JP2009203125A - Novel basic aluminum chloride, its manufacturing method and its application - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To provide a novel basic aluminum chloride having low residual aluminum concentration and having excellent organic material removing performance in particular at water treatment and to provide its manufacturing method. <P>SOLUTION: In the basic aluminum chloride, a composition M/Al<SB>2</SB>O<SB>3</SB>(molar ratio) is 0.08 to 1.40 (wherein, M represents a molar number of an alkali metal and/or 2 times molar number of an alkaline earth metal), Cl/Al<SB>2</SB>O<SB>3</SB>(molar ratio) is 1.50 to 2.80, and SO<SB>4</SB>/Al<SB>2</SB>O<SB>3</SB>(molar ratio) is 0.10 to 0.35. The novel basic aluminum chloride has peaks of chemical shift of 0 ppm, 3-5 ppm, 6-14 ppm, and 50-65 ppm in<SP>27</SP>Al-NMR spectrum. <P>COPYRIGHT: (C)2009,JPO&INPIT

Description

  The present invention relates to a basic aluminum chloride used for a water treatment flocculant and the like, and relates to a novel basic aluminum chloride having excellent flocculation performance and excellent organic substance removal performance, a method for producing the same, and use thereof.

  In recent years, in the field of water purification and wastewater treatment, not only turbidity is removed, but also the odor generated from various organic substances dissolved in water and the reaction between organic substances and disinfectant sodium hypochlorite. There is a demand for removal of various organic substances such as reduction of by-products such as trihalomethane, or removal of low molecular weight organic substances that cause membrane clogging of membrane treatment modules.

  Under such circumstances, the inorganic water treatment chemicals currently used include aluminum flocculants such as aluminum sulfate, aluminum chloride, basic aluminum chloride, ferrous chloride, ferric chloride, sulfuric acid. Iron-based flocculants such as ferrous sulfate, ferric sulfate, and polyferric sulfate are used.

  Among these flocculating agents, iron-based flocculating agents have excellent flocculation performance and high organic substance removal performance. However, they contain Mn and other heavy metals derived from raw materials as impurities. It is rarely used in the field of sewage treatment, which is strictly regulated because the generated sludge is colored brown from iron oxide, and is mainly used in the field of wastewater treatment. Also in the field of wastewater treatment, aluminum-based flocculants are used when heavy metals are mixed or sludge coloring becomes a problem.

  On the other hand, aluminum flocculants such as aluminum sulfate and basic aluminum chloride are widely used as flocculants that do not have the above problems in the field of water purification treatment. Among them, basic aluminum chloride is particularly excellent in flocculation performance and has high removal efficiency. Since it shows turbidity, it is the main chemical for water purification.

  Currently, the basicity standard in basic aluminum chloride of the Japan Water Works Association standard, which is said to have the best agglomeration performance, is 45 to 65%, and the commercial product is in the range of 49 to 60% basicity. .

  Many improvement studies such as increasing the basicity with the aim of improving the performance of such basic aluminum chloride have been carried out, but there has been no technique capable of improving the removal performance of organic substances.

For example, Japanese Patent Publication No. 7-10727 discloses a method for producing basic aluminum chloride having a high basicity in order to reduce the residual aluminum concentration after the coagulation-precipitation treatment. In the atmospheric pressure method, aluminum ions, chloride ions and sulfate ions are disclosed. A basic chlorosulfone comprising: (a) a step of preparing an aqueous solution comprising: (b) a step of contacting the aqueous solution with an alkaline earth metal compound; and (c) a step of removing alkaline earth sulfate. A method for producing aluminum oxide is disclosed. (See Patent Document 1)
However, the highly basic aluminum chloride produced by this method can reduce the residual aluminum concentration, but the organic substance removal performance is almost the same as the conventional basic aluminum chloride, and no performance improvement is observed.

  As described above, various technical improvements of basic aluminum chloride have been attempted, and technical improvements such as improvement of agglomeration performance, improvement of storage stability or reduction of residual aluminum concentration have been made. There was no technique for improving the organic substance removal performance.

  In this way, regulations are expected to be strengthened in the future, and removal of organic substances contained in raw water, which has been hated by consumers from the viewpoint of mold odor and taste, is strongly resistant to basic aluminum chloride. Although requested, there has been a situation where no effective solution has been found so far.

Japanese Patent Publication No. 7-10727

As described above, a conventional method for producing basic aluminum chloride with excellent organic substance removal performance has not been found. Therefore, the inventors of the present invention, with respect to basic aluminum chloride produced by the various production methods described above, the basicity, the temperature during production, the aluminum raw material, the addition rate of the raw material, the order of addition, the alkali used to increase the basicity As a result of intensive studies on the type of agent, etc., in order to improve the organic substance removal rate with basic aluminum chloride, the composition Al ₂ O ₃ concentration is 5 to 17%, Cl / Al ₂ O ₃ (molar ratio) = Alkaline metal in a basic aluminum chloride solution of 1.80 to 3.60, SO ₄ / Al ₂ O ₃ (molar ratio) = 0 to 0.35 and basicity of 40 to 63% at a temperature of 85 ° C. or lower. And / or after adding an alkaline earth metal compound, aging at 65 to 85 ° C. for 0.5 to 2 hours can produce basic aluminum chloride with a remarkably excellent removal rate of organic matter. discovered.

  The present invention has been made based on these findings, and aims to produce basic aluminum chloride that retains the excellent cohesiveness of basic aluminum chloride and has excellent organic substance removal performance. To do.

That is, the present invention has a composition M / Al ₂ O ₃ (molar ratio) = 0.08 to 1.40 (where M is a mole twice the number of moles of alkali metal and / or alkaline earth metal). The basic aluminum chloride in which Cl / Al ₂ O ₃ (molar ratio) = 1.50 to 2.80 and SO ₄ / Al ₂ O ₃ (molar ratio) = 0.10 to 0.35 The present invention relates to a novel basic aluminum chloride characterized in that chemical shifts have peaks at 0 ppm, 3-5 ppm, 6-14 ppm and 50-65 ppm in a ²⁷ Al-NMR spectrum under the following conditions.

Further, the present invention has a composition Al ₂ O ₃ concentration of 5 to 17%, Cl / Al ₂ O ₃ (molar ratio) = 1.80 to 3.60, SO ₄ / Al ₂ O ₃ (molar ratio) = 0 to 0. After adding an alkali metal and / or alkaline earth metal compound to a basic aluminum chloride solution having a basicity of .35 and a basicity of 40 to 63% at a temperature of 85 ° C. or below, The present invention relates to a novel method for producing basic aluminum chloride characterized by aging for 5 to 2 hours.

  Since the novel basic aluminum chloride of the present invention has excellent cohesiveness and excellent organic substance removal performance, it is particularly useful as a water treatment agent for purified water.

