JP2013188726A - Recovery agent for ammoniacal nitrogen and phosphorus and method for producing the same - Google Patents

Abstract

PROBLEM TO BE SOLVED: To efficiently recover phosphorus that is contained in drainage including sewer in a large amount and whose depleting as a resource is pointed out, and to reuse it as a chemical fertilizer.SOLUTION: A recovery agent for ammoniacal nitrogen and phosphorus is for recovering ammoniacal nitrogen and phosphorus from wastewater containing at least ammoniacal nitrogen and phosphorus, and comprises a composition represented by the general formula: (MO(MCO)) γSiOδKO (0≤α≤1, 0≤β≤1, α+β=1, 0.1≤γ≤20, 0<δ≤10, M: at least one of magnesium and calcium).

Description

  Embodiments described herein relate generally to an ammoniacal nitrogen and phosphorus recovery agent and a method for producing the same.

  In recent years, due to the rapid globalization of economic activities, global environmental pollution and water pollution have become serious problems. In addition, worldwide production activities simultaneously lead to resource depletion, and the types of elements recognized as rare elements tend to increase. Recently, the reduction of phosphorus ore on a global scale has progressed, and in recent years phosphorus has also been recognized as a rare element.

  On the other hand, strict emission standards for phosphorus have been established as measures against eutrophication problems in closed waters such as lakes and bays. As means for removing phosphorus from water (actually in the form of phosphate ions), ions of polyvalent metals such as iron, magnesium, aluminum, and calcium are supplied into waste water, and this is combined with phosphate. A reactive agglomeration method is often used in which a solid or particle is formed by reacting with ions and then removed by precipitation, flotation, filtration, or the like. As a method for supplying polyvalent metal ions into wastewater, there is a coagulant addition method in which an aqueous coagulant such as ferric chloride, polyferric sulfate, or polyaluminum chloride is supplied by an injection pump (Patent Document). 1).

  In addition to the agglomeration method by addition of such chemicals, adsorption methods using ion exchange resins, hydrotalcite-like clay minerals, zirconium oxide and the like are known. This is a method of removing phosphorus by passing phosphorus-containing treated water through a packed bed filled with a phosphorus adsorbent (Patent Document 2). In addition, a method in which granular calcium phosphate-based phosphate ore is used as a seed crystal, filled in a reaction tank, and in the presence of calcium salt, phosphate in waste water is precipitated as calcium phosphate on the surface of the phosphate ore. A crystal that removes phosphorus by using granular ammonium magnesium phosphate as a seed crystal, filling it into a reaction tank, crystallizing ammonium magnesium phosphate on the seed crystal surface from wastewater containing ammoniacal nitrogen and phosphorus There is an analysis method (Patent Document 3).

  As described above, phosphorus is recognized as a rare element, and the adsorbent after adsorbing phosphorus is treated as industrial waste, resulting in additional costs. It is an essential requirement to use it. Since phosphorus can be used as a constituent element of chemical fertilizer, phosphorus recovered from water can be reused as chemical fertilizer.

  However, the chemical fertilizer needs to contain two or more types of phosphorus, nitrogen, and potassium, and therefore the chemical fertilizer cannot be produced only with the recovered phosphorus. In the above-described crystallization method using ammonium magnesium phosphate as a seed crystal, ammonium magnesium phosphate can be crystallized on the surface of the seed crystal, so that nitrogen can be secured in addition to phosphorus constituting the chemical fertilizer. However, in this method, potassium cannot be contained, and attempts have been made to add potassium to the recovered ammonium magnesium phosphate to obtain a chemical fertilizer. However, when potassium was added later, only potassium was dissolved into the soil immediately after fertilization, and a chemical fertilizer for practical use could not be obtained.

  In other words, in the conventional method, a practical reuse technique of adsorbed phosphorus as a chemical fertilizer has not been established.

JP 2001-48791 A JP 2009-113034 A JP 2004-89931A

  An object of the present invention is to efficiently recover phosphorus that is contained in a large amount in wastewater such as sewage and that is depleted as a resource, and to reuse it as a chemical fertilizer.

