JP2008132432A - Manufacturing method of water clean grain, and water clean grain - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To obtain water clean grains from dewatered cake. <P>SOLUTION: This manufacturing method of the water clean grains is characterized in that pellets are formed by pressure-extrusing crushed stone sludge by an extrusion molding machine, are air-dried to control their water content to ≤10%, and are fired at 800 to 1,050°C and then heat-dissioated. Thereafter, titanium oxide film is formed on the outer faces of the fired pellets. <P>COPYRIGHT: (C)2008,JPO&INPIT

Description

  The present invention relates to a method for producing water-purified granules and a water-purified granule for the purpose of effectively using crushed sludge to obtain granules capable of water purification.

  Conventionally, water purification products using titanium oxide are known.

Moreover, the purification effect produced by applying sunlight to titanium oxide has been known, and a water purifier using this has been proposed.
JP-A-11-268948 Japanese Patent No. 3628661 JP 2005-162514 A JP2003-144939

  For the effective use of sludge (hereinafter referred to as “dehydrated cake”) generated in the conventional crushed stone process, some are used as materials for building materials, but most are used for in-situ deposition (backfilling of mining traces). The fact is. Therefore, effective utilization was studied, succeeded in making effective particles as a water purification material, and completed the present invention.

  Conventionally, there is a proposal of a hydraulic composition (eco-cement) in which municipal waste incineration ash or sewage sludge incineration ash is used as a raw material and titanium oxide or other substances are added to this (cited reference 1).

  There is also a proposal of a method for producing a porous granule obtained by hydrothermally treating inorganic waste (130 ° C. to 220 ° C.) (Cited document 2).

  Further, there is also a proposal of a foam using crushed sludge and the like for the purpose of obtaining foamed building materials and the like from crushed stone slurry (Cited document 3).

  Although each of the above-mentioned known inventions is consistent with the point of reusing waste, there is a limited or quantitative limitation in use, and as continuous reuse of dehydrated cake produced in large quantities and continuously, Insufficient.

  In addition, a photocatalytic technology has been proposed in which photocatalyst particles are fixed to the outside of a substrate in which a glassy shell is coated on the surface of an artificial lightweight aggregate obtained by granulating and firing crushed waste mud (same as sludge) (patent) Reference 4) differs from the present invention in that it covers the glassy shell.

  However, the present invention is expected to be used continuously and in large quantities and solves the above problems.

  In this invention, dehydrated cake is formed into granules (with the same shape to facilitate post-processing) and fired (toughen) to remove harmful substances and improve solidification strength It is.

  And it succeeded in obtaining the water-purified grain which improved the water-purifying power which was not able to be achieved conventionally by layering titanium oxide on the outside of the granule.

  The dehydrated cake is expected to be generated at about 500,000 tons per year. However, the amount of the dehydrated cake is increased by the above processing, and most of the dehydrated cake can be converted into an effective utilization product.

  That is, in the present invention, crushed sludge or a mixture obtained by adding 0.1 wt% to 1.0 wt% of barium carbonate to crushed sludge is formed on a molding machine to form granules, and the granules are naturally dried to have a water content of 10% or less. And then, after cooling at 800 ° C. to 1050 ° C. and allowing to cool, a titanium oxide film is provided on the outer side of the fired granule, and a method for producing water-purified grains is provided. Add and mix 10 wt% to 40 wt% of the additive, form the granule by applying this mixture to a molding machine, dry it naturally to a moisture content of 10% or less, then bake it at 800 ° C to 1050 ° C and release it. A method for producing water-purified grains, wherein a titanium oxide film is provided on the outside of the fired granules after cooling. In addition, water and hydrogen peroxide are added to crushed sludge to form a mixture, and this mixture is subjected to a molding machine to form granules. Then, after cooling, a titanium oxide film is provided on the outside of the fired granule, and the method for producing water-purified granules is provided.

  The sludge has 95.0 wt% of 75.0 microns or less, 22.0 wt% of which is 1.2 microns or less, and has a moisture content of 10% to 20%. Still another invention is a water-purified granule produced by the method according to claims 1 to 4.

