Basic aluminum chloride-containing composition

Abstract

To provide basic aluminum chloride and a coagulant for water treatment that have high coagulating ability and excellent storage stability.SOLUTION: A basic aluminum chloride-containing composition having an Al2O3 concentration of 9.0 to 14.0 mass% and a basicity of 65.0% or more, comprising B, and satisfying the following formula (1): Formula (1): B / Al≥0.001. (In the formula, B and Al represent the contents (unit: mol) of the respective elements contained in the basic aluminum chloride-containing composition.)SELECTED DRAWING: None

Description

[Technical Field]

[0001] The present invention relates to a basic aluminum chloride-containing composition, a flocculant for water treatment containing the basic aluminum chloride-containing composition, and a flocculation treatment method. [Background technology]

[0002] The basic aluminum chloride-containing composition is used as a flocculant in the treatment of various types of wastewater and water (collectively referred to as water treatment). In recent years, there has been a demand for the market introduction of high-basicity basic aluminum chloride with higher performance. The use of such high-basicity basic aluminum chloride increases the ionization number of the basic aluminum chloride, strengthening the positive charge and enabling efficient coagulation of suspended solids. Furthermore, the use of high-basicity basic aluminum chloride can reduce the residual aluminum concentration derived from the coagulant. Furthermore, since it consumes less alkali than conventional basic aluminum chloride, it can also suppress the accompanying drop in pH.

[0003] Patent Document 1 discloses a basic aluminum chloride with a high basicity. Specifically, the molar ratios of Si to Al2O3, alkali metal to Al2O3, alkaline earth metal to Al2O3, Cl to Al2O3, and SO4 to Al2O3 are specified within predetermined ranges, and basic aluminum chloride with a basicity of 45 to 80% is described. [Prior art documents] [Patent documents]

[0004] [Patent Document 1] Japanese Patent Application Laid-Open No. 2018-154543 Summary of the Invention [Problem to be solved by the invention]

[0005] Under these circumstances, there is a demand for basic aluminum chloride and a flocculant for water treatment that have high flocculation properties and excellent storage stability. [Means for solving the problem]

[0006] One aspect of the present invention includes, for example, the following aspect of the invention. [1] A basic aluminum chloride-containing composition having an Al2O3 concentration of 9.0 to 14.0 mass % and a basicity of 65.0% or more, containing B, and satisfying the following formula (1): Formula (1): B / Al≧0.001 [In the above formula, B and Al represent the content (unit: mole) of each element contained in the basic aluminum chloride-containing composition.] [2] The basicity is 70.0% or more and 80.0% or less, B / Al in formula (1) is 5.00 or less; [1] The basic aluminum chloride-containing composition according to [1]. [3] The basic aluminum chloride-containing composition according to [1] or [2], wherein B is derived from one or more compounds selected from the group consisting of NaBO2, NaBO3, and Na2B4O7. [4] The basic aluminum chloride-containing composition according to any one of [1] to [3], wherein the concentration of Al2O3 is 10.0 to 13.0 mass %. [5] The basic aluminum chloride-containing composition according to any one of [1] to [4], further containing sulfate ions. [6] The basic aluminum chloride-containing composition according to any one of [1] to [5], which is a flocculant for water treatment. [7] A coagulation treatment method comprising the step of adding the basic aluminum chloride-containing composition according to any one of [1] to [5] to water to be treated. [Effects of the Invention]

[0007] The basic aluminum chloride-containing composition according to a preferred embodiment of the present invention has excellent storage stability, and a water treatment flocculant using the basic aluminum chloride-containing composition according to a preferred embodiment of the present invention has high flocculation properties. DETAILED DESCRIPTION OF THE INVENTION

[0008] The upper and lower limit values ​​of the numerical ranges described herein can be arbitrarily combined. For example, when a numerical range is described as "preferably 30 to 100, more preferably 40 to 80," the ranges "30 to 80" and "40 to 100" are also included in the numerical ranges described herein. Furthermore, when a numerical range is described as "30 or more, 40 or more, and may be 100 or less, or 80 or less," the ranges "30 to 80" and "40 to 100" are also included in the numerical ranges described herein. In addition, as a numerical range described in this specification, for example, "60 to 100" means a range of "60 or more (60 or more) to 100 or less (100 or less)."