The recovery agent for ammonia nitrogen and phosphorus of the embodiment is a recovery agent for recovering ammonia nitrogen and phosphorus from waste water containing at least ammonia nitrogen and phosphorus, and has the general formula (MO _α (MCO ₃ ) _β ). γSiO ₂ · δK ₂ O (0 ≦ α ≦ 1, 0 ≦ β ≦ 1, α + β = 1, 0.1 ≦ γ ≦ 20, 0 <δ ≦ 10, M: at least one of magnesium and calcium) Including things.

(Ammonia nitrogen and phosphorus recovery agent)
The recovery agent of ammonia nitrogen and phosphorus in this embodiment is a general formula (MO _α (MCO ₃ ) _β ) · γSiO ₂ · δK ₂ O (0 ≦ α ≦ 1, 0 ≦ β ≦ 1, α + β = 1, 0). 1 ≦ γ ≦ 20, 0 <δ ≦ 10, M: at least one of magnesium and calcium).

  In the above recovery agent, when the recovery agent is immersed in the wastewater, magnesium and calcium are dissolved as ions, and ammonium ions (ammonia nitrogen) and phosphoric acid in the wastewater are based on the reaction formula as shown below. Reaction with ions (phosphorus) yields reaction products such as magnesium ammonium phosphate, hydroxyapatite, and magnesium phosphate.

Mg ²⁺ + NH ⁴⁺ + PO ₄ ³⁻ + 6H ₂ O → MgNH ₄ PO ₄ .6H ₂ O (1)
10Ca ²⁺ + 2OH ⁻ + 6PO ₄ ³⁻ → Ca ₁₀ (OH) ₂ (PO ₄ ) ₆ (2)
Mg ²⁺ + PO ₄ ³⁻ → Mg ₃ (PO ₄ ) ₃ (3)

  In the waste water, magnesium ions and calcium ions are eluted sequentially, and the elution occurs on the surface of the recovery agent. Therefore, the above reaction products such as magnesium ammonium phosphate, hydroxyapatite, and magnesium phosphate are the surface of the recovery agent. It will be adsorbed and deposited.

In addition, magnesium and calcium that adsorb ammonium ions (ammonia nitrogen) and phosphate ions (phosphorus) in waste water by ionization as described above are (MO _α (MCO ₃ ) _β ) in the above general formula. Although included as a composition, such a composition is dependent on the raw material used in the manufacturing method demonstrated below, Comprising: The form of the composition is ammonium ion (ammonia nitrogen) of the collection | recovery agent mentioned above. And has no effect on the adsorption of phosphate ions (phosphorus).

Therefore, based on the range of α and β, the composition has a composition of MO (α = 1, β = 0), (MO _α (MCO ₃ ) _β ) and MCO ₃ (α = 0, β = 1). Even if it has, it does not have any influence on the adsorptivity of ammonium ions (ammonia nitrogen) and phosphate ions (phosphorus) in the waste water.

The silicon compound of the above general formula (anhydrous silica, silica; SiO ₂ ) is a substance for retaining at least one of a magnesium compound and a calcium compound represented by (MO _α (MCO ₃ ) _β ) in the general formula. . In this case, γ represented by the above general formula needs to be in a range of 0.1 ≦ γ ≦ 20. When γ is less than 0.1, the magnesium compound and calcium compound cannot be sufficiently retained, and when γ is greater than 20, the amount of magnesium compound and calcium compound in the recovery agent is relatively decreased. Since the amounts of magnesium (ion) and calcium (ion) that can be supplied into the wastewater are relatively reduced, the recovery efficiency of ammonium ions (ammonia nitrogen) and phosphate ions (phosphorus) in the wastewater is lowered.

In addition, potassium oxide (K ₂ O) of the above general formula does not contribute to the adsorption and recovery of ammonium ions (ammonia nitrogen) and phosphate ions (phosphorus) in the waste water, and is carried out as described above. The recovery agent in the form is an element of chemical fertilizer so that the recovery agent after adsorbing ammonium ions (ammonia nitrogen) and phosphate ions (phosphorus) in the waste water can be used as it is as a chemical fertilizer. Potassium is previously contained in the recovery agent as a composition. Therefore, unlike the case where potassium is added later, it is possible to avoid the problem that only potassium is dissolved into the soil immediately after fertilization.

