Method for adding chemicals to treated water

Abstract

To improve handling of chemical containing carboxylic acid polymer often used as a scale inhibitor for water treated in water treatment equipment such as heat source equipment.SOLUTION: A method for adding carboxylic polymer-containing agent to water to be treated in water treatment equipment includes: Step 1 of preparing a chemical solution containing a carboxylic acid polymer-containing chemical, and Step 2 of adding the chemical solution prepared in Step 1 to water to be treated. In Step 1, a solution is prepared by dissolving a carboxylic acid-based polymer-containing chemical in a solvent and freeze-drying or spray-drying a resulting solution, and then dissolving the solid chemical in the solvent again to prepare a chemical solution. The chemical solution is preferably prepared at a place where the chemical solution is added to the water to be treated.SELECTED DRAWING: None

Description

[Technical Field]

[0001] The present invention relates to a method for adding a chemical to water to be treated, and more particularly to a method for adding a chemical containing a carboxylic acid polymer to water to be treated in a water treatment device. [Background technology]

[0002] Heat source equipment such as boilers and open cooling towers require scale control in the boiler body and cooling system to suppress various problems caused by boiler water, circulating cooling water, and other service water, and to continue stable operation. At the same time, corrosion and slime generation in each part must be suppressed. Therefore, water quality management of service water is necessary for the operation of heat source equipment.

[0003] Known methods for water quality control include physical methods such as filtering water, as well as chemical methods that involve adding chemicals to water. Chemicals added to water include scale inhibitors, pH adjusters, anticorrosives, oxygen scavengers, and disinfectants, all of which have the desired effects for water quality control purposes. However, adding these chemicals individually to water is cumbersome in terms of both the work involved and chemical management. Therefore, composite agents that combine multiple chemicals have been proposed as chemicals to be added to water. For example, Patent Document 1 discloses a composite boiler compound to be added to boiler water, which is an aqueous solution containing both sodium polyacrylate as a scale inhibitor and sulfite as an oxygen scavenger.

[0004] Complex compounds, such as the complex boiler compound described in Patent Document 1, are typically kept on hand at the installation site of heat source equipment and added to service water as needed. However, complex compounds are aqueous solutions, with 70 to 80% by mass of the compound being water as a solvent. Due to their weight and bulk, transporting them to the installation site of the heat source equipment is laborious, and storage space is required. Quality maintenance and other inventory management are also required. While the issues of weight and bulk can be resolved to some extent by using concentrated complex compounds, such complex compounds can be considered deleterious or hazardous materials depending on their ingredients, or can have poor storage stability. Therefore, safe use and storage as well as advanced quality control are required, imposing a significant management burden on the site of use. [Prior art documents] [Patent documents]

[0005] [Patent Document 1] Japanese Patent Application Laid-Open No. 63-166981 Summary of the Invention [Problem to be solved by the invention]

[0006] The present invention aims to improve the handleability of chemicals containing carboxylic acid polymers, which are often used as scale inhibitors for water to be treated in water treatment equipment such as heat source equipment. [Means for solving the problem]

[0007] The present invention relates to a method for adding a chemical containing a carboxylic acid polymer to water to be treated in a water treatment device. This chemical addition method includes step 1 of preparing a chemical solution containing the chemical containing a carboxylic acid polymer, and step 2 of adding the chemical solution prepared in step 1 to the water to be treated. In step 1, the chemical containing a carboxylic acid polymer is dissolved in a solvent to prepare a solution, which is then freeze-dried or spray-dried to obtain a solid agent, which is then redissolved in the solvent to prepare the chemical solution.

[0008] In the chemical addition method of the present invention, for example, the chemical solution is prepared at the site where the chemical solution is to be added to the water to be treated.

[0009] Another aspect of the present invention relates to a method for producing a solid agent for preparing a chemical solution containing a carboxylic acid polymer to be added to water to be treated in a water treatment device. The method includes the steps of dissolving a chemical containing a carboxylic acid polymer in a solvent to prepare a solution, and freeze-drying or spray-drying the prepared solution.

[0010] According to yet another aspect, the present invention relates to a method for producing a chemical solution containing a carboxylic acid polymer to be added to water to be treated in a water treatment device, the method comprising the step of dissolving a solid agent for preparing a chemical solution containing a carboxylic acid polymer produced by the production method of the present invention in a solvent.