[0009] 1. Basic aluminum chloride-containing composition The basic aluminum chloride contained in the basic aluminum chloride-containing composition of the present invention is [Al(OH) n Cl 6-n ] m (wherein n is an integer of 1 to 5, and m is a natural number).

[0010] The concentration of Al2O3 in the basic aluminum chloride-containing composition of the present invention is 9.0 to 14.0% by mass. However, since the higher the concentration of Al2O3 in the composition, the better the flocculation performance, it is preferably 9.1% by mass or more, 9.2% by mass or more, 9.3% by mass or more, 9.4% by mass or more, 9.5% by mass or more, 9.6% by mass or more, 9.7% by mass or more, 9.8% by mass or more, 9.9% by mass or more, 10.0% by mass or more, 10.1% by mass or more, 10.2% by mass or more, 10.3% by mass or more, 10.4% by mass or more, 10.5% by mass or more, 10.6% by mass or more, 10.7% by mass or more, 10.8% by mass or more, or 10.9% by mass or more, and more preferably 11.0% by mass or more, 11.1% by mass or more. Top, 11.2% by mass or more, 11.3% by mass or more, 11.4% by mass or more, 11.5% by mass or more, 11.6% by mass or more, 11.7% by mass or more, 11.8% by mass or more, 1 1.9 mass% or more, 12.0 mass% or more, 12.1 mass% or more, 12.2 mass% or more, 12.3 mass% or more, 12.4 mass% or more, 12.5 mass% or more, 12.6 Mass% or more, 12.7 mass% or more, 12.8 mass% or more, 12.9 mass% or more, 13.0 mass% or more, 13.1 mass% or more, 13.2 mass% or more, 13.3 mass% or more, 13.4 mass% or more, 13.5 mass% or more, 13.6 mass% or more, 13.7 mass% or more, 13.8 mass% or more, or 13.9 mass% or more.Further, the concentration of Al2O3 in the basic aluminum chloride-containing composition of the present invention is 13.9% by mass or less, 13.8% by mass or less, 13.7% by mass or less, 13.6% by mass or less, 13.5% by mass or less, 13.4% by mass or less, 13.3% by mass or less, 13.2% by mass or less, 13.1% by mass or less, 13.0% by mass or less mass% or less, 12.9 mass% or less, 12.8 mass% or less, 12.7 mass% or less, 12.6 mass% or less, 12.5 mass% or less, 12.4 mass% or less, 12.3 mass% or less, 12.2 mass% or less, 12.1 mass% or less, 12.0 mass% or less, 11.9 mass% or less, 11.8 mass% or less, 11.7 mass% 11.6 mass% or less, 11.5 mass% or less, 11.4 mass% or less, 11.3 mass% or less, 11.2 mass% or less, 11.1 mass% or less, 11.0 mass% or less, 10.9 mass% or less, 10.8 mass% or less, 10.7 mass% or less, 10.6 mass% or less, 10.5 mass% or less, 10.4 mass% or less Below, 10.3% by mass or less, 10.2% by mass or less, 10.1% by mass or less, 10.0% by mass or less, 9.9% by mass or less, 9.8% by mass or less, 9.7% by mass or less, 9.6% by mass or less, 9.5% by mass or less, 9.4% by mass or less, 9.3% by mass or less, 9.2% by mass or less, or 9.1% by mass or less. In this specification, the concentration of Al2O3 contained in the basic aluminum chloride-containing composition is determined in accordance with JIS K1475:2006.

[0011] The basic aluminum chloride-containing composition of the present invention contains B (boron atom). B has the property of forming a stable bond with oxygen atoms, and in water it becomes boric acid, an oxoacid, and ionizes to form borate ions, which are anions. Therefore, when the boron-containing composition of the present invention is added to water to be treated, the borate ions further promote the binding due to the adsorption action of the aluminum-based flocculant, making it easier to form flocs. As a result, when the composition of the present invention is used as a water treatment flocculant, it can more effectively flocculate turbid matter contained in the water to be treated. In this specification, the water to be treated is not particularly limited, but examples include raw water for drinking water supply (surface water from rivers, etc.), industrial water, industrial wastewater, domestic wastewater, livestock wastewater, and the like. The origin of the B contained in the composition is not particularly limited, but B derived from a salt of a boron oxoacid is preferred. Examples include B derived from sodium perborate (NaBO), sodium tetraborate (NaBO), sodium metaborate (NaBO), and hydrates thereof, with B derived from sodium metaborate (NaBO) being more preferred.