The basic aluminum chloride of the present invention has a composition of M / Al ₂ O ₃ (molar ratio) = 0.08 to 1.40 (where M is the number of moles of alkali metal and / or the number of moles of alkaline earth metal). Twice the number of moles.), Cl / Al ₂ O ₃ (molar ratio) = 1.50 to 2.80 and SO ₄ / Al ₂ O ₃ (molar ratio) = 0.10 to 0.35 In basic aluminum chloride, basic aluminum chloride having peaks in chemical shifts of 0 ppm, 3-5 ppm, 6-14 ppm, and 50-65 ppm in a ²⁷ Al-NMR spectrum under the following conditions. The following NMR measurement conditions (hereinafter referred to as predetermined NMR measurement conditions) are shown.

<NMR measurement conditions>
Apparatus: Nuclear magnetic resonance spectrophotometer Sample dilution ratio: Undiluted temperature: Room temperature Probe: 5 mmφ
Measurement mode: Reverse gated coupling irradiation quantitative measurement resonance frequency: 103 MHz
Pulse width: 0.410 seconds Pulse repetition: 5.41 seconds Integration count: 1024 times Chemical shift standard: Al (H ₂ O) ₆ ³⁺ in a 3 mol / L aluminum nitrate solution is set to 0 ppm by an external standard method.

Next, the physical properties of the basic aluminum chloride of the present invention will be described. The concentration of Al ₂ O ₃ contained in the basic aluminum chloride solution of the present invention is higher when considering the practicality as a water treatment flocculant. However, it is preferably 10% or more, but not particularly limited thereto.

First, M / Al ₂ O ₃ (molar ratio) of the present invention is in the range of 0.08 to 1.40 (where M is a mole twice the number of moles of alkali metal and / or alkaline earth metal). In this case, the organic substance removing performance is reduced below this range. Moreover, when this range is exceeded, storage stability will worsen. A more preferable range of M / Al ₂ O ₃ (molar ratio) is 0.2 to 1.2.

Next, Cl / Al ₂ O ₃ (molar ratio) is in the range of 1.50 to 2.80, and below this range, it becomes difficult to produce the basic aluminum chloride of the present invention, for example, production. Even if it can be done, the cohesiveness decreases. On the other hand, if it exceeds this range, the above-mentioned alkali metal or alkaline earth metal necessary for obtaining the basic aluminum chloride of the present invention becomes too much, so that the storage stability is lowered. A more preferable range of Cl / Al ₂ O ₃ (molar ratio) is 1.80 to 2.60.

The SO ₄ / Al ₂ O ₃ (molar ratio) is in the range of 0.10 to 0.35, and if it falls below this range, the cohesiveness decreases. Conversely, if it exceeds this range, the basic chloride obtained The storage stability of aluminum is significantly reduced. A more preferable range of SO ₄ / Al ₂ O ₃ (molar ratio) is 0.15 to 0.30.

  As described above, the basicity of the basic aluminum chloride of the present invention is generally in the range of 65 to 75%.

By the way, in addition to the above physical properties, the novel basic aluminum chloride of the present invention has chemical shifts of 0 ppm, 3-5 ppm, 6-14 ppm, 50- in the ²⁷ Al-NMR spectrum obtained under predetermined NMR measurement conditions. It has a peak at 65 ppm.

When the process for producing the novel becomes basic aluminum chloride of the present invention having such physical properties, first, the composition M / _Al 2 _{O 3} (molar ratio) = 0.08 to 1.40 (however, M is Represents the number of moles of alkali metal and / or twice the number of moles of alkaline earth metal.), Cl / Al ₂ O ₃ (molar ratio) = 1.50-2.80 and SO ₄ / Al ₂ A first step for producing basic aluminum chloride of O ₃ (molar ratio) = 0.10 to 0.35 and a second step for aging the basic aluminum chloride produced in the first step for a certain period of time within a certain temperature range. Divided into processes.

The first step is usually divided into two stages. That is, (1) composition the concentration of _Al 2 _{O 3 5~17%, Cl / Al 2 O} 3 ( molar _{ratio) = 1.80~3.60, SO 4 / Al} 2 O 3 ( molar ratio) = 0-0 1. A first step of producing a basic aluminum chloride solution (hereinafter referred to as basic aluminum chloride before adjustment) having a basicity of 40 to 63%, and (2) basic aluminum chloride before adjustment In addition, an alkali metal and / or alkaline earth metal compound is added at a temperature of 85 ° C. or lower, and an aluminum raw material is added as necessary, so that the composition M / Al ₂ O ₃ (molar ratio) = 0. 08 to 1.40 (where M represents the number of moles of alkali metal and / or twice the number of moles of alkaline earth metal), Cl / Al ₂ O ₃ (molar ratio) = 1.50 ～2.80 and _SO 4 / _Al 2 _{O 3} (molar ratio) = 0.10 to 0. 5 become basic aluminum chloride (hereinafter, referred to as basic aluminum chloride before ripening.) A second step of manufacturing a.

  Any known production method may be used for the first step of producing basic aluminum chloride before adjustment in the first step.

Usually, the method used to manufacture the basic aluminum chloride, for example, an aluminum compound such as aluminum hydroxide was dissolved in hydrochloric acid in an autoclave, Cl / _Al 2 _{O 3} (molar ratio) = 3.00 to 3 And a method for producing basic aluminum chloride before adjustment having a basicity of 40 to 50% can be used.

In addition, if an example of a known production method for producing basic aluminum chloride before adjustment in the first stage of the first step is given,
(1) Method of dissolving metallic aluminum in hydrochloric acid or aluminum chloride (Japanese Patent Publication No. 49-47639, etc.)
(2) A method in which an aluminum-containing substance is decomposed with a mixed acid of a monovalent acid such as hydrochloric acid and sulfuric acid, and then sulfate ions are removed as an insoluble precipitate (Japanese Examined Patent Publication Nos. 44-24883, 45-6687, etc.) )
(3) A method of separating insoluble calcium sulfate by adding calcium chloride and calcium carbonate to this solution after dissolving an aluminum-containing substance such as aluminum hydroxide in sulfuric acid (JP-A-48-50998, etc.)
(4) A method of preparing an acid-soluble alumina gel in advance and mixing and dissolving the alumina gel with hydrochloric acid, aluminum chloride or basic aluminum chloride (Japanese Patent Publication No. 50-5159, Japanese Patent Publication No. 45-38121, JP-A-7-172824)
Etc. Note that SO ₄ is adjusted with sulfuric acid or aluminum sulfate. Briefly describing the characteristics of these manufacturing methods:
In the method (1) of dissolving metal aluminum in hydrochloric acid or aluminum chloride, it is necessary to dissolve excess metal aluminum in hydrochloric acid or aluminum chloride, so that the dissolution time becomes longer. For this reason, it is better to raise the melting temperature, but in order to obtain basic aluminum chloride with good cohesiveness, it is not preferable that the melting temperature is too high, and it is important to produce while balancing the two. . Basic aluminum chloride that can be produced by this production method has an Al ₂ O ₃ concentration of 10 to 23%, a composition Cl / Al ₂ O ₃ (molar ratio) = 1.00 to 3.60, and a basicity of 40 to 80. % Basic aluminum chloride solution. Regarding the Cl / _Al 2 _{O 3} (molar ratio), may be manufactured such that two or more.

