JP2005270790A - Adsorbent adsorbing fluorine and/or boron - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To provide an adsorbent effectively adsorbing fluorine and/or boron, in particular, an adsorbent adsorbing fluorine and/or boron in coal ash, and quickly and efficiently adsorbing/insolubilizing fluorine and/or boron, even if coexistence ions exist. <P>SOLUTION: This adsorbent adsorbs fluorine and/or boron in solid containing fluorine and/or boron. The adsorbent contains calcium aluminate such as Ca<SB>12</SB>Al<SB>14</SB>O<SB>33</SB>, Ca<SB>3</SB>Al<SB>2</SB>O<SB>6</SB>, and has a content of calcium in the adsorbent of 40-90 wt. % in terms of an oxide (CaO). <P>COPYRIGHT: (C)2006,JPO&NCIPI

Description

  The present invention provides an adsorbent that effectively adsorbs and insolubilizes fluorine and / or boron, and in particular, adsorbs fluorine and / or boron in coal ash, and there are coexisting ions. However, it is possible to provide an adsorbent capable of adsorbing and insolubilizing fluorine and / or boron quickly and efficiently.

  Conventionally, coal ash after using coal as an energy source has been used as a cement raw material, a soil improvement material, and the like from the viewpoint of effective use of resources.

  However, coal ash contains soluble fluorine and / or soluble boron above environmental standards, and when used for applications other than cement raw materials, there is a possibility of secondary contamination.

  Conventionally, many environmental technologies that adsorb and remove harmful ions in water systems and soils have been proposed, but it is efficient without adding harmful anions such as fluorine and / or boron in a wide concentration range to the environment. There are currently no known materials that can be processed selectively and inexpensively.

  Therefore, a material that is harmless and inexpensive and that efficiently adsorbs and insolubilizes fluorine and / or boron in coal ash is required.

  Conventionally, techniques for adsorbing fluorine and the like using calcium aluminate (Patent Documents 1 to 5) and techniques for adsorbing fluorine and the like using calcium silicate (Patent Document 6) are known.

JP 2000-93927 A JP 2000-225383 A JP 2000-335946 A JP 2000-336421 A Japanese Patent Laid-Open No. 2003-211118 JP 2004-41890 A

  A material that can efficiently adsorb fluorine and / or boron in coal ash is currently most demanded, but an adsorbent that satisfies this requirement has not yet been provided.

  That is, in the aforementioned Patent Documents 1 to 5, it is described that calcium metalate is used to immobilize heavy metals or fluorine in solids such as steelmaking slag, but calcium aluminate alone with a small amount of calcium is described. Therefore, it is difficult to sufficiently remove fluorine and boron.

  Patent Document 6 described above describes a technique for immobilizing fluorine using calcium silicate, but it does not use calcium aluminate and it is difficult to sufficiently remove fluorine and boron.

  The technical problem can be achieved by the present invention as follows.

  That is, the present invention is an adsorbent that adsorbs fluorine and / or boron in a solid containing fluorine and / or boron, the adsorbent contains calcium aluminate, and calcium in the adsorbent It is an adsorbent that adsorbs fluorine and / or boron, characterized in that the content is 40 to 90% by weight in terms of oxide (CaO) (Invention 1).

The present invention is the adsorbent for adsorbing fluorine and / or boron according to claim 1, wherein the calcium aluminate is Ca ₁₂ Al ₁₄ O ₃₃ and / or Ca ₃ Al ₂ O ₆ ( Invention 2).

  Further, the present invention is the adsorbent for adsorbing fluorine and / or boron according to the present invention 1 or 2, wherein the adsorbent contains at least calcium aluminate and calcium oxide. It is an adsorbent that adsorbs boron (Invention 3).

  Further, the present invention is an adsorbent that adsorbs fluorine and / or boron according to any one of the present invention 1 to 3, wherein the adsorbent contains at least calcium aluminate and calcium silicate. An adsorbent that adsorbs fluorine and / or boron (Invention 4).

Further, the present invention is the adsorbent for adsorbing fluorine and / or boron according to the present invention 4, wherein the calcium silicate is either 3CaO.SiO ₂ or 2CaO.SiO _2. And / or an adsorbent that adsorbs boron (present invention 5).