ΔK ₂ O also has a role of holding at least one of a magnesium compound and a calcium compound represented by (MO _α (MCO ₃ ) _β ) in the general formula, as in the case of the silicon compound.

Therefore, δ that determines the content ratio of K ₂ O needs to be in the range of 0 <δ ≦ 10. That is, if K ₂ O is contained even in a trace amount, phosphorus and nitrogen that are constituent elements of the chemical fertilizer in conjunction with the adsorption operation of ammonium ions (ammonia nitrogen) and phosphate ions (phosphorus) from the waste water described above. However, if δ exceeds 10 and the amount of magnesium compound and calcium compound in the recovery agent is relatively reduced, magnesium (ion) and calcium (ion) that can be supplied into the waste water. Therefore, the recovery efficiency of ammonium ions (ammonia nitrogen) and phosphate ions (phosphorus) in the waste water is lowered.

  As a result, the recovery agent that adsorbs (deposits) the reaction product described above contains phosphorus, nitrogen and potassium, which are constituent elements of the chemical fertilizer, and as it is as a chemical fertilizer without recovering the adsorbed phosphorus and the like. Can be used.

  Thus, in this embodiment, it is not possible to separate and remove phosphorus adsorbed from the recovery agent and reuse the recovery agent. However, as described above, the recovery agent itself containing phosphorus or the like is reused as a chemical fertilizer. can do. Separation of phosphorus and the like from the recovery agent requires a separate operation such as a separation step. Therefore, as in this embodiment, without separating phosphorus or the like adsorbed from the recovery agent, it can be used as a chemical fertilizer as it is. Although the form of reuse is different, the recovery agent can be reused at low cost.

  The shape of the recovery agent is not particularly limited, and if necessary, spherical, granular, angular, fibrous, thread-like, rod-like, tubular, sheet-like, film-like Any shape such as a plate-like material can be used.

  Moreover, the magnitude | size can also be set suitably as needed. However, if the size of the recovery agent is too small, the recovery agent is immersed in the waste water and magnesium ions and calcium ions are dissolved in the waste water, and phosphoric acid obtained according to the above reaction formulas (1) to (3) When a reaction product such as magnesium ammonium is obtained, the size of the reaction product becomes too fine and tends to be liberated in waste water. Moreover, it is not preferable when the recovered agent is sprayed as fertilizer. Therefore, in order to avoid such a problem, the size of the recovery agent is preferably on the order of submicron to millimeter, and more preferably 0.1 to 5 mm. In addition, the collection | recovery agent of such a magnitude | size can be formed comparatively easily according to the manufacturing method demonstrated below.

  The ammonia nitrogen and phosphorus recovery agent of the present embodiment is preferably porous particles. In this case, since the surface area of the recovery agent increases, the amount of the reaction product obtained as described above that can be adsorbed and deposited on the surface of the recovery agent increases. In addition, the ammonium ions (ammonia nitrogen) and phosphate ions (phosphorus) in the waste water can be adsorbed and recovered also in the holes of the recovery agent. Therefore, ammonium ions (ammonia nitrogen) and phosphate ions (phosphorus) in the wastewater can be adsorbed and recovered more efficiently and effectively.

  The porosity of the recovery agent is preferably 30% or more and 80% or less. When the porosity of the recovery agent exceeds 80%, the strength of the recovery agent decreases, and it may not be possible to obtain a recovery agent having a strength that can withstand practical use. For the reasons described above, the upper limit of the porosity of the recovery agent is more preferably 60%. Further, if the porosity of the recovery agent is less than 30%, the effect of increasing the surface area of the recovery agent cannot be obtained sufficiently, and adsorption of ammonium ions (ammonia nitrogen) and phosphate ions (phosphorus) in the waste water Efficiency and recovery efficiency cannot be improved sufficiently. From such a viewpoint, the lower limit of the porosity of the recovery agent is more preferably 35% or more, and further preferably 40% or more.