[0011] According to yet another aspect, the present invention relates to a solid agent for preparing a chemical solution containing a carboxylic acid polymer to be added to water to be treated in a water treatment device. The solid agent contains a carboxylic acid polymer, and is sealed together with water in a 133 mL container so that the converted mass of the carboxylic acid polymer is 10 g and the total mass with the water is 100 g. The solid agent dissolves in at least 200 seconds when shaken at 25°C at 200 rpm using a shaker set to orbit with a diameter of 2 cm to 3 cm. [Effects of the Invention]

[0012] The method of adding a chemical according to the present invention involves dissolving a carboxylic acid polymer-containing chemical in a solvent to prepare a solution, which is then freeze-dried or spray-dried to obtain a solid agent, which is then re-dissolved in a solvent to prepare a chemical solution to be added to the water to be treated in a water treatment device.Therefore, the carboxylic acid polymer-containing chemical can be easily handled in terms of transportation, storage, quality control, and handling safety.

[0013] The method for producing a solid preparation according to the present invention can produce a solid preparation that can be used to quickly prepare a chemical solution containing a carboxylic acid polymer to be added to water to be treated in a water treatment device.

[0014] The method for producing a chemical solution according to the present invention involves dissolving the solid agent produced by the production method according to the present invention in a solvent, and therefore makes it possible to quickly prepare a chemical solution containing a carboxylic acid polymer to be added to the water to be treated in a water treatment device.

[0015] The solid agent according to the present invention allows for the rapid preparation of a carboxylic acid polymer-containing chemical solution to be added to water to be treated in a water treatment device, and is easy to handle in terms of transportation, storage, quality control, and the like. [Brief explanation of the drawings]

[0016] [Figure 1] FIG. 1 shows the evaluation results of the solid preparations of the examples and the mixed preparations of the comparative examples. DETAILED DESCRIPTION OF THE INVENTION

[0017] The chemical addition method according to the present invention is a method for adding a carboxylic acid polymer-containing chemical to water to be treated in water treatment equipment. Water treatment equipment to which this chemical addition method is applicable includes heat source equipment such as boilers and open-type cooling towers, as well as filtration equipment such as reverse osmosis membrane filtration systems and wastewater filtration systems. Concentration of water to be treated containing hardness (calcium ions and magnesium ions) can lead to problems caused by scale formation. The water to be treated, i.e., boiler water, used in a typical heat source, i.e., boiler water, is the feedwater supplied to the boiler to generate steam. The boiler water is concentrated by heating within the boiler, increasing the hardness concentration and forming scale within the boiler that impairs thermal conductivity. The water to be treated in an open-type cooling tower is circulating cooling water. The circulating cooling water is concentrated by evaporation and cooling, increasing the hardness concentration and forming scale within the cooling tower and heat exchangers that reduces heat exchange efficiency. The water to be treated in filtration devices such as reverse osmosis membrane filtration devices and wastewater filtration devices is raw water or wastewater used to produce pure water, and the concentration of dissolved components, especially hardness, increases on the filtration membrane surface, causing scale to form on the filtration surface.

[0018] In the addition method of the present invention, first, a drug solution containing a drug containing a carboxylic acid polymer is prepared (Step 1). Here, the target drug solution is prepared by dissolving a solid agent containing a carboxylic acid polymer in a solvent. The solid agent used here is obtained in advance by freeze-drying or spray-drying a solution prepared by dissolving the drug containing a carboxylic acid polymer in a solvent.

[0019] The carboxylic acid polymer-containing agent used to obtain the solid agent contains a carboxylic acid polymer and, if necessary, other agents. The carboxylic acid polymer used here functions as a scale inhibitor, and examples thereof include carboxylic acid homopolymers such as polyacrylic acid and its salts, polymethacrylic acid and its salts, and polymaleic acid and its salts; carboxylic acid copolymers such as acrylic acid / 2-acrylamido-2-methylpropanesulfonic acid binary copolymer, acrylic acid / maleic acid binary copolymer, maleic acid / methyl vinyl ether binary copolymer, acrylic acid / hydroxypropyl acrylate binary copolymer, and sulfonated styrene / maleic anhydride binary copolymer; and terpolymers such as maleic acid / acrylic acid alkyl ester / vinyl acetate terpolymer, acrylic acid / sulfonic acid / sodium styrenesulfonate terpolymer, and acrylic acid / sulfonic acid / substituted acrylamide terpolymer. Two or more of these carboxylic acid polymers may be used in combination.

[0020] Examples of other components contained in the agent containing a carboxylic acid polymer include tracer substances as well as active ingredients such as scale inhibitors, anticorrosive agents, stabilizers, and bactericides other than the carboxylic acid polymer. The other components may be of two or more types.

