JP5878278B2 - Boron removal water treatment agent and water treatment method - Google Patents

Description

  The present invention relates to a water treatment agent and a water treatment method. More specifically, a water treatment agent that can easily and efficiently remove harmful substances from harmful substance-containing water, and water that can efficiently remove harmful substances with a small amount of drug by simple equipment and operation. It relates to the processing method.

  Industrial wastewater generated from various product manufacturing processes, combustion gas smoke cleaning processes, and contaminated soil purification processes include selenium, copper, chromium, molybdenum, antimony, lead, arsenic, zinc, cadmium, nickel, manganese, Various harmful substances such as heavy metals such as iron, tin and cobalt, and boron, fluorine and phosphorus may be contained. Since these harmful substances may adversely affect animals and plants, it is required by law that the wastewater is discharged into public waters such as rivers, lakes and marshes after removing these harmful substances.

  Known methods for removing harmful substances include alkali precipitation, coprecipitation, ion exchange, and biological treatment. However, the alkali precipitation method is effective for alkali-forming precipitates, but is not effective for alkaline and non-precipitation substances such as fluorine and boron. There is a problem that it is necessary to add the chemicals and increase the amount of the chemicals used and the amount of sludge generated. Similarly, the coprecipitation method has harmful substances that do not have a removal effect depending on the type of coprecipitation agent, and it is necessary to add a large amount of chemicals. There is a problem that secondary contamination is also a concern due to the addition of a coprecipitation agent. The ion exchange method saturates immediately when the concentration of harmful substances is high, so that there is a problem that efficiency is low and cost is high. Biological treatment is susceptible to the effects of coexisting substances, and it is necessary to maintain growth conditions suitable for the treatment.

Among harmful substances, boron is concerned about plant growth inhibition, animal reproductive inhibition toxicity, and nervous / digestive system disorders due to excessive intake. In 2001, the Water Pollution Control Law Enforcement Order was partially revised, The drainage standard for boron and its compounds in public water areas other than sea areas such as rivers and lakes was set at 10 mg / L or less.
Boron is used in various industrial applications such as materials such as dyes, raw materials such as dyes, components of alloys and semiconductor materials, and electroplating in the glass industry, and wastewater generated from these manufacturing processes contains boron. In addition, boron is often contained in wastewater generated from power plants, smoke washing wastewater in garbage incineration sites, landfill disposal site leachate wastewater, and the like. Boron may also be contained in wastewater from the inn business that runs hot springs. Thus, boron is contained in various wastewaters.

  Known boron treatment techniques include a coagulation precipitation method, an ion adsorption method, a solvent extraction method, an evaporation concentration method, and a reverse osmosis membrane method, but each has its own problems. In the coagulation sedimentation method, it is necessary to use a large amount of chemical in order to sufficiently remove boron, and there is a problem in that the amount of chemical used is increased and the amount of sludge generated is increased. Further, when chloride ions coexist in the treated water, there is a problem that the removal rate is lowered. In the ion adsorption method, in order to treat water containing a relatively high concentration of boron, the load on the chelate resin used is inefficient, and not only the cost of the chelate resin itself but also the regeneration treatment. There is a problem of cost. In the solvent extraction method, since the organic solvent as an extractant is dissolved in the treated water from which boron has been removed, it is necessary to remove the organic solvent, and there is a problem in that the cost is increased due to the loss of chemicals. The evaporation and concentration method requires a heat source for evaporation, enormous energy is required to crystallize the boron compound, and the reverse osmosis membrane method has a low boron removal rate and has a problem of membrane clogging.

  In order to solve these problems, a method of treating boron-containing water by combining an aggregation precipitation method using an aluminum compound and a calcium compound and an ion adsorption method using an anion exchange resin has been proposed (Patent Document 1). 2). However, even in this method, it is necessary to add a large amount of chemicals, the amount of generated sludge is large, and the treatment is difficult. Also, a method of treating boron-containing water by combining the evaporation concentration method and the coagulation precipitation method (Patent Document 3), or a method of treating the boron-containing water by combining the evaporation concentration method, the aggregation precipitation method and the ion adsorption method (Patent Document 3). 4) has also been proposed. However, even with these methods, there is a problem that a large amount of heat is required for evaporation, the apparatus becomes large-scale, the processing steps become complicated, and the cost increases. In addition, a harmful substance immobilization material that removes fluorine in waste liquid and phosphate ions in sludge has been proposed (Patent Document 5). unknown. Moreover, although the wastewater treatment method which adjusts pH by adding an aluminum salt, a hardly soluble calcium salt, and slaked lime to the wastewater containing boron is proposed (patent document 6), the calcium aluminate hydration produced | generated in water is proposed. There is a problem that a sufficient boron removing power cannot be obtained with a combination of a product and a sparingly soluble calcium salt.

JP-A-57-81881 JP-A-57-180493 JP 7-323292 A Japanese Patent Laid-Open No. 10-314798 JP 2000-93927 A JP 2004-283731 A

  An object of the present invention is to solve the conventional problems and achieve the following objects. That is, the present invention can remove harmful substances efficiently with a small amount of chemicals by a water treatment agent capable of easily and efficiently removing harmful substances from water containing harmful substances, and a simple apparatus and operation. An object is to provide a water treatment method.

  As a result of intensive studies to achieve the above object, the present inventors obtained (A) calcium sulfoaluminate hydrate and / or calcium sulfoaluminate hydrate by heat treatment. By using a water treatment agent containing at least one of a substance, and (B) calcium aluminate and / or a mixture of a substance obtained by heat-treating calcium aluminate and a sulfate, The inventors have found that harmful substances can be efficiently removed from water containing harmful substances, and have completed the present invention. The present invention also provides a water treatment method using the above water treatment agent.

The present invention is based on the above findings by the present inventors, and means for solving the above problems are as follows. That is,
<1> A water treatment agent containing at least one of the following (A) and (B).
(A) Calcium sulfoaluminate hydrate and / or substance obtained by heat-treating calcium sulfoaluminate hydrate (B) Obtained by heat-treating calcium aluminate and / or calcium aluminate A mixture of a substance obtained and a sulfate <2> (A) Calcium sulfoaluminate hydrate and / or a water treatment agent containing a substance obtained by heat-treating calcium sulfoaluminate hydrate The water treatment agent according to <1>, further comprising (C) calcium aluminate and / or a substance obtained by heat treating calcium aluminate.
<3> The water treatment agent according to any one of <1> to <2>, further comprising (D) a carbonate.
<4> The water treatment agent according to any one of <1> to <3>, further comprising (E) an aluminum compound.
<5> Contains a substance obtained by heat-treating a water-insoluble substance recovered after water treatment using the water treatment agent according to any one of <1> to <4>. It is the water treatment agent characterized by this.
<6> A water treatment method using the water treatment agent according to any one of <1> to <5>.

  According to the present invention, a water treatment agent capable of solving the conventional problems and achieving the object and easily and efficiently removing harmful substances from harmful substance-containing water, and a simple apparatus By the operation, it is possible to provide a water treatment method capable of efficiently removing harmful substances with a small amount of drug.

FIG. 1 is a view showing a method for evaluating the cohesiveness (sedimentability) of a water treatment agent (a: height of gas-liquid interface (mm), b: height of solid-liquid interface (mm)). . FIG. 2 is a diagram showing how the water treatment agents of Example 7 and Example 24 were actually evaluated for cohesiveness (precipitation) after water treatment (left: Example 7, right: implemented). Example 24). FIG. 3 is an X-ray diffraction chart of ettringite. FIG. 4 is an X-ray diffraction chart of calcium aluminate. FIG. 5 is an X-ray diffraction chart of a coexisting body of ettringite and calcium aluminate.

(Water treatment agent)
The water treatment agent of the present invention comprises (A) calcium sulfoaluminate hydrate and / or a substance obtained by heat-treating calcium sulfoaluminate hydrate, and (B) calcium aluminate and / or Or it contains at least any one of the mixture of the substance obtained by heat-processing calcium aluminate, and a sulfate, It is characterized by the above-mentioned. The water treatment agent preferably further comprises (C) calcium aluminate and / or a substance obtained by heat treating calcium aluminate, (D) carbonate, and (E) aluminum compound, It contains at least one of the above, and further contains other components as necessary.
In addition, “(A) Calcium sulfoaluminate hydrate and / or substance obtained by heat-treating calcium sulfoaluminate hydrate”, “(B) Calcium aluminate and / or calcium aluminum” A mixture of a substance obtained by heat-treating an nate and a sulfate ", the above-mentioned" (C) calcium aluminate and / or a substance obtained by heat-treating calcium aluminate ", the above" (D In the present specification, “(carbonate)” and “(E) aluminum compound” are simply “(A) component”, “(B) component”, “(C) component”, “(D)”, respectively. “Component” and “(E) component”.

