JP4841916B2 - Method for producing solid phosphorus remover - Google Patents

Description

  The present invention treats combined wastewater (hereinafter simply referred to as wastewater) such as human wastewater, domestic wastewater, and organic wastewater discharged from small-scale building facilities such as detached houses, apartment houses, and convenience stores. It is related with the manufacturing method of the solid phosphorus removal agent containing especially the iron salt or aluminum salt and water-soluble resin which are used for the waste water septic tank which also removes a phosphorus content.

  Wastewater discharged from the above facilities is treated by a wastewater septic tank mainly composed of anaerobic and aerobic biological treatment functions, disinfected, and then discharged. These wastewater septic tanks remove solids and organic matter in the wastewater to reduce (remove) the BOD of the pollution index, and further circulate the wastewater in an anaerobic and aerobic treatment system to remove nitrogen. To do. However, even if such a treatment is performed, the phosphorus content (phosphate ions) cannot be removed and is released as it is. Therefore, in the wastewater septic tank, for the purpose of removing phosphate ions, polyvalent metal ions such as iron, aluminum, and calcium are supplied into the wastewater, and the polyvalent metal ions and phosphate ions are reacted to react with each other. A reaction agglomeration method is used in which the particles are converted (or granulated) and removed by precipitation, flotation, filtration, or the like.

And as a method of supplying this polyvalent metal ion into wastewater, for example, a polyvalent metal salt that reacts with phosphate ions and a chlorine-based compound having a disinfecting ability are mixed to form a tablet, and this tablet is subjected to purification treatment. There exists a phosphorus removal disinfection solid agent which makes it contact with the treated water which ended and removes phosphate ion and disinfects treated water (refer to patent documents 1). Furthermore, since polyvalent metal salts are highly soluble in water, heat them by mixing organic compounds such as higher fatty acids, higher alcohols and paraffins with iron salts, aluminum salts, etc. in order to give them sustained release properties. There is a solid denitrification and dephosphorization accelerator that dissolves, solidifies by cooling, and adds this lump to an activated sludge type aeration tank for dissolution (see Patent Document 2).
On the other hand, there is an example in which activated sludge or the like is fixed to polyvinyl alcohol although it is not directly related to the removal of phosphorus. That is, after adding an aqueous polyvinyl alcohol solution of a water-soluble resin to activated sludge, etc., adding inorganic salts (sodium sulfate, potassium sulfate, etc.) to this mixture causes the polyvinyl alcohol solubility to decrease and precipitate (salt out). Shrink further. In this salting out, activated sludge is comprehensively fixed to the polyvinyl alcohol shell (see Patent Document 3).

JP 2000-210676 A JP 2001-269689 A JP-A-5-301094

In an example such as a phosphorus removal sterilizing solid agent, since it contains a sterilizing agent, it needs to be contacted with treated water after the biological treatment is completed, and in an example such as a solid denitrification / dephosphorization accelerator, It is presumed that excess or deficiency occurs in the polyvalent metal ions corresponding to the reaction amount.
Therefore, the present inventors have arrived at the technical idea of coating a polyvalent metal salt with polyvinyl alcohol in order to give sustained release to the polyvalent metal salt from an example of fixing activated sludge or the like to polyvinyl alcohol. . However, when polyvinyl alcohol aqueous solution and inorganic salts are mixed as in Patent Document 3, polyvinyl alcohol itself is salted out, so that the object of coating with a polyvalent metal salt cannot be achieved.
The present invention solves the above-mentioned problems, and among the polyvalent metal salts, an iron salt or an aluminum salt that is rich in reactivity with a phosphate ion and can solidify the phosphorus content can be provided with a sustained release property. It aims at providing the manufacturing method of the solid phosphorus removal agent containing salt or aluminum salt, and water-soluble resin.