  In the above, the reason why 0.1 wt% to 1.0 wt% of barium carbonate is added to the crushed sludge is to prevent the white matter phenomenon of the granules. When the white flower phenomenon occurs, there is a possibility that the titanium oxide film is difficult to adhere or the adhesion strength of the film is weakened. The amount of barium carbonate used is generally 0.3 wt% to 0.5 wt%, but is not limited thereto. If the amount of barium carbonate is less than 0.1 wt%, the white flower phenomenon tends to be insufficiently prevented, and even if it exceeds 1.0 wt%, the upper limit is set to 1.0 wt% because the effect remains unchanged.

  The reason why the lower limit of the biomass-based additive is 10 wt% is that the lower limit of foaming at the time of high-temperature firing is considered, and the upper limit is 40 wt% because the amount of foaming is lost, strength and other catalysts Since it is not preferable as a carrier, the addition amount is set to 10 wt% to 40 wt%.

  Moreover, although there is no limitation in particular about a water | moisture content, when the load reduction at the time of high temperature processing is considered, the water | moisture content after natural drying is preferable 5% or less.

  As described above, the water content after natural drying of the granule is preferably 5% or less, but may exceed 5%. Moreover, the granule before providing a titanium oxide membrane | film | coat can be used as it is as a herbicidal grain (weed reproduction prevention).

  The particle size of the granules is 3 to 30 mm in diameter. When pellets are used, the diameter is 3 to 5 mm and the length is 10 to 20 mm. However, the size is not limited.

  In the said invention, a molding machine means a rotary granulator or an extrusion molding machine. And a granule is spherical or a pellet (thing by a short column shape and an extrusion-molding machine), and there exists a substantially the same effect even if it uses which.

  Although the method of attaching titanium oxide to the granule of the present invention has shown the dipping method or spraying method, it is not limited to the above method as long as a certain amount or more of titanium oxide can be attached.

  In the above-mentioned invention, the granule formed from the dehydrated cake is used as the catalyst carrier, but crushed stone may be used.

  The crushed stone is handled in a size of 2.5 mm to 30 mm. Therefore, titanium oxide can be adhered to the outside of the crushed stone and used as water purification grains similar to the present invention.

  In the above, a titanium layer is provided for each crushed stone size. For example, there are 20 mm to 30 mm (No. 4), 13 mm to 20 mm (No. 5), 5 mm to 13 mm (No. 6), 2.5 mm to 5 mm (No. 7), etc., but also in this case, it has a water purification function. .

  The biomass-based additive in the above refers to wood flour, rice husk, sawdust, and the like. Since this additive material burns at the time of high-temperature firing, the particles are made porous.

  The molding machine in the invention includes a rotary granulator and an extrusion molding machine, and any of them is the same. In the rotary granulator, spherical particles are formed, and in the extruder, pellets (cylindrical body, for example, 4 mm in diameter and 15 mm in length) are formed.

  The dehydrated cake used in the present invention has the following characteristics.

(1) Chemical composition and properties The dehydrated cake is composed of minerals such as quartz, feldspar, chlorite and calcite from the X-ray diffraction results, and the chemical composition is as shown in Table 1.

  The particle size of the dehydrated cake is 95.0% of the whole is 75.0 microns or less, and 27.7% of the particle size is 1.2 microns or less. The water content is 10% to 20%, and the bulk specific gravity is around 2.0.

(2) High temperature characteristics Next, attention was paid to the hot characteristics (fine particles, plasticity, sinterability) of the dehydrated cake, and ceramics were produced.

  The manufacturing method is as shown in FIG.

  Moreover, after extruding the dehydrated cake, it was dried at room temperature for several days to make the moisture 5%, baked in the atmosphere at 800 ° C. to 1050 ° C. for 4 hours, and investigated the hot characteristics. This is shown in FIG. The melting point of the dehydrated cake was around 1200 ° C.