[0021] Examples of scale inhibitors other than carboxylic acid polymers include chelating agents, such as phosphonic acids and their salts (usually alkali metal salts), and phosphonocarboxylic acids or phosphonocarboxylates, such as tetrasodium phosphonoethane-1,2-dicarboxylate, hexasodium phosphonobutane-1,2,3,4-tetracarboxylate, and 2-phosphonobutane-1,2,4-tricarboxylic acid.

[0022] Anticorrosive agents are used to suppress corrosion that may occur due to the concentration of salts in the treated water in heat exchangers of heat source equipment, pipes made of metals such as copper or iron, and other water systems through which the treated water flows. Examples of anticorrosive agents for copper-based pipes include azole compounds such as pyrrole, diazole, triazole, tetrazole, benzoazole, benzodiazole, and benzotriazole, phosphorus compounds, zinc compounds, and lignin. Examples of anticorrosive agents for iron-based pipes include silica, amine compounds such as diethylhydroxylamine and 2-amino-2-methyl-1-propanol, phosphorus compounds, zinc compounds, lignin, and alkaline agents such as potassium hydroxide and sodium hydroxide.

[0023] The stabilizer is used to enhance the stability of the target solid preparation, and examples thereof include pH adjusters such as sodium hydroxide, potassium hydroxide, sulfuric acid, and hydrochloric acid, magnesium compounds such as magnesium nitrate and magnesium chloride, and surfactants.

[0024] Bactericides are used to prevent the growth of Legionella and other bacteria and the formation of slime in water supplies. Examples of disinfectants include 2-bromo-2-nitro-1,3-propanediol, 2,2-dibromo-2-nitro-1-ethanol, 1,5-pentanedial, 2,2-dibromo-3-nitrilopropionamide, 1-bromo-3-chloro-5,5-dimethylhydantoin, N-decyl-N-isononyl-N,N-dimethylammonium chloride, hydrazine, sodium 2-pyrilthio-1-oxide, zinc pyrithione, methylene bisthiocyanate, and 3-(3,4-dichlorophenyl)-1,1-dimethylammonium chloride. Examples of such thiazoline compounds include thiurea, 2-(4-thiazolyl)-benzimidazole, 1,2-benzisothiazolin-3-one, 2,3,3-triiodoallyl alcohol, poly[oxyethylene(dimethylimino)ethylene(dimethylimino)ethylene chloride], and thiazoline compounds such as 2-methyl-3-isothiazolone, 2-ethyl-3-isothiazolone, 2-octyl-4-chloro-isothiazolone, 2-benzyl-4,5-dichloro-3-isothiazolone, 2-allyl-3-isothiazolone, 2-propynyl-3-isothiazolone, 5-chloro-2-methyl-3-isothiazolone, and 1,2-benzothiazolone.

[0025] The tracer substance is used to indirectly measure the concentration of carboxylic acid polymers and other active ingredients derived from the agent, which are contained in the treated water to which a carboxylic acid polymer-containing agent has been added, by fluorometry. Examples of the tracer substance include sulfonated pyrene compounds such as pyrenesulfonic acid or alkali metal salts such as its sodium salt, fluorescein, molybdic acid or its salts, vanadic acid or its salts, or sodium naphthalenedisulfonic acid.

[0026] In preparing a solid formulation, the carboxylic acid polymer and other necessary components are mixed uniformly, and the mixed drug is dissolved in a solvent to prepare a solution. In this case, the carboxylic acid polymer and other components can be added separately to the solvent, and the components can be mixed uniformly in the solvent. The proportion of the carboxylic acid polymer in the total amount of the carboxylic acid polymer and other components is usually set to preferably 10 to 70% by mass, more preferably 20 to 60% by mass.

[0027] The solvent used to prepare the mixed drug solution is usually purified water such as distilled water, pure water, or ion-exchanged water. However, various organic solvents, such as water-soluble organic solvents such as methanol, ethanol, or 2-propanol, can also be used as long as they can dissolve the components. Two or more solvents may be used in combination. In preparing the solution, the components may be mixed uniformly by stirring or heating, or may be vibrated by bubbling or ultrasonic waves.