  Further, the smaller the pore size of the recovery agent, the larger the contact area between the recovery agent and the waste water, which is preferable. However, if the pore size is too small, it becomes difficult for the recovery agent to flow into the pores. Therefore, the amount of ions adsorbed in the holes of the recovery agent is reduced, and the recovery efficiency of ammonium ions (ammonia nitrogen) and phosphate ions (phosphorus) in the waste water may be reduced. From such a viewpoint, the pore diameter of the recovery agent is preferably in the range of 0.1 μm to 500 μm, more preferably in the range of 0.5 μm to 500 μm, and in the range of 10 μm to 500 μm. Is particularly preferred. The porosity and pore diameter can be measured, for example, by measuring the pore distribution by mercury porosimetry.

When the recovery agent has the porosity and the pore diameter as described above, the specific surface area becomes 0.1 m ² / g or more and 500 m ² / g or less, and the amount of adsorption and deposition of the reaction product increases as described above. . The specific surface area is determined by the BET method.

  In addition, the porous and particulate recovery agent described above is naturally manufactured by manufacturing according to the manufacturing method described below.

(Method for producing ammonia nitrogen and phosphorus recovery agent)
Next, the manufacturing method of the recovery agent of ammonia nitrogen and phosphorus of this embodiment is demonstrated.

(Method for producing phosphorus recovery agent)
Next, the manufacturing method of the phosphorus collection | recovery agent of this embodiment is demonstrated.

(Mixing process)
First, a raw material for the composition represented by the above general formula constituting the recovery agent of this embodiment is prepared. In addition, according to the kind of raw material, the kind of raw material to prepare can be divided into the following four forms.
(i) at least one of a magnesium source and a calcium source, a silicon source and a potassium source
(ii) Magnesium-calcium source, silicon source and potassium source
(iii) at least one of a magnesium source and a calcium source, and a silicon-potassium source
(iv) Magnesium-calcium source, silicon-potassium source

  Since the magnesium source is easily available and inexpensive, it can be at least one selected from the group consisting of magnesium hydroxide, magnesium oxide and magnesium carbonate. The calcium source can be at least one selected from the group consisting of calcium hydroxide, calcium oxide and calcium carbonate for the same reason.

The silicon source can be at least one selected from the group consisting of quartz sand, diatomaceous earth, waste glass, fly ash, rice husk, rice husk ash, and steel slag. Among these, fly ash, rice husk, rice husk ash, steel slag, and the like, in particular, are wastes generated from coal firing, rice threshing, iron refining, etc., but these wastes are silicic acid (silica; Since SiO ₂ ) is contained as a main component, the waste can be effectively used by using these wastes as a silicon source.

Further, the potassium source can be at least one of potassium hydroxide and potassium carbonate, and the magnesium-calcium source can be at least one of dolomite (CaMg (CO ₃ ) ₂ ) and half-burned dolomite (MgO · CaCO ₃ ). The silicon-potassium source can be potassium silicate.

  As is clear from the above (i) to (iv), (ii) to (iv) simplify the manufacturing process of the recovery agent because the types of raw materials used are small compared to (i). be able to.

  After preparing the raw materials described above, each raw material is weighed and mixed so as to satisfy the element ratio of the composition represented by the general formula. In mixing, a solvent is appropriately used, and the raw materials are dispersed and stirred in the solvent to form a slurry.

(Molding process)
Next, the slurry (mixture) obtained as described above can be dried, and the granular material obtained using a granulator or the like can be formed into various shapes, for example, extrusion such as strand cutting, sheet cutting, etc. It can shape | mold using arbitrary granulation methods, such as the extrusion molding method including a granulation method, a compression molding method, a pressure molding granulation method, a rolling granulation method, and a rounding method. However, the molding step is not an essential requirement, and the above-described slurry (mixture) can be directly subjected to the firing step described below.

(Baking process)
Next, the molded product obtained in the molding step or the slurry obtained in the mixing step is put in a predetermined mold and subjected to a drying treatment as necessary, and then, for example, a temperature of 300 ° C. or higher and 1200 ° C. or lower, preferably in the atmosphere. Is fired at a temperature of 550 ° C. or higher and 1000 ° C. or lower. About temperature, it sets suitably according to melting | fusing point of a silicon source. As a result, the raw materials in the mixture (molded product) react with each other to form the composition represented by the above general formula. At this time, the raw material in the mixture (molded product) is decomposed (for example, magnesium carbonate is decomposed and carbon dioxide gas is released to the outside), and further, a part of the raw material is partially liquefied. The resulting composition becomes porous particles.