The method (2), in which the aluminum-containing substance is decomposed with a mixed acid of monovalent acid such as hydrochloric acid and sulfuric acid, and then the sulfate ions are removed as an insoluble precipitate, does not require a pressurizing device, etc., and is relatively short Although it can be produced, solid-liquid separation at the time of removing sulfate ions as insoluble salts is important, and insoluble sulfate compounds remain in the product and impair stability unless they are precisely filtered. Basic aluminum chloride that can be produced by this production method has an Al ₂ O ₃ concentration of 10 to 11%, a composition Cl / Al ₂ O ₃ (molar ratio) = 2.00 to 2.50, and SO ₄ / Al ₂ O. ₃ (molar ratio) = 0.10 to 0.30, basic aluminum chloride solution having a basicity of about 45 to 60%.

The method of separating the insoluble calcium sulfate by adding calcium chloride and calcium carbonate to this solution after dissolving an aluminum-containing substance such as aluminum hydroxide in (3) with sulfuric acid is almost the same as the method of (2). You need to be careful. Basic aluminum chloride that can be produced by this production method has an Al ₂ O ₃ concentration of 10 to 11%, a composition Cl / Al ₂ O ₃ (molar ratio) = 2.50 to 3.50, and SO ₄ / Al ₂ O. ₃ (molar ratio) = 0.10 to 0.20, basic aluminum chloride solution having a basicity of about 45 to 55%.

In order to produce basic aluminum chloride with good cohesion even in the method (4) of preparing a readily acid-soluble alumina gel and mixing and dissolving this alumina gel with hydrochloric acid, aluminum chloride or basic aluminum chloride. For this, the temperature at which the alumina gel is dissolved is also important. When the temperature is high, the dissolution is easy, but the cohesiveness is sacrificed for the reason described above. It is necessary to manufacture while balancing the two. Basic aluminum chloride that can be produced by this production method has an Al ₂ O ₃ concentration of 10 to 14%, a composition Cl / Al ₂ O ₃ (molar ratio) = 2.00 to 3.50, and SO ₄ / Al ₂ O. ₃ (molar ratio) = 0.15 to 0.30, basic aluminum chloride solution having a basicity of about 45 to 70%.

  The basic aluminum chloride solution before adjustment is manufactured in the first step of the first step using the above-described known manufacturing method. Then, as a second stage of the first step, basic aluminum chloride before aging is produced from basic aluminum chloride before adjustment.

For example, in the first step of the first step, Cl / Al ₂ O ₃ (molar ratio) produced using the above-described autoclave = 3.00 to 3.60, basicity before adjustment of 40 to 50% basicity. When producing basic aluminum chloride before aging in the second stage from aluminum chloride, it is produced as follows.

First, basic aluminum chloride before the adjustment made using an autoclave in the first stage, due to the high Cl / _Al 2 _{O 3} (molar ratio), Cl / _Al 2 _{O 3} is (molar ratio) 1. An aluminum raw material is added and dissolved so as to be 50 to 2.80. That is, by neutralizing aluminum sulfate or aluminum chloride with a hydroxide or carbonate of an alkali metal or alkaline earth metal as described in JP-A-7-172824, and washing the produced neutralized product. An aluminum raw material such as a known alumina gel (aluminum hydroxide gel) or a highly basic aluminum chloride having a basicity of 80% or more is added and dissolved to obtain a Cl / Al ₂ O ₃ (molar ratio) of 1.50-2. Adjust to 80. Thereafter, sulfate such as sulfuric acid or aluminum sulfate is added so that SO ₄ / Al ₂ O ₃ (molar ratio) = 0.10 to 0.35, and then an alkali metal or alkaline earth metal compound is added to M / Al ₂ O ₃ (molar ratio) = 0.08 to 1.40 (where M represents the number of moles of alkali metal and / or twice the number of moles of alkaline earth metal). When added to the above, a basic aluminum chloride solution before aging can be produced.

  The reaction condition for the second stage of the first step is that the temperature at which the alkali metal or alkaline earth metal compound is added is below 85 ° C. When the temperature exceeds 85 ° C. during the addition / reaction, the storage stability of the novel basic aluminum chloride solution of the present invention finally produced is deteriorated.

  Further, hydroxides, carbonates, hydrogen carbonates, and the like can be used as the alkali metal or alkaline earth metal compounds that can be used at this time. More specifically, sodium hydroxide, potassium hydroxide, sodium carbonate, potassium carbonate, sodium bicarbonate, potassium bicarbonate, sodium aluminate, potassium aluminate, calcium hydroxide, magnesium hydroxide, calcium carbonate, magnesium carbonate , Calcium hydrogen carbonate, magnesium hydrogen carbonate and the like, and most preferred are sodium carbonate and potassium carbonate.

  The above is an example of producing basic aluminum chloride before aging in the second stage from basic aluminum chloride before adjustment produced using an autoclave in the first stage.

Thus, when the composition of the basic aluminum chloride before adjustment obtained by a known method in the first stage of the first step is Cl / Al ₂ O ₃ (molar ratio) = 2.80 or more, the aluminum raw material Are added and dissolved while stirring to adjust the Cl / Al ₂ O ₃ (molar ratio) to 1.50 to 2.80. Similarly, as necessary was added to a sulfuric acid salt such as sulfate or aluminum sulfate to _SO 4 / _Al 2 _{O 3} (molar ratio) = 0.10 to 0.35, then, 85 ° C. below the temperature Under the conditions, the compound of alkali metal or alkaline earth metal is M / Al ₂ O ₃ (molar ratio) = 0.08 to 1.40 (where M is the number of moles of alkali metal and / or the mole of alkaline earth metal) The basic aluminum chloride solution before the aging in the second stage of the first step can be produced.

  Although basic aluminum chloride before aging can be produced by the above-described method, the basicity of basic aluminum chloride before aging obtained in this first step is approximately 65 to 75%.

In addition, for example, when using the above-described production method in which an acid-soluble aluminum gel is produced and the aluminum gel is dissolved with hydrochloric acid, the produced alumina gel, so-called active alumina gel, ant potassium metal such as sodium carbonate is used. The compound or alkaline earth metal compound is previously added to M / Al ₂ O ₃ (molar ratio) = 0.08 to 1.40 (where M is the number of moles of alkali metal and / or the number of moles of alkaline earth metal). And a mixed solution of hydrochloric acid and sulfuric acid was added to this mixture with Cl / Al ₂ O ₃ (molar ratio) = 1.50 to 2.80, SO ₄ / Al. _If it is gradually added with stirring so that ₂ O ₃ (molar ratio) = 0.10 to 0.35 and reacted at a temperature of 85 ° C. or lower, the first stage and the second stage of the first step Can be performed simultaneously.

  Thus, the basic aluminum chloride before aging obtained in the first step is known to have excellent agglomeration performance as a water treatment flocculant and low performance of residual aluminum remaining after the agglomeration treatment. However, in practice, basic aluminum chloride before aging is actually used because of its high viscosity and difficulty in use, or very short storage stability. There was no. In addition, such basic aluminum chloride is not used due to the fact that there was no significant difference in the organic substance removal performance from commercially available basic aluminum chloride (basicity 65% or less). is there.

