Basic aluminum lactate solution

Abstract

The objective of this invention is to develop a basic aluminum lactate solution with excellent storage stability. [Solution] The solution is a basic aluminum lactate solution that satisfies the following requirements (1) to (3): (1) It contains D-lactic acid, which is an optical isomer of lactic acid, and the proportion of D-lactic acid in the total lactic acid (L-lactic acid + D-lactic acid) is 5 mol% or more; (2) The total lactic acid / Al2O3 (molar ratio) is in the range of 1.0 to 4.0; and (3) It contains a sulfuric acid component.

Description

Technical Field

[0001] The present invention relates to a basic aluminum lactate solution.

Background Art

[0002] Basic aluminum lactate solutions have been used, for example, as additives for alkaline refractories to improve air permeability and suppress digestion of basic aggregates, or as aluminum dopants for raw materials of composite oxides.

[0003] There are many known documents regarding basic aluminum lactate solutions, including Patent Document 1. Although not specified in most documents, basic aluminum lactate solutions have some difficulty in storage stability and tend to form precipitates when stored for a long time.

[0004] In order to maintain long-term stability, Patent Document 2 discloses a method of controlling the contents of Fe, Ca, Mg, Si, carbonate ions, sulfate ions, and phosphate ions (hereinafter collectively referred to as "secondary components") at low levels during production. The production method involves mixing an aluminum chloride solution, an alkali metal aluminate solution, and water to form a gel of aluminum hydroxide, washing the gel with water, adding water to obtain an aluminum hydroxide slurry, and then adding lactic acid and reacting them.

Prior Art Documents

Patent Documents

[0005]

Patent Document 1

Patent Document 2

Summary of the Invention

Problems to be Solved by the Invention

[0006] The basic aluminum lactate solution described in Patent Document 2 is suitable for ceramic formation applications because it contains a small amount of auxiliary components. However, in applications where it is used in mixing with raw materials containing auxiliary components, the presence of auxiliary components in the basic aluminum lactate solution does not pose a problem. For example, in refractory applications where the basic aluminum lactate solution is mixed with magnesia aggregate, alumina cement, silica, etc., the presence of auxiliary components in the basic aluminum lactate solution does not pose any problem.

[0007] The present invention aims to develop a basic aluminum lactate solution with excellent storage stability by a method other than controlling the minor components. [Means for solving the problem]

[0008] As a result of diligent research into the above-mentioned problems, the inventors of this invention have, to their surprise, discovered that by including a predetermined amount of D-lactic acid, one of the optical isomers of lactic acid, as lactic acid, a basic aluminum lactate solution with long-term stability can be obtained. Based on this finding, the inventors have completed the present invention.

[0009] The present invention is as follows: [1] A basic aluminum lactate solution that satisfies the following requirements (1) to (3). (1) Contains D-lactic acid, which is an optical isomer of lactic acid, and the proportion of D-lactic acid in the total lactic acid (L-lactic acid + D-lactic acid) is 5 mol% or more. (2) The molar ratio of total lactic acid to Al2O3 is in the range of 1.0 to 4.0. (3) Contains sulfuric acid components. [2] The basic aluminum lactate solution described in [1] above, wherein the aluminum index is in the range of 0.90 to 1.10 in the storage test described below. [Storage Test] As the Al2O3 concentration before testing, the Al2O3 concentration of the basic aluminum lactate solution described above is measured before being subjected to the storage test. Measure 20 g of the above basic aluminum lactate solution into a 50 mL iBoy PP wide-mouth bottle sold by AS ONE Corporation, seal it tightly, and leave it standing in a constant temperature bath set to 50°C for two weeks. Then measure the Al2O3 concentration in the portion from the top surface to a depth of 5 mm and record this as the Al2O3 concentration after the test. The aluminum index is calculated using the following formula. Aluminum index = Al2O3 concentration after testing ÷ Al2O3 concentration before testing [3] A method for producing the basic aluminum lactate solution described in [1] or [2] above, comprising the following steps. (1) Step 1: Mix an aqueous solution of aluminum sulfate with lactic acid to prepare a mixed solution. (2) A second step in which sulfate ions in the above mixture are precipitated as alkaline earth metal sulfates using alkaline earth metals. [4] A powder obtained by drying the basic aluminum lactate solution described in [1] or [2] above. [Modes for carrying out the invention]

[0010] The present invention will be described in detail below based on preferred embodiments, but the present invention is not limited to the following embodiments, and various modifications are possible within the scope of the claims. In this invention, the notation "value 1 to value 2" in relation to a numerical range means a numerical range that includes both values ​​1 and 2, with value 1 as the lower limit and value 2 as the upper limit, and is synonymous with "value 1 or greater and value 2 or less".

