JP2991987B2 - Basic aluminum chloride and method for producing the same - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

TECHNICAL FIELD The present invention relates to a basic aluminum chloride used as a coagulant for water treatment and the like, which exhibits a high coagulation performance in a wide pH range and makes it possible to reduce residual aluminum in tap water. The present invention relates to aluminum chloride and a method for producing the same.

[0002]

2. Description of the Related Art Basic aluminum chloride has a high cohesive property, and by utilizing this property, a water treatment coagulant for various wastewaters such as water and sewage, industrial wastewater, civil engineering wastewater, a sizing agent, an antiperspirant, It is used for a wide range of applications such as cosmetic raw materials and pharmaceuticals.

[0003] Methods for producing such a basic aluminum chloride solution have been studied for a long time, and many methods have been developed. For example, 1) a method in which metallic aluminum is dissolved with an equivalent amount or less of hydrochloric acid. 2) A method in which an aluminum compound such as metallic aluminum or aluminum hydroxide is dissolved in an autoclave. 3) A method of dissolving aluminum compounds such as metallic aluminum and aluminum hydroxide at normal pressure. 4) A method of adding an alkali or aluminate to an aluminum chloride solution for neutralization. 5) A method of removing chloride ions in an aluminum chloride solution with an ion exchange resin. 6) Dissolve aluminum hydroxide with a mixed acid of hydrochloric acid and sulfuric acid,
A method in which a calcium compound such as calcium carbonate and calcium hydroxide is added thereto to remove calcium sulfate. 7)
It is a method of removing chloride ions from an aluminum chloride solution using an ion exchange membrane.

[0004] In recent years, it has been a big topic since aluminum may be strongly involved in the cause of Alzheimer's disease, and the target value of aluminum remaining in treated water in the item of clean water comfort water quality is 0. It is set to 2 ppm or less.

Japanese Patent Publication No. 7-10727 discloses a method for producing basic aluminum chloride for reducing residual aluminum, which comprises preparing an aqueous solution containing aluminum ions, chloride ions and sulfate ions in a normal pressure method (a). Contacting the aqueous solution with an alkaline earth metal compound (b)
A method for producing basic aluminum chlorosulfonate comprising a step and a step (c) of removing alkaline earth sulfate is disclosed. However, the basic aluminum chloride actually produced by such a method has poor cohesiveness.

[0006] The Japanese Patent 6-16416 discloses a small basic aluminum chloride residual aluminum, the following formula in its _{claim: Al (OH) a Cl b} (SO 4) c M d N e
(Where M represents an alkaline earth metal, N represents an alkali metal, and a, b, c, d and e are 1.95 <a <
2.4, 0 <c <0.15, 0 <d <0.16, 0 <e
<1.7, which is a number satisfying a + b + 2c = 3 + 2d + e) and having a basicity of 1 mol% or more of aluminum in the form of Al ₁₃ when the aluminum concentration is 0.01 M. Sulfates are disclosed. However, the method for producing polyaluminum chlorosulfate disclosed in this publication cannot produce the basic aluminum chloride having low residual aluminum as the object of the present invention.

By the way, the basicity of basic aluminum chloride according to the Japan Water Works Association standard, which is considered to present the most excellent coagulation performance, is 45 to 65%, and that of a commercially available product is 49 to 60%. . The residual aluminum value of such a currently commercially available basic aluminum chloride treated water at pH 7 or higher is extremely high.

In order to achieve the above-mentioned target value, in the present water treatment method, when aluminum sulfate or the above-mentioned basic aluminum chloride is used as a coagulant, the solubility of aluminum hydroxide formed as a precipitate is minimized at pH6. The water to be treated is treated in Steps (1) to (7), and in the case of clean water, the pH is adjusted using an alkaline agent to make the pH close to 7.5 which is regarded as delicious water.

The present inventors use the basic aluminum chloride produced by the above-described various methods to increase the basicity, the temperature during production, the aluminum raw material, the rate of addition of the raw material, the order of addition, and the basicity. As a result of intensive studies on the types of alkaline agents, it was found that the major factors related to the residual aluminum are the temperature and basicity during the production of basic aluminum chloride.