[0028] The resulting solution is then freeze-dried or spray-dried to prepare a solid formulation, preferably with a solvent content controlled to 20% by mass or less. Here, the solvent content refers to the mass ratio of the solvent to the solid formulation. When the solvent is water (i.e., the above-mentioned purified water), the solvent content may hereinafter be referred to as the water content. When preparing a solid formulation by freeze-drying, it is preferable to set the pressure to 600 Pa or less (particularly, 100 Pa or less), the initial temperature (pre-freezing temperature) to -30°C or higher (particularly, -15°C or higher), and the freezing time to within 2 days. While freeze-drying produces a solid formulation in a bulk form, this solid formulation may be pulverized into powder. When preparing a solid formulation by spray-drying, the spraying method may be a two-fluid method, a one-fluid method, an ultrasonic method, or a rotary method, and it is preferable to set the inlet temperature to 100 to 300°C and the outlet temperature to 70 to 200°C. It is particularly preferable to select a two-fluid method as the spraying method, and set the inlet temperature to 250°C or lower and the outlet temperature to 150°C or lower. The target droplet size during spray drying is preferably set to 500 μm or less, particularly 300 μm or less. Spray drying produces a powdery solid formulation. The solid formulation obtained by freeze drying or spray drying may be secondary processed into tablets, granules, flakes, or fine particles using a tablet press or a pulverizer to improve handling.

[0029] The solid preparation obtained by freeze-drying or spray-drying is a dried product, so it is resistant to deterioration during storage, and because it is porous, it exhibits a specific solubility in water, i.e., rapid solubility. Specifically, the solid preparation is sealed together with water in a 133 mL container so that the converted mass of the carboxylic acid polymer is 10 g and the total mass with water is 100 g. When the solid preparation is shaken at 200 rpm at 25 ° C using a shaker set to orbital shake with a diameter of 2 cm to 3 cm, the time to complete dissolution is at most 200 seconds. The solvent content of the solid preparation is preferably 20% by mass or less, more preferably 15% by mass or less. Here, the solvent content is a value calculated based on the mass loss rate before and after freeze-drying and the solid content concentration of the mixed drug solution in freeze-drying, and a value calculated based on the mass loss rate when placed in a thermostatic chamber maintained at 105 ° C for 60 minutes in spray-drying.

[0030] In preparing a chemical solution, the solid agent is dissolved in the solvent by adding the solid agent to the solvent or by adding the solvent to the solid agent. In this case, to prepare a homogeneous chemical solution, the solvent may be stirred or heated, or may be subjected to bubbling or ultrasonic vibration. The solvent for dissolving the solid agent is usually water or a water-soluble organic solvent. As water, tap water, well water, ion-exchanged water, purified water such as reverse osmosis membrane treated water or forward osmosis membrane treated water is used, with purified water being particularly preferred. Furthermore, water to be treated, such as boiler feedwater, boiler water, or cooling water, to which the chemical solution is to be added, can also be used. As the water-soluble organic solvent, methanol, ethanol, or 2-propanol is used, with ethanol being particularly preferred. Furthermore, water and a water-soluble organic solvent may be used in combination. Since the solid agent exhibits the above-mentioned unique solubility and dissolves rapidly in water, the desired chemical solution can be quickly prepared.

[0031] In the addition method of the present invention, the prepared chemical solution is then added to the water to be treated (step 2). The added chemical solution contains a carboxylic acid polymer, so it can suppress scale formation in water treatment equipment, and if it contains an active ingredient other than the carboxylic acid polymer, it can further impart the efficacy of that ingredient to the water to be treated.

[0032] The water to be treated to which the chemical solution is added can be selected depending on the type of water treatment equipment. If the water treatment equipment is a boiler, the water to be treated to which the chemical solution is added is the boiler feedwater or boiler water. In the case of an open cooling tower, the water to be treated to which the chemical solution is added is circulating cooling water. In the case of filtration equipment such as a reverse osmosis membrane filtration system or a wastewater filtration system, the water to be treated to which the chemical solution is added is raw water or wastewater being filtered.

[0033] The solid agent used in step 1 of the addition method of the present invention is a dry product, so it is lightweight and small in volume, and is also stable and safe, so it can be easily transported to a storage location and moved from the storage location to a chemical solution preparation location, and can be stored efficiently and safely in a limited space. Therefore, in step 1 of the addition method of the present invention, the chemical solution can be prepared at the site where the chemical solution is to be added to the water to be treated, for example, at the location where a boiler or cooling tower is installed, and the required amount of this chemical solution can be added to the water to be treated.