[0011] The present invention relates to a basic aluminum lactate solution that satisfies the following requirements (1) to (3). (1) Contains D-lactic acid, which is an optical isomer of lactic acid, and the proportion of D-lactic acid in the total lactic acid (L-lactic acid + D-lactic acid) is 5 mol% or more. (2) The molar ratio of total lactic acid to Al2O3 is in the range of 1.0 to 4.0. (3) Contains sulfuric acid components.

[0012] (Requirement 1) Lactic acid has two optical isomers, L-lactic acid and D-lactic acid, which are called L-lactic acid and D-lactic acid, respectively. In literature, it is common technical knowledge to assume that simply "lactic acid" refers to L-lactic acid. Generally, when "L-lactic acid" is specified, it is often necessary to distinguish it from D-lactic acid.

[0013] The basic aluminum lactate solution of the present invention contains D-lactic acid as lactic acid, and the proportion of D-lactic acid in the total lactic acid, i.e., [L-lactic acid + D-lactic acid] (hereinafter referred to as "D-lactic acid ratio") is 5 mol% or more. In other words, when 100 moles of total lactic acid are contained, 5 moles or more of D-lactic acid are contained.

[0014] Since the D-part content is 5 mol% or more, the basic aluminum lactate solution of the present invention includes not only an embodiment containing both L-lactic acid and D-lactic acid, but also an embodiment that does not contain L-lactic acid, i.e., an embodiment containing only D-lactic acid. Note that if the D-part content is less than 5 mol%, precipitation is likely to occur. The D-part content is preferably 7 mol% or more, more preferably 8 mol% or more, and particularly preferably 10 mol% or more.

[0015] In this invention, the measurement method for determining the D content is as follows. (Treatment with basic aluminum lactate solution) To enable measurement of the optical rotation of lactic acid in the basic aluminum lactate solution, the aluminum in the solution is dissolved in hydrochloric acid. Specifically, concentrated hydrochloric acid is added to the basic aluminum lactate solution in a molar ratio of Cl in the concentrated hydrochloric acid to Al2O3 in the basic aluminum lactate solution (molar ratio) of 3 to 10, and then the solution is boiled for 10 minutes. After cooling, the solution is used as the sample for measurement. Note that the boiling should be done gently to prevent evaporation to dryness. (Creating a calibration curve) The lactic acids used to obtain the calibration curve are DL-lactic acid (a mixture of 50 mol% of L-lactic acid and D-lactic acid) and L-lactic acid. As the DL-lactic acid, "DL-Lactic Acid Special Grade" (product code: 000-43525) manufactured by Kinoshita Chemical Co., Ltd. is used. As the L-lactic acid, "L-Lactic Acid Special Grade" (product code: 129-02666) manufactured by Fujifilm Wako Pure Chemical Corporation is used. Precisely weigh 0.5 g each of the above DL-lactic acid and L-lactic acid with an analytical balance as a guide, put them into a 100 mL volumetric flask, add about 20 mL of distilled water and 2 mL of concentrated hydrochloric acid, then boil for 10 minutes, let it cool, and make up to the mark with distilled water to prepare a standard solution. In the above boiling, boil gently so as not to evaporate to dryness. The discrimination of optical isomers (L-form, D-form) is carried out by measuring the specific rotation. As the measuring device, the polarimeter P-2200 manufactured by JASCO Corporation is used. If the same measured value as that of the measuring device can be obtained, another measuring device may be used. Using the standard solutions of DL-lactic acid and L-lactic acid prepared as above, measure the specific rotation of each with the above measuring device to create a calibration curve. Next, measure the specific rotation of the sample, and obtain the D-form ratio of the sample from the calibration curve. For the blank measurement, distilled water is used. In this measurement method, since a standard solution consisting only of D-lactic acid is not used, depending on the calibration curve, for example, when measuring D-lactic acid, the D-form ratio may exceed 100 mol%, but even if it does, there is no problem, and the value exceeding 100 mol% may be adopted as it is. By the way, when obtaining the D-form ratio with the lactic acid used as the raw material as the sample, the addition of concentrated hydrochloric acid and heat treatment for the sample and the standard solution are not necessary. On the other hand, when using the basic aluminum lactate solution as the sample as described above, by performing the addition of concentrated hydrochloric acid and heat treatment on the standard solution as well as on the sample, a D-form ratio value consistent with the D-form ratio of the lactic acid used as the raw material can be obtained.