That is, the temperature at the time of production is equal to or higher than a certain temperature, and the basicity at the time of manufacturing in the first step described later is equal to or higher than a certain basicity.

The method most well known as a production method in which the production temperature is high and the basicity is relatively high at the same time is the pressure heating method, that is, the autoclave method. Regarding the method for producing basic aluminum chloride using an autoclave, JP-A-47-20096, JP-A-48-10139
8 gazette, JP-A-48-101399, JP-B-50-839,
JP-A-50-137897, JP-A-53-37596, JP-B-53-43739, JP-A-59-116125, JP-A-2-4
There is no shortage of technical disclosures in Japanese Patent Publication No. 533 and the like.

Although these publications disclose that a basic aluminum chloride having a basicity of 70% can be produced, there is no example of actual production and the maximum is 57%. However, Japanese Patent Application Laid-Open No. 50-137897 discloses an example in which a product having a basicity of 65.0% (Example 2) is produced, but such a production method produces a water treatment agent having good cohesiveness. It is not possible. On the other hand, a method for producing a basic aluminum chloride having a high basicity by carrying out a reaction at a high temperature near the boiling point also in the normal pressure method is disclosed (JP-A-52-111496). According to this method, it is described that a basic aluminum chloride having a basicity of 83% can be produced. However, an example of an actual production is at most 54.9% basicity. 7-10
No. 727 also discloses a technique of reacting at a high temperature of 70 to 115 ° C. in the normal pressure method.

The present applicant also discloses in Japanese Patent Publication No. 2-58209 a method for producing a basic aluminum chloride solution having a high basicity by adding aluminum sulfate and a calcium compound to an aluminum chloride or basic aluminum chloride solution at a high temperature. Is disclosed. JP-A-52-11384 also discloses a base having good cohesiveness by adding an alkali compound or an alkaline earth compound to aluminum chloride or basic aluminum chloride at a temperature of 60 ° C. or higher to increase the basicity to 65 to 70%. A method for producing crystalline aluminum chloride is described.

JP-A-53-1699 discloses a method for producing basic aluminum chloride having good cohesiveness and storage stability, by adding calcium carbonate to a basic aluminum chloride solution having a basicity of 42 to 45% containing sulfate ions. Basicity 55-58
% And then add an alkali metal compound or an alkaline earth metal compound at a temperature of 60 ° C. or lower to add a basicity of 60%.
A method for producing ~ 70% basic aluminum chloride is disclosed.

[0015]

As described above, when the temperature during the production of basic aluminum chloride is above a certain temperature, and when the basicity at the time of production in the first step described later is more than a certain basicity. Certain basic aluminum chlorides have been found to have very low residual aluminum when used as a flocculant, but the basic aluminum chloride thus produced has been found to have poor cohesiveness.

Therefore, as a result of further study, it was found that when an alkali agent was added thereto at a low temperature and the basicity was further increased, the cohesiveness was remarkably improved and the residual aluminum was reduced.

The present invention has been made based on these findings, and it is an object of the present invention to produce a novel basic aluminum chloride having a small amount of residual aluminum and excellent cohesiveness when used as a water treatment agent. I do.

[0018]

That is, the present invention provides a composition, M
/ Al (molar ratio) (where M represents an alkali metal or an alkaline earth metal) 0.04 to 1.80, Cl / Al
(Molar ratio) from 0.50 to 1.95, in the basicity from 65 to 83% of basic aluminum chloride, Al ₂ the basic aluminum chloride in distilled water about 500 ml (20 ± 2 ° C.)
10 ppm was added as O ₃ , the pH was adjusted to 7.8 to 8.2 with a 5% by weight sodium bicarbonate (NaHCO ₃ ) solution, the mixture was stirred at 50 rpm for 30 minutes, and allowed to stand for 30 minutes.
o. The amount of residual aluminum (Al) in the filtered water after filtration through 5C filter paper (corresponding to 5 types C specified in JIS P 3801 [filter paper (for chemical analysis)]) is Y ≦ 0.62.
A new basic aluminum chloride characterized by satisfying 5X-4.625 (where Y represents the amount of Al (ppm), X represents pH and 7.8 ≦ X ≦ 8.2); It relates to the manufacturing method.