  Further, the present invention is an adsorbent that adsorbs fluorine and / or boron according to any one of the present invention 1 to 5, wherein the adsorbent further contains calcium sulfate and / or calcium sulfate hydrate. It is a characteristic adsorbent that adsorbs fluorine and / or boron (Invention 6).

  Further, the present invention is the adsorbent for adsorbing fluorine and / or boron according to any one of the present inventions 1 to 6, wherein the solid content containing fluorine and / or boron is coal ash or incinerated ash. There is (Invention 7).

  Since the adsorbent for adsorbing fluorine and / or boron according to the present invention can adsorb and capture a wide concentration range of fluorine and / or boron, the detoxified coal ash is added to the coal ash beforehand. In the case of effective use or in the case of disposal as it is, even if the treated coal ash is in contact with moisture such as rainwater or groundwater, elution of fluorine and / or boron can be suppressed to an environmental standard value or less. Therefore, it is suitable as an adsorbent for fluorine and / or boron.

  In addition, even when coal ash treated with an adsorbent that adsorbs fluorine and / or boron according to the present invention is reused for roadbed materials, soil improvement materials, etc., because the adsorbent itself is harmless and nontoxic, The impact on the environment is small.

  The configuration of the present invention will be described in more detail as follows.

  First, an adsorbent that adsorbs fluorine and / or boron according to the present invention (hereinafter referred to as “adsorbent”) will be described.

  The adsorbent according to the present invention contains one or more selected from calcium oxide, calcium silicate and calcium sulfate together with calcium aluminate.

Calcium aluminate _{is Ca 12 Al 14 O 33, Ca} 3 Al 2 O 6 and CaAl ₂ O ₄ or the like, preferably a _{Ca 12 Al 14 O 33, Ca} 3 Al 2 O 6.

  The calcium content in the adsorbent according to the present invention 1 is 40 to 90% by weight in terms of oxide (CaO). When the calcium content in the adsorbent is outside the above range, it is difficult to say that the effect of adsorption / insolubilization of fluorine / boron is sufficient. Preferably it is 40 to 85 weight%, More preferably, it is 40 to 80 weight%.

  The adsorbent according to the present invention 3 comprises at least calcium aluminate and calcium oxide. By containing calcium oxide, the effect of adsorbing fluorine is particularly high, and a high adsorbing / insolubilizing effect is exhibited even for a solid content containing a high concentration of fluorine.

  In the adsorbent according to the present invention 3, the content ratio of calcium aluminate and calcium oxide is the peak intensity ratio of the X-ray diffraction of the adsorbent, and when calcium aluminate is 100, calcium oxide is 1 to 2000. It is preferable. When it is less than 1, the adsorption / insolubilization ability of fluorine / boron is lowered, which is not preferable. When it exceeds 2000, there are few sites for fixing harmful anions of calcium aluminate, and a sufficient effect cannot be exhibited. More preferably, it is 3 to 1500.

  The adsorbent according to the present invention 4 or 5 comprises at least calcium aluminate and calcium silicate. By containing calcium silicate, the adsorption effect of fluorine and boron is further enhanced.

The calcium silicate in the present _{invention, 3CaO · SiO 2, CaSiO 3} , 2CaO · SiO 2 · H 2 O, preferably 2CaO · SiO _2, etc., more preferably 3CaO · SiO ₂ and / or 2CaO · SiO ₂ preferably .

  The content ratio of calcium aluminate and calcium silicate in the adsorbent according to the present invention 4 or 5 is the peak intensity ratio of the X-ray diffraction of the adsorbent, and when calcium aluminate is 100, the calcium silicate is 10 to 10. 2000 is preferred. If it is less than 10, sufficient effects due to the addition of calcium silicate cannot be obtained. When it exceeds 2000, the site which fixes the harmful anion of calcium aluminate decreases, and a sufficient effect cannot be exhibited. More preferably, it is 20-1000, More preferably, it is 20-700.

  The adsorbent according to the present invention 6 comprises at least calcium aluminate and calcium sulfate. By containing calcium sulfate, the adsorption effect becomes higher.

The calcium sulfate in the present invention, CaSO ₄ or CaSO ₄ · nH ₂ O is preferable.

  The content ratio of calcium aluminate and calcium sulfate of the adsorbent according to the present invention 6 is the peak intensity ratio of the X-ray diffraction of the adsorbent, and the calcium aluminate is 100, and the calcium sulfate is 10 to 2000. Is preferred. If it is less than 10, sufficient effects due to the addition of calcium sulfate cannot be obtained. When it exceeds 2000, the site which fixes the harmful anion of calcium aluminate decreases, and a sufficient effect cannot be exhibited. More preferably, it is 20-1000, More preferably, it is 20-700.