[0016] (Requirement 2) The basic aluminum lactate solution of the present invention has a total lactic acid / Al2O3 (molar ratio) in the range of 1.0 to 4.0. When the total lactic acid / Al2O3 (molar ratio) is less than 1.0, precipitation tends to occur easily, and the solution stability tends to be impaired. On the other hand, when it exceeds 4.0, a stable basic aluminum lactate solution can be obtained regardless of the ratio of the optical isomers of lactic acid, but it is not economical to contain a large amount of lactic acid. The lower limit of this range is preferably 1.1, more preferably 1.2. Therefore, more preferable ranges can be exemplified as 1.1 to 4.0 and 1.2 to 4.0.

[0017] (Requirement 3) The basic aluminum lactate solution of the present invention contains a sulfuric acid component. In the sulfuric acid component, in addition to sulfate ions, when there are dispersed particles of alkaline earth metal sulfates, the sulfuric acid in the salt is included. The sulfuric acid component preferably has a range of SO4 / Al2O3 (molar ratio) = 0.01 to 0.5. The concentration of sulfate ions is not particularly limited as long as it is below the maximum concentration that can be contained as an ion.

[0018] The Al2O3 concentration of the basic aluminum lactate solution of the present invention is preferably in the range of 1 to 20% by mass. From the economic viewpoints of production and transportation, the lower limit is more preferably 3% by mass, and even more preferably 5% by mass. The upper limit is more preferably 15% by mass.

[0019] A preferred embodiment of the basic aluminum lactate solution of the present invention is one that contains an alkaline earth metal component. The alkaline earth metal component includes alkaline earth metal ions, and if dispersed particles of alkaline earth metal sulfate are present, the alkaline earth metal in the salt. Good examples of alkaline earth metals include calcium, strontium, and barium, with calcium being particularly preferred. The alkaline earth metal component is preferably in the range of alkaline earth metal oxide / Al2O3 (molar ratio) = 0.01 to 0.3. Here, the alkaline earth metal oxide refers to, for example, CaO when the alkaline earth metal is calcium. The concentration of alkaline earth metal ions is not particularly limited as long as it is below the maximum concentration that can be contained as an ion.

[0020] (Aluminum index) Another preferred embodiment of the basic aluminum lactate solution of the present invention is one in which the aluminum index is in the range of 0.90 to 1.10 in the storage test described below. [Storage Test] As the Al2O3 concentration before testing, the Al2O3 concentration of the basic aluminum lactate solution is measured before being subjected to the storage test. Measure 20 g of basic aluminum lactate solution into a 50 mL iBoy PP wide-mouth bottle sold by AS ONE Corporation, seal it tightly, and leave it standing in a constant temperature bath set to 50°C for two weeks. Then measure the Al2O3 concentration in the portion from the top to a depth of 5 mm and record it as the post-test Al2O3 concentration. The aluminum index is calculated using the following formula. Aluminum index = Al2O3 concentration after testing ÷ Al2O3 concentration before testing Furthermore, in the above, when measuring the Al2O3 concentration after the test, it is preferable to take a sample from the top surface to a depth of 5 mm and measure the Al2O3 concentration in the sampled portion. When taking the sample, it is preferable to take it as gently as possible, that is, to take it carefully while suppressing fluidity as much as possible. A pipette or syringe is preferred as the sampling instrument.

[0021] If the aluminum index is in the range of 0.90 to 1.10, the change in Al2O3 concentration of the basic aluminum lactate solution before and after the test is small, indicating high storage stability, and long-term stability can also be expected. The lower limit of this range is preferably 0.95. The upper limit of this range is preferably 1.05. Therefore, examples of preferred ranges include 0.95 to 1.10, 0.90 to 1.05, and 0.95 to 1.05.

[0022] (Total light transmittance) A preferred embodiment of the basic aluminum lactate solution of the present invention is one in which the total light transmittance of the basic aluminum lactate solution of the present invention, adjusted to an Al2O3 concentration of 9.0% by mass, is preferably 80% or more. A further preferred embodiment is one in which the total light transmittance after being stored in a sealed container at 50°C for two weeks is 80% or more. Methods for adjusting the Al2O3 concentration to 9.0% by mass include dilution with distilled water and heating to concentrate.