In order to solve the above-mentioned problems, the inventors coated a bulk phosphorus remover having a sustained release property in which an iron salt or an aluminum salt is coated (or bonded) with a water-soluble resin such as a polyvinyl alcohol resin. investigated. While proceeding with the study, as described above, the polyvinyl alcohol resin is usually dissolved in water and used, but when this aqueous solution is mixed with an iron salt or an aluminum salt, the polyvinyl alcohol resin is caused by a phenomenon that appears to be salting out. Gelled and could not be coated with a water-soluble resin. Thus, it has been found that when a water-soluble resin is dissolved in a mixed solvent of water and an organic solvent to form a water-soluble resin solution and this is brought into contact with an iron salt or an aluminum salt, salting out can be prevented and coating can be performed. As a result of intensive studies based on these, the present invention has been found. That is,
The present invention is (1) a method for producing a solid phosphorus removing agent produced through the following production steps.
(A) dissolving a water-soluble resin in a solvent to obtain a resin solution;
(B) a step of spray-coating the resin solution obtained in (a) on a powdered iron salt or aluminum salt in a heated atmosphere to obtain a dried product;
(C) A step of compression-molding the dried product obtained in (b) to obtain a solid phosphorus removing agent.
However, the water-soluble resin is any one of a polyvinyl alcohol resin, a cellulose resin, a resin having an ether bond, and a resin having a carbamoyl group, and the solvent is a mixed solvent of water and an organic solvent.
Moreover, this invention is a manufacturing method of the solid phosphorus removal agent produced through the following manufacturing process (2).
(A) dissolving a water-soluble resin in a solvent to obtain a resin solution;
(B) a powdered iron or aluminum salts, step of mixing the powdered polysaccharides,
(C) A step of spray coating the resin solution obtained in (a) on a mixture of the iron salt or aluminum salt obtained in (b) and the polysaccharide in a heated atmosphere to obtain a dried product,
(D) A step of compression-molding the dried product obtained in (c) to obtain a solid phosphorus removing agent.
However, the water-soluble resin is any one of a polyvinyl alcohol resin, a cellulose resin, a resin having an ether bond, and a resin having a carbamoyl group, and the solvent is a mixed solvent of water and an organic solvent.
Moreover, this invention is a manufacturing method of the solid phosphorus removal agent produced through the ( 3 ) next manufacturing process.
(A) dissolving a water-soluble resin in a solvent to obtain a resin solution;
(B) a step of mixing a powdered iron salt or aluminum salt with the resin solution obtained in (a) to obtain a mixed solution (or suspension),
(C) a step of spray-drying the mixed liquid obtained in (b) to a heated atmosphere site to obtain a dried product,
(D) A step of compression-molding the dried product obtained in (c) to obtain a solid phosphorus removing agent.
However, the water-soluble resin is any one of a polyvinyl alcohol resin, a cellulose resin, a resin having an ether bond, and a resin having a carbamoyl group, and the solvent is a mixed solvent of water and an organic solvent.
Moreover, this invention is a manufacturing method of the solid phosphorus removal agent produced through the following manufacturing process of ( 4 ).
(A) dissolving a water-soluble resin in a solvent to obtain a resin solution;
(B) a powdered iron or aluminum salts, step of mixing the powdered polysaccharides,
(C) a step of mixing a mixture of the iron salt or aluminum salt obtained in (b) with a polysaccharide and the resin solution obtained in (a) to form a mixed solution (or suspension);
(D) a step of spray-drying the liquid mixture obtained in (c) to a heated atmosphere site to obtain a dried product,
(E) A step of compression-molding the dried product obtained in (d) to obtain a solid phosphorus removing agent.
However, the water-soluble resin is any one of a polyvinyl alcohol resin, a cellulose resin, a resin having an ether bond, and a resin having a carbamoyl group, and the solvent is a mixed solvent of water and an organic solvent.
In the present invention, (5) the iron salt or aluminum salt is ferrous sulfate, ferric sulfate, ferrous chloride, ferric chloride and iron salts of hydrates thereof, aluminum sulfate, sulfuric acid. Any one selected from the group consisting of aluminum potassium, sodium aluminum sulfate, and aluminum salts of hydrates thereof.
In the present invention, (6) the polysaccharide is any one selected from the group consisting of starch, dextrin, cellulose, cellobiose, chitins, and chitosans.