  The particle shape of the adsorbent according to the present invention is plate or granular.

  The average particle size of the adsorbent according to the present invention is preferably 0.1 to 50.0 μm. The adsorbent according to the present invention is a method in which various raw material powders are baked at a high temperature of 850 to 1200 ° C., or after preparing calcium aluminate, calcium oxide, calcium silicate, calcium sulfate, etc. However, since any method involves high-temperature firing, it is difficult to industrially produce particles having a size of 0.1 μm or less. Even if the average particle size is less than 0.1 μm, there is no functional problem, but it is difficult to handle the powder. If it exceeds 50 μm, the contact efficiency between the harmful anion and the adsorbent decreases, which is not preferable. Preferably it is 0.2-10.0 micrometers.

The BET specific surface area value of the adsorbent according to the present invention is preferably 0.1 to 10 m ² / g. When the BET specific surface area value is less than 0.1 m ² / g, the contact efficiency between the harmful anion and the adsorbent decreases, which is not preferable. Adsorbents exceeding 10 m ² / g are difficult to industrially produce because they are prepared by firing at a high temperature of 850 to 1200 ° C. An adsorbent having a BET specific surface area value exceeding 10 m ² / g has no functional problem, but is difficult to handle as a powder. More preferably, it is 0.1-5 m < ² > / g, More preferably, it is 0.2-5 m < ² > / g.

  Next, the manufacturing method of the adsorbent according to the present invention will be described.

  First, the manufacturing method of the calcium aluminate in this invention is described.

  The calcium aluminate in the present invention can be obtained by mixing a calcium compound and an aluminum compound and then heat-treating at a temperature of 850 to 1200 ° C. in an oxidizing or atmospheric atmosphere. Further, if necessary, a pulverization treatment or a surface treatment with an inorganic substance, an organic substance or a polymer can be performed.

  As the calcium compound, calcium hydroxide (slaked lime), calcium carbonate, calcium oxide, calcium nitrate and the like can be used, and calcium hydroxide and calcium carbonate are preferred. The average particle size of the calcium compound is preferably 0.2 to 20 μm.

  As the aluminum compound, aluminum hydroxide, aluminum oxide, aluminum nitrate or the like can be used, and aluminum hydroxide is preferable. The average particle size of the aluminum compound is preferably 0.1 to 20 μm.

  What is necessary is just to mix the mixing ratio of a calcium compound and an aluminum compound so that it may become a predetermined | prescribed composition ratio.

  As a mixer in the manufacturing method, a raking machine, a roller type mixer, a vibration mill, a bead mill, a disk type wet stirring and mixing tank, or the like can be used.

  In the mixing state of the mixture that is the precursor of the adsorbent in the present invention, the subsequent solid phase reaction is caused uniformly and promptly, so selection of the mixer and mixing conditions is important. It is preferable to use a machine in terms of uniform mixing.

  When the heating temperature is less than 850 ° C., the dehydration reaction, decarboxylation reaction and solid phase reaction of the mixed powder do not proceed, or the proceeding speed is extremely slow, which is not preferable. On the other hand, when the heating temperature exceeds 1200 ° C., the particle size of the generated composite oxide particles increases, and the reactivity with harmful anions in the aqueous system decreases, which is not preferable. The heat treatment temperature is more preferably 900 to 1150 ° C. In consideration of industrial productivity, the heating time is preferably 30 minutes to 180 minutes. The heating atmosphere may be an oxidizing or atmospheric atmosphere. When a large amount of carbonate ions are contained in the heated product particles, the reactivity with harmful anions in the aqueous system is lowered, so heat treatment in carbon dioxide gas is not preferable.

  In the present invention, the powder after the heat treatment may be dry-pulverized and surface-treated with an inorganic material, an organic material, or a polymer.

  Since the dry pulverization treatment can reduce the average particle size of the powder after the heat treatment, the reactivity of the powder of the present invention with fluorine in coal ash can be improved. As an apparatus that can be used for the dry pulverization treatment, a free pulverizer, a hammer mill, or the like can be used.