[0023] (powder) The basic aluminum lactate solution of the present invention may be dried to obtain a powder. This powder can be used as is or dispersed in water. Commonly used drying methods such as spray drying, static drying, and air-flow drying can be employed. The drying temperature is preferably 300°C or lower.

[0024] (Manufacturing method) A preferred method for producing the basic aluminum lactate solution of the present invention includes the following steps. (1) Step 1: Mix an aqueous solution of aluminum sulfate with lactic acid to prepare a mixed solution. (2) A second step in which sulfate ions in the above mixture are precipitated as alkaline earth metal sulfates using alkaline earth metals.

[0025] In the first step, the aluminum sulfate aqueous solution is preferably one with an Al2O3 concentration of 1 to 14% by mass. Alternatively, a basic aluminum sulfate aqueous solution may be used instead of the aluminum sulfate aqueous solution. The lactic acid only needs to contain at least D-lactic acid. That is, the entire amount may be D-lactic acid, or a combination of D-lactic acid and L-lactic acid may be used. There are no particular restrictions on the method of mixing the aluminum sulfate aqueous solution and lactic acid; lactic acid may be added to the aluminum sulfate aqueous solution, or vice versa. The mixing ratio of the aluminum sulfate aqueous solution and lactic acid is in the range of total lactic acid / Al2O3 (molar ratio) = 1.0 to 4.0, as shown in requirement 2.

[0026] The second step involves precipitating the sulfate ions in the mixture obtained in the first step as alkaline earth metal sulfates using alkaline earth metals. However, complete precipitation is not required, and the remaining sulfate ions are acceptable. Good examples of alkaline earth metals are calcium, strontium, and barium. Heating is preferable to efficiently produce alkaline earth metal sulfates. The heating temperature is preferably, for example, 50 to 100°C. The heating time can be set appropriately according to the heating temperature, for example, preferably 0 to 12 hours. In the above, a heating time of 0 hours means stopping heating when the predetermined heating temperature is reached after heating has started.

[0027] In the second step, it is preferable to use methods such as filtration, sedimentation, or centrifugation to remove the alkaline earth metal sulfate precipitated in the second step. It is acceptable for dispersed particles of alkaline earth metal sulfate to remain in the basic aluminum lactate solution of the present invention.

[0028] Furthermore, concentration adjustment steps, concentration steps, etc., may be carried out as needed. [Examples]

[0029] The present invention will be described in more detail below with reference to examples, but the present invention is not limited thereto.

[0030] (Types of lactic acid) The types of lactic acid used are as follows: • DL-Lactic Acid: "DL-Lactic Acid Special Grade" manufactured by Kishida Chemical Co., Ltd. (Product Code: 000-43525) (Lactic acid concentration as stated in the test report issued by the company: 91.8% by mass) • L-Lactic Acid: "L-Lactic Acid, Special Grade" manufactured by Fujifilm Wako Pure Chemical Industries, Ltd. (Product Code: 129-02666) (Lactic acid concentration as stated in the inspection report issued by the company: 88.3% by mass) • D-Lactic Acid: Corbion's "D-Lactic Acid" (Lactic acid concentration as stated in the analysis certificate issued by the company: 92.3% by mass)

[0031] (Examples 1-8 and Comparative Examples 1-2) In Examples 1-8 and Comparative Examples 1-2, basic aluminum lactate solutions were prepared using the following manufacturing method. Table 1 shows the amounts of each raw material (aluminum sulfate aqueous solution, lactic acid solution, calcium carbonate) added. The aluminum sulfate aqueous solution had an Al2O3 concentration of 8% by mass. The lactic acid solution was prepared by pre-mixing the DL-lactic acid, L-lactic acid, and D-lactic acid listed in Table 1.

[0032] <Manufacturing method> A lactic acid solution was added to an aqueous solution of aluminum sulfate. This mixture was heated with stirring until it reached 90°C, then calcium carbonate was slowly added, and the mixture was heated at 90°C for 1 hour. After cooling, the mixture was centrifuged (5000 rpm, 20 minutes), and the supernatant was collected. This supernatant was used as the basic aluminum lactate solution. The heating conditions for Example 8 were 140°C for 1 hour.