  The compressive strength, bending strength, and shrinkage ratio of the product increased in proportion to the firing temperature (FIG. 2).

  From these results, the sintering temperature of the dehydrated cake was selected to be 800 ° C to 1050 ° C.

  According to this invention, since the porous granule is manufactured from the dehydrated cake and titanium oxide is deposited on the surface thereof, it can be sterilized and purified by projecting sunlight (similarly with ultraviolet light). In addition, there is an effect that BOD can be processed effectively.

  Moreover, by such a process, there exists an effect which can convert a lot of dehydrated cake into a reuse thing efficiently.

  Next, according to the manufacturing method of the present invention, an easily deformable object (fine sand or mud) such as a dehydrated cake is formed into a strong granule of an appropriate size, so that it is easy to handle. In addition, it is excellent as a catalyst carrier for titanium oxide and the like, and is effective as a horticultural particle if it is provided with appropriate water retention.

  Furthermore, there is an effect that it can be used for lightweight concrete aggregates, brick materials, and the like.

  In the present invention, if necessary for a dehydrated cake, an appropriate amount of water is added, put into a molding machine, a granule is formed, this is naturally dried to a moisture content of about 5%, and then fired at 900 ° C. Allow to cool. Subsequently, titanium oxide was sprayed to the outside of the granules to provide a titanium oxide thin layer, whereby the water-purified granules of the present invention were formed.

[Experimental Example 1]
In order to complete this invention, the following experiment was conducted and the characteristics were investigated.

(1) Dehydrated cake simple substance In order to investigate the hot characteristics in more detail, the dehydrated cake simple substance was granulated (diameter 5 mm to 10 mm) with an extruder, dried, and then at 800 ° C. to 1050 ° C. in the atmosphere for 1 hour. The porous pellet was obtained by baking.

  As the calcination temperature increased, the color changed to a bright color (gray → brown → orange). This is thought to be due to the oxidation reaction of the iron content of the dehydrated cake.

In order to evaluate the basic performance of the porous pellets, water resistance, water absorption, crushing strength (in the atmosphere), and pH were investigated, and Table 2 was obtained.

  About water resistance, it melt | dissolved at the calcination temperature of 400 degrees C or less, but in 500 degrees C or less, although the shape was hold | maintained, the underwater intensity | strength fell (the extent which can be easily ground with bare hands). The crushing strength became 0.3 MPa at 600 ° C. or higher, and it was confirmed that it can withstand normal external force (external force during handling).

  The water absorption increased in proportion to the firing temperature and decreased to a peak at 900 ° C.

  The crushing strength increased in proportion to the firing temperature and increased rapidly from 900 ° C. Therefore, it is estimated that the crushing strength suddenly increases at 800 ° C. to 900 ° C., so the lower limit of the firing temperature in the present invention was set to 800 ° C. In the case of rotary granulation, a rapid increase in crushing strength was observed after baking at 800 ° C. (Table 6).

  About pH, it rose in proportion to calcination temperature and showed alkalinity.

(2) Addition of wood flour Next, in order to improve water retention, about 10% by weight, 15% by weight, 20% by weight, 30% by weight, 40% by weight of wood powder (unused resources) added to the dehydrated cake by extrusion molding. Table 3 was obtained as a result of pelletization (columnar diameter: 4 mm, length: 15 mm), drying, baking at 900 ° C. and evaluation in the same manner. Although 20 wt% or less is preferable from the viewpoint of strength, the upper limit is set to 40 wt% in consideration of a case where improvement in water absorption is required.

[Experiment 2]
In addition, the following experiment was conducted to foam the particles of the present invention.

  Paying attention to the foaming action of hydrogen peroxide, a predetermined amount of hydrogen peroxide (3%) and water are added to the dehydrated cake, mixed and stirred to form a slurry (water 20% to 30%), molded, dried and separated. Molded and fired in air for 1 hour to obtain foam ceramics.

  The bubble state on the surface of the produced foam is shown in FIG.