<(A) component>
The component (A) is calcium sulfoaluminate hydrate and / or a substance obtained by heat-treating calcium sulfoaluminate hydrate (in this specification, simply referred to as “calcium sulfoaluminate hydrate”). It may be referred to as a “material heat-treated product”.

-Calcium sulfoaluminate hydrate-
There is no restriction | limiting in particular as said calcium sulfoaluminate hydrate, For example, there exist a trisulfate type and a monosulfate type, It is preferable to use the trisulfate type calcium sulfoaluminate hydrate among these. Examples of the trisulfate-type calcium sulfoaluminate hydrate include ettringite. Moreover, as the calcium sulfoaluminate hydrate, one obtained by synthesis may be used, or one existing in nature may be used.

--Synthesis of calcium sulfoaluminate hydrate--
The calcium sulfoaluminate hydrate can be obtained, for example, by synthesis, and the synthesis is not particularly limited and can be performed by a known method. For example, it can be synthesized by mixing a calcium compound, an aluminum compound, and a sulfuric acid compound in water. Alternatively, the calcium compound, the aluminum compound, and the sulfuric acid compound can be mixed, baked and hydrated (solid phase method). You can also There is no restriction | limiting in particular also as an apparatus used for the said baking process, For example, it can carry out using a well-known hot air dryer, an electric furnace, a thermostat, a fluidized bed dryer, a vacuum dryer, a spray dryer, a rotary kiln etc.
The calcium compound at this time is not particularly limited as long as it contains calcium, and examples thereof include calcium hydroxide, calcium nitrate, calcium sulfate, calcium oxide, calcium carbonate, calcium chloride, and hydrates thereof. These can be used alone or in combination of two or more. The aluminum compound is not particularly limited as long as it contains aluminum. For example, aluminum sulfate, aluminum nitrate, aluminum hydroxide, aluminum oxide, aluminum chloride, polyaluminum chloride (PAC), aluminum carbonate, sodium aluminate, aluminum Examples thereof include potassium acid and the like and hydrates thereof, and these can be used alone or in combination of two or more. The sulfuric acid compound is not particularly limited as long as it contains sulfuric acid, and examples thereof include aluminum sulfate, sodium sulfate, calcium sulfate, potassium sulfate, aluminum potassium potassium, magnesium sulfate, sulfuric acid, and hydrates thereof. These can be used singly or in appropriate combination of two or more. Further, these raw materials can be used not only as pure products but also as containing impurities such as aluminum sludge.

--PH of calcium sulfoaluminate hydrate and stirring aging--
In the synthesis reaction of the calcium sulfoaluminate hydrate, the pH is preferably 9 or more, and more preferably 11 or more. When pH adjustment is necessary, a general pH adjuster can be used. The pH adjuster is not particularly limited, and examples thereof include acids such as carbon dioxide, sulfuric acid, hydrochloric acid, and nitric acid, sodium hydroxide, potassium hydroxide, calcium hydroxide, aluminum hydroxide, sodium carbonate, potassium carbonate, and sodium bicarbonate. In addition, alkali agents such as potassium bicarbonate and ammonia can be used singly or in appropriate combination of two or more.
In the synthesis reaction of the calcium sulfoaluminate hydrate, stirring may or may not be carried out after pH adjustment. Stirring may be performed at room temperature or while heating. Moreover, after stirring, it may or may not be aged.

-Calcium sulfoaluminate hydrate heat treatment-
The calcium sulfoaluminate hydrate heat-treated product can be obtained by heat-treating the calcium sulfoaluminate hydrate. The heat treatment of calcium sulfoaluminate hydrate is preferably performed at a temperature of 60 ° C. or higher, more preferably 100 ° C. or higher for 10 minutes or more, and more preferably 30 minutes or more. Although there is no restriction | limiting in particular as an upper limit of the said heating temperature, 1600 degrees C or less is preferable. The upper limit of the heating time is not particularly limited, but is preferably within 24 hours.
In this heat treatment, the weight of the calcium sulfoaluminate hydrate is reduced due to dehydration of hydrated water. For example, by the heat treatment, the weight reduction rate is preferably 15% or more, more preferably 20% or more, and further preferably 30% or more. The weight reduction rate is the ratio (%) of the weight reduction after the heat treatment relative to the initial weight of calcium sulfoaluminate hydrate.
The heat treatment may be performed under an atmospheric pressure environment or may be performed while reducing the pressure. Moreover, after drying the synthesized calcium sulfoaluminate hydrate, the heat treatment may be performed, or the heat treatment may be performed without drying. Moreover, when synthesizing calcium sulfoaluminate hydrate by the solid phase method as described above, a mixture and calcined product can be used as the heat-treated calcium sulfoaluminate hydrate. There is no restriction | limiting in particular as an apparatus used for the said heat processing, For example, it can carry out using a well-known hot air dryer, an electric furnace, a thermostat, a fluidized bed dryer, a vacuum dryer, a spray dryer, a rotary kiln etc.

-Calcium sulfoaluminate hydrate / heat-treated product-
Any of the calcium sulfoaluminate hydrate and the calcium sulfoaluminate hydrate heat-treated product may be used alone as the component (A), or both of them may be used together as the component (A ) Component may be used. When both are used in combination, the amount ratio of the calcium sulfoaluminate hydrate to the heat-treated calcium sulfoaluminate hydrate is not particularly limited and may be appropriately selected depending on the purpose. .
In the calcium sulfoaluminate hydrate and the calcium sulfoaluminate hydrate heat-treated product, the calcium sulfoaluminate hydrate heat-treated product has a higher ability to remove harmful substances. Therefore, from the viewpoint of improving harmful substance removing power, it is preferable to use a large amount of the calcium sulfoaluminate hydrate heat-treated as the component (A), and the calcium sulfoaluminate hydrate heat-treated. More preferably, the product is used alone.

<(B) component>
The component (B) includes calcium aluminate and / or a substance obtained by heat-treating calcium aluminate (sometimes referred to simply as “calcium aluminate heat-treated product”), sulfuric acid, It is a mixture with salt.

-Calcium aluminate-
The calcium aluminate is a general term for compounds mainly composed of CaO and Al ₂ O ₃ , and is not particularly limited and can be appropriately selected depending on the purpose. For example, CaAl ₂ O ₄ , CaAl ₄ O ₇ , CaAl ₁₂ O ₁₉ , Ca ₃ Al ₂ O ₆ , Ca ₁₂ Al ₁₄ O ₃₃ , Ca ₅ Al ₆ O ₁₄ , Ca ₉ Al ₁₀ O ₂₄ , Ca ₂ Al ₂ O ₅ and the like, a mixture thereof, and a water thereof Japanese products are listed. Among these, as the calcium aluminate, Ca ₁₂ Al ₁₄ O ₃₃ , Ca ₃ Al ₂ O _6, and mixtures thereof are preferable in that the ability to remove harmful substances can be improved. The said calcium aluminate can be used individually by 1 type or in combination of 2 or more types as appropriate.
The calcium aluminate may contain impurities, but the type and content thereof are not particularly limited as long as they do not impair the effects of the present invention. As a specific example, for example, Fe ₂ Examples include O ₃ , SiO ₂ , MgO, TiO ₂ , P ₂ O ₅ , Cl, and the like. The calcium aluminate may be a crystalline compound, a non-crystalline compound, a synthetic product, or a product naturally produced. Also good. The particle diameter is not particularly limited, and is preferably 0.1 μm or more from the viewpoint of handling.