(Crushing process)
Next, the composition obtained as described above is used as a recovery agent having a desired size using a pulverizer or a granulator. In addition, when the molding process is performed as described above, the composition has a desired size in advance, and thus the composition obtained in the firing process can be used as it is as a recovery agent without passing through this process. .

  If necessary, an acid treatment or a washing treatment can be performed on the recovered agent after pulverization or the composition before pulverization. Thereby, residues (potassium salts and the like) can be removed from the recovery agent or the surface of the composition, and the recovery ability of the recovery agent can be improved.

(Usage method of ammonia nitrogen and phosphorus recovery agent)
A method of using the ammonia nitrogen and phosphorus recovery agent of this embodiment will be described.

  The usage method of the phosphorus collection | recovery agent in this embodiment is very simple, Comprising: It carries out by making the collection | recovery agent obtained as mentioned above contact waste water. Accordingly, the above-described principle, that is, magnesium ions or calcium ions contained in the recovery agent are combined with ammonium ions (ammonia nitrogen) and phosphate ions (phosphorus) in the waste water, so that ammonia nitrogen in the waste water and It can recover phosphorus. Furthermore, when drainage is taken into the pores, ammonium ions (ammonia nitrogen) and phosphate ions (phosphorus) are adsorbed in the pores, and ammonia nitrogen and phosphorus in the drainage are recovered. It can be done.

  As a specific method of bringing the recovery agent into contact with the waste water, for example, the recovery agent is put into the waste water, and stirred as necessary to ammonium ions (ammonia nitrogen) and phosphate ions (phosphorus). And a method of sedimentation after recovery. This method is effective when treating a relatively large amount of waste water. According to this method, there is a concern that the water purification equipment becomes relatively large, but there is an advantage that a large amount of waste water can be treated at one time.

  In addition, it is possible to collect ammonium ions (ammonia nitrogen) and phosphate ions (phosphorus) in the waste water by filling the recovery agent into a column and bringing the waste water into contact with the column. This method is suitable for treating a small amount of wastewater because the amount of wastewater treatment is limited although the treatment apparatus is relatively small.

  In addition, the collection | recovery agent in this embodiment can be applied with respect to the waste_water | drain of arbitrary pH. However, there is a possibility that the recovery agent dissolves under strong acidity. Therefore, a preferable pH range for applying the ion recovery agent according to the present embodiment is 5.0 or more and 12.0 or less, and a more preferable pH range is 7.0 or more and 10.0 or less.

Example 1
As a raw material, magnesium hydroxide and potassium silicate solution (SiO ₂ : 27.5% to 29%, K ₂ O: 21% to 23%) and distilled water in a weight ratio of 1: 0.5: 5 (Mixing process). Thereafter, the mixture was poured into a Teflon (registered trademark) beaker and dried in a dryer at 50 ° C. for 24 hours. Then, it further baked at 300 degreeC for 3 hours with the electric furnace (baking process). Subsequently, the heat-treated mixture was pulverized to 0.5 mm or more and 2 mm or less using a pulverizer to obtain a target recovery agent.

  Subsequently, a mixed aqueous solution prepared to have a phosphate ion concentration of 60 mg / l, a magnesium ion concentration of 24 mg / l, a carbonate ion concentration of 3000 mg / l, and an ammonium ion of 500 mg / l was prepared as a drainage simulation solution. 62.5 mg of the recovery agent was added to 250 mL of this drainage simulation liquid, and mixed and stirred for 24 hours for water purification treatment. After the treatment, the recovered agent was recovered, and the soluble phosphoric acid, nitrogen content and potassium content in the recovered recovered agent were evaluated.

  The soluble phosphoric acid was derived by the measurement method shown below, and the nitrogen content and the potassium content were derived by the composition evaluation method shown below. Further, the composition of the recovery agent was identified by appropriately combining the analysis result of the composition by the above-described composition evaluation method and the structural analysis by XPS, IR measurement, X-ray diffraction and the like.

In addition, quasi-soluble phosphoric acid is a characteristic required for phosphate fertilizers, and after measuring the phosphorus concentration (P) measured by the measurement method shown below and converting it to phosphoric acid (P ₂ O ₅ ) , Refers to the calculated ratio of the amount of elution per recovered product. Since the phosphate fertilizer is required to have a high solubility of phosphoric acid, it is preferable that the proportion of phosphorus eluted by citric acid is as high as possible.

(Method for measuring the amount of soluble phosphoric acid)
The recovered material after the water purification test was immersed in a 2 wt% citric acid solution with a liquid temperature of 30 ° C. for 60 minutes, then the recovered material was taken out and filtered as necessary, and then the phosphorus concentration in the citric acid solution was measured by ICP emission spectroscopy. It measured with the analyzer (SP-1500V made from SII nanotechnology).

(Composition evaluation method)
The water content was measured by TG and quantified using fluorescent X-ray and chemical analysis.
Specifically, for fluorescent X-rays, qualitatively determined the assignment of peaks to each element in the fluorescent X-ray spectrum. Quantification was performed by measuring the intensity of the fluorescent X-ray spectrum (FP method and calibration curve method). The FP method is a calculation method in which the sensitivity coefficient for each element is theoretically obtained from the measured intensity, and the concentration is 100% in the total of detected elements. The calibration curve method is a method in which a sample with a known concentration is measured at several points to create a calibration curve, and then an unknown sample is measured to quantify the concentration.

  Next, the chemical analysis used an ion chromatograph or an ICP emission spectroscopic analyzer. The sample was completely dissolved with, for example, nitric acid, and various ion concentrations were measured and quantified.

  In addition, about the specific composition of the collection | recovery agent, in addition to the composition analysis mentioned above, structural analysis, such as XPS, IR analysis, and X-ray diffraction, was suitably used together.

  Table 1 shows the results of the composition components of the recovery agent, the soluble phosphoric acid, the nitrogen content and the potassium content after immersion of the recovery agent drainage simulation liquid.

(Example 2)
A recovery agent was produced in the same manner as in Example 1 except that magnesium oxide was used instead of magnesium hydroxide. Moreover, the drainage simulation liquid was prepared like Example 1, and the water quality purification process was performed on the same conditions. Further, the composition of the recovery agent, the soluble phosphoric acid, the nitrogen content, and the potassium content in the recovered recovery agent were also identified and evaluated in the same manner as in Example 1. The results are shown in Table 1.

(Example 3)
A recovery agent was produced in the same manner as in Example 1 except that calcium oxide was used instead of magnesium hydroxide. Moreover, the drainage simulation liquid was prepared like Example 1, and the water quality purification process was performed on the same conditions. Further, the composition of the recovery agent, the soluble phosphoric acid, the nitrogen content, and the potassium content in the recovered recovery agent were also identified and evaluated in the same manner as in Example 1. The results are shown in Table 1.

Example 4
A recovery agent was produced in the same manner as in Example 1 except that dolomite ((CaMg (CO ₃ ) ₂ ) was used instead of magnesium hydroxide and the calcination temperature was 550 ° C. Further, in the same manner as in Example 1. A drainage simulation liquid was prepared and subjected to water purification treatment under the same conditions, and the composition of the recovery agent, the soluble phosphoric acid, the nitrogen content and the potassium content in the recovery agent after the treatment were also as in Example 1. Identification and evaluation were conducted in the same manner, and the results are shown in Table 1.

(Example 5)
Dolomite ((CaMg (CO ₃ ) ₂ ) was used instead of magnesium hydroxide, and these were mixed at a weight ratio of 1: 0.1: 1 to obtain a mixture, and the firing temperature was 550 ° C. A recovery agent was produced in the same manner as in Example 1. A drainage simulation liquid was prepared in the same manner as in Example 1, and water purification treatment was performed under the same conditions. The soluble phosphoric acid, nitrogen content and potassium content in the recovery agent were also identified and evaluated in the same manner as in Example 1. The results are shown in Table 1.

(Example 6)
Example 1 except that dolomite ((CaMg (CO ₃ ) ₂ ) was used instead of magnesium hydroxide and these were mixed at a weight ratio of 1: 4: 40 to obtain a mixture and the firing temperature was 550 ° C. A recovery agent was produced in the same manner as in Example 1. In addition, a simulated drainage solution was prepared in the same manner as in Example 1, and water purification treatment was performed under the same conditions as that of the recovery agent. The soluble phosphate, nitrogen content and potassium content were identified and evaluated in the same manner as in Example 1. The results are shown in Table 1.

(Example 7)
Dolomite ((CaMg (CO ₃ ) ₂ ) is used in place of magnesium hydroxide, and silica sand and potassium hydroxide are used in place of the potassium silicate solution. A mixture was obtained by mixing at a weight ratio of 1.25: 16, and a recovery agent was obtained in the same manner as in Example 1 except that the firing temperature was 1000 ° C. Further, the composition of the recovery agent and the post-treatment The soluble phosphoric acid, nitrogen content and potassium content in the recovery agent were also identified and evaluated in the same manner as in Example 1. The results are shown in Table 1.

(Example 8)
Magnesium oxide is used instead of magnesium hydroxide, fly ash and potassium hydroxide are used instead of potassium silicate solution, and the weight ratio of these raw materials and distilled water is 1: 1.6: 1.25: 16 A recovery agent was obtained in the same manner as in Example 1, except that the mixture was obtained by mixing at a temperature of 1000 ° C. Further, the composition of the recovery agent, the soluble phosphoric acid, the nitrogen content, and the potassium content in the recovered recovery agent were also identified and evaluated in the same manner as in Example 1. The results are shown in Table 1.

Example 9
Dolomite ((CaMg (CO ₃ ) ₂ ) is used in place of magnesium hydroxide, rice husk and potassium hydroxide are used in place of the potassium silicate solution, and these raw materials and distilled water are mixed at 1: 1.6: 1. A mixture was obtained by mixing at a weight ratio of 25:16, and a recovery agent was obtained in the same manner as in Example 1 except that the firing temperature was 800 ° C. Further, the composition of the recovery agent and the recovery after the treatment The soluble phosphoric acid, nitrogen content and potassium content in the agent were also identified and evaluated in the same manner as in Example 1. The results are shown in Table 1.

(Example 10)
Dolomite ((CaMg (CO ₃ ) ₂ ) is used instead of magnesium hydroxide, steel slag and potassium hydroxide are used instead of potassium silicate solution, and these raw materials and distilled water are used at 1: 1.6: A mixture was obtained by mixing at a weight ratio of 1.25: 16, and a recovery agent was obtained in the same manner as in Example 1 except that the firing temperature was 1000 ° C. Further, the composition of the recovery agent and the post-treatment The soluble phosphoric acid, nitrogen content and potassium content in the recovery agent were also identified and evaluated in the same manner as in Example 1. The results are shown in Table 1.

(Comparative Example 1)
Dolomite ((CaMg (CO ₃ ) ₂ ) was used instead of magnesium hydroxide, and these were mixed at a weight ratio of 1: 0.05: 0.5 to obtain a mixture, except that the firing temperature was set to 550 ° C. Produced a recovery agent in the same manner as in Example 1. In addition, a drainage simulation liquid was prepared in the same manner as in Example 1, and water purification treatment was performed under the same conditions. The soluble phosphonic acid, nitrogen content and potassium content in the later recovery agent were also identified and evaluated in the same manner as in Example 1. The results are shown in Table 1.

(Comparative Example 2)
Example except that dolomite ((CaMg (CO ₃ ) ₂ ) was used instead of magnesium hydroxide and these were mixed at a weight ratio of 1: 10: 100 to obtain a mixture and the firing temperature was 550 ° C. A recovery agent was produced in the same manner as in Example 1. In addition, a simulated drainage solution was prepared in the same manner as in Example 1, and water purification treatment was performed under the same conditions as that of the recovery agent. The soluble phosphate, nitrogen content and potassium content were identified and evaluated in the same manner as in Example 1. The results are shown in Table 1.