  In the figure, the top is without vacuum drying, and the bottom is after vacuum drying. By drying under reduced pressure, a considerably large void is formed on the surface. By performing drying under reduced pressure, the porosity of about 50% can be improved to about 80%. Moreover, the pores themselves could be made continuous.

[Experiment 3]
Moreover, the following experiment was performed in order to impart photocatalytic function to the granules.

  We conducted research on photocatalyst application using the features of porous and foamed dehydrated cake at Chiba Institute of Technology.

  A titanium complex solution, carbonate and hydrogen peroxide are added to the dehydrated cake to form a slurry. After the slurry is put into a mold and molded, it is released from the mold, dried under reduced pressure, and then fired at 500 to 700 ° C. An attempt was made to apply a photocatalyst to foam ceramics.

  The photocatalyst application method is shown in FIG.

(1) Mixing method The photocatalytic property provision by the mixing method was examined.

  The foam obtained by mixing and stirring the titanium complex to which citric acid was added and solidified at a low temperature showed a decolorization rate of about 70% by the methylene blue method. As a result of EPMA analysis of the foam surface, the presence of titanium was confirmed throughout.

(2) Immersion method Next, the photocatalytic property imparting by the immersion method was examined.

An attempt was made to immerse foam ceramics in a solution obtained by diluting 100 ml of the prepared titanium complex solution to 500 ml with ion-exchanged water, and coat the surface of the foam with a TiO ₂ film. The solution temperature was immersed at 80 ° C. for 3 hours. As a result of evaluating the photocatalytic property of the foam coated with the TiO ₂ film by this immersion method, the decolorization rate was about 40%. As a result of EPMA analysis of the foam surface, the presence of titanium was confirmed throughout.

[Experimental Example 4]
Next, experiments were conducted on the herbicidal activity as follows (the granules before the titanium oxide coating had a herbicidal effect).

  Paying attention to the characteristics that the surface of the dehydrated cake becomes alkaline and the brown color of the dehydrated cake, we tried to develop a product as a mulching material with good landscape and weed germination / reproduction control.

(1) Weed control test An outdoor verification test was conducted to evaluate the herbicidal performance of the porous pellets. As a control, non-installed, natural crushed stone (our No. 5 crushed stone) and calcined crushed stone were used, and the installation thickness was 5 cm.

  As a result of the test, it was found that the herbicidal effect was high in the order of porous pellets, calcined crushed stone, natural crushed stone, and non-installed.

(2) Damage test Although the porous pellets have a high herbicidal effect due to their alkali properties, there is a concern about the growth failure of garden trees and flowers at the same time. Therefore, a planting test was conducted using “Satsuki” which is a typical garden tree that prefers acidic soil. 100% Kanuma soil was used as the cultivated soil, and porous pellets were installed with a thickness of 5 cm on the surface layer.

  As a result of the test, when two months passed, the flowers bloomed, the plant height and the trunk grew steadily, and no growth disorder was observed. Moreover, it was equivalent even when compared with the case where the porous pellet was not installed.

[Experimental Example 5]
Moreover, it experimented as follows about a photocatalyst.

In order to evaluate the water purification performance of porous pellets obtained by coating titanium on the dehydrated cake (manufactured by Sumitomo Chemical Co., Ltd.), a rainwater purification test was conducted, and water analysis was conducted six months later. As a control group, photocatalyst No. 5 crushed stone, no installation (no photocatalyst) was used, and analysis result Table 4 was obtained.

  BOD (biochemical oxygen consumption) and turbidity were low for the photocatalytic porous pellets, and the viable count was low for the photocatalytic crushed stone.

  In order to improve the performance of photocatalyst products, it is desired to increase the specific surface area by foaming and ensure the strength by adding a sintering aid.

  An embodiment of the present invention will be described with reference to FIGS. As for the particle size of the dehydrated cake used in this example, 94.5% of the whole is 75.0 microns or less, and 27.7% of them is fine particles of 1.2 microns or less. Since the water content was 20% to 25%, it was not necessary to add water, and the bulk specific gravity was around 2.0.

