JP3333483B2 - Treatment method and treatment agent for boron-containing water - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a method for treating boron-containing water, and more particularly to a method for treating boron-containing water that efficiently removes boron and generates a small amount of sludge, a treating agent used in the method, and a treatment. For kits.

[0002]

2. Description of the Related Art Boron compounds are used in glass materials, pharmaceutical raw materials, cosmetic raw materials, etc., and are contained not only in wastewater but also in wastewater generated from geothermal power plants, nuclear power plants, and flue gas desulfurization plants. Have been. Conventionally, as a method of treating boron-containing water, a method of adsorbing with an ion exchange resin, a method of forming an insoluble precipitate with aluminum sulfate and calcium hydroxide, and the like are known, but none of these methods can be said to be efficient methods. In addition, there is a problem that a large amount of sludge is generated.

[0003]

SUMMARY OF THE INVENTION Accordingly, an object of the present invention is to provide a method for treating boron-containing water that efficiently removes boron and generates a small amount of sludge. It is another object of the present invention to provide a treating agent and a treating kit used in the method.

[0004]

According to the present invention, an aluminum compound and a sulfuric acid compound are present in boron-containing water, the amount of aluminum is at least 2 moles per mole of boron, and a sulfate group is added to 1 mole of aluminum. To make a solution in which an aluminum compound is dissolved with a pH of 12.5 or more,
An object of the present invention is to provide a method for treating boron-containing water, characterized by adding a water-soluble alkaline earth metal salt to the solution to form an insoluble precipitate. The present invention also provides a treating agent for boron-containing water, comprising an aluminum compound and a sulfuric acid compound, wherein the amount of sulfate groups per mole of aluminum is 0.7 mol or more. The present invention further comprises a mixture of an aluminum compound and a sulfuric acid compound, and a water-soluble alkaline earth metal salt, wherein the amount of sulfate groups per mole of aluminum is 0.7 mol or more, and the water-soluble alkaline earth metal per 1 mol of aluminum is contained. An object of the present invention is to provide a kit for treating boron-containing water, wherein the amount of the salt is 2.5 to 5.0 mol.

[0005]

BEST MODE FOR CARRYING OUT THE INVENTION The method of the present invention comprises the steps of: presenting an aluminum compound and a sulfuric acid compound; making the amount of aluminum per mole of boron at least 2 moles; Mol or more, producing a solution in which an aluminum compound is dissolved at a pH of 12.5 or more, and adding a water-soluble alkaline earth metal salt to the solution to form an insoluble precipitate. This is a method for treating contained water. In the present invention, any of the steps may be performed first, or the steps may be performed simultaneously. Examples of the aluminum compound used in the process include aluminum chloride, polyaluminum chloride, aluminum sulfate, sodium aluminate, potassium aluminate, aluminum nitrate, aluminum hydroxide, alum, aluminum oxide, and metal aluminum. Examples of the sulfate compound include sodium sulfate, potassium sulfate, aluminum sulfate, calcium sulfate, magnesium sulfate, and sulfuric acid.

[0006] The aluminum compound and the sulfate compound are adjusted so that the amount of sulfate groups is 0.7 mole or more per mole of aluminum in the boron-containing water. From the viewpoint of removing boron, the content of the sulfate group may be 0.7 mol or more, and there is no particular upper limit. However, the object of the present invention is sufficiently achieved if almost 1 mol of sulfate is present per 1 mol of aluminum.Therefore, there is no particular advantage in that sulfate is present in a large amount exceeding 1 mol. If it is made to exist, it remains in the treated water, which is not preferable. Generally, 10 mol or less, preferably 5 mol or less, more preferably 3 mol or less, usually 1.5 mol or less is sufficient for 1 mol of aluminum, preferably 0.7 to 1.3 mol, more preferably 0.7 to 1.3 mol.
0.8-1.2 mol, even 0.9-1.1 mol, most preferably
1.0 mole.

When aluminum sulfate is used as the aluminum compound and the sulfuric acid compound, aluminum salts other than aluminum sulfate, for example, aluminum chloride, polyaluminum chloride, sodium aluminate, potassium aluminate, etc. are supplemented to reduce the amount of aluminum present. May be increased. The amount of aluminum per mole of boron in boron-containing water depends on the concentration of boron,
For example, when treating 50 ppm boron-containing water, 2 mol or more, preferably 2.0 to 10.0 mol, more preferably
It is 2.5-5.0 mol, most preferably 2.5-4.0 mol. When the concentration of boron is low, it is desirable to increase the ratio of aluminum to boron. However, if the amount of aluminum present is increased, the amount of sludge increases accordingly. Therefore, it is desirable to treat with a minimum amount of aluminum that is effective for removing boron.