[0012] The basic aluminum chloride-containing composition of the present invention satisfies the following formula (1). Formula (1): B / Al≧0.001 [In the above formula, B and Al represent the content (unit: mole) of the element contained in the basic aluminum chloride-containing composition.] In this specification, the contents of the elements B, Al, and Cl refer to values ​​measured by inductively coupled plasma (ICP) emission spectrometry.

[0013] In the above formula (1), B / Al is 0.001 or more, but from the viewpoint of storage stability, it is preferably 0.002 or more, 0.004 or more, 0.006 or more, 0.008 or more, 0.01 or more, 0.012 or more, 0.014 or more, 0.016 or more, 0.018 or more, 0.02 or more, 0.03 or more, 0.04 or more, or 0.05 or more. Furthermore, B / Al may be 0.06 or more, 0.07 or more, 0.08 or more, 0.09 or more, 0.10 or more, 0.11 or more, 0.12 or more, 0.13 or more, 0.14 or more, 0.15 or more, 0.16 or more, 0.17 or more, 0.18 or more, 0.19 or more, 0.20 or more, 0.25 or more, 0.30 or more, 0.35 or more, or 0.40 or more. Furthermore, B / Al may be 0.50 or less, 0.45 or less, 0.40 or less, 0.35 or less, 0.30 or less, 0.25 or less, 0.20 or less, 0.15 or less, 0.10 or less, 0.09 or less, 0.08 or less, 0.07 or less, 0.06 or less, 0.05 or less, 0.04 or less, 0.03 or less, 0.02 or less, 0.018 or less, 0.016 or less, 0.014 or less, 0.012 or less, 0.01 or less, 0.008 or less, 0.006 or less, 0.004 or less, or 0.002 or less. B (boron atom) means all B contained in the basic aluminum chloride-containing composition of the present invention, and is the total amount of B bound to alkali metals, alkaline earth metals, etc. that may be contained in the composition.

[0014] The basicity of the basic aluminum chloride-containing composition of the present invention is 65.0% or more. Since a high basicity of the basic aluminum chloride-containing composition of the present invention improves flocculation performance, the basicity is preferably 66.0% or more, 67.0% or more, 68.0% or more, 69.0% or more, 70.0% or more, 71.0% or more, 72.0% or more, 73.0% or more, or 74.0% or more, and may also be 75.0% or more, 76.0% or more, 77.0% or more, 78.0% or more, 79.0% or more, 80.0% or more, 81.0% or more, 82.0% or more, 83.0% or more, 84.0% or more, or 85.0% or more. Furthermore, if the basicity of the basic aluminum chloride-containing composition is too high, the alkaline components increase relatively, and the undissolved and unreacted components increase, making it more likely that the amount of residue during production will increase. Therefore, the basicity may be 90.0% or less, 85.0% or less, 82.0% or less, 80.0% or less, 79.0% or less, 78.0% or less, 77.0% or less, 76.0% or less, 75.0% or less, 74.0% or less, 73.0% or less, 72.0% or less, 71.0% or less, 70.0% or less, 69.0% or less, 68.0% or less, 67.0% or less, or 66.0% or less. In this specification, the basicity of the basic aluminum chloride-containing composition is measured in accordance with JIS K1475:2006.

[0015] The basic aluminum chloride-containing composition of the present invention has an Al2O3 concentration of 9.0 to 14.0 mass%, a basicity of 65.0% or more, contains B, and may contain other components as long as it satisfies the above formula (1). Specifically, the composition of the present invention may contain alkali metals, alkaline earth metals, sulfate ions, etc.