  100 kg of the dehydrated cake was put into an extruder to obtain 90 kg of pellets having a diameter of 4 to 6 mm and a length of 10 mm to 15 mm. The pellets were naturally dried in a ventilation drying room at 15 ° C., stirred once or twice a day, and dried to 5% in 6 days.

  Next, it is put into an incinerator, heated up to 1000 ° C. at a rate of 120 ° C./hr, baked at 1000 ° C. for 2 hours, and then naturally cooled in the furnace to obtain 75 kg of pellets having a moisture content of 1% to 3%. It was. Although the said Example shape | molded the pellet using the extrusion molding machine, it is the same also as a spherical granule (diameter 4mm-20mm) using a rotary granulator.

  The pellets were immersed in 500 ml of a titanium complex solution at 80 ° C. for 3 hours to obtain photocatalyst pellets (FIG. 4B). In this case, the thickness of the titanium oxide film was 20 to 40 microns. It is the same when titanium oxide is coated instead of the treatment of immersing the pellet in the titanium complex solution.

  In Example 1, 5 kg of 3% hydrogen peroxide was added to 100 kg of dehydrated cake and mixed, and this mixture was subjected to an extruder to obtain 92 kg of pellets having a diameter of 4 to 6 mm and a length of 10 to 75 mm. The pellets were dried at room temperature of 15 ° C. for 6 days to obtain 80 kg of pellets having a moisture content of 5%. The pellets were heated at a rate of 120 ° C./hr, baked at 1000 ° C. for 2 hours, and then naturally cooled in a furnace to obtain 75 kg of pellets having a moisture content of 1% to 3% (FIG. 4A). This granule can also be used as a herbicidal granule.

  The pellets were immersed in 500 ml of a titanium complex solution at 80 ° C. for 3 hours to obtain photocatalyst pellets (FIG. 4B). In this case, the thickness of the titanium oxide film was 20 to 40 microns. It is the same when titanium oxide is coated instead of the treatment of immersing the pellet in the titanium complex solution.

  The embodiment of the present invention will be described with reference to FIG. 5 (a). To 100kg of dehydrated cake (water content 20% to 25% water content adjustment), 0.3kg of barium carbonate is added and stirred uniformly, and then subjected to a rotary granulator. 100 kg of granules having a diameter of 5 to 30 mm were obtained. This was naturally dried in a ventilation drying room at 15 ° C., stirred once or twice a day, and dried to 5% in 6 days.

  Next, the granule is put in an incinerator, heated to 1000 ° C. at a rate of 120 ° C./hr, baked at 1000 ° C. for 2 hours, and then naturally cooled in the furnace to give 73 kg of 3% moisture. Got.

  In the above, granules granulated by a rotary granulator are sieved to 10 mm or less, 15 mm or less, 20 mm or less, 25 mm or less, 30 mm or less, dried and fired.

  If the titanium complex solution is sprayed on the granules produced as described above and a titanium oxide film is provided on the outer wall of the granules, the purified water granules of this invention can be obtained.

  In this case, the thickness of the titanium oxide film is about 20 to 40 microns. Since the present invention aims to provide a titanium oxide film on the outer wall of the granule, this method can be used as long as a titanium oxide film having a predetermined thickness can be formed by a method other than the spraying method.

  An embodiment of the present invention will be described with reference to FIG. 5 (b). 25 kg of wood flour is added to 100 kg of dehydrated cake (water content: 20% to 25%), and the mixture is stirred uniformly, and then applied to a rotary granulator to have a diameter of 5 mm to 30 mm. 125 kg of granules were obtained. This was naturally dried in a ventilation drying room at 15 ° C., stirred once or twice a day, and dried to 5% in 6 days.

  Next, the granule is put into an incinerator, heated to 1000 ° C. at a rate of 120 ° C./hr, baked at 1000 ° C. for 2 hours, and then naturally cooled in the furnace to give 80 kg of 3% moisture. Got.