--Synthesis of calcium aluminate--
The calcium aluminate can be obtained, for example, by synthesis, and the synthesis is not particularly limited and can be performed by a known method. For example, it can be synthesized by mixing a calcium compound and an aluminum compound in water, and can be synthesized by mixing an aluminum compound and a calcium compound and firing at a high temperature of 1000 ° C. or higher, preferably 1300 ° C. or higher. (Solid phase method). There is no restriction | limiting in particular also as an apparatus used for the said baking process, For example, it can carry out using a well-known hot air dryer, an electric furnace, a thermostat, a fluidized bed dryer, a vacuum dryer, a spray dryer, a rotary kiln etc. The calcium compound at this time is not particularly limited as long as it contains calcium, and examples thereof include calcium hydroxide, calcium nitrate, calcium oxide, calcium carbonate, calcium chloride, and hydrates thereof. Can be used singly or in appropriate combination of two or more. The aluminum compound is not particularly limited as long as it contains aluminum. For example, aluminum nitrate, aluminum hydroxide, aluminum oxide, aluminum chloride, polyaluminum chloride (PAC), aluminum carbonate, sodium aluminate, potassium aluminate, etc. And hydrates of these, and the like can be used singly or in appropriate combination of two or more. Further, these raw materials can be used not only as pure products but also as containing impurities such as aluminum sludge.

-Calcium aluminate synthesis reaction pH and stirring aging-
In the synthesis reaction of calcium aluminate, the pH is preferably 9 or more. When pH adjustment is necessary, a general pH adjuster can be used. The pH adjuster is not particularly limited, and examples thereof include acids such as carbon dioxide, hydrochloric acid and nitric acid, sodium hydroxide, potassium hydroxide, calcium hydroxide, aluminum hydroxide, sodium carbonate, potassium carbonate, sodium bicarbonate, Alkaline agents such as potassium carbonate and ammonia can be used singly or in appropriate combination of two or more.
In the calcium aluminate synthesis reaction, stirring may or may not be performed after pH adjustment. Stirring may be performed at room temperature or while heating. Moreover, after stirring, it may or may not be aged.

-Calcium aluminate heat treatment-
The calcium aluminate heat-treated product can be obtained by heat-treating the calcium aluminate. The heat treatment of calcium aluminate is preferably performed at a temperature of 60 ° C. or higher, more preferably 100 ° C. or higher for 10 minutes or longer, and more preferably for 30 minutes or longer. Although there is no restriction | limiting in particular as an upper limit of the said heating temperature, 1600 degrees C or less is preferable. The upper limit of the heating time is not particularly limited, but is preferably within 24 hours.
The heat treatment may be performed under an atmospheric pressure environment or may be performed while reducing the pressure. Moreover, after drying the synthesized calcium aluminate, the heat treatment may be performed, or the heat treatment may be performed without drying. There is no restriction | limiting in particular as an apparatus used for the said heat processing, For example, it can carry out using a well-known hot air dryer, an electric furnace, a thermostat, a fluidized bed dryer, a vacuum dryer, a spray dryer, a rotary kiln etc.

-Sulfate-
There is no restriction | limiting in particular as said sulfate, According to the objective, it can select suitably, For example, sodium sulfate, potassium sulfate, lithium sulfate, silver sulfate, calcium sulfate, ferrous sulfate, ferric sulfate, sulfuric acid Examples include nickel, cobalt sulfate, magnesium sulfate, barium sulfate, copper sulfate, manganese sulfate, aluminum sulfate, sodium aluminum sulfate, and potassium aluminum sulfate. Further, the sulfate may be a hydrate thereof.
Among these, as the sulfate, at least one selected from calcium sulfate, sodium sulfate, and aluminum sulfate is preferable, and calcium sulfate is particularly preferable. A water treatment agent containing at least calcium sulfate as the sulfate salt is excellent in low sulfate ion concentration in the treated water in addition to the ability to remove harmful substances. This is advantageous in that it can be removed and secondary contamination by sulfate ions can be reduced. Examples of the calcium sulfate include calcium sulfate (anhydrous), calcium sulfate dihydrate, calcium sulfate 0.5 hydrate, and the like. Anhydrous)> Calcium sulfate dihydrate ≒ Calcium sulfate 0.5 hemihydrate. Further, when calcium sulfate is used as the sulfate, it is advantageous to use sodium sulfate or aluminum sulfate having high water solubility in that the ability to remove harmful substances can be improved. The said sulfate can be used individually by 1 type or in combination of 2 or more types.

  The sulfate may be used as it is, or may be used in a state dissolved or dispersed in water. In addition, the sulfate can be produced, for example, by mixing sulfuric acid and a corresponding hydroxide in water (for example, calcium sulfate can be produced with sulfuric acid and calcium hydroxide, and sulfuric acid and water can be produced. Sodium oxide can produce sodium sulfate), but it may also be used in the form of an aqueous solution containing this produced sulfate.

-Calcium aluminate and / or heat-treated product thereof / sulfate-
The calcium aluminate and / or the heat-treated product thereof and the sulfate are used in combination as the component (B). The “calcium aluminate and / or heat-treated product thereof and sulfate” is used in a state where the calcium aluminate and / or heat-treated product and the sulfate are mixed in advance. However, the calcium aluminate and / or the heat-treated product thereof and the sulfate may be used separately in water. In addition, when using the calcium aluminate and / or its heat-treated product and the sulfate separately in water, the sulfate is added first, and then the calcium aluminate and / or later. An embodiment in which the heat-treated product is added and used is advantageous in that the ability to remove harmful substances can be further improved.
There is no restriction | limiting in particular as usage-amount ratio of the said calcium aluminate and / or its heat-processed material, and the said sulfate, Although it can select suitably according to the objective, For example, a calcium aluminate is mass ratio. And / or its heat-treated product: sulfate = 20: 80 to 90:10 is preferable, 25:75 to 75:25 is more preferable, and 30:70 to 70:30 is still more preferable. It is advantageous in that the use amount ratio is within the preferable range in that the harmful substance removing power can be improved and the generation of sludge after the hazardous substance treatment can be suppressed.

<(A) component / (B) component>
The water treatment agent only needs to contain at least one of the component (A) and the component (B), that is, as a combination of the component (A) and the component (B). Examples of the following (1) to (7) are mentioned.
(1) A water treatment agent containing calcium sulfoaluminate hydrate (component (A)).
(2) A water treatment agent containing a substance (component (A)) obtained by heat-treating calcium sulfoaluminate hydrate.
(3) A water treatment agent containing calcium sulfoaluminate hydrate and a substance (component (A)) obtained by heat-treating calcium sulfoaluminate hydrate.
(4) A water treatment agent containing a mixture of calcium aluminate and / or a substance obtained by heat-treating calcium aluminate and a sulfate (component (B)).
(5) Calcium sulfoaluminate hydrate (component (A)), and a mixture of calcium aluminate and / or a substance obtained by heat-treating calcium aluminate and sulfate (component (B)) Water treatment agent containing
(6) Substance obtained by heat-treating calcium sulfoaluminate hydrate (component (A)), substance obtained by heat-treating calcium aluminate and / or calcium aluminate, and sulfate And a water treatment agent containing a mixture (component (B)).
(7) Calcium sulfoaluminate hydrate, and a substance (component (A)) obtained by heat-treating calcium sulfoaluminate hydrate, and heat-treating calcium aluminate and / or calcium aluminate A water treatment agent containing a mixture (component (B)) of a substance obtained by doing and a sulfate.

The water treatment agents according to the above aspects (1) to (7) all have a high ability to remove harmful substances, and therefore can easily and efficiently remove harmful substances from harmful substance-containing water. is there.
Among these, the water treatment agent according to the embodiments (4) to (7) containing at least the component (B) is excellent in cohesiveness (sedimentability) of the water treatment agent in addition to the ability to remove harmful substances. Therefore, it is not necessary to add an expensive flocculant or leave for a long time until aggregation (sedimentation) in order to recover the water treatment agent after the hazardous substance treatment, This is advantageous in that the water treatment agent can be easily separated. Furthermore, as a sulfate of the component (B), the water treatment agent containing at least calcium sulfate or its hydrate has a harmful substance removing ability and excellent cohesiveness (sedimentation), It also has an excellent low sulfate ion concentration, which is advantageous in that harmful substances can be efficiently removed with a small amount of drug and secondary contamination by sulfate ions can be reduced.

  In addition, like the aspect of said (5)-(7), when using together said (A) component and said (B) component, the usage-amount ratio of said (A) component and said (B) component Is not particularly limited and can be appropriately selected according to the purpose. For example, the mass ratio is preferably (A) component: (B) component = 5: 95 to 90:10, 10:90 to 80:20 is more preferable. It is advantageous that the use ratio is within the preferable range in that the cohesiveness (settlement) is improved.