Next, in the 2nd process which is the characteristics of this invention, the basic aluminum chloride solution before ageing | curing | ripening manufactured at the 1st process is heat-aged at the temperature of 65-85 degreeC. The approximate relationship between the aging time and the aging temperature at this time is described. For example, aging is performed at 65 ° C. for 2 hours, at 70 ° C. for 1 hour, and at 85 ° C. for 30 minutes. However, since the optimal aging time at each temperature is slightly different when the composition or the concentration of sulfate ions contained is different, a predetermined peak in the ²⁷ Al-NMR spectrum is determined under predetermined NMR measurement conditions after determining the composition to be produced. The optimal aging temperature and time may be determined so that

  Although the novel basic aluminum chloride of the present invention is produced as a solution as described above, it can be dried and used as a powder by a conventional method using a dryer such as a hot air dryer.

Although the mechanism of the excellent organic substance removal performance of the novel basic aluminum chloride of the present invention is not clear, as described above, the novel basic aluminum chloride of the present invention has a predetermined position in the ²⁷ Al-NMR spectrum. It can be considered that the form of contained aluminum is changed from the form of aluminum contained in the conventional basic aluminum chloride. In general, aluminum in a basic aluminum chloride solution is said to form a polynuclear complex, but various physical properties were measured in order to investigate the aluminum form of the basic aluminum chloride of the present invention.

First, aluminum hydroxide is dissolved with a mixed acid of hydrochloric acid and sulfuric acid, and calcium carbonate is added thereto to remove calcium sulfate. Composition (number of moles of Ca × 2) / Al ₂ O ₃ (molar ratio) = 0 .16, basic aluminum chloride (base) with Cl / Al ₂ O ₃ (molar ratio) = 2.3, SO ₄ / Al ₂ O ₃ (molar ratio) = 0.29, Al ₂ O ₃ concentration = about 12% Degree (54.8%) was produced (hereinafter referred to as (A)). The reaction temperature during production was 80 ° C. This was diluted with water to produce a commercially available basic aluminum chloride having an Al ₂ O ₃ concentration of 10.2% (hereinafter referred to as a commercially available equivalent basic aluminum chloride). This commercially available equivalent basic aluminum chloride has chemical shift peaks at 0 ppm and 3-5 ppm in the ²⁷ Al-NMR spectrum under predetermined NMR measurement conditions, but peaks at 6-14 ppm and 50-65 ppm. There was nothing.

Next, while stirring the above (A) at 75 ° C., 21% sodium carbonate solution added over about 40 minutes (hereinafter referred to as (B)) was added at 75 ° C. for 1 hour after the addition. Aging, composition (number of moles of Na + number of moles of Ca × 2) / Al ₂ O ₃ (molar ratio) = 1.10, Cl / Al ₂ O ₃ (molar ratio) = 2.3, SO ₄ / Al ₂ A basic aluminum chloride (basicity: 70.1%) having an O ₃ (molar ratio) = 0.29 and an Al ₂ O ₃ concentration = 10.5% was produced, and this was diluted with water to produce Al ₂ O _3. The concentration was 10.2% of the novel basic aluminum chloride of the present invention (hereinafter referred to as the basic aluminum chloride of the present invention). The basic aluminum chloride of the product of the present invention had ²⁷ Al-NMR spectra with chemical shift peaks at 0 ppm, 3-5 ppm, 6-14 ppm, and 50-65 ppm under predetermined NMR measurement conditions.

  Next, when the particle size distribution of commercially available equivalent basic aluminum chloride was measured by a dynamic scattering light method, the primary particle diameter and secondary particle diameter were 14 to 18 nm and 1100 to 1300 nm, respectively. The primary particle size and the secondary particle size of the basic aluminum chloride of the product of the present invention measured under the same conditions are 20 to 24 nm and 1350 to 1550 nm, respectively, and both the primary particles and the secondary particles are large. It was shown that the basic aluminum chloride has a larger particle size and more aluminum nucleation.

  Also, in the molecular weight measurement by the static scattering light method, the same sample as that used for the particle size distribution measurement was used. The molecular weight of the commercially available basic aluminum chloride was about 30 kDa, which was the same. The molecular weight of the basic aluminum chloride of the product of the present invention measured under the conditions was as large as about 50 kDa, showing the same results as the particle size distribution measurement.

Furthermore, in addition to particle size distribution measurement and molecular weight measurement, the aluminum component fractionated by an ultrafiltration membrane (manufactured by Polysulfone) having a molecular weight cut-off of 10,000 was measured. In the measurement method, the basic aluminum chloride solution to be measured is diluted so that the Al ₂ O ₃ concentration is 1.0%, and this is passed through an ultrafiltration membrane by a pressurization method, and the Al ₂ O in the passed solution is passed through. _Three concentrations were measured and the fractionated aluminum component ratio was calculated. As a result, the commercially available basic aluminum chloride solution was 59.5%. On the other hand, that of the product of the present invention had a high fractionation ratio of 70.2%, indicating that multinucleation was progressing.

  In addition, the freezing points of the commercially available equivalent basic aluminum chloride and the basic aluminum chloride of the present invention were measured to be −14 ° C. and −7 ° C., respectively, and the freezing point of the basic aluminum chloride of the present invention was commercially available. The result was about 7 ° C. higher than the freezing point of the equivalent basic aluminum chloride. From this result, it can be seen that the basic aluminum chloride of the present invention is not only multinucleated but also less affected by water, which is a solvent, as compared with the commercially available equivalent basic aluminum chloride. This suggests that in addition to multinuclearization, crystallization may be progressing.

Therefore, when the Raman spectrum of 1800-1900 cm ⁻¹ was confirmed by Raman spectroscopic analysis (measurement wavelength: 532 nm, 180 degree scattering, Cret triple), the peak intensity was slightly stronger in the spectrum of the basic aluminum chloride of the present invention. However, it was not enough to show that crystallization had progressed.

Next, in order to further confirm the aging process during production, that is, the influence of the second step on the multinucleation of aluminum, the composition (B) (without heat aging) described above (number of moles of Na + number of moles of Ca × 2 ) / Al ₂ O ₃ (molar ratio) = 1.10 composition, Cl / Al ₂ O ₃ (molar ratio) = 2.3, SO ₄ / Al ₂ O ₃ (molar ratio) = 0.29, Al ₂ O ₃ concentration = 10.5% basic aluminum chloride (basicity 70.1%) was produced and diluted with water to obtain Al ₂ O ₃ concentration = 10.2% basic aluminum chloride (heat-aged) None) was manufactured. In this basic aluminum chloride, the ²⁷ Al-NMR spectrum had peaks at chemical shifts of 0 ppm and 3-5 ppm in a predetermined NMR measurement, but did not have peaks at 6-14 ppm and 50-65 ppm.

  The particle size distribution of the basic aluminum chloride thus obtained (without heat aging) measured by the dynamic scattering light method was measured under the same conditions as described above. The primary particle size and the secondary particle size were 16 to 16, respectively. They were 20 nm and 1200-1400 nm. Similarly, the molecular weight measurement result by the static scattering light method was about 40 kDa, but considering the measurement error etc., the difference in physical properties from the basic aluminum chloride of the present invention is unclear. It was not possible to clearly determine whether the multinucleation of aluminum further progressed. Furthermore, although the freezing point and the Raman spectrum were measured in the same manner, it could not be shown whether the crystallization of the aluminum multinuclear complex proceeded by heat aging.