  As is clear from Table 1, the recovery agent obtained in the examples is a fertilizer because the total of the soluble phosphonic acid, the total amount of nitrogen and the total amount of potassium is 10 wt% or more, and each concentration is 1% or more. Satisfies the chemical fertilizer standards of the Control Law. Therefore, it turns out that these collection | recovery agents can be used as a chemical fertilizer as it is.

On the other hand, in Comparative Example 1, since the amount of potassium oxide (K ₂ O) as a recovery agent was too low, potassium could not be detected after recovering ammonia nitrogen and phosphorus. In Comparative Example 2, since the ratio of silica (SiO ₂ ) and potassium oxide (K ₂ O) is too high, the amounts of magnesium compound and calcium compound are relatively reduced, so ammoniacal nitrogen and phosphorus cannot be recovered, and the solubility is high. The total amount of phosphoric acid and nitrogen could not be detected.

  As mentioned above, although several embodiment of this invention was described, these embodiment was posted as an example and is not intending limiting the range of invention. These novel embodiments can be implemented in various other forms, and various omissions, replacements, and changes can be made without departing from the scope of the invention. These embodiments and modifications thereof are included in the scope and gist of the invention, and are included in the invention described in the claims and the equivalents thereof.

Claims (13)

A recovery agent for recovering ammonia nitrogen and phosphorus from waste water containing at least ammonia nitrogen and phosphorus,
General formula (MO _α (MCO ₃ ) _β ) · γSiO ₂ · δK ₂ O
(0 ≦ α ≦ 1, 0 ≦ β ≦ 1, α + β = 1, 0.1 ≦ γ ≦ 20, 0 <δ ≦ 10, M: at least one of magnesium and calcium)
A recovery agent for ammoniacal nitrogen and phosphorus, comprising a composition represented by:   The ammonia nitrogen and phosphorus recovery agent according to claim 1, wherein the recovery agent is porous particles. The porosity of the recovery agent is 30% or more and 80% or less,
The pore diameter of the recovery agent is 0.1 μm or more and 500 μm or less,
The ammonia nitrogen and phosphorus recovery agent according to claim 2, wherein a specific surface area of the recovery agent is 0.1 m ² / g or more and 500 m ² / g or less. Mixing at least one of a magnesium source and a calcium source, a silicon source and a potassium source to obtain a mixture;
Firing the mixture;
A method for producing a recovery agent for ammoniacal nitrogen and phosphorus, comprising: Mixing a magnesium-calcium source, a silicon source and a potassium source to obtain a mixture;
Firing the mixture;
A method for producing a recovery agent for ammoniacal nitrogen and phosphorus, comprising: Mixing a magnesium-calcium source and a silicon-potassium source to obtain a mixture;
Firing the mixture;
A method for producing a recovery agent for ammoniacal nitrogen and phosphorus, comprising: Mixing at least one of a magnesium source and a calcium source and a silicon-potassium source to obtain a mixture;
Firing the mixture;
A method for producing a recovery agent for ammoniacal nitrogen and phosphorus, comprising:   The method for producing an ammonia nitrogen and phosphorus recovery agent according to claim 4 or 7, wherein the magnesium source is at least one selected from the group consisting of magnesium hydroxide, magnesium oxide and magnesium carbonate.   The method for producing an ammonia nitrogen and phosphorus recovery agent according to claim 4 or 7, wherein the calcium source is at least one selected from the group consisting of calcium hydroxide, calcium oxide and calcium carbonate.   6. The ammoniacal material according to claim 4, wherein the silicon source is at least one selected from the group consisting of quartz sand, diatomaceous earth, waste glass, fly ash, rice husk, rice husk ash, and steel slag. A method for producing a nitrogen and phosphorus recovery agent.   The method for producing an ammonia nitrogen and phosphorus recovery agent according to claim 4 or 5, wherein the potassium source is at least one of potassium hydroxide and potassium carbonate.   The method for producing an ammonia nitrogen and phosphorus recovery agent according to claim 5 or 6, wherein the magnesium-calcium source is at least one of dolomite and semi-burned dolomite.   The method for producing an ammonia nitrogen and phosphorus recovery agent according to claim 6 or 7, wherein the silicon-potassium source is potassium silicate.