[0033] Herein, regarding the above manufacturing method, the case of Example 1 is as follows. First, 5.54 g of DL-lactic acid and 23.05 g of L-lactic acid were mixed (with a mixing ratio of D-isomer to L-isomer of 10:90) to prepare a lactic acid solution with a D-isomer content of 10 mol%, which was the same as the raw material's value. 28.59 g of the above lactic acid solution was added to 225.0 g of an aqueous aluminum sulfate solution (Al2O3 concentration: 8% by mass). This mixed solution was heated to 90 °C with stirring, and 56.67 g of calcium carbonate was slowly added thereto, followed by heating at 90 °C for 1 hour. The addition ratio of calcium carbonate was set so that calcium carbonate / SO4 (molar ratio) = 1.07. After cooling, centrifugation (5000 rpm, 20 minutes) was performed to collect the supernatant, and this supernatant was used as the basic aluminum lactate solution of Example 1.

[0034]

Table 1

[0035] <D-isomer ratio> For each of the basic aluminum lactate solutions obtained in Examples 1 to 8 and Comparative Examples 1 and 2, the D-isomer ratios in Table 1 are the values determined as follows. (1) Raw material charged value It is a value calculated from the mixing ratio of DL-lactic acid, L-lactic acid and D-lactic acid used in the preparation of the raw material lactic acid solution. (2) Lactic acid solution analysis value The prepared lactic acid solution was used as a sample (hereinafter referred to as "Sample A"). 0.5 g each of the above DL-lactic acid and L-lactic acid was accurately weighed using an analytical balance as a guide and placed in a 100 mL volumetric flask. After dissolving in distilled water, it was made up to the mark to prepare standard solutions of DL-lactic acid and L-lactic acid. For the measurement of the specific rotation, a polarimeter P-2200 manufactured by JASCO Corporation was used and measured according to the measurement procedure. Distilled water was used for the blank measurement, and the specific rotations of the standard solutions of DL-lactic acid and L-lactic acid prepared as described above were measured to create a calibration curve. The calibration curve was y = 0.3271x - 16.317 when the D-isomer ratio was x and the specific rotation was y. Next, the specific rotation of Sample A was measured, and the D-isomer ratio was determined from the above calibration curve. (3) Basic aluminum lactate solution analysis value Concentrated hydrochloric acid was added to the basic aluminum lactate solution such that the molar ratio of Cl in the concentrated hydrochloric acid to Al2O3 in the basic aluminum lactate solution was 6, and then it was gently boiled for 10 minutes without covering. Then, the cooled solution was used as a sample for measurement (hereinafter referred to as "Sample B"). Approximately 0.5 g each of the above DL-lactic acid and L-lactic acid were accurately weighed using an analytical balance, placed in a 100 mL volumetric flask, about 20 mL of distilled water and 2 mL of concentrated hydrochloric acid were added, and then it was gently boiled for 10 minutes without covering. After cooling, it was made up to the mark with distilled water to prepare a standard solution. For the measurement of the specific rotation, a polarimeter P-2200 manufactured by JASCO Corporation was used and measured according to the measurement procedure. Distilled water was used for the blank measurement, and the specific rotations of the standard solutions of DL-lactic acid and L-lactic acid prepared as above were measured to create a calibration curve. The calibration curve was y = -0.0292x + 1.5467 when the D-form ratio was x and the specific rotation was y. Next, the specific rotation of Sample B was measured, and the D-form ratio was determined from the above calibration curve.