  As described above, various studies were conducted to elucidate the mechanism of the excellent organic substance removal performance of the novel basic aluminum chloride of the present invention. It was suggested that the crystallization of the polynuclear complex was progressing, but the mechanism of organic substance removal performance could not be clarified.

  The present invention will be further described with reference to the following examples. In the examples, “%” means “% by mass” unless otherwise specified.

  E260 used as an index of the organic substance concentration used in the present invention is in accordance with “Water Supply Test Method 2001 Version (published by Japan Water Works Association)”, and is the absorbance at a wavelength of 260 nm of raw water or treated water. . According to this “Water Supply Test Method 2001 Edition”, “Organic substances having unsaturated bonds in water absorb in the ultraviolet region, so the absorbance at a wavelength of 250 to 260 nm is measured, and the organic contamination is in the raw water state. In this example, the organic substance concentration was measured by E260, and the difference from the comparative control was confirmed.

[Example 1 and Comparative Example 1]
A commercially available basic aluminum chloride solution was prepared by the following method.

First, aluminum hydroxide is dissolved in a mixed acid of hydrochloric acid and sulfuric acid, and calcium carbonate is added thereto to remove the calcium sulfate produced. The composition (number of moles of Ca × 2) / Al ₂ O ₃ (molar ratio) = 0.16, Cl / Al ₂ O ₃ (molar ratio) = 2.0, SO ₄ / Al ₂ O ₃ (molar ratio) = 0.29, Al ₂ O ₃ concentration = 12% basic aluminum chloride solution (Basicity 59.9%) was produced (hereinafter referred to as (C)). This was diluted with water to produce a basic aluminum chloride solution having an Al ₂ O ₃ concentration of 10.2% (Comparative Example 1). This basic aluminum chloride solution had peaks at chemical shifts of 0 ppm and 3-5 ppm in the ²⁷ Al-NMR spectrum under the following measurement conditions, but did not have peaks at 6-14 ppm and 50-65 ppm.

<NMR measurement conditions>
Apparatus: Nuclear magnetic resonance spectrophotometer Sample dilution ratio: Undiluted temperature: Room temperature Probe: 5 mmφ
Measurement mode: Reverse gated coupling irradiation quantitative measurement resonance frequency: 103 MHz
Pulse width: 0.410 seconds Pulse repetition: 5.41 seconds Integration count: 1024 times Chemical shift standard: Al (H ₂ O) ₆ ³⁺ in a 3 mol / L aluminum nitrate solution is set to 0 ppm by an external standard method.

Next, in order to produce the basic aluminum chloride solution of the present invention, 21% sodium carbonate solution was added over 40 minutes while stirring the above (C) at 75 ° C. Aged for time, composition (number of moles of Na + number of moles of Ca × 2) / Al ₂ O ₃ (molar ratio) = 0.77, Cl / Al ₂ O ₃ (molar ratio) = 2.0, SO ₄ / Al A basic aluminum chloride solution (basicity: 70.0%) with ₂ O ₃ (molar ratio) = 0.29 and Al ₂ O ₃ concentration = 10.5% was prepared and diluted with water to produce Al ₂ A novel basic aluminum chloride solution of the present invention having an O ₃ concentration of 10.2% was prepared (Example 1). This basic aluminum chloride solution of the present invention had chemical shift peaks at 0 ppm, 3-5 ppm, 6-14 ppm, and 50-65 ppm in the ²⁷ Al-NMR spectrum under the measurement conditions described above.

  The organic substance removal test was carried out using the novel basic aluminum chloride solution of the present invention thus produced and the basic aluminum chloride solution of Comparative Example 1.

  For the organic matter removal test, the river water in the vicinity of Hokkaido Shin-Kushiro River Aikoku Water Treatment Plant shown in Table 1 was used. In addition, in this test, the treated water pH after removing organic matter by adding 0.1 N hydrochloric acid and sodium hydroxide solution to the river water in consideration of the temporal change and seasonal variation of the river water pH is pH 7 ~ Adjusted to about 8. A predetermined amount of basic aluminum chloride solution was added to the river water thus adjusted for pH, and an organic matter removal test was conducted.

  The specific method for the organic matter removal test is to add 1L of pH adjusted river water to a 1L glass beaker, add a basic aluminum chloride solution to 30mg / L, and then change the stirring condition to the water purification test method. Similarly, the mixture was stirred at 120 rpm for 3 minutes, further stirred at 40 rpm × 10 minutes to form and grow aggregated flocs, and then allowed to stand for 10 minutes to settle the aggregated flocs, and then the supernatant was collected. In addition, the liquid temperature of the treated water at this time was about 20 degreeC. The turbidity of the collected sample was measured with a turbidimeter, and the pH was measured with a glass electrode type pH meter. Moreover, after filtering a sample with glass fiber filter paper, E260 was measured with the spectrophotometer using the quartz glass cell of 1-cm optical path length. In addition, the residual aluminum concentration was measured by ICP emission spectroscopy. The results are shown in Table 2.

  As is clear from Table 2, the basic aluminum chloride of the present invention was able to significantly reduce E260 as compared with the commercially available basic aluminum chloride (Comparative Example 1).

  Furthermore, the basic aluminum chloride of the present invention is excellent as a water treatment flocculant having a significantly lower residual aluminum concentration and a high turbidity as compared with a commercially available basic aluminum chloride (Comparative Example 1). Demonstrated its performance.

[Example 2 and Comparative Example 2]
A basic aluminum chloride solution (Al ₂ O ₃ 16.0%, Cl 20.0%) obtained by dissolving aluminum hydroxide (Al ₂ O ₃ 64.0%) with hydrochloric acid under pressure using an autoclave. An aluminum hydroxide gel (Al ₂ O ₃ 10.4%) obtained by neutralizing an aluminum sulfate solution with a sodium hydroxide solution to 1000 g and thoroughly washing the resulting neutralized precipitate. ) 1200 g was added and dissolved over about 60 minutes, and further 200 g of an aluminum sulfate solution (Al ₂ O ₃ 8.0%, SO ₄ 22.5%) was mixed with this solution to obtain an Al ₂ O ₃ concentration of 12. 5%, Cl concentration 8.3%, Composition Cl / Al ₂ O ₃ (molar ratio) = 1.91, SO ₄ / Al ₂ O ₃ (molar ratio) = 0.16 and basicity 62.8% The basic aluminum chloride Beam solution was obtained 2400g a. The entire amount of the basic aluminum chloride solution was put in a reaction vessel equipped with a stirrer, a condenser tube, and a thermometer and heated to 50 ° C. Thereafter, 330 g of 5% sodium hydroxide solution was gradually added over about 30 minutes. After completion of the addition, after aging at 85 ° C. for 30 minutes, 200 g of water was added and the composition Na / Al ₂ O ₃ (molar ratio) = 0.14, Cl / Al ₂ O ₃ (molar ratio) = 1. 2930 g of a novel basic aluminum chloride solution of the present invention having a .91, SO ₄ / Al ₂ O ₃ (molar ratio) = 0.16, Al ₂ O ₃ concentration = 10.3% was prepared. The other concentrations were Cl 6.8%, Na 0.3%, SO ₄ 1.5%, and the basicity was 65.2%.