<(C) component>
The component (C) is calcium aluminate and / or a substance obtained by heat-treating calcium aluminate (in the present specification, simply referred to as “calcium aluminate heat-treated product”). is there.
In the water treatment agent of the aspect (1) to (3) (the aspect containing only the component (A) among the component (A) and the component (B)), the component (C) It is preferable to contain calcium aluminate and / or a calcium aluminate heat-treated product. In addition to the component (A), the water treatment agent containing the component (C) is excellent in the low concentration of sulfate ions in the treated water in addition to the ability to remove harmful substances. This is advantageous in that it can efficiently remove harmful substances and reduce secondary contamination by sulfate ions.

-Calcium aluminate-
There is no restriction | limiting in particular as a kind of calcium aluminate as said (C) component, According to the objective, it can select suitably, For example, it is the same as that of the calcium aluminate mentioned by the item of the said (B) component. calcium aluminate _{(e.g., CaAl 2 O 4, CaAl 4} O 7, CaAl 12 O 19, Ca 3 Al 2 O 6, Ca 12 Al 14 O 33, Ca 5 Al 6 O 14, Ca 9 Al 10 O 24, Ca ₂ Al ₂ O ₅ or the like, a mixture thereof, a hydrate of these, or the like) can be preferably used. Moreover, there is no restriction | limiting in particular also as the acquisition method of the said calcium aluminate, For example, it can synthesize | combine by the method similar to the synthesis method described in the item of the said (B) component.

-Calcium aluminate heat treatment-
Further, the calcium aluminate heat-treated product as the component (C) is not particularly limited and can be appropriately selected depending on the purpose. For example, the calcium aluminate listed in the item of the component (B) It can obtain by heat-processing the said calcium aluminate similarly to a heat-processed material. There is no restriction | limiting in particular also as the heat processing method of the said calcium aluminate, For example, it can carry out by the method similar to the heat processing method of the calcium aluminate described in the item of the said (B) component.

-Calcium aluminate / heat-treated product-
Any of the calcium aluminate and the heat-treated calcium aluminate may be used alone as the component (C), or both may be used in combination as the component (C). . There is no restriction | limiting in particular as usage-amount ratio of the said calcium aluminate and the said calcium aluminate heat-processing thing when using both together, According to the objective, it can select suitably.

<(A) component / (C) component>
As described above, the component (C) is used in combination with at least the component (A). There is no restriction | limiting in particular as usage-amount ratio of the said (A) component and the said (C) component, Although it can select suitably according to the objective, For example, (A) component: (C) by mass ratio Component = 35: 65 to 95: 5 is preferable, and 45:55 to 85:15 is more preferable. When the use ratio is within the preferable range, in addition to the ability to remove harmful substances, it also excels in low sulfate ion concentration in the water after treatment, so that harmful substances can be efficiently removed with a small amount of drug. At the same time, it is advantageous in that secondary contamination by sulfate ions can be reduced.

-Coexistence of calcium sulfoaluminate hydrate and calcium aluminate-
In addition, as the component (A) and the component (C), for example, calcium sulfoaluminate hydrate which is a kind of the component (A) and calcium aluminate which is a kind of the component (C) A coexisting body (in the present specification, it may be simply referred to as “coexisting body”) may be used. Here, the coexisting body is a structure in which both peaks of calcium sulfoaluminate hydrate and calcium aluminate can be observed by wide-angle X-ray diffraction measurement. For reference, the X-ray diffraction chart of ettringite, a kind of calcium sulfoaluminate hydrate, is shown in FIG. 3, the X-ray diffraction chart of calcium aluminate in FIG. 4, and the coexisting substance of ettringite and calcium aluminate. An X-ray diffraction chart is shown in FIG. The wide-angle X-ray diffraction measurement was performed using an X-ray diffractometer (RINT2100, manufactured by Rigaku Corporation) at a light source of Cu-K-ALPHA 1/40 kV / 20 mA and a scanning speed of 4.0 ° / min.

--Synthesis of calcium sulfoaluminate hydrate and calcium aluminate ---
When preparing calcium sulfoaluminate hydrate, the coexistent can be synthesized by adding a sulfuric acid compound having a mole number less than the theoretical amount. Here, the addition amount of the sulfate compound is not particularly limited as long as the sulfate compound is added, but is preferably 20% to 80% of the theoretical amount.

-Heat treatment of coexisting body of calcium sulfoaluminate hydrate and calcium aluminate-
In addition, as the component (A) and the component (C), a substance obtained by heat-treating the coexisting body (in this specification, sometimes simply referred to as “coexisting body heat-treated product”). May be used. The heat treatment of the coexisting body is preferably performed at a temperature of 60 ° C. or higher, more preferably 100 ° C. or higher for 10 minutes or longer, and more preferably for 30 minutes or longer. Although there is no restriction | limiting in particular as an upper limit of the said heating temperature, 1600 degrees C or less is preferable. The upper limit of the heating time is not particularly limited, but is preferably within 24 hours.
The heat treatment may be performed under an atmospheric pressure environment or may be performed while reducing the pressure. Further, the heat treatment may be performed after the synthesized coexisting body is dried, or the heat treatment may be performed without drying. There is no restriction | limiting in particular also as an apparatus used for heat processing, For example, it can carry out using a well-known hot air dryer, an electric furnace, a thermostat, a fluidized bed dryer, a vacuum dryer, a spray dryer, a rotary kiln etc.

<(D) component>
The component (D) is a carbonate.
It is preferable that the water treatment agent further contains a carbonate as the component (D). The water treatment agent containing the carbonate is advantageous in that the ability to remove harmful substances can be further improved.

  There is no restriction | limiting in particular as said carbonate, According to the objective, it can select suitably, For example, calcium carbonate, potassium carbonate, sodium carbonate, sodium hydrogencarbonate, potassium hydrogencarbonate, sodium potassium carbonate, ammonium carbonate, hydrogencarbonate Examples include ammonium, magnesium carbonate, and hydrates thereof. Among these, as the carbonate, calcium carbonate, potassium carbonate, and sodium carbonate are preferable in that the ability to remove harmful substances can be further improved. The said carbonate can be used individually by 1 type or in combination of 2 or more types as appropriate.

  There is no restriction | limiting in particular as usage-amount of the said carbonate, Although it can select suitably according to the objective, For example, the total usage-amount (the said (A) component and said (A) component and said (B) component) When only any one of the said (B) component is included, 1-50 mass% is preferable with respect to the content of only that one), and 5-35 mass% is more preferable. When the amount used is within the preferable range, it is advantageous in that the ability to remove harmful substances can be further improved.

<(E) component>
The component (E) is an aluminum compound.
The water treatment agent preferably further contains an aluminum compound as the component (E). The water treatment agent containing the aluminum compound is advantageous in that the ability to remove harmful substances can be further improved.
There is no restriction | limiting in particular as said aluminum compound, According to the objective, it can select suitably, For example, aluminum hydroxide, aluminum oxide, etc. are mentioned. In addition, about the water treatment agent of the aspect of said (4)-(7) containing said (B) component, as said aluminum compound, what is contained in the sulfate in said (B) component (aluminum sulfate, sulfuric acid) Excluding aluminum sodium and potassium aluminum sulfate). The said aluminum compound can be used individually by 1 type or in combination of 2 or more types as appropriate.

  There is no restriction | limiting in particular as usage-amount of the said aluminum compound, Although it can select suitably according to the objective, For example, the total content (the said (A) component and said (A) component and said (B) component) When only any one of the said (B) component is included, 1-50 mass% is preferable with respect to the content of only that one), and 5-35 mass% is more preferable.

<Other ingredients>
The water treatment agent of the present invention is at least one of the component (A) and the component (B), preferably the component (C), the component (D), and the component (E). It may consist of only at least one of the components, or may further contain other components as appropriate.
The other components are not particularly limited and may be appropriately selected depending on the purpose within a range not impairing the effects of the present invention. For example, calcium compounds used as raw materials, pH of acids, alkalis, and the like Examples thereof include regulators and water-soluble alkaline earth metal salts.
There is no restriction | limiting in particular as usage-amount of the said other component, According to the objective, it can select suitably.