In the method for producing a solid phosphorus removing agent of the present invention, a water-soluble resin is dissolved in a solvent to form a resin solution, and then the resin solution is spray-coated toward an iron salt or an aluminum salt to obtain a dried product. The solid phosphorus removing agent is formed by compression molding, and a solid phosphorus removing agent having sustained release can be easily obtained by this method. Further, the sustained release can be further enhanced by adding a polysaccharide in addition to the iron salt or aluminum salt.
According to another method for producing the solid phosphorus removing agent of the present invention, a water-soluble resin is dissolved in a solvent to obtain a resin solution, and the resin solution is mixed with an iron salt or an aluminum salt to obtain a mixed solution. Is sprayed on a heated atmosphere portion to obtain a dried product, and the dried product is compression-molded to obtain a solid phosphorus removing agent. Even by this method, a solid phosphorus removing agent having a sustained release property can be easily obtained. Further, the sustained release can be further enhanced by adding a polysaccharide in addition to the iron salt or aluminum salt.

The present invention will be described below.
Before describing the method for producing a solid phosphorus remover, the solid phosphorus remover obtained by the production method of the present invention will be described. The biggest feature of the solid phosphorus remover is that it slows the dissolution rate of polyvalent metal salts that react with phosphate ions in the waste water to form insoluble or hardly soluble salts, that is, by providing sustained release. is there. The main component of the solid phosphorus removing agent is composed of an iron salt or aluminum salt which is a polyvalent metal salt, and a water-soluble resin coating these polyvalent metal salts. Further, in addition to the above main components, it further comprises a polysaccharide added as a binder.

  Among the solid phosphorus removing agents, the iron salt or aluminum salt includes ferrous sulfate, ferric sulfate, ferrous chloride, ferric chloride and iron salts such as hydrates thereof, aluminum sulfate, Examples thereof include aluminum salts such as potassium aluminum sulfate, sodium aluminum sulfate and hydrates thereof. Among these compounds, non-deliquescent ones are preferable. In addition, although calcium salt, magnesium salt, etc. are mentioned, Preferably they are iron salt or aluminum salt.

  The water-soluble resin is, for example, a polyvinyl alcohol resin that is a resin having a hydroxyl group (hydroxyl group) as a hydrophilic structural unit {polyvinyl alcohol (PVA), acetoacetyl-modified polyvinyl alcohol, cation-modified polyvinyl alcohol, anion-modified polyvinyl alcohol. , Silanol-modified polyvinyl alcohol, polyvinyl acetal, etc.}, cellulose resin having a hydroxy group {methyl cellulose (MC), ethyl cellulose (EC), hydroxyethyl cellulose (HEC), carboxymethyl cellulose (CMC), hydroxypropyl cellulose (HPC), hydroxyethyl Methyl cellulose, hydroxypropyl methyl cellulose, etc.}, resin having an ether bond {polyethylene oxide (PEO), polyp Pyrene oxide (PPO), polyethylene glycol (PEG), poly ether (PVE)}, resins {polyacrylamide having a carbamoyl group (PAAM), polyvinyl pyrrolidone (PVP), polyacrylic acid hydrazide, and the like}. Among these water-soluble resins, it is preferable not to contain N atoms, and the polyvinyl alcohol-based resin is biodegradable and does not contain a nitrogen content, so it is suitable for application to a wastewater (or sewage) septic tank. It is.

  Examples of the polysaccharide include starch, dextrin, cellulose, cellobiose, chitins, and chitosans. Since the polysaccharide is biodegradable and does not contain nitrogen, it is suitable for application to a wastewater (or sewage) septic tank as in the case of the water-soluble resin.