When the boron-containing water (raw water) contains an aluminum compound and a sulfate compound, the amounts of the aluminum compound and / or the sulfate compound to be added are appropriately adjusted. The aluminum compound and the sulfuric acid compound may be in a solid / powder form or in a liquid form, respectively. However, it is preferable to use a required amount in an aqueous solution. Further, the aluminum compound and the sulfuric acid compound are added at a fixed molar ratio (for example,
Amount in which the abundance of aluminum and sulfate is approximately equimolar)
A treatment agent (solid / powder or liquid) prepared in advance by mixing with boron-containing water may be prepared, and a necessary amount may be used.

Before, during or after the adjustment of the amounts of the aluminum compound and the sulfate compound in the boron-containing water, the pH is adjusted by adding an alkali agent. The pH may be any pH required to dissolve the aluminum compound, and is 12.5 or more,
It is preferably at least 12.8, most preferably at least 13.0.
As the alkali agent, it is desirable to use an alkali metal hydroxide, for example, sodium hydroxide, potassium hydroxide or the like. By increasing the pH, the aluminum compound dissolves and produces aluminate ions. At this time, when an alkaline earth metal hydroxide, for example, calcium hydroxide is used, an insoluble precipitate is formed before the pH rises to 13, and the boron removing effect is reduced.

Next, a water-soluble alkaline earth metal salt is added to the dissolved boron-containing water in the presence of a predetermined amount of the aluminum compound and the sulfate compound to form an insoluble precipitate. Examples of the water-soluble alkaline earth metal salt used in the present invention include calcium chloride, magnesium chloride, calcium carbonate and the like. The alkaline earth metal salt may be in a solid / powder or liquid form, but is preferably used as an aqueous solution and used in a required amount. Particularly, calcium chloride is preferred. The amount of the water-soluble alkaline earth metal salt to be added is preferably 2.0 to 10.0 mol, more preferably 2.5 to 5.0 mol, and most preferably 3.0 to 4.0 mol, per mol of aluminum present in the boron-containing water.

[0011] The insoluble precipitate is separated by decantation, filtration, centrifugation or other means. At this time, when a flocculant, for example, an anionic polymer flocculant is added,
Flock can be formed in a short time. The boron content in the liquid after the solid-liquid separation varies depending on the boron content in the raw water, but decreases to about 1/5 to 1/100. If necessary, this treatment solution is subjected to the same treatment repeatedly to further reduce the boron content by 1 /.
It can be reduced to about 5 to 1/100. Generally, when the boron content in raw water is 100 ppm or more, it is desirable to repeat the treatment method of the present invention. Further, the liquid treated by the method of the present invention may be further treated with an ion exchange resin (for example, an anion exchange resin).

The treating agent for boron-containing water according to the present invention comprises, when added to boron-containing water, an appropriate amount of an aluminum compound and a sulfuric acid compound such that the amount of sulfate groups per mol of aluminum becomes 0.7 mol or more. Contains. The treating agent of the boron-containing water of the present invention, the aluminum compound and the sulfuric acid compound, with respect to 1 mol of aluminum, the sulfate is preferably 0.7 to 1.3 mol, more preferably 0.8 to 1.2 mol, more preferably 0.9 to 1.1 mol. , Most preferably 1.0 mole. The aluminum compound and the sulfuric acid compound are as described above, and it is most preferable to use polyaluminum chloride or sodium aluminate as the aluminum compound and sodium sulfate as the sulfuric acid compound. The aluminum compound and the sulfuric acid compound may be added separately at the time of use, or may be added as a mixture, but it is convenient to mix the two in advance.

[0013] The kit for treating boron-containing water of the present invention comprises:
It contains the treatment agent for boron-containing water of the present invention comprising a mixture of an aluminum compound and a sulfate compound, and a water-soluble alkaline earth metal salt. In the kit for treating boron-containing water of the present invention, the aluminum compound and the sulfuric acid compound are preferably used in an amount of 0.7 to 1.3 with respect to 1 mol of aluminum.
Mol, more preferably 0.8 to 1.2 mol, more preferably 0.9 to 1.1 mol, and most preferably 1.0 mol. The amount of the water-soluble alkaline earth metal salt is preferably 2.5 to 5.0 mol per mol of aluminum. Aluminum compounds include polyaluminum chloride, aluminum chloride, sodium aluminate,
Aluminum sulfate or a mixture of two or more thereof is preferred, and the sulfate compound is preferably sodium sulfate,
Calcium chloride is preferred as the water-soluble alkaline earth metal salt. The molar ratio of the aluminum compound, the sulfate compound and the water-soluble alkaline earth metal salt in the treatment kit (aluminum: sulfate group: alkaline earth metal) is preferably from 1: 0.9 to
1.1: 3 to 5, most preferably 1: 1: 4.