[0019]

Basic aluminum chloride DETAILED DESCRIPTION OF THE INVENTION The present invention has the general formula ^{_{M a L Al M (OH)}} N Cl P Y Q b ( where, M represents an alkali metal or alkaline earth metal Y is a polyvalent anion And a and b represent the valences of M and Y, respectively.
aL + 3M = N + P + bQ. ), And the basicity in the present invention is represented by N / 3M × 100.

First, the physical properties of the basic aluminum chloride of the present invention will be described. The M / Al (molar ratio) of the present invention is in the range of 0.04 to 1.80. Below this range, the coagulation ability is significantly reduced. . Above this range, the basic aluminum chloride solution becomes extremely unstable.

The basicity is in the range of 65-83% basicity, and if it is less than this range, the cohesive ability is reduced and the residual aluminum is increased. On the other hand, if it exceeds the above range, not only is production difficult, but such a basic aluminum chloride solution becomes extremely unstable.

By the way, the feature of the novel basic aluminum chloride of the present invention is that, in addition to the above-mentioned physical properties, it is added to 500 ml of distilled water (20 ± 2 ° C.) as Al ₂ O _3.
ppm, and 5% by weight of sodium hydrogen carbonate (NaHCO
₃ ) Adjust the pH to 7.8-8.2 with the solution, and rotate at 50 rpm for 30 minutes.
, And allowed to stand for 30 minutes. The amount of residual aluminum (Al) in the filtered water after filtration through 5C filter paper is Y ≦
0.625X-4.625 (where Y is the amount of Al (pp
m), X indicates pH, and 7.8 ≦ X ≦ 8.2. ).

The production method of the novel basic aluminum chloride of the present invention having such physical properties will be described. The production method of the present invention can be roughly divided into two steps.

First, the first step is a step for producing basic aluminum chloride having a low basicity, and the second step is a step for further increasing the basicity using an alkali metal or an alkaline earth metal.

As the method for producing the basic aluminum chloride in the first step, any known method may be used, but the most preferable method is an autoclave method, that is, a method in which hydrochloric acid or aluminum chloride is added to aluminum hydroxide at 140 ° C.
This is a method of dissolving at ~ 180 ° C for 4 to 8 hours.

The main reason for recommending this method is that the reaction temperature is high, ie above 80 ° C. When the reaction temperature is 80 ° C. or lower, it is not possible to produce basic aluminum chloride with little residual aluminum. When the autoclave method is used, the activity is as large as possible.
That is, it is desirable to use easily soluble aluminum hydroxide.

Therefore, in the case of producing by a normal pressure method, for example, a method of dissolving metallic aluminum or aluminum hydroxide with a mixed acid of hydrochloric acid and sulfuric acid and adding a calcium compound such as calcium carbonate or calcium hydroxide to remove calcium sulfate. The reaction temperature must be maintained at 80 ° C. or higher during the dissolution of metallic aluminum or aluminum hydroxide, that is, during the reaction.

The basic aluminum chloride in the first step can also be produced by reacting concentrated hydrochloric acid with aluminum hydroxide near the boiling point as described in JP-A-52-111496.

In any case, it is extremely important in the present invention that the reaction temperature is maintained at 80 ° C. or higher during the dissolution of aluminum compounds such as metallic aluminum or aluminum hydroxide or during the desulfurization step in the mixed acid method. That is.

The second point to be noted in the first step is that
Composition of manufactured basic aluminum chloride Cl / Al
(Molar ratio) is in the range of 0.5 to 1.2.
That is, the basicity represented by the general formula is in the range of 60 to 80%. Generally, the higher the reaction temperature and the higher the basicity, the lower the residual aluminum.

Next, the second step will be described. The second step is a step of increasing the basicity. The basicity is determined by adding a hydroxide, carbonate or hydrogen carbonate of an alkali metal or alkaline earth metal. Raised by things. Specific examples include sodium hydroxide, potassium hydroxide, sodium carbonate, potassium carbonate, sodium hydrogen carbonate, potassium hydrogen carbonate, calcium hydroxide, magnesium hydroxide, calcium carbonate, magnesium carbonate, calcium hydrogen carbonate, and magnesium hydrogen carbonate. The most preferred alkaline agents are sodium carbonate and potassium carbonate.