  Furthermore, the said polyvinyl alcohol-type resin is explained in full detail. Polyvinyl alcohol-based resin having a hydroxyl group, a hydroxyl group and an acetyl group, or a hydroxyl group, an acetyl group, and an acetal group is obtained by saponifying polyvinyl acetate to give a hydroxyl group, and further reacting with an aldehyde to give an acetal group. . These are shown in the following structural formula. If 100% of polyvinyl acetate is saponified, it has a hydroxyl group as shown in the general formula (1), and if partially saponified, it is a hydroxyl group as shown in the general formula (2). And having an acetyl group and further acetalized, it has a hydroxyl group, an acetyl group, and an acetal group (in this case, also referred to as a polyvinyl acetal resin) as shown in the general formula (3). In addition, R shown by General formula (3) is an alkyl group. In the general formulas (1), (2), and (3), n, m, and l each represent an integer.

  These water-soluble resins typified by polyvinyl alcohol resins are usually used after being dissolved in water or hot water. However, for this purpose, this solution (aqueous solution) and iron salt or aluminum salt powder (powder, fine particles or powder, fine particles, etc.) are called powder. )), The water-soluble resin solidifies into a gum shape due to salting out action or the like. Therefore, the coating on the iron salt or the aluminum salt is not performed well, and the purpose of coating or bonding these inorganic salts cannot be achieved.

  However, a water-soluble resin solution dissolved in a mixed solvent of water and an organic solvent does not cause a salting-out phenomenon even if these resin solutions are mixed with an iron salt or an aluminum salt, and can be coated satisfactorily. The organic solvent is not particularly limited as long as it dissolves a water-soluble resin and does not cause a salting-out phenomenon, and can be used alone or in combination of two or more. As the organic solvent, alcohol solvents such as isopropyl alcohol, ethyl alcohol, and methyl alcohol or ketone solvents such as acetone, methyl ethyl ketone, diethyl ketone, cyclopentanone, and cyclohexanone are preferable. The amount of the water-soluble resin in the water-soluble resin solution dissolved in a mixed solvent of water and an organic solvent is preferably 0.1 to 5 parts by weight, more preferably 0.5 to 3 parts by weight. By adjusting to this range, it becomes easy to spray (spray) the resin solution in a mist form. And in the said organic solvent, 10 / 90-90 / 10 are preferable for the mixture ratio of water and an organic solvent by water / organic solvent (volume ratio).

  The compounding amount of the solid phosphorus removing agent is preferably 1 to 10 parts by weight of the water-soluble resin when the iron salt hydrate or aluminum salt hydrate is 100 parts by weight. When a lubricant is added to improve the releasability at the time of compression molding, 0.2 to 1 part by weight of the lubricant is added. As the lubricant, stearates such as calcium stearate and magnesium stearate, orthoboric acid, sodium benzoate and the like can be used.

Next, the manufacturing method of a solid phosphorus removal agent is demonstrated. FIG. 1 is an exemplary process chart showing a method for producing a solid phosphorus removing agent comprising an iron salt or aluminum salt and a water-soluble resin according to the present invention.
First, a water-soluble resin is dissolved in a mixed solvent of water and an organic solvent to prepare a resin solution. At the time of dissolution, it is preferable to disperse the water-soluble resin in a mixed solvent and then heat it at 80 to 90 ° C. On the other hand, it is preferable to use a separately prepared iron salt or aluminum salt that is pulverized into a powder.

  Next, the water-soluble resin solution is sprayed on the iron salt or aluminum salt powder, that is, spray-coated. In the spray coating, the following operations are taken. A powder of iron salt or aluminum salt is put in a container-like dish or the like that rotates or reciprocates, and a water-soluble resin solution is sprayed in a mist form while giving vibration. As another spray coating, a powder of iron salt or aluminum salt is put in a fluidized bed container to float and flow, and a water-soluble resin solution is sprayed in the form of a mist toward this. In the above-described spray coating operation, it is preferable to spray in an environment of a heating atmosphere lower than the temperature at which the water-soluble resin melts in order to coat and dry while evaporating the solvent.