[0016] The basic aluminum chloride-containing composition of the present invention preferably contains sulfate ions from the viewpoint of improving flocculation performance. The content of sulfate ions is preferably 0.1 to 3.5 mass %, more preferably 1.0 to 2.5 mass %. The content of sulfate ions is preferably SO4 2- It is preferable that the molar ratio of SO4 / Al is 0 or more and 0.18 or less. 2- The upper limit of the molar ratio of / Al is more preferably 0.16, and even more preferably 0.14. When sulfate ions are contained, for example, SO4 2- It is preferable that the molar ratio of Al to Al is 0.01 or more and 0.14 or less.

[0017] The basic aluminum chloride-containing composition of the present invention may contain an alkali metal. With regard to the content of the alkali metal, when the alkali metal is M, the molar ratio M / Al is preferably 0 or more and 1 or less. The upper limit of the molar ratio M / Al is more preferably 0.8, and even more preferably 0.7. When an alkali metal is contained, the molar ratio M / Al is preferably 0.01 or more and 0.70 or less, for example.

[0018] The form of the basic aluminum chloride-containing composition of the present invention is not particularly limited, but is preferably an aqueous solution.

[0019] 2. Method for producing basic aluminum chloride-containing composition The method for producing the basic aluminum chloride-containing composition of the present invention is not particularly limited, but it can be produced, for example, through the following steps. (Step 1) A process in which an aluminum compound such as aluminum hydroxide and hydrochloric acid are placed in an autoclave and subjected to hydrothermal treatment to produce basic aluminum chloride. (Step 2) Adding a boron compound (Step 3) Step of adjusting basicity

[0020] In step 1, the aluminum compound and hydrochloric acid are preferably mixed so as to obtain a basicity of the final basic aluminum chloride. The pressure during the hydrothermal treatment in step 1 is not particularly limited, but is preferably higher than atmospheric pressure; specifically, treatment is preferably carried out at 0.1 to 1.5 MPa, more preferably 0.1 to 1.2 MPa, even more preferably 0.2 to 1.0 MPa, and particularly preferably 0.2 to 0.8 MPa. The temperature during the hydrothermal treatment in step 1 is also not particularly limited, but aluminum hydroxide is preferably dissolved in hydrochloric acid at a temperature in the range of 90 to 200°C, more preferably 90 to 190°C, even more preferably 100 to 180°C, and particularly preferably 90 to 170°C.

[0021] In step 1, a basicity adjuster may be used to change the basicity of the basic aluminum chloride. Examples of basicity adjusters include alkali metal hydroxides, alkaline earth metal hydroxides, alkali metal carbonates, alkaline earth metal carbonates, alkali metal bicarbonates, alkaline earth metal bicarbonates, and alkali metal aluminates. Specific examples of alkali metal and alkaline earth metal hydroxides include lithium hydroxide, sodium hydroxide, potassium hydroxide, calcium hydroxide, and magnesium hydroxide. Specific examples of alkali metal and alkaline earth metal carbonates and bicarbonates include lithium carbonate, sodium carbonate, potassium carbonate, calcium carbonate, magnesium carbonate, sodium bicarbonate, potassium bicarbonate, and calcium bicarbonate. Specific examples of alkali metal aluminates include sodium aluminate.

[0022] In step 2, the boron compound is blended so as to satisfy the above formula (1). The content of B in the composition of the present invention can be changed by the amount of boron compound added. The method of adding the boron compound is not particularly limited, and the boron compound may be added in the above amount in any step of the process for producing basic aluminum chloride. Preferably, the boron compound is added in the final step of producing basic aluminum chloride, or boron may be added in advance to the hydrochloric acid used in step 1. After these steps, further purification, drying, etc. may be performed according to conventional methods. The boron compound used in step 2 is not particularly limited, but a salt of a boron oxoacid is preferred. Representative salts of boron oxoacids include sodium metaborate (NaBO), sodium tetraborate, potassium tetraborate, and sodium perborate. The above-mentioned salts of boron oxoacids may be formed by dissolving boric acid or diboron trioxide in water to generate borate ions, and then neutralizing the liberated hydrogen ions with a basic substance to form a salt of a boron oxoacid.