-Water-soluble alkaline earth metal salt-
Here, the water-soluble alkaline earth metal salt may be contained in the water treatment agent of any aspect, but among them, the aspects (1) to (3) (the component (A) and the above ( It is preferable to contain in the water treatment agent of the aspect which contains only the said (A) component among B) components.
The water-soluble alkaline earth metal salt is not particularly limited and may be appropriately selected depending on the intended purpose. For example, calcium chloride, calcium nitrate, calcium nitrite, calcium iodide, calcium bromide, barium bromide , Barium iodide, barium chloride, barium nitrate, barium nitrite, barium sulfide, barium hydroxide, barium acetate, strontium chloride, strontium bromide, strontium iodide, strontium hydroxide, strontium nitrate, strontium nitrite, strontium acetate, A substance that has a binding ability to sulfate ions, such as radium chloride, radium nitrate, radium hydroxide, and radium bromide, and can form a precipitate with low solubility by binding to sulfate ions can be preferably used. . The water-soluble alkaline earth metal salts can be used alone or in combination of two or more. Here, water solubility means that the solubility in 100 g of water at 20 ° C. is 1 g or more.

<Manufacturing, dosage form>
The water treatment agent of the present invention is, for example, at least one of the component (A) and the component (B), preferably the component (C), the component (D), and the component (E). It can be produced by mixing at least one of the components and, if necessary, other components. Moreover, the said water treatment agent can be used in any states, such as lump shape, a granular form, and powder form. Granular and powdery water treatment agents can be produced, for example, by pulverization. The pulverization method is not particularly limited and can be performed using a known apparatus. At least one of the component (A) and the component (B), preferably the component (C) and the component (D) ) Component, and at least one of the component (E) and, if necessary, each of the other components may be pulverized before mixing, the component (A), and the component (B). ) At least one of the components, preferably further, pulverized after mixing at least one of the component (C), the component (D), and the component (E), and other components as necessary. May be.

  The water treatment agent is at least one of the component (A) and the component (B), preferably the component (C), the component (D), and the component (E). At least one of the above, and a mixture in which other components are mixed in advance as necessary, is not limited to the one in an aspect of being added to water at one time. For example, the component (A) and the above (B) at least one of the components, preferably further, at least one of the component (C), the component (D), and the component (E) and, if necessary, other components in water. The thing of the aspect added and used separately may be sufficient.

<Application>
According to the water treatment agent of the present invention, harmful substances can be easily and efficiently removed from harmful substance-containing water. Therefore, the water treatment agent of the present invention can be suitably used for, for example, the water treatment method of the present invention described later.

(Water treatment method)
The water treatment method of the present invention is performed using the above-described water treatment agent of the present invention.

<Target water>
The water to be treated in the water treatment method of the present invention (treatment target water) is not particularly limited as long as it contains water that contains some harmful substance. For example, the manufacturing process of various products and the washing of combustion gas The industrial wastewater etc. which arise from a smoke process, the purification process of contaminated soil, etc. are mentioned. There are no particular restrictions on the hazardous substances to be treated. For example, heavy metals such as selenium, copper, chromium, molybdenum, antimony, lead, arsenic, zinc, cadmium, nickel, manganese, iron, tin, cobalt, and boron , Fluorine, phosphorus and the like. In particular, the water treatment method of the present invention is suitable for water containing boron. Boron-containing water usually contains boron in the form of orthoboric acid (H ₃ BO ₄ ), but may contain borate or other forms of boron, and as such boron-containing water, For example, waste water from the glass industry or electroplating industry can be used. Moreover, the water treatment agent of this invention can be used in the range whose pH of process target water is 2-14, and can be used even if other ions, such as a chloride ion, coexist. In addition, since the said water treatment agent is alkaline, the harmful substance containing water at the time of a process becomes weak alkalinity normally. When the harmful substance-containing water is a strongly acidic solution, sodium hydroxide or calcium hydroxide can be added to make it weakly alkaline as necessary.

<Treatment method with water treatment agent>
The water treatment method of the present invention is not particularly limited as long as the water treatment agent can be brought into contact with harmful substance-containing water. For example, after adding a predetermined amount of the water treatment agent to harmful substance-containing water to remove the harmful substance, the water treatment agent is separated by solid-liquid separation (addition method) or the water treatment agent is filled. Examples include a method (packing method) for removing harmful substances by passing water through the packed tower. In either method, it is possible to efficiently remove harmful substances. In addition, a pretreatment step such as a pH adjustment step may be provided before the harmful substance-containing water comes into contact with the water treatment agent.

-Treatment conditions for the addition method-
There is no restriction | limiting in particular in the addition amount of the water treatment agent in an addition method, According to the hazardous | toxic substance density | concentration of harmful substance containing water, it determines suitably.
There is no restriction | limiting in particular as the addition method of the water treatment agent in an addition method, For example, the method of adding to flow paths, such as piping of a water treatment facility, and a water tank.
The treatment time in the addition method is not particularly limited, and can be, for example, 10 minutes or longer, preferably 30 minutes or longer. Further, it may or may not be stirred during the treatment. When stirring, the apparatus and operation are not particularly limited, and conventionally known apparatus and operation can be used.
The solid-liquid separation after the harmful substance treatment in the addition method can be carried out using a normal apparatus by means such as decantation, filtration, and centrifugation. The water treatment agent of the present invention is excellent in cohesiveness (sedimentability) in the embodiments (4) to (7) containing at least the component (B), for example. Although solid-liquid separation can be performed, a flocculant may be further added as necessary. The flocculant to be used is not particularly limited, and conventionally known substances can be used. For example, anionic polymer flocculants, nonionic polymer flocculants, cationic polymer flocculants, amphoteric polymer flocculants, An inorganic flocculant etc. are mentioned.
By performing the solid-liquid separation, it is possible to easily recover the water treatment agent after water treatment. Can be used for material removal. Specifically, the heat-treated product obtained by performing heat treatment on a water-insoluble substance (water treatment agent) recovered after water treatment can be used again for removing harmful substances containing water. it can. The heat-treated product can be suitably reused for removing harmful substances containing water, until the saturated harmful substance adsorption amount is reached.
The heat treatment of the water-insoluble substance (water treatment agent) recovered after the water treatment is preferably performed at a temperature of 60 ° C. or higher, more preferably 100 ° C. or higher, preferably for 10 minutes or longer, and for 30 minutes or longer. More preferably. Although there is no restriction | limiting in particular as an upper limit of the said heating temperature, 1600 degrees C or less is preferable. The upper limit of the heating time is not particularly limited, but is preferably within 24 hours.
This heat treatment causes weight loss. For example, by the heat treatment, the weight reduction rate is preferably 15% or more, more preferably 20% or more, and further preferably 25% or more. The weight reduction rate is the ratio (%) of the weight reduction after the heat treatment to the dry weight of the recovered water-insoluble substance.
The heat treatment may be performed under an atmospheric pressure environment or may be performed while reducing the pressure. Further, the heat treatment may be performed after the collected substance is dried, or the heat treatment may be performed without drying. There is no restriction | limiting in particular as an apparatus used for the said heat processing, For example, it can carry out using a well-known hot air dryer, an electric furnace, a thermostat, a fluidized bed dryer, a vacuum dryer, a spray dryer, a rotary kiln etc.

-Processing conditions for filling method-
The amount of the water treatment agent packed into the packed tower in the packing method is not particularly limited, and is appropriately determined according to the size of the packed tower, the water flow rate of harmful substance-containing water, and the like.
The packed tower in the packing method is not particularly limited, and known ones can be used, and the number thereof is also not particularly limited. For example, only one packed tower can be used, or a plurality of packed towers can be used. Can be connected in series.
The inflow of the water treatment agent into the packed bed in the filling method may be an upward flow or a downward flow, and the space velocity (SV) is not particularly limited, but is, for example, ^{1 to} 120 hr ⁻¹ , preferably 5 to 50 hr ^−1. It can be.
In addition, the water treatment agent recovered from the packed tower can be used again for removing harmful substances in water containing harmful substances after appropriate treatment.

<Application>
According to the water treatment method of the present invention, harmful substances can be efficiently removed with a small amount of chemical (amount of water treatment agent) with a simple apparatus and operation. Therefore, the water treatment method of the present invention can be suitably used for removing harmful substances in various industrial wastewaters, for example.