The kit for treating boron-containing water of the present invention comprises:
Further, it preferably contains sodium hydroxide as an alkali agent. In the present invention, sludge is produced promptly, and the reason why the amount of the produced sludge is small is unknown.However, boron, aluminum ion, sulfate ion, and alkaline earth metal salt are combined at a predetermined ratio and settled. This is presumably because a composite having excellent properties was formed.

[0015]

According to the method of the present invention, boron can be efficiently removed, and the amount of sludge generated is much smaller than that of the conventional method.

[0016]

The present invention will be described in more detail with reference to the following examples. Production Example 1 Polyaluminum chloride (Al ₂ O ₃ : 10 w / w%) (510 g: 1 mol of aluminum) and sodium sulfate (142 g: 1 mol of sulfate group) were mixed to produce the boron-containing water treating agent of the present invention. did.

Production Example 2 Aluminum sulfate (342 g: sulfate 3 mol, aluminum 2 mol) and polyaluminum chloride (Al ₂ O ₃ : 10 w / w%) (51
0 g: 1 mol of aluminum) to produce the treating agent for boron-containing water of the present invention.

Production Example 3 A container A containing a mixture of polyaluminum chloride (Al ₂ O ₃ : 10 w / w%) (510 g: 1 mol of aluminum) and sodium sulfate (142 g: 1 mol of sulfate group) 44
(4 g: 4 mol) was prepared, and a kit for treating boron-containing water of the present invention was produced.

Production Example 4 Sodium aluminate (Al ₂ O ₃ : 20 w / w%) (255 g: 1 mol of aluminum) and sodium sulfate (142 g: 1 mol of sulfate group) were mixed and treated with the boron-containing water of the present invention. An agent was manufactured.

Production Example 5 Aluminum sulfate (342 g: sulfate 3 mol, aluminum 2 mol) and sodium aluminate (Al ₂ O ₃ : 20 w / w%) (25
5 g: 1 mol of aluminum) to produce a treating agent for boron-containing water of the present invention.

Production Example 6 A container A containing a mixture of sodium aluminate (Al ₂ O ₃ : 20 w / w%) (255 g: 1 mol of aluminum) and sodium sulfate (142 g: 1 mol of sulfate group) 44
(4 g: 4 mol) was prepared, and a kit for treating boron-containing water of the present invention was produced.

Example 1 100 ml of boron-containing raw water (boron content: 50 ppm (4.63 mM))
To this were added predetermined amounts of a 10 w / w% (as Al ₂ O ₃ ) aqueous solution of polyaluminum chloride and a 20 w / w% aqueous solution of sodium sulfate, and the mixture was thoroughly stirred. To this was added a 10N aqueous sodium hydroxide solution until the pH reached 13.0. The aluminum compound dissolved completely. A predetermined amount of a 30 w / w% aqueous solution of calcium chloride was added thereto, and the mixture was stirred for 10 minutes.
After adding ppm and stirring, the mixture was allowed to stand for 10 minutes to settle a precipitate. The supernatant was collected, and the amount of boron in the supernatant was quantified using an ICP analyzer according to JISK0102. Table 1 shows the results
Shown in The numbers in parentheses indicate the molar ratio to the boron content in the raw water.

[0023]

[Table 1]

Example 2 100 ml of boron-containing raw water (boron content: 50 ppm (4.63 mM))
To this were added predetermined amounts of a 10 w / w% aqueous solution of polyaluminum chloride and a 20 w / w% aqueous solution of sodium sulfate, followed by thorough stirring. To this was added a 10N aqueous sodium hydroxide solution until the pH reached 13.0. The aluminum compound dissolved completely.
A predetermined amount of a 30 w / w% aqueous solution of calcium chloride is added to this,
After stirring for 10 minutes, 10 ppm of an anionic coagulant was added, and the mixture was stirred and allowed to stand for 10 minutes to settle a precipitate. The supernatant was collected with a syringe, and the amount of boron in the supernatant was determined by the determination method described in Example 1. Table 2 shows the results.
The numbers in parentheses indicate the molar ratio to the boron content in the raw water.