[0023] In step 3, the basicity of the composition is adjusted. If the basicity of the final composition falls within a predetermined range, step 3 need not be performed. The basicity can be adjusted, for example, by adding an alkaline agent such as carbonate or bicarbonate. The basicity can be increased by substituting OH for Cl in the basic aluminum chloride molecule, thereby reducing the Cl content and increasing the OH content.

[0024] Examples of alkaline agents that can be used in step 3 include alkali metal salts and alkaline earth metal salts such as sodium carbonate, sodium bicarbonate, calcium carbonate, and calcium bicarbonate. Among these, sodium carbonate and sodium bicarbonate are preferred because of their high solubility in water and low cost. These compounds may be used alone or in combination of two or more. The order of step 3 is not particularly limited, but it is preferably carried out between steps 1 and 2 or after steps 1 and 2.

[0025] In addition to steps 1, 2 and 3, other steps may be included. For example, the B / Al ratio defined by formula (1) can be adjusted in step 1, but a step for adjusting the B / Al ratio may be further provided. Specifically, the B / Al ratio can be adjusted by adding an aluminum compound.

[0026] In addition to the basic aluminum chloride produced in step 1, commercially available products sold under the names of basic aluminum chloride and polyaluminum chlorides of normal basicity, high basicity, ultra-high basicity, etc. may also be used as the basic aluminum chloride.

[0027] 3. Flocculants for water treatment Generally, suspended solids contained in water often have the properties of a colloidal solution, with the particle surfaces carrying a negative charge, which repel each other, creating a stable state. When ordinary aluminum-based flocculants are diluted with water, hydrolysis progresses, forming aluminum polymers with larger positive charges, which neutralize the surface charge of the suspended solids, creating an attractive force between the particles and forming fine clumps (flocs). Furthermore, the hydrolyzed product of the aluminum-based flocculant bonds the suspended solids together, mainly through adsorption, to form flocs, which then precipitate. The basic aluminum chloride-containing composition of the present invention also contains a certain amount of B. Boron atoms have the property of forming stable bonds with oxygen atoms, and boron compounds typically become boric acid, an oxoacid, in water and ionize to form borate ions, an anion. Therefore, when the boron-containing composition of the present invention is added to water to be treated, flocs are more likely to be formed, in which the bonding due to the adsorption action of the aluminum-based flocculant is further promoted by the borate ions. This enhances the flocculation action of suspended matter when the composition of the present invention is used as a flocculant for water treatment. As described above, the basic aluminum chloride composition of the present invention has the ability to flocculate impurities in the water to be treated, and therefore can be used as a water treatment flocculant containing the composition. In particular, the water treatment flocculant of the present invention has a relatively high basicity, and therefore has a high flocculation ability for suspended matter.

[0028] The water treatment flocculant of the basic aluminum chloride-containing composition of the present invention may further contain a flocculant other than basic aluminum chloride. For example, the composition of the present invention may contain, in addition to basic aluminum chloride, an inorganic flocculant such as ferric polysulfate or an organic polymer flocculant.

[0029] There is a high correlation between the amount of suspended solids in water and turbidity, and turbidity is generally used as an indicator of the amount of impurities in water (dirt, turbidity). Therefore, coagulation can be evaluated by the change in turbidity before and after coagulation treatment.

[0030] 4. Coagulation treatment method The flocculation treatment method of the present invention is carried out by adding the basic aluminum chloride-containing composition of the present invention to water to be treated. The amount of the basic aluminum chloride-containing composition to be added when flocculating impurities in the water to be treated is not particularly limited, but is, for example, 1 to 1000 mg / L, preferably 3 to 300 mg / L. The basic aluminum chloride-containing composition of the present invention may be added to the water to be treated all at once, or may be added in two or more portions. After addition, it is preferable to stir the mixture for about 10 minutes.

[0031] The coagulation treatment method of the present invention can coagulate impurities in the water to be treated by the action of positively charged aluminum polymers, etc. The coagulation treatment method of the present invention can be used in various water treatments similar to various water treatments that utilize conventional coagulation methods that use aluminum salt-based inorganic coagulants to coagulate impurities in the water to be treated. After the coagulation treatment, treated water can be obtained by solid-liquid separation using a known method such as sedimentation or filtration.

