfate lump collapsed immediately and could not be measured.

  From the result of Table 1, the fibrous basic magnesium sulfate lump (Examples 1-5) couple | bonded with the binder is the fibrous basic magnesium sulfate lump (Comparative Example 1) manufactured without using the binder. ), It can be seen that it is more stable against contact with running water. Moreover, since the surface of the fibrous basic magnesium sulfate fiber is exposed, it can be seen that the ability to aggregate silica and the ability to precipitate and aggregate lead ions as hydroxide particles are high.

It is sectional drawing of an example of the waste water treatment equipment according to this invention.

Explanation of symbols

DESCRIPTION OF SYMBOLS 1 Outer cylindrical body 1a 1st cylindrical body 1b 1st porous material 2 Inner cylindrical body 2a 2nd cylindrical body 2b 2nd porous material 2c Blind part 3 Waste water treatment material 4 Filter 6 Support body 7 Holding plate 7a Spring receiving portion 8 Spring receiving portion 9 Spring 10 Container 10a Inlet port 10b Outlet port 10c Container portion 10d Air vent 10e Lid portion 10f Support plate 11 Spring

Claims (8)

  A large number of fibrous basic magnesium sulfates having an average length of 5 to 200 μm and an average diameter of 0.2 to 1.0 μm are formed by a binder in a state where at least a part of the fiber surface is exposed. A fibrous basic magnesium sulfate lump formed by bonding.   The fibrous basic magnesium sulfate lump according to claim 1, wherein the binder is water-insoluble.   The fibrous basic magnesium sulfate lump according to claim 2, wherein the binder is a fibrous inorganic compound other than the fibrous basic magnesium sulfate, which is shorter than the fibrous basic magnesium sulfate.   The fibrous basic magnesium sulfate lump according to claim 2 or 3, wherein the binder is zonotolite or sepiolite.   The fibrous basic magnesium sulfate lump according to claim 2, wherein the binder is made of a polymer material.   The fibrous basic magnesium sulfate lump according to claim 5, wherein the binder is fibrillated polytetrafluoroethylene.   A wastewater treatment material comprising the fibrous basic magnesium sulfate lump according to any one of claims 1 to 6. A wastewater treatment apparatus in which the wastewater treatment material according to claim 7 is filled between an outer cylindrical body made of a porous material and an inner cylindrical body made of a porous material that are concentrically combined with each other.

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