  Further, by subjecting the powder after the heat treatment to a surface treatment with an inorganic substance, an organic substance or a polymer, the reactivity with fluorine and / or boron and the dispersibility in soil and water can be controlled. As the surface treatment agent, hydrophilic organic substances, polymers and inorganic substances can be used to promote the reactivity, and conversely, the reaction is made hydrophobic with rosin compounds, silane coupling agents, higher fatty acids, etc. It can also be controlled so that gradually advances. The coating amount on the adsorbent powder by the surface treatment agent is preferably 0.1 to 5% by weight in terms of C with respect to the composite oxide particle powder. As the surface treatment machine, it is possible to use a roughing machine, a vibration mill, a roller type mixer, a wet tank equipped with a stirrer, or the like.

  The adsorbent according to the present invention 3 is a method of manufacturing the calcium aluminate by adjusting the ratio of the calcium compound and the aluminum compound to cause the calcium to exist in an excessive amount. It can be obtained by a method of mixing with calcium. Further, if necessary, a pulverization treatment or a surface treatment with an inorganic substance, an organic substance or a polymer can be performed.

  The adsorbent according to the present invention 4 or 5 is prepared by mixing calcium compound, aluminum compound and silicon compound and then oxidizing and heating at a temperature of 850 to 1200 ° C. It can be obtained by a method of mixing aluminate and calcium silicate. Further, if necessary, a pulverization treatment or a surface treatment with an inorganic substance, an organic substance or a polymer can be performed.

  The adsorbent according to the present invention 6 can be obtained by a method of mixing calcium aluminate and calcium sulfate prepared in advance. Further, if necessary, a pulverization treatment or a surface treatment with an inorganic substance, an organic substance or a polymer can be performed.

  Next, a treatment method using the adsorbent according to the present invention will be described.

  The treatment method in the present invention includes the case of fixing and separating dissolved harmful anions and the aqueous system of harmful anions by coexisting an adsorbent with solids (such as coal ash) that may release harmful anions. The case where elution to is suppressed is included.

  In the present invention, the method for bringing the water to be treated into contact with the adsorbent is not particularly limited. For example, a filtration tank filled with a powdery adsorbent and / or a granular adsorbent, a method of circulating treated water through a column, a method of combining a stirring tank and a precipitation tank, and the like can be used.

  Although there is no restriction | limiting in particular about the liquid temperature when making adsorbent contact, The adsorbent of this invention has a big merit that it can process at normal temperature. When the temperature is extremely low, the reaction rate of the adsorbent becomes small, and the trapping rate of harmful anions becomes small. The normally used temperature range is preferably 5 to 90 ° C, more preferably 10 to 50 ° C. The contact time between the adsorbent and the liquid to be treated is preferably 5 minutes or longer, more preferably 30 minutes or longer. There is no upper limit for the contact time.

  Moreover, the processing method which adds a fixed quantity to coal ash etc. and mixes can be performed. In this case, a shaking test according to Environment Agency Notification No. 46 can be performed to evaluate the elution amount of fluorine and boron and confirm the treatment effect.

  What is necessary is just to select the addition amount with respect to solid content of adsorption agent suitably according to the kind of solid content, and content of fluorine and boron, but 0.1 to 20 weight% is preferable. If it is less than 0.1% by weight, it is difficult to mix uniformly in the solid content, and a sufficient effect cannot be exhibited. If it exceeds 20% by weight, the effect is saturated, so there is no point in adding more than necessary. More preferably, it is 0.3 to 15% by weight.

<Action>
The important point in the present invention is that the adsorbent according to the present invention can adsorb and trap fluorine and / or boron eluted from waste water or solid matter in a wide concentration range from low concentration to high concentration.

In the present invention, if calcium aluminate, for example, Ca ₁₂ Al ₁₄ O ₃₃ is shown as an example, a specific O in Ca ₁₂ Al ₁₄ O ₃₃ (which can be expressed as 12CaO7Al ₂ O ₃ ) in an aqueous solution is fluorine. And / or boron is considered to be able to remove fluorine and / or boron, and after substitution, 11CaO7Al ₂ O ₃ CaF ₂ or 11CaO7Al ₂ O ₃ CaY (F is a fluorine ion, Y is a divalent anion) The inventor presumes that it becomes fixed.

In addition, the function of calcium oxide has not been fully elucidated, but once it has a form (adsorption site) such as CaF ₂ and CaY, it functions to bridge monovalent or divalent anions harmful to Ca ₁₂ Al ₁₄ O _33. The present inventor thinks that this may be achieved.