[0025]

[Table 2]

Example 3 100 ml of boron-containing raw water (boron content 50 ppm (4.63 mM))
To, 7.8 mM polyaluminum chloride (10w / w% as Al ₂ O ₃₎ as an aluminum, was added to a 7.8 mM sodium 20% aqueous solution of sulfuric acid as sulfate radical (S0 ₄ ^2-), 1ON sodium hydroxide An aqueous solution was added to pH13. When a 30% aqueous solution of calcium chloride was added thereto to have a calcium concentration of 31 mM, a white precipitate was formed. The mixture was stirred for 30 minutes, added with 10 ppm of an anionic coagulant, stirred, and allowed to stand for 10 minutes. The supernatant was collected, and the boron concentration was measured.

Example 4 In Example 3, the order of addition of polyaluminum chloride, sodium sulfate, and sodium hydroxide is six, including the order of Example 3, but any order other than Example 3 can be used. , The same results were obtained.

Comparative Example 1 The procedure of Example 3 was repeated except that sodium sulfate was not added. Boron concentration of treated water is 50pp
m and no boron was removed.

Comparative Example 2 In Example 3, when the order of adding sodium hydroxide and calcium chloride was reversed, the boron concentration of the treated water became 50%.
ppm.

Example 5 Examples 3 and 4 were processed in the same manner as in Examples 3 and 4 except that sodium aluminate (20 w / w% as Al ₂ O ₃ ) was added in the same amount as aluminum instead of polyaluminum chloride. Was obtained.

Example 6 100 ml of boron-containing raw water (containing 100 ppm (9.26 mM) of boron)
In addition, 17 mM poly aluminum chloride as aluminum,
A 20% aqueous solution of sodium sulfate was added as a sulfate group to a concentration of 17 mM.
It was set to 3. When a 30% aqueous solution of calcium chloride was added to the solution so as to have a concentration of 68 mM as calcium, a white precipitate was formed. After stirring for 30 minutes, 20 ppm of an anionic flocculant was added and stirred, and the mixture was allowed to stand for 10 minutes. The supernatant was collected, and the boron concentration was measured, which was 4.1 ppm.

Example 7 In Example 6, the treating agent of Production Examples 1 and 2 and Production Example 3
When the same treatment was carried out using the processing kit described above, similar results were obtained. Example 8 To 100 ml of boron-containing raw water (boron content: 20 ppm (1.85 mM)), 6 mM of polyaluminum chloride as aluminum and 20% of sodium sulfate aqueous solution as a sulfate group were added at 6 mM, and a 2N aqueous sodium hydroxide solution was added. It was added to pH13. When a 30% aqueous solution of calcium chloride was added to the solution so that the concentration became 24 mM as calcium, a white precipitate was formed. After stirring for 30 minutes,
After adding 5 ppm of an anionic coagulant and stirring, the mixture was allowed to stand for 10 minutes, the supernatant was collected, and its boron concentration was measured. As a result, it was 0.3 ppm.

Comparative Example 3 In Example 8, a 20% aqueous solution of aluminum sulfate was added so as to have a concentration of 6 mM as aluminum and 9 mM as a sulfate group, and a 30% slurry of calcium hydroxide was converted into calcium.
When the same treatment was carried out except that the pH was adjusted to 12.5 by adding the solution to 53 mM, the boron concentration of the treated water was 5.2 ppm.

Example 9 To 100 ml of waste water containing 60 ppm (5.6 mM) of boron and 100 ppm (5.3 mM) of fluorine, 12 mM of polyaluminum chloride as aluminum and 12 mM of a 20% aqueous solution of sodium sulfate as a sulfate group were added. Then, a 1ON aqueous sodium hydroxide solution was added to adjust the pH to 13. 30% calcium chloride
When the aqueous solution was added to 48 mM as calcium, a white precipitate was formed. After stirring for 30 minutes, 10 ppm of an anionic flocculant was added, and after stirring, the mixture was allowed to stand for 10 minutes, and the supernatant was collected, and the boron concentration and the fluorine concentration were measured to be 2.0 ppm and 11 ppm, respectively. Was. It can be seen that not only boron but also fluorine can be removed by the method of the present invention.

Example 10 In 100 ml of boron-containing raw water (boron content 50 ppm (4.63 mM)),
Polyaluminum chloride was added to a concentration of 12 mM as aluminum and a 20% aqueous solution of sodium sulfate to 12 mM as a sulfate group.
Adjusted to 11.0, 11.5, 12.0, 12.5 and 13.0. A 30% aqueous solution of calcium chloride was added to these so that the concentration became 36 mM as calcium. In the case of pH 11.0 and pH 11.5, no precipitate was formed. In the case of pH 12.0, 12.5 and 13.0, a white precipitate was formed, so after stirring for 30 minutes, the anionic flocculant 10pp
After adding and stirring, the mixture was allowed to stand for 10 minutes, the supernatant was collected, and its boron concentration was measured.
ppm, 7.7 ppm at pH 12.5 and 0.58 ppm at pH 13.