[0036] For each of the basic aluminum lactate solutions obtained in Examples 1 to 8 and Comparative Examples 1 to 2, the measurement methods for each analysis item described in "Analysis Values of Basic Aluminum Lactate Solution" in Table 1 are as follows. Note that for Comparative Example 2, precipitation occurred in the obtained basic aluminum lactate solution, so some analysis items were not analyzed. <Al2O3 Concentration> A chelate titration method according to a conventional method was used. The outline is a method in which the basic aluminum lactate solution is dissolved with hydrochloric acid, the aluminum ions are chelated with EDTA / 2Na, the pH is adjusted with sodium acetate, and then xylenol orange is used as an indicator and titrated with a zinc solution. <CaO / Al2O3 (Molar Ratio)> The calcium concentration was measured by atomic absorption spectrophotometry according to a conventional method and calculated from the above Al2O3 concentration. <SO4 / Al2O3 (Molar Ratio)> The sulfuric acid concentration was measured by a turbidimetry method using barium chloride according to a conventional method and calculated from the above Al2O3 concentration. <ph> The measurement was taken using a portable pH meter, LAQUAact, manufactured by Horiba, Ltd. <ec> The measurement was taken using a CM-42X electrical conductivity meter manufactured by Toa DKK Corporation. <Total light transmittance> Basic aluminum lactate solutions were measured immediately after manufacturing and after being stored in a sealed container at 50°C for two weeks. The measurements were taken using a haze meter "COH7700" manufactured by Nippon Denshoku Industries, Ltd., under conditions of wavelength 400-700 nm (10 nm intervals) and optical path length 10 mm. <Aluminum Index> The Al2O3 concentration of the basic aluminum lactate solution was measured before storage testing (pre-test Al2O3 concentration). 20 g of basic aluminum lactate solution was measured into a 50 mL iBoy PP wide-mouth bottle sold by AS ONE Corporation, sealed tightly, and left to stand in a constant temperature bath set to 50°C for two weeks. After that, a portion from the top to a depth of 5 mm was carefully collected using a pipette, and the Al2O3 concentration in the collected portion was measured (post-test Al2O3 concentration). The aluminum index was calculated using the following formula. Aluminum index = Al2O3 concentration after testing ÷ Al2O3 concentration before testing

[0037] In Examples 1-8 and Comparative Examples 1-2, the D-part ratios of each basic aluminum lactate solution were found to be approximately the same for (1) raw material preparation, (2) lactic acid solution analysis, and (3) basic aluminum lactate solution analysis. Therefore, the analytical methods were considered to be appropriate.

[0038] The total light transmittance was measured directly from each basic aluminum lactate solution obtained in Examples 1-8 and Comparative Example 1. For Examples 2-7, where the Al2O3 concentration is not 9.0% by mass, it is estimated that even if the Al2O3 concentration were adjusted to 9.0% by mass and the total light transmittance was measured, the total light transmittance would still be 80% or higher immediately after production and after storage at 50°C for two weeks.

[0039] The aluminum index of each basic aluminum lactate solution obtained in Examples 1 to 8 was within the range of 0.90 to 1.10, indicating high storage stability.

[0040] (powder) The basic aluminum lactate solution obtained in Example 5 was dried statically in a forced-air dryer at 100°C to obtain a powder. This powder was dissolved in deionized water to the same concentration as before drying, yielding a solution. The properties of this solution were the same as those of the basic aluminum lactate solution before drying. The pH of this solution was 5.5 and the EC was 2.3 mS / cm.< / ec> < / ph>

Claims

1. A basic aluminum lactate solution that meets the following requirements (1) to (3). (1) Contains D-lactic acid, which is an optical isomer of lactic acid, and the proportion of D-lactic acid in the total lactic acid (L-lactic acid + D-lactic acid) is 5 mol% or more. (2) Total lactic acid / Al 2 O 3 The molar ratio is in the range of 1.0 to 4.

0. (3) Contains sulfuric acid components.

2. The basic aluminum lactate solution according to claim 1, wherein the aluminum index is in the range of 0.90 to 1.10 in the storage test described below. [Storage Test] Before the exam Al 2 O 3 As for the concentration, the Al of the above basic aluminum lactate solution before storage test. 2 O 3 Measure the concentration. Measure 20 g of the above basic aluminum lactate solution into a 50 mL IBOY PP wide-mouth bottle sold by AS ONE Corporation, seal it, and let it stand in a thermostat set at 50°C for 2 weeks. Then, measure the Al concentration in the portion from the upper surface to a depth of 5 mm. Take the Al concentration after the test as the concentration. 2 O 3 concentration and take the Al concentration after the test as the concentration. 2 O 3 concentration. The aluminum index is calculated using the following formula. Aluminum index = Al after testing 2 O 3 Concentration ÷ Al before test 2 O 3 concentration

3. A method for producing a basic aluminum lactate solution according to claim 1 or 2, comprising the following steps. (1) Step 1: Mix an aqueous solution of aluminum sulfate with lactic acid to prepare a mixed solution. (2) A second step in which sulfate ions in the above mixture are precipitated as alkaline earth metal sulfates using alkaline earth metals.

4. A powder obtained by drying the basic aluminum lactate solution according to claim 1 or 2.

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