  Next, the dried product obtained by spray coating and drying is compression molded. A tableting machine or a press molding machine is used as the molding means. The shape may be any shape such as a tablet shape such as a columnar shape, a meteorite shape, a football shape, a rounded round triangle, a rounded round polygonal shape, or a lump shape larger than a tablet. In addition, in order to improve mold release properties when performing the compression molding, a lubricant may be added in the process before compression molding.

  A solid phosphorus removing agent can be obtained through the above-described series of steps.

  FIG. 2 is an example of a process diagram illustrating a method for producing an iron salt or aluminum salt according to the present invention, and a solid phosphorus removing agent comprising a polysaccharide and a water-soluble resin. FIG. 2 includes a step of uniformly mixing polysaccharide powder with iron salt or aluminum salt powder in advance. The mixed powder is sprayed with a water-soluble resin solution in the form of a mist, and the other steps are the same as those shown in FIG. In addition, a lubricant may be added in the step before compression molding in order to improve the releasability when compression molding as described above.

  In the above production method, a polyvinyl alcohol resin is preferably used as the water-soluble resin. Further, as the solvent for these water-soluble resins, a mixed solvent of water and an alcohol solvent or a mixed solvent of water, an alcohol solvent and a ketone solvent is preferably used.

FIG. 3 is an exemplary process chart showing another method for producing a solid phosphorus removing agent comprising an iron salt or aluminum salt and a water-soluble resin according to the present invention.
First, a water-soluble resin is dissolved in a mixed solvent of water and an organic solvent to prepare a resin solution. At the time of dissolution, it is preferable to disperse the water-soluble resin in a mixed solvent and then heat it at 80 to 90 ° C.

  On the other hand, an iron salt or aluminum salt pulverized into a powder is separately prepared. Next, the iron salt or aluminum salt is put into the resin solution, or the iron salt or aluminum salt is put into the resin solution and mixed by stirring or the like to prepare a mixed solution (or suspension).

  The mixed liquid is sprayed in the form of a mist at a heated atmosphere, and the mist is dried, that is, spray-dried. The heating atmosphere is preferably in a container adjusted to a temperature lower than the temperature at which the water-soluble resin melts and at which the solvent of the water-soluble resin solution is likely to evaporate. In spraying the mixed liquid, for example, a two-fluid nozzle is used. That is, nonflammable gas such as nitrogen gas is ejected from one nozzle of the two-fluid nozzle. At this time, if the opening portion of the other nozzle is set to a negative pressure, a part of the mixed solution is sucked and sprayed into the container in the form of a mist by the incombustible gas. Alternatively, the mixed liquid can be supplied to the opening portion of the other nozzle by using a pump, and at the same time, it can be ejected in a mist form into the container by the incombustible gas. In addition, it is preferable to take means, such as stirring, in order for the said liquid mixture to maintain the dispersion state of particle | grains appropriately. Since the inside of the container is in a heated atmosphere in which the solvent evaporates, the mist drops evaporate the solvent and the residue becomes a powdery dry powder that falls to the bottom of the container. The obtained powder becomes a dried product of iron salt or aluminum salt coated with a water-soluble resin. In addition, the method of spray drying in a heating atmosphere part is not limited to the above-mentioned method, What is necessary is just the method based on spray drying.

  Next, the dried product obtained by the spray drying is compression molded. A tableting machine or a press molding machine is used as the molding means. The shape may be any shape such as a tablet shape such as a columnar shape, a meteorite shape, a football shape, a rounded round triangle, a rounded round polygonal shape, or a lump shape larger than a tablet. In addition, in order to improve mold release properties when performing the compression molding, a lubricant may be added in the process before compression molding.