[0032] The impurities in the water to be treated are insoluble substances suspended in water, such as suspended solids. The substances that can be flocculated by the flocculation treatment method of the present invention are not particularly limited, but examples include rock debris such as clay (particle size 0.004 mm or less) and silt (particle size 0.06 mm or less), inorganic substances such as metals, metal hydroxides, and metal oxides, suspended matter derived from living organisms such as fungi and algae, and organic substances such as oil. Examples of water to be treated that contains such impurities include raw water for drinking water (surface water from rivers, etc.), industrial water, industrial wastewater, domestic wastewater, and livestock wastewater. [Example]

[0033] The present invention will be explained in more detail below with reference to examples, but the present invention is not limited to these examples.

[0034] In the examples and comparative examples herein, storage stability and cohesion were measured as follows.

[0035] [Storage stability] In the present invention, the storage stability of the basic aluminum chloride-containing composition was evaluated by calculating the difference in turbidity before and after storage at 50° C. for 21 days, as calculated by the following formula. Turbidity difference (degrees) = (turbidity after storage at 50°C for 21 days) - (turbidity before storage) These turbidities were measured using a turbidity meter TR-55 (Kasahara Chemical Industries Co., Ltd.).

[0036] [Cohesion] In the present invention, the flocculation property was evaluated by the turbidity reduction rate calculated by the following formula using a Jar test in which turbidity is used as an index. Coagulation = Turbidity reduction rate (%) = {(Turbidity of test water before jar test) - (Turbidity of supernatant water after jar test)} / (Turbidity of test water before jar test) The jar test was conducted at 25°C using a jar tester MJS-6T (Daido Kogyosho Co., Ltd.) on test water containing 50 mg / L of kaolin (aluminum earth) as a simulated turbid substance. The flocculation conditions for the jar test were as follows: 1 L of test water was placed in a 1 L beaker and stirred at 100 rpm, while a basic aluminum chloride-containing composition was added at an injection rate of 10 mg / L. This was followed by rapid stirring at the same 100 rpm for 1 minute, slow stirring at 60 rpm for 10 minutes, and then allowed to stand for 10 minutes. The test water before the jar test and the supernatant water after the jar test were sampled, and their turbidities were measured using a WA7700 turbidity meter / colorimeter (Nippon Denshoku Industries Co., Ltd.).

[0037] Storage stability of 10 degrees or less was considered pass, and above 10 degrees was considered fail. Cohesion of 85% or more was considered pass, and below 85% was considered fail. Test examples that met the pass criteria for storage stability and cohesion were given an overall rating of A, test examples that failed either one were given an overall rating of B, and test examples that failed both were given an overall rating of C.

[0038] [Example 1] Using an autoclave, 9.0 g of aluminum hydroxide was dissolved in 17.7 g of 35 mass % hydrochloric acid at a temperature of 100 to 150°C and a pressure of 0.2 to 0.4 MPa to obtain 26.7 g of basic aluminum chloride solution. Next, the obtained basic aluminum chloride solution and aluminum sulfate (Al2O3: 8.0 mass %, SO4 2- 3.4 g of aluminum chloride (22.4 mass%) and 19.1 g of 21% sodium carbonate solution were mixed at a liquid temperature of 100°C or less, and 1.4 g of sodium metaborate and 6.9 g of water were added, followed by filtration to obtain 48.7 g of a basic aluminum chloride-containing composition (solution).

[0039] The basicity (%), Al2O3 concentration (mass %), B / Al (molar ratio), storage stability (degree), and cohesion (%) of this basic aluminum chloride-containing composition (solution) are shown in Table 1.

[0040] [Example 2] A basic aluminum chloride-containing composition (solution) was prepared under the same conditions as in Example 1, except that 15.8 g of 21% sodium carbonate solution was mixed and no water was added together with 1.4 g of sodium metaborate. The resulting basic aluminum chloride-containing composition (solution) weighed 39.5 g.