What is essential in the second step is that the alkali metal or alkaline earth metal is added at a solution temperature of 40 ° C. or lower, and the amount of addition is M / Al (molar). Ratio) in the range of 0.04 to 1.80. If the ratio deviates from this range, as described above, the novel basic aluminum chloride of the present invention cannot be produced.

That is, if an alkali metal or alkaline earth metal is added at a solution temperature of 40 ° C. or more, a new basic aluminum chloride having excellent cohesiveness cannot be produced. Generally, the range of 10 to 40 ° C. is preferable. The basicity of the basic aluminum chloride thus produced ranges from 65 to 83%.

The method of increasing the basicity by using an alkali agent is a well-known method as described in JP-B-53-43739 or JP-A-52-111496, and the above items are strictly observed. You may follow the law as far as possible.

Next, the method for further improving the aggregation ability and storage stability of the novel basic aluminum chloride of the present invention is described in that a polyvalent anion such as a sulfate ion or a phosphate ion is allowed to exist.

As a method for causing a polyvalent anion to be present, when the above-mentioned mixed acid method is used, a calcium compound having a chemical equivalent or less to sulfuric acid may be added to the solution after dissolving aluminum. If you use any other method,
A polyacid or a water-soluble salt thereof may be added during the first step of producing the basic aluminum chloride, or may be added after the production. As a further alternative, it may be added during the second step or after the second step.

The most preferred polyvalent anion is a sulfate ion. Specifically, sulfuric acid, sodium sulfate, potassium sulfate, and aluminum sulfate are added. The amount of the polyvalent anion to be present in the basic aluminum chloride is Y / Al
(Molar ratio) It is in the range of 0.05 to 0.20. Below the lower limit, the cohesiveness and storage stability do not increase, while above the upper limit, the solution becomes extremely unstable and precipitates during storage.

The novel basic aluminum chloride of the present invention is produced as a solution as described above, but it can also be dried as a powder using a dryer such as a hot-air dryer in accordance with a conventional method.

Hereinafter, the present invention will be described in more detail with reference to examples. All percentages are by weight unless otherwise specified.

[0040]

【Example】

(Example 1) Aluminum hydroxide (Al ₂ O ₃ 65.4)
%) Was dissolved in hydrochloric acid under pressure using an autoclave to obtain basic aluminum chloride (Al ₂
O ₃ 13.96%, Cl 15.79%, basicity 45.7
%) 400 g of 1 L equipped with a stirrer, cooling tube and thermometer
Place in a four-necked flask and heat to 90 ° C. Under stirring, 78 g of calcium carbonate powder and 312 g of an aluminum sulfate solution (8.20% of Al ₂ O ₃ , 23.0% of SO ₄ ) were simultaneously added over 30 minutes. After subsequent aging at this temperature for 30 minutes, the formed gypsum is separated by filtration and Al ₂ O ₃
13.39%, Cl 10.59%, SO ₄ 1.40%,
497 g of a basic aluminum chloride solution having a composition of 1.09% Ca and a basicity of 65.3% was obtained. While maintaining 80 g of this basic aluminum chloride solution at room temperature, a solution obtained by dissolving 5.96 g of sodium carbonate in 18.7 g of distilled water was gradually added and dissolved by stirring, and 4.8 g of an aluminum sulfate solution was further mixed. , 107 g of the basic aluminum chloride solution of the invention were obtained. The analysis values are as follows. Al ₂ O ₃ 10.40%, Cl 7.82%, C
a 0.81%, Na 2.67%, SO ₄ 2.05
%, Basicity 82.6%

Example 2 Instead of 5.96 g of sodium carbonate of Example 1, a solution in which 5.3 g of magnesium carbonate was dissolved in 24.5 g of distilled water was gradually added and dissolved by stirring. Mix 4.8 g of the solution,
109 g of a basic aluminum chloride solution according to the invention were obtained. The analytical values are as follows. Al ₂ O ₃ 10.
20%, Cl 7.77%, Ca 0.80%, Mg
1.40%, SO ₄ 2.04% basicity 82.2%