  FIG. 4 is an exemplary process chart showing a method for producing a solid phosphorus removing agent comprising an iron salt or an aluminum salt, and a polysaccharide and a water-soluble resin according to the present invention. FIG. 4 includes a step of uniformly mixing polysaccharide powder in advance with iron salt or aluminum salt powder. Then, the mixture of the iron salt or aluminum salt and the polysaccharide is put into the resin solution, or the mixture of the iron salt or aluminum salt and the polysaccharide is put into the resin solution, and mixed by stirring or the like. Make a liquid (or suspension). Subsequent processes, that is, processes such as spray drying and compression molding are the same as those in FIG. 3, and thus detailed description thereof is omitted. In addition, a lubricant may be added in the step before compression molding in order to improve the releasability when compression molding as described above.

  In the above production method, a polyvinyl alcohol resin is preferably used as the water-soluble resin. Further, as the solvent for these water-soluble resins, a mixed solvent of water and an alcohol solvent or a mixed solvent of water, an alcohol solvent and a ketone solvent is preferably used.

Example 1
A solid phosphorus removing agent was produced according to the production method shown in FIG. Ferrous sulfate heptahydrate (Kanto Chemical Co., Ltd., reagent grade 1) is used for iron salts, and fully saponified polyvinyl alcohol resin (Nippon Gosei Chemical Co., Ltd., Gohsenol NL type) is used for water-soluble resins. Was used. In addition, the apparatus for spray coating the resin solution on the ferrous sulfate heptahydrate powder in a heated atmosphere is a rotating pan-type granulator (As One Corporation, DPZ-01 type) that rotates. Using. The dried product after the spray coating was finally blended to 100 parts by weight as ferrous sulfate heptahydrate and 6 parts by weight of Gohsenol NL type.

(Resin solution)
Gohsenol NL type is added to and dispersed in a mixed solvent of water (60) / IPA (isopropyl alcohol, 40) (volume ratio), dissolved while heating to 80 to 90 ° C., and then this resin solution is hand-type spray container Filled. The Gohsenol NL type in the resin solution was 2 parts by weight.
(Spray coating)
The pan of the heated pan granulator was tilted appropriately, and the powder was put into this pan and rotated. And the whole quantity of the resin solution was sprayed intermittently toward this powder. At this time, the dish temperature was set to about 95 ° C. As a result, the solvent in the sprayed resin solution was evaporated to obtain a dried ferrous sulfate salt coated with GOHSENOL NL type.
(Compression molding)
Using 5 g of the resulting dried product, a cylindrical tablet having a diameter of 20 mm and a height of about 10.5 mm, ie, a solid phosphorus removing agent, is compression-molded with a molding pressure of 40 MP (product pressure) a by a hand press type tablet molding machine. Got.

(Example 2)
A solid phosphorus removing agent was produced according to the production method shown in FIG. The same ferrous sulfate heptahydrate and Gohsenol NL type as in Example 1 were used as the iron salt and the water-soluble resin. As the polysaccharide to be mixed with ferrous sulfate heptahydrate, dextrin (Kanto Chemical Co., Ltd., reagent grade 1) was used, and both were pulverized and mixed. The spray-coated dried product was finally blended as 100 parts by weight of ferrous sulfate heptahydrate, 9 parts by weight of dextrin, and 6 parts by weight of Gohsenol NL type. The above (resin solution), (spray coating), and (compression molding) were performed in the same manner as in Example 1 to obtain a cylindrical tablet having a diameter of 20 mm and a height of about 10.5 mm, that is, a solid phosphorus removing agent. .

(Example 3)
A solid phosphorus removing agent was produced according to the production method shown in FIG. The same ferrous sulfate heptahydrate and Gohsenol NL type as in Example 1 were used as the iron salt and the water-soluble resin. In addition, a spray drying apparatus (Yamato Scientific Co., Ltd., GS310 type) was used for the heated atmosphere part. The dried product coated with GOHSENOL NL type after spray drying was blended so that the final ferrous sulfate heptahydrate was 100 parts by weight and GOHSENOL NL type 6 parts by weight.

(Resin solution)
Gohsenol NL type was added to and dispersed in a mixed solvent of water (60) / IPA (isopropyl alcohol, 40) (volume ratio) and dissolved while heating at 80 to 90 ° C. The GOHSENOL NL type in the resin solution was 0.9 parts by weight.
(Mixture)
Ferrous sulfate heptahydrate was dispersed in the resin solution so as to be 15 parts by weight to obtain a mixed solution (or suspension).
(Spray drying)
In the spray drying apparatus, the liquid mixture is supplied to one of the two fluid nozzles attached to the drying chamber using a metering pump, the nitrogen gas is supplied to the other nozzle, and the liquid mixture is supplied by the jet power of the nitrogen gas. Sprayed in mist. The temperature was adjusted so that the inlet temperature of the drying chamber was 140 ° C. and the outlet temperature was 80 ° C. Since the solvent in the sprayed mist drops evaporates, particles coated with the Gohsenol NL type remain, and these particles are collected by a cyclone connected to a drying chamber to obtain a dried product.

(Compression molding)
Using 5 g of the obtained dried product, compression molding was performed at a molding pressure of 40 MPa (product pressure) with a hand press type tablet molding machine, and a cylindrical tablet having a diameter of 20 mm and a height of about 10.5 mm, that is, a solid phosphorus removing agent was obtained. Obtained.

(Example 4)
A solid phosphorus removing agent was produced according to the production method shown in FIG. The same ferrous sulfate heptahydrate and Gohsenol NL type as in Example 1 were used as the iron salt and the water-soluble resin. The same dextrin as Example 2 was used for the polysaccharide mixed with ferrous sulfate heptahydrate. The dried product after spray drying was blended so as to be finally 100 parts by weight as ferrous sulfate heptahydrate, 9 parts by weight of dextrin, and 6 parts by weight of Gohsenol NL type. The above (resin solution) was the same as in Example 3. Further, the above (mixed solution) was dispersed in the resin solution so as to be 15 parts by weight of ferrous sulfate heptahydrate and 1.4 parts by weight of dextrin. The above (spray drying) and (compression molding) were carried out in the same manner as in Example 3 to obtain a columnar tablet having a diameter of 20 mm and a height of about 10.5 mm, that is, a solid phosphorus removing agent.

(Comparative Example 1)
The same ferrous sulfate heptahydrate as in Example 1 and the same dextrin as in Example 2 were combined and ground and mixed in a mortar. The blending ratio was 100 parts by weight as ferrous sulfate heptahydrate and 9 parts by weight of dextrin. 5 g of this mixed powder was compression molded at a pressure of 40 MPa (product pressure) with a hand press type tablet molding machine to obtain a cylindrical tablet having a diameter of 20 mm and a height of about 10.5 mm.

(Solubility test)
The tablets prepared in Examples 1, 2, 3, 4 and Comparative Example 1 were placed in a vinyl chloride tray having a width of 23 mm and a length of 60 mm for each test, and 10 ml / min of tap water was quantified from the upstream side of the tray. The pump was continuously supplied for 10 minutes. At this time, a height of about 2 mm from the lower end of the tablet was in contact with tap water. After contact with the tablet, the container received the total amount of effluent flowing from the tray. And the iron ion density | concentration melt | dissolved in the outflow water was measured, and the melt | dissolution weight of the tablet was computed from the content rate of the iron content in a tablet. The tablet dissolution test results are shown in Table 1. In addition, a digital simple water quality meter (Kyoritsu Riken, Inc., Λ-8000 type) was used for the measurement of the iron ion concentration.

  From Table 1, when the dissolution weight ratio of the tablet is seen, Examples 1, 2, 3, and 4 show significantly smaller values than Comparative Example 1, and the dissolution amount is small. That is, a tablet comprising ferrous sulfate heptahydrate and a water-soluble resin, a polyvinyl alcohol-based resin, has a low dissolution rate and sustained release properties.

The process drawing of an example which shows the manufacturing method of the solid phosphorus removal agent by spray coating which consists of iron salt or aluminum salt of this invention, and water-soluble resin (polyvinyl alcohol-type resin). The process drawing of an example which shows the manufacturing method of the solid phosphorus removal agent by spray coating which consists of iron salt or aluminum salt and polysaccharide of this invention, and water-soluble resin (polyvinyl alcohol-type resin). The process drawing of an example which shows the manufacturing method of the solid phosphorus removal agent by spray drying which consists of iron salt or aluminum salt of this invention, and water-soluble resin (polyvinyl alcohol-type resin). The process drawing of an example which shows the manufacturing method of the solid phosphorus removal agent by spray drying which consists of iron salt or aluminum salt and polysaccharide of this invention, and water-soluble resin (polyvinyl alcohol-type resin).

Claims (6)

A method for producing a solid phosphorus removing agent produced through the following production process;
(A) dissolving a water-soluble resin in a solvent to obtain a resin solution;
(B) a step of spray-coating the resin solution obtained in (a) on a powdered iron salt or aluminum salt in a heated atmosphere to obtain a dried product,
(C) A step of compression-molding the dried product obtained in (b) to obtain a solid phosphorus removing agent.
However, the water-soluble resin is any one of a polyvinyl alcohol resin, a cellulose resin, a resin having an ether bond, and a resin having a carbamoyl group, and the solvent is a mixed solvent of water and an organic solvent. A method for producing a solid phosphorus removing agent produced through the following production process;
(A) dissolving a water-soluble resin in a solvent to obtain a resin solution;
(B) a powdered iron or aluminum salts, step of mixing the powdered polysaccharides,
(C) A step of spray coating the resin solution obtained in (a) on a mixture of the iron salt or aluminum salt obtained in (b) and the polysaccharide in a heated atmosphere to obtain a dried product,
(D) A step of compression-molding the dried product obtained in (c) to obtain a solid phosphorus removing agent.
However, the water-soluble resin is any one of a polyvinyl alcohol resin, a cellulose resin, a resin having an ether bond, and a resin having a carbamoyl group, and the solvent is a mixed solvent of water and an organic solvent. A method for producing a solid phosphorus removing agent produced through the following production process;
(A) dissolving a water-soluble resin in a solvent to obtain a resin solution;
(B) a step of mixing a powdered iron salt or aluminum salt with the resin solution obtained in (a) to form a mixed solution;
(C) a step of spray-drying the mixed liquid obtained in (b) to a heated atmosphere site to obtain a dried product,
(D) A step of compression-molding the dried product obtained in (c) to obtain a solid phosphorus removing agent.
However, the water-soluble resin is any one of a polyvinyl alcohol resin, a cellulose resin, a resin having an ether bond, and a resin having a carbamoyl group, and the solvent is a mixed solvent of water and an organic solvent. A method for producing a solid phosphorus removing agent produced through the following production process;
(A) dissolving a water-soluble resin in a solvent to obtain a resin solution;
(B) a powdered iron or aluminum salts, step of mixing the powdered polysaccharides,
(C) a step of mixing a mixture of the iron salt or aluminum salt obtained in (b) with a polysaccharide and the resin solution obtained in (a) to form a mixed solution;
(D) a step of spray-drying the liquid mixture obtained in (c) to a heated atmosphere site to obtain a dried product,
(E) A step of compression-molding the dried product obtained in (d) to obtain a solid phosphorus removing agent.
However, the water-soluble resin is any one of a polyvinyl alcohol resin, a cellulose resin, a resin having an ether bond, and a resin having a carbamoyl group, and the solvent is a mixed solvent of water and an organic solvent. The iron salt or aluminum salt is ferrous sulfate, ferric sulfate, ferrous chloride, ferric chloride and iron hydrates thereof, aluminum sulfate, potassium aluminum sulfate, sodium aluminum sulfate and their The method for producing a solid phosphorus removing agent according to any one of claims 1 to 4, wherein the method is any one selected from the group consisting of aluminum salts of hydrates . The method for producing a solid phosphorus removing agent according to claim 2 or 4, wherein the polysaccharide is any one selected from the group consisting of starch, dextrin, cellulose, cellobiose, chitins, and chitosans .

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