  In the above, granules granulated by a rotary granulator are sieved to 10 mm or less, 15 mm or less, 20 mm or less, 25 mm or less, 30 mm or less, dried and fired.

  In the above embodiment, the wood powder burns and extinguishes, so that the total amount of the product (carrier) particles is about 80 kg.

  If the titanium complex solution is sprayed on the granules produced as described above and a titanium oxide film is provided on the outer wall of the granules, the purified water granules of this invention can be obtained.

  In this case, the thickness of the titanium oxide film is about 20 to 40 microns. Since the present invention is intended to provide a titanium oxide film on the outer wall of the granule, this method can be used if a titanium oxide film having a predetermined thickness can be formed by a method other than the spraying method.

[Experimental Example 6]
When the dehydrated cake (scientific composition, Table 5) was pressure-extruded to produce pellets and the physical properties were tested, the results shown in Tables 6, 7, 8, and 9 were obtained.

  As described above, it was determined that the firing temperature is preferably 800 ° C. to 1050 ° C. in consideration of crushing strength, water absorption rate, pH, and the like.

  When the pellets were laid on the upper surface of the flower bed soil to a thickness of 40 mm to 50 mm and subjected to a weedproof test, there was a weedproof (ordinary weed prevention) effect even after 1 month.

  Moreover, since the water retention (water absorption rate 14%) is large, a heat island mitigation effect by water hammering can be expected. Furthermore, when laid between garden plants, footsteps are higher than gravel, so a crime prevention effect can be expected.

[Experimental Example 7]
Using the titanium oxide-coated pellets obtained in this invention, a water purification test was conducted under the following conditions.

Specification of Photocatalyst Container Plastic container having a width of 300 mm, a length of 180 mm, and a depth of 30 mm Pellets Pellets of dehydrated cake were baked at 1050 ° C., coated with titanium of 10 to 50 μm, and dried at 180 ° C. 800 g of the pellets were uniformly spread on the bottom of the container.

  Implementation method Raw water was recycled, bubbling, and mixed. The amount of air used was 1 liter / min.

Results When the test was performed, Tables 10 and 11 were obtained.

The block diagram of the Example of this invention. (A) Graph of compressive strength of the pellet of the present invention, (b) Graph of bending strength, and (c) Graph of shrinkage of firing temperature. (A) The photograph which shows the bubble state of the surface of the foam which is not dried under reduced pressure, (b) The photograph which shows the bubble state of the surface of the foam dried under reduced pressure. (A) The block diagram of the Example of a granular material manufacture similarly, (b) The block diagram of the Example which similarly attached the titanium membrane | film | coat to the foaming granular material. (A) The block diagram of another Example similarly, (b) The block diagram of the Example of foaming similarly.

Claims (5)

  Granules are formed by applying crushed sludge to a molding machine, the granules are naturally dried to a moisture content of 10% or less, then calcined at 800 ° C. to 1050 ° C., allowed to cool, and then oxidized to the outside of the calcined granules. A method for producing water-purified granules, characterized in that a titanium film is provided.   A mixture obtained by adding 0.1 wt% to 1.0 wt% of barium carbonate to crushed sludge is formed in a molding machine to form granules. The granules are naturally dried to a water content of 10% or less, and then 800 ° C. to 1050 ° C. A method for producing water-purified grains, comprising a titanium oxide film provided on the outside of the fired granules after being fired and allowed to cool.   Add 10 wt% to 40 wt% of biomass-based additive to crushed sludge, mix this mixture, form the granule by applying it to a molding machine, dry it naturally to 10% or less, and then 800 ° C to 1050 ° C A method for producing water-purified grains, comprising a titanium oxide film provided on the outside of the fired granules after being fired and allowed to cool.   Water and hydrogen peroxide are added to the crushed sludge to form a mixture, and the mixture is subjected to a molding machine to form granules. A method for producing water-purified granules, comprising a titanium oxide film provided outside the fired granules after being allowed to cool.   A water purification grain produced by the method according to any one of claims 1, 2, 3, and 4.

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