Example 3 Aluminum hydroxide was dissolved in a mixed acid of hydrochloric acid and sulfuric acid, and calcium carbonate was added to the solution to remove calcium sulfate. Basic aluminum chloride (Al ₂ O ₃ 12.42) was obtained. %, Cl 9.6
_{6%, SO 4 3.17%,} Ca 0.53%, basicity 5
7.3%) into a reactor as in Example 1
Heated to ° C. Under stirring, 27.4 g of calcium carbonate and an aluminum sulfate solution (8.20% of Al ₂ O ₃ , SO ₄ 2
(3.0%) was added simultaneously over 17 minutes. After subsequently aged at this temperature for 15 minutes, the product gypsum is filtered _{off, Al 2 O 3 13.20%,} Cl 10.
Basic aluminum chloride solution 647 having a composition of 7%, 1.62% SO ₄ , 1.32% Ca and a basicity of 67.6%.
g was obtained. While maintaining 647 g of this basic aluminum chloride solution at 40 ° C. or less, 20 g of aluminum sulfate solution
Was further added, and 124 g of a 30% sodium carbonate solution was gradually added thereto, and the mixture was dissolved by stirring. Then, 80 g of distilled water was added to obtain 856 g of a basic aluminum chloride solution of the present invention. The analysis values are as follows. Al ₂ O ₃ 1
0.16%, Cl 7.74%, Ca 1.01%, N
a2.01%, SO ₄ 1.79%, basicity 80.3%

Example 4 Aluminum hydroxide (Al ₂
(35.4% O ₃ ), 375 g of 35% hydrochloric acid in 280 g, 7
467 g of 0% sulfuric acid and 190 g of distilled water were put into a 3 L four-necked flask equipped with a stirrer, a condenser, and a thermometer, and 10 g
The mixture was heated to 0 ° C. or higher to dissolve the aluminum hydroxide. After cooling to 90 ° C., the calcium carbonate 5
705 g of a 0% slurry was gradually added in 35 minutes. During and after the addition, the temperature was maintained at 90 ° C., and after aging at this temperature for 60 minutes, the formed gypsum was separated by filtration, and 14.39% of Al ₂ O ₃ , 10.28% of Cl, and SO.
₄ 1.58% Ca, 1.05% Ca and basicity 6
1060 g of a 8.3% basic aluminum chloride solution were obtained. 6.1 g of an aluminum sulfate solution was mixed with 67.4 g of this basic aluminum chloride solution at room temperature,
After slowly adding 15.5 g of a 1% sodium carbonate solution and stirring to dissolve, 11 g of distilled water was added to obtain 98 g of a basic aluminum chloride solution of the present invention. The analysis values are as follows. Al ₂ O ₃ 10.41%, Cl
6.94%, Ca 0.66%, Na 1.56%, SO
₄ 2.48%, basicity 76.1%

Example 5 45 g of metallic aluminum was added to 3
A. By slowly adding and dissolving while stirring at 99 ° C. in 109 g of 5% hydrochloric acid and 273 g of distilled water, A
425 g of a basic aluminum chloride solution having a composition of 1 ₂ O ₃ 20.0% Cl 8.34% and a basicity of 80% was obtained.
While keeping 100 g of the basic aluminum chloride at room temperature, 18.8 g of the aluminum sulfate solution was mixed, 27.8 g of a 21% sodium carbonate solution was added, and the mixture was stirred to dissolve, and then 67 g of distilled water was added. 211 g of a basic aluminum chloride solution according to the invention were obtained. The analysis values are as follows. Al ₂ O ₃ 10.21%, C
l 3.95%, Na 1.20%, SO 4 2.05%,
83% basicity

(Example 6) In Example 5, without adding the aluminum sulfate solution in the second step, 5.94 g of a 21% sodium carbonate solution was added, and 89 g of distilled water was added to obtain 192 g of the present invention. A basic aluminum chloride solution was obtained. The analytical values are as follows. Al ₂ O ₃ 1
0.40%, Cl 4.33%, Na 0.28%, basicity 81.7%