  EXAMPLES Hereinafter, although an Example and a comparative example are given and this invention is demonstrated in detail, this invention is not limited to these Examples at all.

[Examples 1 to 62, Comparative Examples 1 to 12]
Each water treatment agent of Examples 1-62 and Comparative Examples 1-12 was manufactured by mixing each component shown to the following Tables 1-13. Examples 1-6, 13-16, 24-37, 40-42, and 46-56 are reference examples. In addition, in Tables 1-13, "addition density | concentration" shows the density | concentration (mass%) of each component with respect to process target water. In Tables 1 to 13, “A-1” to “A-5”, “B-1” to “B-7”, “b-1” to “b-6”, “C-1” to Details of each component of “C-7”, “D-1” to “D-3”, and “E-1” to “E-2” are as shown in Table 14.

(1) Evaluation of harmful substance removal power About the obtained water treatment agents of Examples 1 to 62 and Comparative Examples 1 to 12, harmful substance-containing water (treatment target water) was treated under the conditions shown in Tables 1 to 13 below. The harmful substance removal power was evaluated by calculating the harmful substance removal rate. Specifically, to a 75 mL commercial mayonnaise bottle, 50.0 g of harmful substance-containing water (treatment target water) and a predetermined amount of water treatment agent were added, stirred vigorously for a predetermined time, and then allowed to stand for 10 minutes. . After the treatment liquid is filtered and diluted with pure water as necessary, an ICP emission analyzer (manufactured by PerkinElmer Japan, optima5300DV) or an ion electrode (manufactured by Thermoelectron, Orion 370) is used. Hazardous substance concentration was measured. The concentration of harmful substances was measured with respect to boron, phosphoric acid, cadmium, chromium, manganese, cobalt, nickel, zinc, copper, iron, and lead using the ICP emission spectrometer. Fluorine was measured using the ion electrode. The harmful substance removal rate was calculated by the following formula (1). The harmful substance removal rate closer to 100% indicates higher harmful substance removal power. In the present invention, 50% or more is regarded as an acceptable level of the harmful substance removal rate. The results are shown in Tables 1-13.
[formula]
Hazardous substance removal rate (%) = (1−C ₁ / C ₀ ) × 100 Formula (1)
C ₁ : Hazardous substance concentration after treatment (mg / L)
C ₀ : Initial hazardous substance concentration (mg / L) before treatment

(2) Evaluation of degree of secondary contamination (low sulfate ion concentration in treated water) For the water treatment agents of Examples 1 to 62 and Comparative Examples 1 to 12, water was used in the same manner as in (1) above. After performing the treatment, filtering the treatment liquid and diluting with pure water as necessary, using an ICP emission analyzer (manufactured by PerkinElmer Japan Co., Ltd., optima5300DV), the sulfate ion concentration in the treated water is measured. did. The results are shown in Tables 1-13. In addition, “ND” in the table indicates that it is less than the detection lower limit value.

(3) Evaluation of cohesiveness (sedimentability) Moreover, about the water treatment agent of Examples 1-62 and Comparative Examples 1-12, the cohesiveness (sedimentability) after removal of harmful substances was evaluated as follows. . To a 75 mL commercial mayonnaise bottle, 50.0 g of harmful substance-containing water (treatment target water) and a predetermined amount of water treatment agent were added, and after vigorous stirring for a predetermined time, the mixture was allowed to stand. After 10 minutes, the height of the gas-liquid interface and the height of the solid-liquid interface were measured, and the aggregation rate (sedimentation rate) was calculated by the following formula (2) (see FIG. 1). In addition, the aggregation rate is closer to 100%, indicating that the aggregation property is better. However, when the aggregation rate is 100%, the water treatment agent is dissolved in the water to be treated, and the aggregation property is excellent. It is not an index of this (Comparative Examples 8, 9, and 11). The results are shown in Tables 1-13.
[formula]
Aggregation rate (%) = (1−b / a) × 100 (2)
a: Height of gas-liquid interface (mm)
b: Height of solid-liquid interface (mm)

  In Table 14, the synthesis method of each “synthetic product” is as follows.

<Synthesis Method of A-1>
6.3 g of aluminum sulfate and 8.9 g of calcium hydroxide were mixed in 1 L of water, and the pH was adjusted to 12 with sodium hydroxide, followed by stirring at room temperature for 1 hour and aging for 24 hours. After completion of the reaction, the precipitate was filtered and dried under reduced pressure at room temperature to obtain an insoluble solid. This solid was analyzed by wide-angle X-ray diffraction measurement and confirmed to be ettringite. 15.0 g of this ettringite was heat-treated at 500 ° C. for 5 hours using a high-temperature electric furnace (manufactured by Yamato Kagaku Co., Ltd., FP41) to obtain 8.6 g of A-1. The weight reduction rate due to the heat treatment was 42.4%.

<Synthesis Method of A-2>
6.3 g of aluminum sulfate and 8.9 g of calcium hydroxide were mixed in 1 L of water, and the pH was adjusted to 12 with sodium hydroxide, followed by stirring at room temperature for 1 hour and aging for 24 hours. After completion of the reaction, the precipitate was filtered and dried under reduced pressure at room temperature to obtain an insoluble solid. This solid was analyzed by wide-angle X-ray diffraction measurement and confirmed to be ettringite. 15.0 g of this ettringite was heat-treated at 200 ° C. for 5 hours using a high-temperature electric furnace (manufactured by Yamato Scientific Co., Ltd., FP41) to obtain 10.0 g of A-2. The weight reduction rate due to the heat treatment was 33.2%.

<Synthesis Method of A-3>
6.3 g of aluminum sulfate and 8.9 g of calcium hydroxide were mixed in 1 L of water, and the pH was adjusted to 12 with sodium hydroxide, followed by stirring at room temperature for 1 hour and aging for 24 hours. After completion of the reaction, the precipitate was filtered and dried under reduced pressure at room temperature to obtain an insoluble solid. This solid was analyzed by wide-angle X-ray diffraction measurement and confirmed to be ettringite. 15.0 g of this ettringite was heat-treated at 150 ° C. for 5 hours using a high-temperature electric furnace (FP41, manufactured by Yamato Kagaku Co., Ltd.) to obtain 10.8 g of A-3. The weight reduction rate due to the heat treatment was 28.0%.

<Synthesis Method of A-4>
6.3 g of aluminum sulfate and 8.9 g of calcium hydroxide were mixed in 1 L of water, and the pH was adjusted to 12 with sodium hydroxide, followed by stirring at room temperature for 1 hour and aging for 24 hours. After completion of the reaction, the precipitate was filtered and dried under reduced pressure at room temperature to obtain an insoluble solid. This solid was analyzed by wide-angle X-ray diffraction measurement and confirmed to be ettringite. 15.0 g of this ettringite was heat-treated at 100 ° C. for 5 hours using a high-temperature electric furnace (manufactured by Yamato Scientific Co., Ltd., FP41) to obtain 12.2 g of A-4. The weight reduction rate due to the heat treatment was 18.6%.

<Synthesis Method of A-5>
6.3 g of aluminum sulfate and 8.9 g of calcium hydroxide were mixed in 1 L of water, and the pH was adjusted to 12 with sodium hydroxide, followed by stirring at room temperature for 1 hour and aging for 24 hours. After completion of the reaction, the precipitate was filtered and dried under reduced pressure at room temperature to obtain an insoluble solid (A-5). This solid A-5 was analyzed by wide-angle X-ray diffraction measurement and confirmed to be ettringite.

<Method for synthesizing B-1 (= C-1) and B-6 (= C-6)>
41.2 g of aluminum hydroxide and 58.8 g of calcium hydroxide were mixed in 1 L of water, stirred at 100 ° C. for 12 hours, and aged for 24 hours to be reacted. After completion of the reaction, the precipitate was filtered and dried at room temperature to obtain 81.7 g of an insoluble solid (B-6). This solid B-6 was calcined at 500 ° C. for 3 hours to obtain 59.5 g of a solid (B-1). Each product was analyzed by wide-angle X-ray diffractometry, solid B-6 is _{Ca 3 Al 2 O 6 · 6H} 2 O, the solid B-1 was identified as _Ca 12 _Al 14 _{O 33.}

<Synthesis Method of B-2 (= C-2)>
4.1 g of aluminum hydroxide and 5.9 g of calcium hydroxide were mixed, put in a crucible, heated at 1400 ° C. for 7 hours using a baking furnace (manufactured by Motoyama Co., Ltd., SUPER BURN), and solid (B- 7.0 g of 2) was obtained. This solid B-2 was analyzed by wide-angle X-ray diffraction measurement and confirmed to be Ca ₃ Al ₂ O ₆ .