The basic aluminum chloride solution of the present invention produced as described above had peaks at 0 ppm, 3-5 ppm, 6-14 ppm, and 50-65 ppm in chemical shift in the ²⁷ Al-NMR spectrum under the above-described measurement conditions (implementation). Example 2).

Moreover, the basic aluminum chloride solution which does not age by the same manufacturing method was also manufactured.
The basic aluminum chloride not subjected to aging had chemical shift peaks at 0 ppm and 3-5 ppm in the ²⁷ Al-NMR spectrum under the measurement conditions described above, but peaks at 6-14 ppm and 50-65 ppm. There was no (Comparative Example 2).

  The basic aluminum chloride solution of the present invention produced as described above and the basic aluminum chloride solution that was not aged were subjected to an organic matter removal test according to Example 1 at pH 7.6 after treatment. As a result, E260 of the basic aluminum chloride solution of the present invention was 0.050, and E260 of the basic aluminum chloride solution that was not aged (Comparative Example 2) was 0.065, which is a reduction rate with respect to E260 of Comparative Example 2 Showed excellent organic substance removal performance of -23%.

[Example 3]
Using an autoclave, aluminum hydroxide _{(Al 2} O 3 64.0%) obtained a basic aluminum chloride solution by the hydrochloric acid dissolved under pressure _{(Al 2 O 3 16.0%,} Cl 20.0% Basicity 40%) Highly basic aluminum chloride solution prepared by dissolving metal aluminum powder in hydrochloric acid in 1000 g (Al ₂ O ₃ 23.0%, Cl 8.4%, basicity 82.5%) Was added and stirred and mixed. To this, 1200 g of water and 300 g of aluminum sulfate (Al ₂ O ₃ 8.0%, SO ₄ 22.6%) were added and mixed with stirring to obtain an Al ₂ O ₃ concentration of 11.8%, a Cl concentration of 8.1%, 3700 g of a basic aluminum chloride solution having a composition Cl / Al ₂ O ₃ (molar ratio) = 1.97, SO ₄ / Al ₂ O ₃ (molar ratio) = 0.17 and having a basicity of 61.3% was obtained. .

While stirring the total amount of the basic aluminum chloride solution at a liquid temperature of 50 ° C., 600 g of a 25% sodium carbonate solution was gradually added over about 50 minutes. After completion of the addition, the liquid temperature was adjusted to 75 ° C. and aging was performed for 1 hour with stirring to obtain a basic aluminum chloride solution of the present invention. The basic aluminum chloride solution of the present invention has an Al ₂ O ₃ concentration of 10.3%, Na / Al ₂ O ₃ (molar ratio) = 0.70, and Cl / Al ₂ O ₃ (molar ratio) = 1. 97, SO ₄ / Al ₂ O ₃ (molar ratio) = 0.17. Chemical shifts had peaks at 0 ppm, 3-5 ppm, 6-14 ppm, and 50-65 ppm in the ²⁷ Al-NMR spectrum under the measurement conditions described above. The basicity was 73.0%.

  In order to confirm the organic substance removal performance of the basic aluminum chloride solution of the present invention, a test was conducted using the river water of the Chikugo River near the Kokoji purification plant in Kurume-shi, Fukuoka as raw water. The test procedure and method were carried out in accordance with Example 1. Table 3 shows the quality of the raw water and Table 4 shows the test results.

[Comparative Example 3]
A basic aluminum chloride solution was produced under the same conditions as in Example 3 except that aging was not performed during production. Therefore, the composition of this basic aluminum chloride solution is the same as in Example 3. However, in the ²⁷ Al-NMR spectrum under the measurement conditions described above, chemical shifts had peaks at 0 ppm and 3-5 ppm, but did not have peaks at 6-14 ppm and 50-65 ppm.

  In order to confirm the organic substance removal performance of this basic aluminum chloride solution, a test was conducted according to Example 3. Table 3 shows the quality of the raw water and Table 4 shows the test results.

  As is apparent from Table 4, the basic aluminum chloride of the present invention was able to significantly reduce E260 compared to the basic aluminum chloride that was not aged (Comparative Example 3).

  Furthermore, the basic aluminum chloride of the present invention has high turbidity as compared with the basic aluminum chloride not subjected to aging (Comparative Example 3) and is excellent as a water treatment flocculant, and at the same time, the residual aluminum concentration can be slightly reduced. Excellent performance.

[Comparative Example 4]
Metal aluminum powder was dissolved in hydrochloric acid in 1000 g of a basic aluminum chloride solution (Al ₂ O ₃ 16.0%, Cl 20.0%, basicity 40%), prepared in the same manner as in Example 3, and adjusted. 1200 g of the prepared highly basic aluminum chloride solution (Al ₂ O ₃ 23.0%, Cl 8.4%, basicity 82.5%) was added and stirred and mixed. To this, 2000 g of water and 200 g of aluminum sulfate (Al ₂ O ₃ 8.0%, SO ₄ 22.6%) were added and mixed with stirring. Al ₂ O ₃ concentration 10.2%, Cl concentration 6.5%, A basic aluminum chloride solution having a composition Cl / Al ₂ O ₃ (molar ratio) = 1.85, SO ₄ / Al ₂ O ₃ (molar ratio) = 0.21 and a basicity of 62.4% was obtained. Then, 60 g of a 25% sodium carbonate solution was gradually added over about 10 minutes while stirring the liquid temperature of this basic aluminum chloride solution at 50 ° C. After completion of the addition, the liquid temperature was adjusted to 75 ° C. and aged for 1 hour with stirring to obtain a basic aluminum chloride solution. This basic aluminum chloride solution has an Al ₂ O ₃ concentration of 10.1%, Na / Al ₂ O ₃ (molar ratio) = 0.06, Cl / Al ₂ O ₃ (molar ratio) = 1.85, SO ₄ / Al ₂ O ₃ (molar ratio) = 0.21. In the ²⁷ Al-NMR spectrum under the measurement conditions described above, chemical shifts had peaks at 0 ppm and 3-5 ppm, but did not have peaks at 6-14 ppm and 50-65 ppm. The basicity was 63.4%.

  In order to confirm the organic substance removal performance of this basic aluminum chloride solution, an organic substance removal test was conducted in accordance with Example 3. E260 was 0.025 to 0.035 depending on the pH after treatment, and was a comparative example. It was equivalent to the organic substance removal performance of conventional basic aluminum chloride solutions such as 3.