Example 11 The procedure of Example 3 was repeated except that polyaluminum chloride was added so as to have a concentration of 12 mM as aluminum, a 20% aqueous solution of sodium sulfate as 14.4 mM as a sulfate group, and a 30% aqueous solution of calcium chloride as 36 mM as calcium. As a result of the same treatment, the concentration of boron in the treated water was 1.25 ppm. The amount of sludge obtained by filtering the generated precipitate under pressure is 1842
mg, and the amount of sludge dried at 100 ° C. was 386 mg.

Comparative Example 4 In Example 11, a 20% aqueous solution of aluminum sulfate was added so as to have a concentration of 36 mM as aluminum and 54 mM as a sulfate group, and a 30% aqueous solution of calcium hydroxide was added so as to have a concentration of 135 mM as calcium. The treatment was carried out in exactly the same manner except that the pH was set to 12.8. As a result, the boron concentration in the treated water was 3.9 ppm. The amount of sludge obtained by filtering the formed precipitate under pressure was 3629 mg, and the amount of sludge obtained by drying the sludge at 100 ° C. was 1336 mg.

──────────────────────────────────────────────────続 き Continuing on the front page (72) Inventor Shinji Wada 16-3 Onogawa, Tsukuba, Ibaraki Pref. National Institute of Advanced Industrial Science and Technology (72) Inventor Yasuhiro Yukawa 2-6-1 Sengen, Tsukuba, Ibaraki Mitsubishi Shoji Co., Ltd. in the examiner Kokubo KatsuI (56) reference Patent Sho 57-180493 (JP, a) JP Akira 58-193786 (JP, a) (58 ) investigated the field (Int.Cl. ⁷ , DB name) C02F 1/58

Claims (10)

(57) [Claims] (1) Aluminum compound in boron-containing water
And the presence of a sulfuric acid compound, per mole of boron
The aluminum content must be at least 2 moles
The amount of sulfates per mole of minium should be 0.7 mole or more.
To do, Adjust the pH to 12.5 or higher to remove aluminum compounds.
Producing a dissolved solution;Present in this solution
2.5 to 5.0 moles per mole of aluminumWater-soluble
Add an insoluble precipitate by adding a Lucari earth metal salt
A method for treating boron-containing water. 2. The method according to claim 1, wherein the molar ratio of boron, aluminum and sulfate in the solution is 1: 2.0 to 10.0: 2.0 to 10.0. 3. The method according to claim 1, wherein the pH is 13.0 or higher. 4. The method according to claim 1, wherein the water-soluble alkaline earth metal salt is calcium chloride. 5. A comprises aluminum compounds and sulfuric acid compounds, wherein the abundance of the sulfate to aluminum 1 mol is 0.7 mol or more, more of claims 1 to 4
A treatment agent for boron-containing water for use in the method for treating boron-containing water according to claim 1 . 6. The agent for treating boron-containing water according to claim 5, wherein the aluminum compound is polyaluminum chloride, aluminum chloride, sodium aluminate, aluminum sulfate or a mixture of two or more thereof, and the sulfate compound is sodium sulfate. . 7. The treating agent for boron-containing water according to claim 5, wherein the amount of the sulfate group per mole of aluminum is 0.7 to 1.3 mol. 8. A mixture of an aluminum compound and a sulfuric acid compound, and a water-soluble alkaline earth metal salt, wherein the amount of sulfate groups per mole of aluminum is 0.7 mol or more;
5. The method according to claim 1 , wherein the amount of the water-soluble alkaline earth metal salt is 2.5 to 5.0 mol per mol of aluminum.
A kit for treating boron-containing water for use in the method for treating boron-containing water according to claim 1 . 9. The aluminum compound is polyaluminum chloride, aluminum chloride, sodium aluminate, aluminum sulfate or a mixture of two or more thereof, the sulfate compound is sodium sulfate, and the water-soluble alkaline earth metal salt is calcium chloride. The boron-containing water treatment kit according to claim 8, wherein the molar ratio (aluminum: sulfate group: alkaline earth metal) is 1: 0.7 to 1.3: 3 to 5. 10. The kit for treating boron-containing water according to claim 8, further comprising sodium hydroxide.