  In addition, the function of calcium silicate and / or calcium sulfate has not been fully elucidated, but hydration caused by calcium silicate and / or calcium sulfate and aluminum silicate, which is the main component of coal ash, in the presence of moisture. The inventor presumes that fluorine and boron are incorporated during the curing reaction.

  Further, in the present invention, the adsorbent according to the present invention has a particle size of submicron or micron order, and a uniform composite of polymer and adsorbent can be produced. By being able to form a complex of adsorbent and polymer, it is possible to arbitrarily control the life of the adsorbent and the hydrophilicity of the complex. That is, when the complex of the polymer and the adsorbent is brought into contact with the aqueous solution, the reaction time can be arbitrarily set, and harmful anions in the aqueous solution can be captured and insolubilized.

  A typical embodiment of the present invention is as follows.

  The average particle diameter of the adsorbent is indicated by an average value of values measured from an electron micrograph.

  The crystal phase of the adsorbent is identified by “X-ray diffractometer RINT2500 (manufactured by Rigaku Corporation)” (tube: Cu, tube voltage: 40 kV, tube current: 300 mA, goniometer: wide angle goniometer, sampling width: 0.010 °, scanning speed: 4.00 ° / min, diverging slit: 1/2 °, scattering slit: 1/2 °, light receiving slit: 0.15 mm).

The intensity ratio of the constituent phases of the adsorbent is the intensity of the (2 2 0) plane of CaO (orthorhombic) in the peak intensity of X-ray diffraction, and the (2 2 4) plane of 3CaO · SiO ₂ (orthorhombic). strength, 2CaO · SiO ₂ of (hexagonal) (1 0 2) plane intensity of, CaSO ₄ in (orthorhombic) (0 2 0) plane intensity or CaSO ₄ · _2H 2 O in (monoclinic) of ( The strength of the 0 2 1) plane is high in the strength of the (2 1 1) plane of Ca ₁₂ Al ₁₄ O ₃₃ (cubic) or the strength of the (4 4 0) plane of Ca ₃ Al ₂ O ₆ (orthorhombic). The direction is 100, and the intensity ratio is shown.

  The BET specific surface area value was shown as a value measured by the BET method.

The analysis of the content of the metal element of the adsorbent and the content of coal ash according to the present invention is performed by dissolving the powder with an acid such as hydrochloric acid or melting it using K ₂ S ₂ O ₇ , Na ₂ CO _3, etc. It was determined by measurement with a “plasma emission spectrometer SPS4000 (Seiko Electronics Co., Ltd.)”. In addition, the fluorine content in coal ash was measured by perchloric acid distillation-absorbance.

  Moreover, the carbon amount and sulfur amount in the coal ash were measured with a “carbon / sulfur analyzer (EMIA-820W, manufactured by Horiba, Ltd.)”.

The concentration of fluorine ions eluted from coal ash was measured using an ion chromatograph. As the ion chromatograph, “ICA-2000 (manufactured by Toa DK Corporation)” was used.
The boron ion concentration eluted from the coal ash was evaluated using the above-mentioned “plasma emission spectroscopic analyzer SPS4000 (Seiko Electronics Co., Ltd.)”.

Properties of coal ash The value obtained by measuring the fluorine content of coal ash 1 used in the evaluation by perchloric acid distillation-absorbance was 103 mg / kg.
Moreover, as a result of measuring the concentration of fluorine and boron eluted by a shaking test according to Environmental Agency Notification No. 46, the fluorine ion concentration was 1.5 mg / L exceeding the environmental standard of 0.8 mg / L. The concentration was 3.4 mg / L.

  Table 1 shows the characteristics of the coal ash used for the evaluation.

<Evaluation method of elution amount of fluorine and boron in coal ash using adsorbent>
Disperse 3.0 g of adsorbent and 100 g of coal ash in water, shake for 6 hours with a shaker (200 shakes / minute, shake width 4.5 cm), and then remove the solids from the aqueous solution. After filtration, the fluorine ion concentration in the filtrate was measured by an ion chromatograph method, and the boron ion concentration was evaluated using a “plasma emission spectrometer SPS4000 (Seiko Electronics Co., Ltd.)”.