[Comparative Example 5]
Metal aluminum powder was dissolved in hydrochloric acid in 500 g of a basic aluminum chloride solution (Al ₂ O ₃ 16.0%, Cl 20.0%, basicity 40%) before adjustment, which was produced by the same method as in Example 3. 500 g of the manufactured highly basic aluminum chloride solution (Al ₂ O ₃ 23.0%, Cl 8.4%, basicity 82.5%) was added and stirred and mixed. To this, 250 g of water and 300 g of aluminum sulfate (Al ₂ O ₃ 8.0%, SO ₄ 22.6%) were added and mixed by stirring. Al ₂ O ₃ concentration was 14.1% and Cl concentration was 9.2%. A basic aluminum chloride solution having a composition of Cl / Al ₂ O ₃ (molar ratio) = 1.86, SO ₄ / Al ₂ O ₃ (molar ratio) = 0.33 and a basicity of 58.0% was obtained. . Then, 700 g of a 25% sodium carbonate solution was gradually added over about 90 minutes while stirring at a temperature of 50 ° C. of the basic aluminum chloride solution. After completion of the addition, the liquid temperature was adjusted to 75 ° C. and aged for 1 hour with stirring to obtain a basic aluminum chloride solution. The concentration of _Al 2 _{O 3} basic aluminum chloride solution at _{10.2%, Na / Al 2 O} 3 ( molar _{ratio) = 1.54, Cl / Al 2} O 3 ( molar ratio) = 1.86, SO ₄ / Al ₂ O ₃ (molar ratio) = 0.33. Chemical shifts had peaks at 0 ppm, 3-5 ppm, 6-14 ppm, and 50-65 ppm in the ²⁷ Al-NMR spectrum under the measurement conditions described above. The basicity was 83.6%.

Since this basic aluminum chloride solution had an excessively high Na / Al ₂ O ₃ (molar ratio), the storage stability was poor such that white turbidity and thickening started in about 30 days when stored at 25 ° C.

[Comparative Example 6]
Metal aluminum powder was dissolved in hydrochloric acid in 250 g of a basic aluminum chloride solution (Al ₂ O ₃ 16.0%, Cl 20.0%, basicity 40%) before adjustment, which was produced by the same method as in Example 3. 1000 g of the produced highly basic aluminum chloride solution (Al ₂ O ₃ 23.0%, Cl 8.4%, basicity 82.5%) was added and stirred and mixed. This water 1100g and aluminum sulfate _{(Al 2 O 3 8.0%,} SO 4 22.6%) was added 300g stirred and mixed, _Al 2 _{O 3} concentration 11.1% Cl concentration 5.1%, A basic aluminum chloride solution having a composition Cl / Al ₂ O ₃ (molar ratio) = 1.31, SO ₄ / Al ₂ O ₃ (molar ratio) = 0.25 and a basicity of 70.0% was obtained. Thereafter, 300 g of a 25% sodium carbonate solution was gradually added over about 40 minutes while stirring the liquid temperature of the basic aluminum chloride solution at 50 ° C. After completion of the addition, the liquid temperature was adjusted to 75 ° C. and aged for 1 hour with stirring to obtain a basic aluminum chloride solution. This basic aluminum chloride solution has an Al ₂ O ₃ concentration of 10.1%, Na / Al ₂ O ₃ (molar ratio) = 0.49, Cl / Al ₂ O ₃ (molar ratio) = 1.31, SO ₄ / Al ₂ O ₃ (molar ratio) = 0.25. Chemical shifts had peaks at 0 ppm, 3-5 ppm, 6-14 ppm, and 50-65 ppm in the ²⁷ Al-NMR spectrum under the measurement conditions described above. The basicity was 78.2%.

  In order to confirm the organic substance removal performance of this basic aluminum chloride solution, an organic substance removal test was conducted according to Example 3. However, the cohesiveness was poor and the turbidity was higher than that of Comparative Example 3. For that reason, E260 was also a value of 0.03 or more, which was worse than the organic substance removing performance of the conventional basic aluminum chloride solution.

[Comparative Example 7]
Metal aluminum powder was dissolved in hydrochloric acid in 1000 g of a basic aluminum chloride solution (Al ₂ O ₃ 16.0%, Cl 20.0%, basicity 40%), prepared in the same manner as in Example 3, and adjusted. 50 g of the prepared highly basic aluminum chloride solution (Al ₂ O ₃ 23.0%, Cl 8.4%, basicity 82.5%) was added and stirred and mixed. To this, 200 g of aluminum sulfate (Al ₂ O ₃ 8.0%, SO ₄ 22.6%) was added and stirred and mixed, and the Al ₂ O ₃ concentration was 15.0%, the Cl concentration was 16.3%, the composition Cl / Al ₂ O ₃ (molar ratio) = _3.13, SO 4 / _Al 2 _{O 3} (molar ratio) = 0.26 at and basicity was obtained 39.3% of basic aluminum chloride solution. Then, 650 g of a 25% sodium carbonate solution was gradually added over about 70 minutes while stirring the liquid temperature of this basic aluminum chloride solution at 50 ° C. After completion of the addition, the liquid temperature was adjusted to 75 ° C. and aged for 1 hour with stirring to obtain a basic aluminum chloride solution. This basic aluminum chloride solution had an Al ₂ O ₃ concentration of 10.4%, Na / Al ₂ O ₃ (molar ratio) = 1.67, Cl / Al ₂ O ₃ (molar ratio) = 3.13, SO ₄ / Al ₂ O ₃ (molar ratio) = 0.26. Chemical shifts had peaks at 0 ppm, 3-5 ppm, 6-14 ppm, and 50-65 ppm in the ²⁷ Al-NMR spectrum under the measurement conditions described above. The basicity was 67.0%. As a result of the Na / Al ₂ O ₃ (molar ratio) being too high, this basic aluminum chloride solution had poor storage stability such as white turbidity and thickening in about 20 days when stored at 25 ° C.

[Comparative Example 8]
Metal aluminum powder was dissolved in hydrochloric acid in 1000 g of a basic aluminum chloride solution (Al ₂ O ₃ 16.0%, Cl 20.0%, basicity 40%), prepared in the same manner as in Example 3, and adjusted. 1200 g of the prepared highly basic aluminum chloride solution (Al ₂ O ₃ 23.0%, Cl 8.4%, basicity 82.5%) was added and stirred and mixed. To this, 1600 g of water and 150 g of aluminum sulfate (Al ₂ O ₃ 8.0%, SO ₄ 22.6%) were added and mixed by stirring. Al ₂ O ₃ concentration 11.3%, Cl concentration 7.6%, composition A basic aluminum chloride solution having Cl / Al ₂ O ₃ (molar ratio) = 1.93, SO ₄ / Al ₂ O ₃ (molar ratio) = 0.08 and a basicity of 65.1% was obtained. Then, 500 g of a 25% sodium carbonate solution was gradually added over about 50 minutes while stirring the basic aluminum chloride solution at a temperature of 50 ° C. After completion of the addition, the liquid temperature was adjusted to 75 ° C. and aged for 1 hour with stirring to obtain a basic aluminum chloride solution. The basic aluminum chloride solution had an Al ₂ O ₃ concentration of 10.2%, Na / Al ₂ O ₃ (molar ratio) = 0.54, Cl / Al ₂ O ₃ (molar ratio) = 1.93, SO ₄ / Al ₂ O ₃ (molar ratio) = 0.08. Chemical shifts had peaks at 0 ppm, 3-5 ppm, 6-14 ppm, and 50-65 ppm in the ²⁷ Al-NMR spectrum under the measurement conditions described above. The basicity was 74.1%.