[0034] In the addition method of the present invention, the water to be treated may be brought into contact with a solid agent in a water distribution pipe for the water to be treated, such as a water supply pipe for a water treatment device (e.g., a water supply pipe to a boiler) or a circulation pipe (e.g., a circulating cooling water pipe for a cooling tower), or in a bypass provided in the circulation pipe, thereby dissolving the solid agent in the water to be treated, thereby preparing a chemical solution and supplying the chemical solution to the water to be treated. For example, if a cylindrical container with an exposed bottom is placed in the circulation pipe or the bypass and the solid agent is filled in this container, the solid agent will gradually come into contact with the water to be treated flowing through the circulation pipe or the bypass, and the chemical solution can be gradually supplied to the water to be treated in accordance with the flow rate of the water to be treated. [Example]

[0035] Example 1 440 g of a 50% by weight aqueous solution of polymaleic acid used for calcium scale prevention, 80 g of a phosphonocarboxylic acid chelating agent, 110 g of sodium hydroxide, 110 g of potassium hydroxide, and trace components such as metal salts were dissolved in pure water to prepare 2.2 kg of an aqueous solution, which was then freeze-dried to produce a solid block.

[0036] For freeze-drying of the prepared aqueous solution, the aqueous solution was placed in a container so that the liquid thickness was 13 mm, and this container was placed in a freeze-dryer (Tokyo Rikakikai Co., Ltd., model number "FDU-1110" combined with a dry chamber (model number "DRC-1000") manufactured by the same company) and pre-frozen to -30°C. The pressure inside the dry chamber was then reduced to 3-15 Pa, and the temperature was maintained at -10°C for 24 hours for primary drying. After that, the temperature was changed to 30°C and maintained for 20 hours or more for secondary drying. During the drying process, the ultimate vacuum was set to 0.7 Pa, the actual vacuum at the end of drying was set to 3 Pa, and the trap temperature was set to -60°C. The obtained solid formulation had a polymaleic acid content of 37% by mass and a water content of 1.5% by mass.

[0037] <Examples 2 and 3> The same aqueous solution as prepared in Example 1 was prepared, and this aqueous solution was spray-dried to produce a powdery solid formulation. The aqueous solution was spray-dried using a spray dryer (Buchi model number "B-290") under the conditions shown in Table 1. In this case, air dehumidified using a dehumidifier (Buchi model number "B-296") was used as the drying gas. The obtained solid formulation had a polymaleic acid content of 37% by mass, and the moisture content was 5.8% by mass in Example 2 and 7.7% by mass in Example 3.

[0038] [Table 1]

[0039] <Comparative Example 1> A paste-like mixture was prepared by kneading 500g of sodium polyacrylate used to prevent calcium scale, 180g of a phosphonocarboxylic acid chelating agent, 170g of sodium hydroxide, trace elements such as metal salts, and pure water. The concentration of sodium polyacrylate in this mixture was 41% by mass (31% by mass in terms of polyacrylic acid).

[0040] <Comparative Example 2> The same aqueous solution as in Example 1 was prepared, and this aqueous solution was left in an environment of 50°C for 6 days to evaporate and dry to prepare a solid mixed drug. The water content of this mixed drug was 40% by mass. This water content was determined based on the mass loss rate before and after evaporation and the solid concentration of the mixed drug solution.

[0041] <Evaluation> The water solubility of the solid preparations obtained in Examples 1 to 3, the paste-like mixed preparation obtained in Comparative Example 1, and the solid mixed preparation obtained in Comparative Example 2 was evaluated. The preparation to be evaluated and city water from Matsuyama City, Ehime Prefecture, were enclosed in a transparent polypropylene bottle (product name "Good Boy 100 mL 110172" by AS ONE Corporation, actual volume 133 mL) to a total mass of 100 g. The amount of the preparation to be evaluated was determined so that the concentration of the carboxylic acid polymer after dissolution in the city water would be 10% by mass (the concentration was polymaleic acid for the solid preparations in Examples 1 to 3 and the mixed preparation in Comparative Example 2, and sodium polyacrylate for the mixed preparation in Comparative Example 1). The transparent polypropylene bottle was then fixed sideways on a shaker (Tokyo Rikakikai Co., Ltd., model "MMS-3010") and orbitally shaken at 200 rpm at a temperature of 25°C with a diameter of 2 cm to 3 cm. The shaking time required for complete dissolution was measured. The complete dissolution of the solid or mixed drug was confirmed by visual inspection to ensure that no undissolved drug remained. The results are shown in Figure 1.

[0042] As shown in Figure 1, the solid preparations of Examples 1 to 3 were completely dissolved in about 100 seconds, which means that the drug solution can be prepared quickly in approximately 1 / 2 to 1 / 3 of the time required to prepare the drug solution using the mixed drug of Comparative Examples 1 and 2.