(Example 7) 45 g of aluminum metal was added to 3
A by slowly adding and dissolving while stirring at 99 ° C. in 203 g of 5% hydrochloric acid and 360 g of distilled water, A
l ₂ O ₃ 14.35%, a composition comprising 11.67% Cl,
592 g of a basic aluminum chloride solution having a basicity of 61% were obtained. While maintaining 100 g of the basic aluminum chloride at room temperature, 17 g of an aluminum sulfate solution was mixed,
Further add 26.7 g of a 21% sodium carbonate solution,
After stirring and dissolving, 11.6 g of distilled water was added to add 15 g.
3 g of a basic aluminum chloride solution according to the invention were obtained. The analysis values are as follows. Al ₂ O ₃ 10.29
%, Cl 7.63%, Na 1.59%, SO ₄ 2.5
6%, basicity 67.1%

Comparative Example 1 A basic aluminum chloride solution prepared in the same manner as in Example 1 until heated to 90 ° C. was heated and stirred at 90 ° C., and 25.1 g of calcium carbonate powder and aluminum sulfate solution were added thereto. 100 g was added at the same time, and after aging, the formed gypsum was separated by filtration, and Al ₂ O ₃ 1
3.20%, Cl 13.00%, SO ₄ 1.30%, C
a 437 g of a basic aluminum chloride solution having a composition of 0.90% and a basicity of 55.0% was obtained. While maintaining 80 g of the basic aluminum chloride solution at room temperature, a solution of 9.6 g of sodium carbonate dissolved in 22.4 g of distilled water was gradually added and dissolved by stirring, and 4.8 g of an aluminum sulfate solution was further mixed. 113 g of a basic aluminum chloride solution was obtained. The analysis values are as follows. A
_{l 2 O 3 9.69%, Cl} 9.20%, Ca 0.6
4%, Na 3.69%, SO ₄ 1.90%, basicity 8
1.3%

(Comparative Example 2) A basic aluminum chloride solution was produced in exactly the same manner as in Example 3, except that the simultaneous addition temperature of the calcium carbonate and aluminum sulfate solutions in the first step was 70 ° C. The analytical values are as follows. _{Al 2 O 3 10.21%, Cl} 7.
80%, Ca 0.90%, Na 2.00%, SO ₄
1.80%, basicity 79.1%

(Comparative Example 3) A basic aluminum chloride solution was produced in exactly the same manner as in Example 4, except that the addition temperature of the sodium carbonate solution in the second step was 90 ° C. The analytical values are as follows. Al ₂ O ₃
10.52%, Cl 6.84%, Ca 0.71%,
Na 1.58%, SO ₄ 2.50%, basicity 77%

Comparative Example 4 In Example 4, without adding the sodium carbonate solution in the second step, 7.0 g of an aluminum sulfate solution and 23.6 g of distilled water were added at room temperature, and 98 g of basic aluminum chloride was added. A solution was prepared. The analytical values are as follows. Al ₂ O ₃ 10.48
%, Cl 7.07%, Ca 0.66%, SO ₄ 2.
73%, basicity 65.2%

Comparative Example 5 A basic aluminum chloride solution having a composition of 20.0% of Al ₂ O ₃ and 8.34% of Cl and a basicity of 80% was prepared by the same operation as in Example 5.
While keeping 0 g at room temperature.
8 g, and then a 21% sodium carbonate solution 2.1
After adding 3 g and dissolving by stirring, 90 g of distilled water was added to prepare 211 g of a basic aluminum chloride solution. The results of this analysis are as follows. Al ₂ O ₃ 1
0.20%, Cl 3.95%, SO ₄ 2.05%, N
a 0.09%, basicity 75.0%

A) Residual aluminum measurement test A basic aluminum chloride solution was added as 10 ppm as Al ₂ O ₃ to 500 ml of distilled water (21 ° C.), and the pH was adjusted with a 5% sodium hydrogen carbonate (NaHCO ₃ ) solution as shown in Table 1. And stirred at 50 rpm for 30 minutes. Then, after standing for 30 minutes, The amount of aluminum in the filtered water after filtration through 5C filter paper was measured. Table 1 shows the results.