<Method for synthesizing B-3 (= C-3)>
4.1 g of aluminum hydroxide and 5.9 g of calcium hydroxide were mixed, put in a crucible, heated at 1380 ° C. for 5 hours using a baking furnace (manufactured by Motoyama Co., Ltd., SUPER BURN), and solid (B− 7.1 g of 3) was obtained. This solid B-3 was analyzed by wide-angle X-ray diffraction measurement and confirmed to be a mixture of Ca ₃ Al ₂ O ₆ / Ca ₁₂ Al ₁₄ O ₃₃ .

<Method for synthesizing B-5 (= C-5) and B-7 (= C-7)>
14.1 g of aluminum nitrate nonahydrate and 26.6 g of calcium nitrate tetrahydrate were mixed in 1 L of water, the pH was adjusted to 12 with sodium hydroxide, and the mixture was stirred at room temperature for 1 hour. Reacted. After completion of the reaction, the precipitate was filtered and dried at room temperature to obtain 10.9 g of an insoluble solid (B-5). This solid B-5 was analyzed by wide-angle X-ray diffraction measurement, and confirmed to be Ca ₂ Al ₂ O _5. 6H ₂ O. This solid B-5 was calcined at 500 ° C. for 3 hours to obtain 7.8 g of a solid (B-7).

From the results of Tables 1 to 13, (A) calcium sulfoaluminate hydrate and / or substance obtained by heat-treating calcium sulfoaluminate hydrate, and (B) calcium aluminate and / or Alternatively, all of the water treatment agents of Examples 1 to 62 containing at least one of a substance obtained by heat-treating calcium aluminate and a sulfate salt have a high harmful substance removal rate and a small drug It was found that harmful substances can be efficiently removed by volume.
Among these, the water treatment agents of Examples 7 to 23 containing (B) calcium aluminate and / or a mixture of a material obtained by heat treating calcium aluminate and a sulfate have a harmful substance removal rate. In addition to being high, the agglomeration rate is also high, so these water treatment agents can efficiently remove harmful substances with a small amount of chemicals, and add expensive flocculants to recover the water treatment agent after treatment. It has been found that it is advantageous in that it can be easily separated from the treated water and the water treatment agent after the treatment without being left to stand for a long time until aggregation (sedimentation). (The state of agglomeration of the water treatment agent of Example 7 after water treatment is shown on the left side of FIG. 2). Particularly, (B) obtained by heat treating calcium aluminate and / or calcium aluminate. A water treatment agent of Examples 7 to 12 and 17 to 23, which is a mixture of a substance and a sulfate and uses calcium sulfate or its hydrate as the sulfate, the harmful substance removal rate and the aggregation rate In addition to the high water content, the concentration of sulfate ions in the treated water is also low. Therefore, these water treatment agents can efficiently remove harmful substances with a small amount of chemicals. It was also found that it is advantageous when separating and from the secondary contamination, and secondary contamination by sulfate ions can be reduced.
(A) Calcium sulfoaluminate hydrate and / or a substance obtained by heat-treating calcium sulfoaluminate hydrate, and (C) calcium aluminate and / or calcium aluminate. The water treatment agents of Examples 24 to 34 containing substances obtained by heat treatment have a high harmful substance removal rate and also a low sulfate ion concentration in the treated water. Therefore, these water treatments It was found that the agent can efficiently remove harmful substances with a small amount of drug and can reduce secondary contamination by sulfate ions.
In addition, all of the water treatment agents of Examples 1 to 62 can be produced at a lower cost than commercially available chelate resins, and can remove harmful substances very efficiently from the viewpoint of economy. It is advantageous.

  On the other hand, (A) calcium sulfoaluminate hydrate and / or a substance obtained by heat-treating calcium sulfoaluminate hydrate, and (B) calcium aluminate and / or calcium aluminate In Comparative Examples 1 to 12, which contain neither a substance obtained by heat treatment and a mixture of sulfates, the water removal agent intended to remove harmful substances has a remarkably low harmful substance removal rate. It was impossible to use as.

[ Reference Example 63 (Coexisting body)]
14.1 g of aluminum nitrate nonahydrate, 26.6 g of calcium nitrate tetrahydrate, and 4.0 g of sodium sulfate were mixed in 1 L of water, and the pH was adjusted to 12, followed by stirring for 1 hour, 24 hours Aged and reacted. After completion of the reaction, the precipitate was filtered and dried at room temperature to obtain an insoluble solid. The solid was analyzed by wide-angle X-ray diffraction measurement and confirmed to be a co-existing body of ettringite, which is a kind of calcium sulfoaluminate hydrate, and calcium aluminate (Ca ₂ Al ₂ O _5. 6H ₂ O). . An X-ray diffraction chart of a coexisting body of ettringite and calcium aluminate is shown in FIG. The wide-angle X-ray diffraction measurement was performed using an X-ray diffractometer (RINT2100, manufactured by Rigaku Corporation) at a light source of Cu-K-ALPHA 1/40 kV / 20 mA and a scanning speed of 4.0 ° / min.
1% by mass of the solid was added to boron-containing water having an initial pH of 12 (boron concentration: 112 mg / L) and stirred for 5 hours. When water treatment was performed, the removal rate of boron, which is a harmful substance, was 55.2%. It was found that the sulfate ion concentration in the treated water was less than the lower limit of detection, and boron could be removed efficiently with a small amount of drug and with little secondary contamination. The aggregation rate at this time was 10%.

[ Reference Example 64 (coexisting heat-treated product)]
The solid obtained in Reference Example 63 was heat-treated at 500 ° C. for 5 hours, and then added to 1% by mass of boron-containing water having an initial pH of 12 (boron concentration 112 mg / L) and stirred for 5 hours, followed by water treatment. The removal rate of boron, which is a harmful substance, was 98.5%, and the sulfate ion concentration in the treated water was 6 mg / L. It was found that boron can be removed efficiently with a small amount of chemicals and with less secondary contamination. . The aggregation rate at this time was 5%.

[ Reference Example 65 (coexisting heat-treated product)]
14.1 g of aluminum nitrate nonahydrate, 26.6 g of calcium nitrate tetrahydrate, and 5.6 g of sodium sulfate were mixed in 1 L of water, and the pH was adjusted to 12, followed by stirring for 1 hour, 24 hours Aged and reacted. After completion of the reaction, the precipitate was filtered and dried at room temperature to obtain an insoluble solid. The solid was analyzed by wide-angle X-ray diffraction measurement and confirmed to be a co-existing body of ettringite, which is a kind of calcium sulfoaluminate hydrate, and calcium aluminate (Ca ₂ Al ₂ O _5. 6H ₂ O). .
The solid was heat treated at 500 ° C. for 5 hours, then added with 1% by mass of boron-containing water having an initial pH of 12 (boron concentration 112 mg / L) and stirred for 5 hours. The removal rate was 97.1%, and the sulfate ion concentration in the treated water was 19 mg / L. It was found that boron can be removed efficiently with a small amount of drug and with little secondary contamination. The aggregation rate at this time was 6%.

[Example 66 (Evaluation of order of addition)]
After adding 0.4 mass% of b-1 (calcium sulfate dihydrate) to boron-containing water (boron concentration 102 mg / L, pH 9) and stirring for 30 minutes, B-1 (Ca ₁₂ Al ₁₄ O ₃₃ ) 0.4% by weight was added. Then, it stirred for 5 hours and implemented boron treatment. The boron removal rate at this time was 87.1%, and the boron removal power was improved as compared with the case where both components were added simultaneously (Example 7). Further, the sulfate ion concentration in the treated water was 18 mg / L, there was little secondary contamination, the aggregation rate was 72%, and the cohesiveness was also good.

[Comparative Example 13 (chelate resin method)]
1% by mass of chelating resin Diaion CRB05 (manufactured by Mitsubishi Chemical Corporation) marketed for boron removal is added to boron-containing water (boron concentration 101 mg / L, pH 9) and stirred for 5 hours to perform water treatment. When carried out, the boron removal rate was 39.1%, the boron concentration was slightly reduced, and the sulfate ion concentration in the water after treatment was also below the lower detection limit, but the commercially available chelate resin was very expensive. In view of economy, boron cannot be removed efficiently. The aggregation rate at this time was 95%.