[0041] [Comparative Example 1] Using an autoclave, 9.0 g of aluminum hydroxide was dissolved in 17.7 g of 35 mass % hydrochloric acid at a temperature of 100 to 150°C and a pressure of 0.2 to 0.4 MPa to obtain 26.7 g of basic aluminum chloride solution. Next, the obtained basic aluminum chloride solution and aluminum sulfate (Al2O3: 8.0 mass %, SO4 2-3.4 g of aluminum chloride (22.4 mass%) and 19.1 g of 21% sodium carbonate solution were mixed at a liquid temperature of 100°C or less, and 1.4 g of sodium metaborate and 22.6 g of water were added, followed by filtration to obtain 64.4 g of a basic aluminum chloride-containing composition (solution). Comparative Example 2 Using an autoclave, 9.1 g of aluminum hydroxide was dissolved in 18.0 g of 35 mass % hydrochloric acid at a temperature of 100 to 150°C and a pressure of 0.2 to 0.4 MPa to obtain 27.1 g of basic aluminum chloride solution. Next, the obtained basic aluminum chloride solution and aluminum sulfate (Al2O3: 8.0 mass %, SO4 2- 3.4 g of aluminum chloride (22.4 mass%) and 19.2 g of 21% sodium carbonate solution were mixed at a liquid temperature of 100°C or less, and 6.9 g of water was added, followed by filtration to obtain 48.8 g of a basic aluminum chloride-containing composition (solution).

[0042] Comparative Example 3 Using an autoclave, 8.6 g of aluminum hydroxide was dissolved in 16.4 g of 35 mass % hydrochloric acid at a temperature of 100 to 150°C and a pressure of 0.2 to 0.4 MPa to obtain 25.0 g of basic aluminum chloride solution. Next, the obtained basic aluminum chloride solution and aluminum sulfate (Al2O3: 8.0 mass %, SO4 2- 3.8 g of aluminum chloride (22.4 mass%) and 14.1 g of 8.8% sodium carbonate solution were mixed at a liquid temperature of 100°C or less, and 1.5 g of sodium metaborate and 7.6 g of water were added, followed by filtration to obtain 47.5 g of a basic aluminum chloride-containing composition (solution).

[0043] Comparative Example 4 A basic aluminum chloride-containing composition (solution) was prepared under the same conditions as in Comparative Example 3, except that 8.6 g of aluminum hydroxide was dissolved in 16.5 g of 35 mass % hydrochloric acid to obtain 25.1 g of a basic aluminum chloride solution and that sodium metaborate was not used. The obtained basic aluminum chloride-containing composition (solution) weighed 45.4 g. Table 1 shows the basicity (%), Al2O3 concentration (mass %), B / Al (molar ratio), storage stability (degree), and aggregation (%) of Example 2 and Comparative Examples 1 to 4.

[0044] [Table 1]

[0045] High storage stability and cohesion were confirmed in Examples 1 and 2. In contrast, Comparative Example 2 had high cohesion but low storage stability. Comparative Examples 1 and 3 had high storage stability but low cohesion. Furthermore, Comparative Example 4 had low storage stability and low cohesion.

Claims

1. Al ２ O ３ A basic aluminum chloride-containing composition having a concentration of 9.0 to 14.0 mass % and a basicity of 65.0% or more, containing B, and satisfying the following formula (1): Formula (1): B / Al≧0.001 [In the above formula, B and Al represent the content (unit: mole) of each element contained in the basic aluminum chloride-containing composition.]

2. The basicity is 70.0% or more and 80.0% or less, B / Al in formula (1) is 5.00 or less; The basic aluminum chloride-containing composition of claim 1 .

3. The B is NaBO ２ , NaBO ３ and Na ２ B ４ O ７ The basic aluminum chloride-containing composition according to claim 1, wherein the basic aluminum chloride-containing composition is derived from one or more compounds selected from the group consisting of:

4. Al ２ O ３ The basic aluminum chloride-containing composition according to claim 1, wherein the concentration of

5. The basic aluminum chloride-containing composition according to claim 1 , further comprising sulfate ions.

6. The basic aluminum chloride-containing composition according to any one of claims 1 to 5, which is a flocculant for water treatment.

7. A coagulation treatment method comprising the step of adding the basic aluminum chloride-containing composition according to any one of claims 1 to 5 to water to be treated.

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