[0053]

[Table 1] ※ 1 Taki Chemical Co. salt production group of aluminum chloride (trade name PAC250A composition Al ₂ O ₃ 10.2%, basicity 50.3%, SO ₄ 2.8%)

From Table 1, it can be seen that the novel basic aluminum chloride of the present invention has much less residual aluminum than the basic aluminum chloride produced by a known method or a commercially available basic aluminum chloride.

B) Coagulation test 1) Test water Kaolinite purified by a tap water test method was dispersed and suspended in tap water. The properties of the test water are as shown in Table 2.

[Table 2] 2) Test method A predetermined amount of the basic aluminum chloride solution of the test example was added to 1,000 ml of test water, and the mixture was rapidly stirred (120 rpm × 3 minutes).
After gentle stirring (40 rpm × 10 minutes), the mixture was allowed to stand for 10 minutes, and then 100 ml of supernatant water was collected to measure turbidity. Table 3 shows the results.

[0056]

[Table 3]

Table 3 shows that the basic aluminum chloride of the present invention has excellent coagulation performance.

C) Stability test After the basic aluminum chloride of the test example was stored at 50 ° C. for 7 days, a cohesion test was performed according to B) cohesion test.
Table 4 shows the results.

[Table 4]

Table 4 shows that when a sulfate group is contained, the basic aluminum chloride solution exhibits excellent storage stability.

[0060]

EFFECT OF THE INVENTION The novel basic aluminum chloride of the present invention avoids the problem of Alzheimer's disease caused by residual aluminum in water that has recently become a problem in water treatment. Very few excellent coagulants for water treatment.

In order to reduce such residual aluminum, the use of a conventional flocculant is limited to a narrow p-type.
It can be used only in the H range and its pH range (pH 6 ~
When deviating from 7), there is a problem that the coagulation performance such as the turbidity performance is reduced and the residual aluminum in the treated water becomes extremely large. However, in the use of the basic aluminum chloride of the present invention,
It is possible to reduce the residual aluminum in the tap water without deteriorating such cohesive performance in a wide pH range.

Further, according to the method for producing basic aluminum chloride of the present invention, it is possible to avoid the problems of a decrease in product stability and a decrease in coagulation performance, which have conventionally been caused by the increase in basicity of basic aluminum chloride. However, it is possible to maintain product stability and coagulation performance for a long period of time.

Therefore, the novel basic aluminum chloride of the present invention exerts its effects best when it is used as a coagulant for water treatment, especially for water supply.
In addition to such utilization, the basic aluminum chloride of the present invention can be used in various applications such as antiperspirants, cosmetic raw materials, sizing agents, pharmaceuticals, etc., similarly to general basic aluminum chloride by utilizing its cohesiveness. Of course, it can be used.

Claims (3)

(57) [Claims] 1. Composition M / Al (molar ratio) 0.04-1.
80 (where M represents an alkali metal or an alkaline earth metal), Cl / Al (molar ratio) 0.50 to 1.9
5. In basic aluminum chloride having a basicity of 65 to 83%, the basic aluminum chloride is distilled water about 500 m.
1 (20 ± 2 ° C.), 10 ppm as Al ₂ O ₃
5% by weight sodium bicarbonate (NaHCO ₃ ) solution
H was adjusted to 7.8 to 8.2, stirred at 50 rpm for 30 minutes, and allowed to stand for 30 minutes. The amount of residual aluminum (Al) in the filtered water after filtration through 5C filter paper is Y ≦ 0.6.
25X-4.625 (where Y is the amount of Al (ppm), X
Represents pH, and 7.8 ≦ X ≦ 8.2. A novel basic aluminum chloride, characterized in that the amount satisfies (1). 2. A coagulant for water treatment comprising the novel basic aluminum chloride according to claim 1. 3. An alkali metal and / or alkaline earth metal carbonate or hydrogen carbonate at a temperature of 40 ° C. or less in a basic aluminum chloride aqueous solution of a basicity of 60% or more having a history of exposure to a temperature of 80 ° C. or more. The method for producing a novel basic aluminum chloride according to claim 1, wherein one or more of sodium and hydroxide are added.