[0043] The solid mixed agent of Comparative Example 2 dissolves in water more quickly than the paste-like mixed agent of Comparative Example 1, but the aqueous solution used to prepare it requires time to evaporate and dry. This is thought to be because the affinity between polymaleic acid, a carboxylic acid polymer used to prevent calcium scale, and water molecules is high, making it difficult to remove water from the aqueous solution. While the water removal efficiency can be improved by heating the aqueous solution to a higher temperature, this may result in thermal decomposition of components in the aqueous solution, such as polymaleic acid. Furthermore, the mixed agent of Comparative Example 2 begins to become viscous during the drying process and ultimately becomes a gel-like solid with a small specific surface area. This is thought to result in a slower dissolution rate in water than the solid agents of Examples 1 to 3. As a result, preparation of the mixed agent requires time, making it difficult to prepare the required amount of solution when needed.

Claims

1. A method for adding a carboxylic acid polymer-containing agent to water to be treated in a water treatment device, comprising: Step 1: preparing a drug solution containing the carboxylic acid polymer-containing drug; Step 2 of adding the chemical solution to the water to be treated, The drug containing a carboxylic acid polymer comprises one carboxylic acid polymer selected from the group consisting of polymethacrylic acid and its salts, polymaleic acid and its salts, acrylic acid / maleic acid binary copolymer, acrylic acid / hydroxypropyl acrylate binary copolymer, sulfonated styrene / maleic anhydride binary copolymer, maleic acid / acrylic acid alkyl ester / vinyl acetate terpolymer, acrylic acid / sulfonic acid / sodium styrene sulfonate terpolymer, and acrylic acid / sulfonic acid / substituted acrylamide terpolymer; In step 1, the drug solution is prepared by dissolving the carboxylic acid polymer-containing drug in a solvent, freeze-drying or spray-drying the solution to obtain a solid drug, and then dissolving the solid drug in the solvent again to prepare the drug solution. A method for adding chemicals to the water to be treated.

2. The method for adding a chemical to water to be treated according to claim 1 , wherein the chemical solution is prepared at the site where the chemical solution is to be added to the water to be treated.

3. A method for producing a solid agent for preparing a chemical solution containing a carboxylic acid polymer to be added to water to be treated in a water treatment device, comprising: a step of dissolving a drug containing one carboxylic acid polymer selected from the group consisting of polymethacrylic acid and its salts, polymaleic acid and its salts, acrylic acid / maleic acid binary copolymer, acrylic acid / hydroxypropyl acrylate binary copolymer, sulfonated styrene / maleic anhydride binary copolymer, maleic acid / acrylic acid alkyl ester / vinyl acetate terpolymer, acrylic acid / sulfonic acid / sodium styrene sulfonate terpolymer, and acrylic acid / sulfonic acid / substituted acrylamide terpolymer in a solvent to prepare a solution; freeze-drying or spray-drying the solution; A method for producing a solid preparation for preparing a medicinal solution containing a carboxylic acid polymer, comprising:

4. A method for producing a carboxylic acid polymer-containing chemical solution to be added to water to be treated in a water treatment device, comprising: The method comprises dissolving the carboxylic acid polymer-containing solid preparation for preparing a medicinal solution, which is produced by the method according to claim 3, in a solvent. A method for producing a chemical solution containing a carboxylic acid polymer.

5. A solid agent for preparing a carboxylic acid polymer-containing chemical solution to be added to water to be treated in a water treatment device, The polymer comprises one carboxylic acid polymer selected from the group consisting of polymethacrylic acid and its salts, polymaleic acid and its salts, acrylic acid / maleic acid binary copolymers, acrylic acid / hydroxypropyl acrylate binary copolymers, sulfonated styrene / maleic anhydride binary copolymers, maleic acid / acrylic acid alkyl ester / vinyl acetate terpolymers, acrylic acid / sulfonic acid / sodium styrene sulfonate terpolymers, and acrylic acid / sulfonic acid / substituted acrylamide terpolymers; the polymer is sealed together with water in a 133 mL container so that the converted mass of the carboxylic acid polymer is 10 g and the total mass with water is 100 g, and the container is shaken at 25°C at 200 rpm using a shaker set to orbitally shake with a diameter of 2 cm to 3 cm, and the time required for complete dissolution is 200 seconds at the latest; A solid formulation containing a carboxylic acid polymer for preparing medicinal solutions.

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