[Comparative Example 14 (chelate resin method)]
1% by mass of chelating resin Diaion CRB05 (manufactured by Mitsubishi Chemical Co., Ltd.) commercially available for boron removal is added to boron-containing water (boron concentration 106 mg / L, pH 12) and stirred for 5 hours to perform water treatment. When carried out, the boron removal rate was 38.9%, the boron concentration was somewhat reduced, and the sulfate ion concentration in the water after treatment was also below the lower detection limit, but the commercially available chelate resin was very expensive. In view of economy, boron cannot be removed efficiently. The aggregation rate at this time was 95%.

[Comparative Example 15 (aggregation precipitation method)]
When 0.5 mass% of aluminum sulfate 18 hydrate and 0.5 mass% of calcium hydroxide were added to boron-containing water (boron concentration 114 mg / L, pH 9) and stirred for 5 hours, water treatment was performed. The boron removal rate was 20.0%, and the boron concentration in water was slightly reduced, but the effect was low, and the sulfate ion concentration was 1406 mg / L, and there was a possibility of secondary contamination. Furthermore, the aggregation rate was 39%, and the aggregation property was not sufficient.

[Comparative Example 16 (when calcium sulfate is added in a system in which calcium aluminate hydrate is produced in water)]
Sodium aluminate 0.5% by mass, calcium hydroxide 0.5% by mass, calcium sulfate dihydrate 0.5% by mass were added simultaneously to boron-containing water (boron concentration 105 mg / L, pH 9). The mixture was stirred for a period of time and boron treatment was performed. The boron removal rate was 20.1%, and the boron concentration was slightly reduced, but the effect was low. Further, the sulfate ion concentration in the water after treatment was 1428 mg / L, and there was a possibility of secondary contamination. The aggregation rate at this time was 72%.

[ Reference Example 67 (Evaluation of reuse of water treatment agent by heat treatment)]
After treating the boron-containing water under the conditions shown in Reference Example 1, filtration was performed to separate water having a sufficiently reduced boron concentration and water-insoluble water treatment agent. The material collected by filtration was vacuum-dried at room temperature for 2 days and then heat-dried at 150 ° C. for 5 hours. The weight reduction rate at this time was 27.1%. 0.8% by mass of the substance obtained by this heat drying was added to boron-containing water (boron concentration 106 mg / L, pH 12) and stirred for 5 hours to carry out water treatment. The boron removal rate at this time was 76.4%, the boron concentration was reduced, and the effect was very high. The sulfate ion concentration was 656 mg / L, and the aggregation rate was 45%.

[Example 68 (Evaluation of reuse of water treatment agent by heat treatment)]
After treating boron-containing water under the conditions shown in Example 7, filtration was performed to separate water having a sufficiently low boron concentration and water-insoluble water treatment agent. The material collected by filtration was vacuum-dried at room temperature for 2 days and then heat-dried at 200 ° C. for 1 hour. The weight loss rate at this time was 25.3%. 0.8% by mass of the substance obtained by this heat drying was added to boron-containing water (boron concentration 104 mg / L, pH 12) and stirred for 5 hours to carry out water treatment. The boron removal rate at this time was 72.9%, the boron concentration was reduced, and the effect was very high. Further, the sulfate ion concentration was 29 mg / L, there was little secondary contamination, the aggregation rate was 83%, and the aggregation property was also good.

[ Reference Example 69]
1 mass% of the water treatment agent used in Reference Example 1 was added to hot spring water having an initial pH of 7.2 (boron concentration: 76 mg / L) composed of the components shown in Table 14, and the mixture was stirred for 5 hours for water treatment. The boron removal rate at this time was 95.0%, the boron concentration was reduced, and the effect was very high. The sulfate ion concentration was 1250 mg / L, and the aggregation rate was 2%.

[Example 70]
The water treatment agent used in Example 7 was added to hot spring water having an initial pH of 7.2 (boron concentration: 76 mg / L) composed of the components shown in Table 14, and the mixture was stirred for 5 hours to carry out water treatment. The boron removal rate at this time was 95.1%, the boron concentration was reduced, and the effect was very high. Further, the sulfate ion concentration was 25 mg / L, there was little secondary contamination, the aggregation rate was 70%, and the aggregation property was also good.

[ Reference Example 71]
The water treatment agent used in Reference Example 24 was added to hot spring water having an initial pH of 7.2 (boron concentration: 76 mg / L) composed of the components shown in Table 14, and the mixture was stirred for 5 hours for water treatment. The boron removal rate at this time was 96.0%, the sulfate ion concentration was 13 mg / L, and it was found that boron can be removed efficiently with a small amount of drug and with little secondary contamination. The aggregation rate was 5%.

[ Reference Example 72 (addition method)]
1% by mass of the water treatment agent used in Reference Example 1 was added to boron-containing water (boron concentration 118 mg / L, pH 12), and the mixture was stirred for 5 hours. Added and stirred for 1 hour. When left standing after stirring, the water treatment agent settles, and when the boron and sulfate ion concentration of the supernatant is measured, the boron removal rate is 85.0%, and it is efficient with a small amount of drug by simple equipment and operation. It was found that boron can be removed. Further, the sulfate ion concentration in the water after treatment was 1204 mg / L.

[ Reference Example 73 (addition method)]
1% by mass of the water treatment agent used in Reference Example 24 was added to boron-containing water (boron concentration 116 mg / L, pH 10), and the mixture was stirred for 5 hours to carry out water treatment, and then an anionic polymer flocculant was added. Added and stirred for 1 hour. When left standing after stirring, the water treatment agent settles, and the boron and sulfate ion concentrations of the supernatant are measured. The boron removal rate is 97.8%, and the sulfate ion concentration in the treated water is 10 mg / L. It has been found that boron can be removed efficiently with a small amount of drug and with little secondary contamination by a simple apparatus and operation.

[ Reference Example 74 (filling method)]
When 15 g of the water treatment agent used in Reference Example 1 is filled and 100 mL of boron-containing water (boron concentration 112 mg / L, pH 12) is allowed to flow in under conditions of SV15 hr ⁻¹ , the boron removal rate is 87.5%. It was found that boron can be efficiently removed with a small amount of drug by a simple apparatus and operation. The sulfate ion concentration in the water after treatment was 1159 mg / L.

[ Reference Example 75 (filling method)]
When 15 g of the water treatment agent used in Reference Example 24 was charged and 100 mL of boron-containing water (boron concentration 112 mg / L, pH 12) was allowed to flow under conditions of SV15 hr ⁻¹ , the boron removal rate was 97.5%, after treatment It was found that the concentration of sulfate ion in water was less than the lower limit of detection, and boron could be removed efficiently with a small amount of drug and with little secondary contamination by a simple apparatus and operation.

[ Reference Example 76]
_{A-1 (Ca 6 Al 2} (SO 4) 3 (OH) 12 · 26H 2 material obtained by O to the heat treatment) and mixed with water treatment and barium chloride dihydrate in a weight ratio of 80:20 The agent was added to 1% by mass of boron-containing water having an initial pH of 12 (boron concentration: 104 mg / L) and stirred for 5 hours, followed by water treatment. The boron removal rate was 92.1%, and the sulfuric acid in the treated water was It was found that the ion concentration was less than the lower limit of detection, and boron could be removed efficiently with a small amount of drug and with little secondary contamination. The aggregation rate at this time was 6%.

  The water treatment agent and water treatment method of the present invention are very useful for removing harmful substances in various industrial wastewaters, for example, for the purpose of satisfying the drainage standards for each harmful substance.

Claims (4)

A boron treatment water treatment agent comprising the following (B1), (B2), and (D).
(B1) Calcium aluminate and / or heat treatment material of calcium aluminate (B2) Calcium sulfate (D) Carbonate   (D) The water treatment agent for boron removal according to claim 1, wherein the carbonate is either calcium carbonate or sodium carbonate.   Furthermore, the water treatment agent for boron removal in any one of Claim 1 to 2 which contains the (E) aluminum compound. A water treatment method using the water treatment agent for removing boron according to any one of claims 1 to 3.