Adsorbent 1: Production of adsorbent 50.0 g of slaked lime powder (JIS special name, BET specific surface area value 15 m ^{2 /} g, equivalent to Ca = 0.67 mol) and aluminum hydroxide 68.6 g (C-301 manufactured by Sumitomo Chemical) BET specific surface area value of 2 m ^{2 /} g, equivalent to Al = 0.88 mol) was mixed for 1 hour using a Reika machine. 70 g of the obtained mixed powder was put in an alumina crucible and heat-treated in a muffle furnace at 1100 ° C. for 2 hours in air.
30 g of the particle powder after heat treatment and 3.3 g of silicon dioxide powder were pulverized for 1 hour using a Reika machine. The obtained particle powder was white.

The resulting adsorbent, calcium aluminate _{(Ca 12 Al 14 O 33,} Ca 3 Al 2 O 6), a mixed phase of CaO and SiO _2, X-ray of Ca _{12 Al} 14 _{O 33} (calcium aluminate) When the intensity in diffraction was 100, the intensity ratio of Ca ₃ Al ₂ O ₆ was 46, and the intensity ratio of CaO was 8. The average particle diameter of the adsorbent was 0.7 μm, and the BET specific surface area value was 2.4 m ² / g. Incidentally, the calcium content in the adsorbent is 46.1 wt% calculated as CaO, was 36.5% as _Al 2 _{O 3.}

Adsorbents 2-8,
Adsorbents 2 to 8 were prepared by changing the type and addition ratio of raw materials and the heating temperature for the production method of adsorbent 1.

  Table 2 shows various properties of the obtained adsorbent.

The adsorbent 7 does not contain calcium aluminate and is mainly a mixture of CaO, Al ₆ Si ₂ O _{13 and the} like, and the adsorbent 8 is a mixture of CaO, Al ₂ O ₃ and SiO ₂ .

Adsorption test Examples 1-11, Comparative Examples 1-6:
In the said adsorption test, the kind and addition amount of adsorbent were changed variously, and the elution amount of the fluorine and boron at the time of using each adsorbent with respect to various coal ash was measured. The evaluation results are shown in Table 3.

Since the adsorbent according to the present invention can adsorb and insolubilize a wide range of harmful anions, particularly fluorine and boron, it is suitable as an adsorbent and insolubilizer for fluorine and boron, which are harmful anions in coal ash.
In addition, the fluorine / boron insolubilization treatment using the adsorbent according to the present invention does not require complicated treatment steps, and thus is suitable as an adsorbent used in a simple treatment method. Furthermore, the adsorbent according to the present invention is also effective for adsorption and insolubilization of fluorine and boron in coal ash in which anions such as chloride ions, sulfate ions and carbonate ions coexist with fluorine and boron.

Furthermore, since the adsorbent according to the present invention is composed of harmless elements or compounds, even when solid content such as coal ash treated with the adsorbent is disposed of in landfill, the burden on the environment is small. is there.

Claims (7)

An adsorbent that adsorbs fluorine and / or boron in a solid content containing fluorine and / or boron, wherein the adsorbent contains calcium aluminate, and the content of calcium in the adsorbent is an oxide ( An adsorbent for adsorbing fluorine and / or boron, characterized by being 40 to 90% by weight in terms of CaO). Fluorine and / or adsorbent for adsorbing boron claim 1, wherein the calcium aluminate is _Ca 12 _Al 14 _{O 33} and / or _Ca 3 _Al 2 _{O 6.} The adsorption agent for adsorbing fluorine and / or boron according to claim 1 or 2, wherein the adsorbent contains at least calcium aluminate and calcium oxide. Agent. The adsorbent for adsorbing fluorine and / or boron according to any one of claims 1 to 3, wherein the adsorbent contains at least calcium aluminate and calcium silicate. Adsorbent that adsorbs boron. A adsorbent to adsorb fluorine and / or boron according to claim 4, adsorbed fluorine and / or boron, wherein the calcium silicate is either 3CaO · SiO ₂ or 2CaO · SiO ₂ Adsorbent. 6. The adsorbent for adsorbing fluorine and / or boron according to claim 1, wherein the adsorbent further contains calcium sulfate and / or calcium sulfate hydrate. And / or an adsorbent that adsorbs boron. The adsorbent for adsorbing fluorine and / or boron according to any one of claims 1 to 6, wherein the solid content containing fluorine and / or boron is coal ash or incinerated ash.