In order to confirm the organic substance removal performance of this basic aluminum chloride solution, an organic substance removal test was conducted according to Example 3. However, SO ₄ / Al ₂ O ₃ (molar ratio) = 0.08 is too low. The cohesiveness was poor and the turbidity was higher than that of Comparative Example 3. For that reason, E260 was also a value of 0.03 or more, which was worse than the organic substance removing performance of the conventional basic aluminum chloride solution.

[Comparative Example 9]
Metal aluminum powder was dissolved in hydrochloric acid in 1000 g of a basic aluminum chloride solution (Al ₂ O ₃ 16.0%, Cl 20.0%, basicity 40%), prepared in the same manner as in Example 3, and adjusted. 1500 g of the prepared highly basic aluminum chloride solution (Al ₂ O ₃ 23.0%, Cl 8.4%, basicity 82.5%) was added and stirred and mixed. To this, 1900 g of water and 900 g of aluminum sulfate (Al ₂ O ₃ 8.0%, SO ₄ 22.6%) were added and mixed by stirring. Al ₂ O ₃ concentration 10.9%, Cl concentration 6.2%, composition A basic aluminum chloride solution having Cl / Al ₂ O ₃ (molar ratio) = 1.62, SO ₄ / Al ₂ O ₃ (molar ratio) = 0.37 and a basicity of 60.5% was obtained. Then, 400 g of 25% sodium carbonate solution was gradually added over about 40 minutes while stirring the basic aluminum chloride solution at 50 ° C. After completion of the addition, the solution temperature was adjusted to 75 ° C. and aged for 1 hour with stirring to obtain a basic aluminum chloride solution. This basic aluminum chloride solution had an Al ₂ O ₃ concentration of 10.2%, Na / Al ₂ O ₃ (molar ratio) = 0.33, Cl / Al ₂ O ₃ (molar ratio) = 1.62, SO ₄ / Al ₂ O ₃ (molar ratio) = 0.37. Chemical shifts had peaks at 0 ppm, 3-5 ppm, 6-14 ppm, and 50-65 ppm in the ²⁷ Al-NMR spectrum under the measurement conditions described above. The basicity was 66.0%.

This basic aluminum chloride solution had a poor storage stability, such as white turbidity and thickening in about 14 days when stored at 25 ° C. because the SO ₄ / Al ₂ O ₃ (molar ratio) was too high at 0.37. It was.

[Example 4 and Comparative Example 10]
To a basic aluminum chloride solution (Al ₂ O ₃ 14.0%, Cl 16.0%, basicity 45.2%) 300 g prepared in the same manner as in Example 3 at room temperature, an aluminum sulfate solution (Al ₂ O _{3 8.0%} by mixing SO 4 22.6%) 50g of water 50 g, _Al 2 _{O 3} concentration 11.5% Cl concentration of 12.0%, the composition Cl / _Al 2 _{O 3} (molar ratio ) = 3.00, SO ₄ / Al ₂ O ₃ (molar ratio) = 0.26, and a basic aluminum chloride solution having a basicity of 41.3% was obtained. Then, an aluminum hydroxide gel (Al ₂₎ containing Cl and Na obtained by neutralizing the aluminum chloride solution with a sodium aluminate solution and lightly washing the produced neutralized precipitate to the basic aluminum chloride solution. 700 g of O ₃ 9.5%, Cl 2.8%, Na 2.0%) was added at 80 ° C. over 45 minutes with stirring. After completion of the addition, the solution temperature was adjusted to 85 ° C. and aged for 30 minutes with stirring to obtain a basic aluminum chloride solution of the present invention. The basic aluminum chloride solution of the present invention has an Al ₂ O ₃ concentration of 10.2%, Na / Al ₂ O ₃ (molar ratio) = 0.55, Cl / Al ₂ O ₃ (molar ratio) = 1. 73, SO ₄ / Al ₂ O ₃ (molar ratio) = 0.11. Chemical shifts had peaks at 0 ppm, 3-5 ppm, 6-14 ppm, and 50-65 ppm in the ²⁷ Al-NMR spectrum under the measurement conditions described above. The basicity was 76.8% (Example 4).

Moreover, the basic aluminum chloride solution which does not age by the same manufacturing method was also manufactured.
The basic aluminum chloride solution that was not aged had chemical shift peaks at 0 ppm and 3-5 ppm in the ²⁷ Al-NMR spectrum under the above-described measurement conditions, but peaks at 6-14 ppm and 50-65 ppm. There was no (Comparative Example 10).

  For the basic aluminum chloride solution of the present invention produced as described above and the basic aluminum chloride solution that was not aged, an organic matter removal test according to Example 1 was performed at pH 7.6 after treatment. As a result, E260 of the basic aluminum chloride solution of the present invention was 0.045, and E260 of the basic aluminum chloride solution that was not aged was 0.067, and the basic aluminum chloride solution that was not aged (Comparative Example) The reduction rate of E) with respect to E260 was -33%, indicating an excellent organic substance removal performance.

[Example 5]
An organic substance removal test was conducted using the basic aluminum chloride solution of the present invention used in Example 1 and a ferric chloride solution (Fe concentration 13%) which is generally said to have excellent organic substance removal performance. It was.
At the same time, the basic aluminum chloride solution of Comparative Example 1 was also tested. The raw water used in the test was model raw water containing a large amount of organic substances by adding kaolin and reagent-grade humic acid to Kakogawa city tap water. Moreover, the basic aluminum chloride solution of this invention, the ferric chloride solution, and the basic aluminum chloride solution of the comparative example 1 were added so that it might become 50 mg / L each. Other test conditions were the same as in Example 1. The test results are shown in Table 6.

As a result, the organic substance removal performance of the basic aluminum chloride of the present invention is not only substantially equal in the neutral region, compared to ferric chloride, which is generally said to have excellent organic substance removal performance. In the range of pH 7.5 to 8.5, the performance of organic aluminum removal of the basic aluminum chloride of the present invention is superior to that of ferric chloride, which was not found in conventional aluminum-based flocculants. showed that.

Claims (3)

Composition M / Al ₂ O ₃ (molar ratio) = 0.08 to 1.40 (where M represents the number of moles of alkali metal and / or twice the number of moles of alkaline earth metal). In basic aluminum chloride in which Cl / Al ₂ O ₃ (molar ratio) = 1.50-2.80 and SO ₄ / Al ₂ O ₃ (molar ratio) = 0.10-0.35, ²⁷ Al -A novel basic aluminum chloride characterized in that chemical shift has peaks at 0 ppm, 3-5 ppm, 6-14 ppm, 50-65 ppm in NMR spectrum. A water treatment flocculant comprising the novel basic aluminum chloride according to claim 1. Composition Al ₂ O ₃ concentration 5-17%, Cl / Al ₂ O ₃ (molar ratio) = 1.80-3.60, SO ₄ / Al ₂ O ₃ (molar ratio) = 0-0.35 and base After adding an alkali metal and / or alkaline earth metal compound to a basic aluminum chloride solution having a degree of 40 to 63% at a temperature of 85 ° C. or less, aging at 65 to 85 ° C. for 0.5 to 2 hours The method for producing a novel basic aluminum chloride according to claim 1, wherein: