Preparation method of obtaining new chlorine oxide composition from degraded hypochlorite

Abstract

To provide a method for manufacturing a new germicidal disinfectant from sodium hypochlorite degraded during storage.SOLUTION: A method for manufacturing a new germicidal disinfectant from a solution including hypochlorite ion, chloric ion, and chloride ion, includes: a first reaction process of adding sulfuric acid to the solution and generating chlorine gas; a process of reacting the chlorine gas generated in a recovery liquid A with sodium hydroxide or calcium hydroxide and recovering it as hypochlorite ion; a second reaction process of adding sulfuric acid having higher concentration than that in the first reaction process to a reaction mother liquid after the first reaction process and generating chlorine dioxide gas; a process of reacting the generated chlorine dioxide gas with sodium hydroxide and hydrogen peroxide in a recovery liquid B and recovering it as chlorous acid ion; and a process of blending the recovery liquid A with the recovery liquid B to obtain the new germicidal disinfectant.SELECTED DRAWING: None

Description

[Technical Field]

[0001] The present invention relates to a method for regenerating sodium hypochlorite in which chlorine has decomposed during storage to produce chloride ions and chlorate ions, thereby obtaining a new and useful bactericidal disinfectant. [Background technology]

[0002] Sodium hypochlorite is a chlorine liquid obtained by adding chlorine to sodium hydroxide solution. It is known as a useful disinfectant for water supply, swimming pools, and food additives. However, it is unstable and the chlorine component decomposes during storage, resulting in the formation of chloride ions (Cl - ) and chlorate ions (ClO3 - ) and loses its effectiveness. Also, chlorate ions (ClO3 - When this substance is dried and crystallized, accidents such as fires and explosions due to friction are common, so care must be taken when disposing of it.

[0003] On the other hand, large-scale manufacturers of sodium hypochlorite prevent quality deterioration by controlling the temperature using cooling machines, etc., but it is difficult for distributors who mainly target small-volume users such as food manufacturers to control the temperature, and the quality deteriorates during storage, resulting in the problems mentioned above.

[0004] Furthermore, when the hypochlorite ions in sodium hypochlorite decrease and the chloride ion and chlorate ion content increases, it becomes difficult to use as normal, and so it must be disposed of by dechlorinating and neutralizing it, or by having a company take it over, and then disposal will be carried out there. [Prior art documents] [Patent documents]

[0005] [Patent Document 1] Patent No. 5931253 Summary of the Invention [Means for solving the problem]

[0006] This invention solves these problems by treating sodium hypochlorite whose quality has deteriorated during storage or recovered sodium hypochlorite as a resource and re-reacting it to produce a new, valuable bactericidal disinfectant. Furthermore, by re-reacting the components of the completed bactericidal disinfectant, a new chlorine oxide liquid containing both hypochlorite ions and chlorite ions was completed, and by further drying, a solid whose components do not change even after long-term storage was also successfully produced. Furthermore, this bactericidal disinfectant not only has improved bactericidal effect, but also has the advantage of having a reduced chlorine odor, and it has also been found to have the advantage of being able to produce a value-added product that can absorb the manufacturing costs associated with recycling.

[0007] We have researched and developed a method for producing a new bactericidal disinfectant that contains both hypochlorous acid and chlorous acid by recovering and re-reacting sodium hypochlorite, which has deteriorated during storage, and also by reacting with chloric acid that was generated during storage.

[0008] It also provides a method for obtaining a new bactericidal disinfectant with added value that can absorb the manufacturing costs associated with recycling.

[0009] In order to solve the above problems, the present inventors decided to re-react sodium hypochlorite whose quality had deteriorated to produce a bactericidal disinfectant with new commercial value.

[0010] This bactericidal disinfectant is a new chlorine oxide liquid or solid that simultaneously contains both hypochlorous acid and chlorous acid by recovering reduced-concentration sodium hypochlorite as chlorine gas and reacting with sodium chlorate, which is difficult to dispose of, to recover it as chlorine dioxide gas and stabilizing it as an alkali.

[0011] First, we investigated the effects of quality degradation on sodium hypochlorite. The key question at the time was whether there were differences in the amounts of chloride ions and chlorate ions produced as available chlorine was lost. While most standard-grade 12% sodium hypochlorite solutions contain approximately 14,000–26,000 ppm of chlorate ions at the time of distribution, low-salt 12% sodium hypochlorite solutions contain chlorate ions at 5,000–6,000 ppm, or at most 12,000 ppm. Furthermore, there were significant differences in the final amount of chloride ions produced. Therefore, when considering a reaction process, it is necessary to consider the maximum amounts of chlorate ions and chloride ions produced. However, even if the available chlorine in sodium hypochlorite is lost through decomposition, a state with an available chlorine content of 4% or less does not meet the sodium hypochlorite specifications, and therefore cannot be considered to have been used as a raw material. Therefore, it was found that the target raw material for sodium hypochlorite of reduced quality (hereinafter referred to as degraded sodium hypochlorite) is one with an available chlorine content of 4% or more and a chlorate ion production amount of up to approximately 48,000 ppm.

[0012] Next, we quantified the hypochlorite ions, chlorate ions, chloride ions, etc. contained in the deteriorated sodium hypochlorite, and considered finding conditions for gasification by reaction to obtain a recovered liquid. However, unlike the commonly known reaction manufacturing methods using various chlorine raw materials, deteriorated sodium hypochlorite simultaneously contains a large amount of various chlorine ion components, and furthermore, chlorate ions and chloride ions are products resulting from the loss of available chlorine, so the reactivity is poor compared to general chemical reaction methods when a single product or saturated liquid is used as a raw material, and so it was necessary to find new reaction conditions and recovery methods.

[0013] Furthermore, with regard to this reaction method, the concentration of sulfuric acid added, the acidity of the reaction mother liquor, and the amount of chloride ions, which are products in the deteriorated sodium hypochlorite, are important. However, it was found that chloride ions in particular are difficult to adjust because they are products of sodium hypochlorite, and that it is necessary to adjust the amount of reaction product by combining temperature, acidity, air blowing conditions, etc., to increase the yield.

[0014] In addition, the chlorine gas and chlorine dioxide gas obtained by the reaction are recovered using sodium hydroxide or calcium hydroxide, but it was found that if they are not recovered separately, it will result in a decrease in yield and the generation of chlorate ions.It was therefore found that a technology is needed to gradually release chlorine gas and then chlorine dioxide gas from the reaction mother liquor to which deteriorated sodium hypochlorite and sulfuric acid have been added.

[0015] That is, the first reaction is to generate chlorine gas from a reaction mother liquor by adding sulfuric acid to deteriorated sodium hypochlorite as a raw material. Next, sulfuric acid and other substances are added, and other conditions are changed, and then the second reaction is carried out to generate chlorine dioxide gas. Furthermore, since it has been found that the chloride ions and chlorate ions increase or decrease during the first reaction depending on the reaction conditions, such as the acidity of the reaction mother liquor, one of the features of this production method is that the second reaction is adjusted for the reaction mother liquor whose composition has changed after the first reaction, and chlorine dioxide gas is generated.

[0016] In addition, the chlorine gas generated in the first reaction can be recovered with a sodium hydroxide solution or a calcium hydroxide solution, but if the chlorine dioxide gas generated mainly in the second reaction is blown into only a sodium hydroxide solution or a calcium hydroxide solution, a large amount of chlorate ions will be generated. For this reason, it is necessary to prevent the generation of chlorate ions by adding hydrogen peroxide water to a sodium hydroxide solution or a calcium hydroxide solution to use as a recovery liquid, but conversely, in the presence of hydrogen peroxide, chlorine gas is decomposed and converted into chloride ions.

[0017] From the above, one of the features of this manufacturing method is that two recovery tanks are provided for the recovery liquid for the first reaction and the recovery liquid for the second reaction, and recovery liquid A mainly made of chlorine gas and recovery liquid B mainly made of chlorine dioxide gas are recovered separately, and then mixed and stabilized later.

[0018] Furthermore, the mixed liquid produced using this method and made to comply with the standards for sodium hypochlorite, a food additive, has poor shelf life and can only be sold refrigerated.

[0019] Therefore, one of the features of the present invention is that the chlorine gas from the first reaction is not only recovered as sodium hydroxide, but also recovered as calcium hydroxide, which is then mixed with the recovered liquid obtained from the second reaction and dried to produce a solid sterilizing disinfectant.

[0020] In the case of solids, it is necessary to concentrate the available chlorine to a high concentration by drying, so it is necessary to reduce the alkalinity of the recovered liquid as much as possible, and also reduce the amount of chloride ions and residual alkaline components as much as possible before recovering it.The solid bactericidal disinfectant produced and dried in this way complies with the standards for high-grade bleaching powder, which is a food additive, and is also characterized by the fact that the composition of its contents does not change even when stored at room temperature.

[0021] Therefore, although the required reaction conditions and the purity of the recovered liquid differ between the liquid and solid cases, the bactericidal disinfectant produced by this method combines the bactericidal properties of both hypochlorous acid and chlorous acid, and is characterized by being provided in a single agent that complies with the standards for sodium hypochlorite and high-grade bleaching powder, which are food additives.

[0022] To achieve this, the reaction conditions are adjusted for low-grade sodium hypochlorite and general-grade sodium hypochlorite. In the first reaction, for low-grade sodium hypochlorite, the sulfuric acid concentration in the reaction mother liquor is set to 4.0% to 6.37%. For general-grade sodium hypochlorite, the sulfuric acid concentration in the reaction mother liquor is set to 4.0% to 4.5%. Next, in the second reaction, for low-grade sodium hypochlorite, if the final product is standard sodium hypochlorite, hydrogen peroxide is added to the reaction mother liquor, and the sulfuric acid concentration in the reaction mother liquor is set to 30.0% to 59.4%. For high-grade bleached powder, the sulfuric acid concentration is set to 30.0% to 40.0%. The sulfuric acid concentration is set to 50.0 w / w% to 70.0 w / w%. In the case of general-grade sodium hypochlorite, the concentration should be 25.0% to 30.0%, and the sulfuric acid concentration used should be 65 w / w%. Furthermore, an intermediate trap tank is provided to wash and remove chlorine gas, preventing it from being mixed into the recovered liquid due to excessive production of chlorine gas.

[0023] In addition, it is necessary to improve the recovery rate by blowing a large amount of air into the reaction vessel immediately after the raw materials are charged.

[0024] Regarding recovered liquid A and recovered liquid B separated and recovered using this manufacturing method, in order to meet the food additive standard for sodium hypochlorite, they must be mixed at an effective chlorine concentration ratio of 1:0.43 to 1:0.6, with recovered liquid A being 1, and in order to meet the food additive standard for high-grade bleaching powder, an effective chlorine concentration ratio of up to 1:33.95 will meet the standard.

[0025] It was also found that the high-grade bleached powder produced with this formulation has a longer shelf life than commonly sold high-grade bleached powder and meets the standards. The present invention also provides the following: (Item 1) A dry solid containing hypochlorite and chlorite. (Item 2) 2. The dry solid according to claim 1, wherein the solid is dry granular. (Item 3) 3. The dry solid according to claim 1 or 2, wherein the solid comprises calcium hypochlorite. (Item 4) The solid is (1) Contains 60.0% or more of available chlorine, (2) There is a chlorine smell. (3) When 0.5 g of the solid is added to 5 ml of water and shaken, and red litmus paper is immersed in the mixture, the litmus paper turns blue and then fades. (4) When 2 ml of acetic acid (1 → 4) is added to 0.1 g of the solid, it dissolves and generates gas. When 5 ml of water is added to the solid and the filtered solution reacts with calcium salt. 4. The dry solid according to any one of items 1 to 3. (Item 5) 5. The dry solid according to any one of items 1 to 4, wherein the solid contains SO4-based components in an amount of not less than the detection limit and not more than 8100 ppm. (Item 6) Items 1 to 5, wherein the ratio of hypochlorite to chlorite in the solid is 1 to 5 to 25. The dry solid according to any one of the preceding claims. (Item 7) 7. The dry solid according to any one of items 1 to 6, wherein the solid has an available chlorine concentration in the range of 600,000 ppm to 900,000 ppm and a free residual chlorine concentration in the range of 900 ppm to 60,000 ppm. (Item 8) A liquid obtained by dissolving the dry solid according to any one of items 1 to 7. (Item 9) Item 9. The liquid according to item 8, wherein when diluted with water to an available chlorine concentration of 1%, the ratio of hypochlorite ions to chlorite ions is 1:7 to 35. (Item 10) 10. The liquid according to item 8 or 9, wherein when diluted with water to an available chlorine concentration of 1%, the free residual chlorine concentration is within the range of 150 ppm to 900 ppm. (Item 11) Item 9. The liquid according to item 8, wherein when diluted with water to an available chlorine concentration of 6%, the ratio of hypochlorite ions to chlorite ions is 1:6 to 30. (Item 12) Item 12. The liquid according to item 8 or 11, wherein when diluted with water to an available chlorine concentration of 6%, the free residual chlorine concentration is within the range of 1,000 ppm to 6,000 ppm. (Item 13) Item 9. The liquid according to item 8, wherein when diluted with water to an available chlorine concentration of 12%, the ratio of hypochlorite ions to chlorite ions is 1:6 to 30. (Item 14) Item 14. The liquid according to item 8 or 13, wherein when diluted with water to an available chlorine concentration of 12%, the free residual chlorine concentration is within the range of 2,500 ppm to 12,000 ppm. (Item 15) 1. A method for producing a dry solid comprising hypochlorite and chlorite, comprising: providing a solution containing hypochlorite ions, chlorate ions, and chloride ions; a first reaction step in which sulfuric acid is added to the solution to generate chlorine gas; A step of reacting the generated chlorine gas with sodium hydroxide or calcium hydroxide in a recovery liquid A to recover hypochlorite ions; adding sulfuric acid having a higher concentration than that in the first reaction step to the reaction mother liquor after the first reaction step; a second reaction step of generating chlorine dioxide gas; a step of reacting the produced chlorine dioxide gas with sodium hydroxide and hydrogen peroxide in a recovery liquid B to recover chlorite ions; A step of mixing recovery liquid A and recovery liquid B; a step of drying and solidifying the resulting mixed solution; The method includes: (Item 16) Item 16. The method according to item 15, wherein the recovery solution A contains calcium hydroxide. (Item 17) Item 17. The method according to item 15 or 16, further comprising adding hydrogen peroxide to the reaction mother liquor after the first reaction. (Item 18) 18. The method according to any one of items 15 to 17, wherein in the step of mixing the recovery liquid A and the recovery liquid B, the effective chlorine concentration of the recovery liquid B is in the range of 9.6 to 33.95 when the effective chlorine concentration of the recovery liquid A is 1. (Item 19) 19. The method according to any one of items 15 to 18, wherein in the step of mixing the recovery liquid A and the recovery liquid B, the recovery liquid A and the recovery liquid B are each slurried and then mixed. (Item 20) 20. The method according to any one of Items 15 to 19, wherein the step of mixing the recovery liquid A and the recovery liquid B comprises the steps of pre-drying the recovery liquid A to form granulation nuclei, slurriing the recovery liquid B, and introducing the dried recovery liquid A into the recovery liquid B slurry. (Item 21) 21. The method according to any one of items 15 to 20, wherein the drying and solidifying step comprises a step of drying with hot air for 20 to 30 minutes. (Item 22) 22. The method according to any one of items 15 to 21, wherein the drying and solidifying step comprises reducing the water content of each of recovery liquid A and recovery liquid B to 20% or less. (Item 23) A method for producing a new germicidal disinfectant from a solution containing hypochlorite ions, chlorate ions, and chloride ions, comprising: Quantifying the concentration of hypochlorite ions, chlorate ions, and chloride ions in the solution; a first reaction step in which sulfuric acid is added to the solution to generate chlorine gas; A step of reacting the generated chlorine gas with sodium hydroxide or calcium hydroxide in a recovery liquid A to recover hypochlorite ions; adding sulfuric acid having a higher concentration than that in the first reaction step to the reaction mother liquor after the first reaction step; a second reaction step of generating chlorine dioxide gas; a step of reacting the produced chlorine dioxide gas with sodium hydroxide and hydrogen peroxide in a recovery liquid B to recover chlorite ions; A step of mixing recovered liquid A and recovered liquid B to obtain a new sterilizing disinfectant; The method includes: (Item 24) Item 24. The method according to Item 23, wherein the solution containing hypochlorite ions, chlorate ions, and chloride ions is a solution containing degraded hypochlorite. (Item 25) 25. The method according to claim 24, wherein the spoiled hypochlorite-containing solution is derived from a low-salt grade sodium hypochlorite solution. (Item 26) 25. The method of claim 24, wherein the spoiled hypochlorite-containing solution is derived from a general-grade sodium hypochlorite solution. (Item 27) Item 26. The method according to Item 25, wherein the sterilizing disinfectant is a solid product, the sulfuric acid concentration in the reaction mother liquor in the first reaction step is 4.00 to 6.37%, the sulfuric acid concentration in the reaction mother liquor in the second reaction step is 30.00 to 40.00%, and the sulfuric acid concentration used in the second reaction step is 50.0 w / w% to 70.0 w / w%. (Item 28) Item 26. The method according to Item 25, wherein the sterilizing disinfectant is a liquid product, the sulfuric acid concentration in the reaction mother liquor in the first reaction step is 4.00 to 6.37%, the sulfuric acid concentration in the reaction mother liquor in the second reaction step is 30.00 to 59.04%, and the sulfuric acid concentration used in the second reaction step is 50.0 w / w% to 70.0 w / w%. (Item 29) Item 27. The method according to Item 26, wherein the sulfuric acid concentration in the reaction mother liquor in the first reaction step is 4.00 to 4.50%, the sulfuric acid concentration in the reaction mother liquor in the second reaction step is 25.00 to 30.00%, and the sulfuric acid concentration used in the second reaction step is 65 w / w%. (Item 30) In the first reaction, when the chloride concentration in the raw material is X% and the sulfuric acid concentration in the reaction mother liquor is Y%, (1) Y = -1.2676X + 9.84393 (2) X≦4 30. The method according to any one of Items 23 to 29, wherein (Item 31) 31. The method according to any one of items 23 to 30, wherein the recovery solution A contains sodium hydroxide or calcium hydroxide. (Item 32) 32. The method according to any one of items 23 to 31, wherein the recovery solution B contains sodium hydroxide and hydrogen peroxide. (Item 33) 33. The method according to any one of items 23 to 32, wherein the first reaction step is carried out while blowing air into the reaction mixture. (Item 34) 34. The method according to any one of items 23 to 33, wherein the second reaction step is carried out while blowing air into the reaction mixture. (Item 35) 35. The method according to any one of items 23 to 34, wherein an intermediate trap tank containing hydrogen peroxide is provided between the reaction tank and the recovery tank containing recovery liquid B. (Item 36) 36. The method according to any one of Items 23 to 35, further comprising the step of adding hydrogen peroxide to the reaction mother liquor after the first reaction. (Item 37) 37. The method according to any one of Items 23 to 36, wherein in the step of mixing the recovery liquid A and the recovery liquid B, the effective chlorine concentration of the recovery liquid B is 0.43 to 0.6, where the effective chlorine concentration of the recovery liquid A is 1. (Item 38) 38. The method according to any one of items 23 to 37, wherein the germicidal disinfectant comprises sodium hypochlorite. (Item 39) The bactericidal disinfectant is (1) Contains 4.0% or more of available chlorine, (2) There is a chlorine smell. (3) Reaction with sodium salts and reaction with hypochlorites; (4) When 4 ml of this aqueous solution (1→25) is added to 100 ml of phosphate buffer solution (pH 8), the maximum absorption occurs at wavelengths of 291 to 294 nm. (5) When red litmus paper is immersed in this product, the litmus paper turns blue and then fades. Item 39. The method according to item 38. (Item 40) 39. The method according to any one of items 23 to 39, wherein the germicidal disinfectant contains SO4-based components in an amount not less than the detection limit and not more than 8100 ppm. (Item 41) 41. The method according to any one of items 23 to 40, wherein the ratio of hypochlorite ions to chlorite ions in the disinfectant is 1 to 0.24 to 0.3. (Item 42) 42. The method according to any one of items 23 to 41, wherein the disinfectant has an available chlorine concentration of about 60,000 ppm and a free residual chlorine concentration of about 60,000 ppm. (Item 43) A germicidal disinfectant produced by the method according to any one of Items 23 to 42. (Item 44) Item 44. The germicidal disinfectant according to Item 43, wherein the ratio of hypochlorite ions to chlorite ions is 1 to 0.24 to 0.3. (Item 45) Item 45. The sterilizing disinfectant according to Item 43 or 44, wherein the disinfectant has an available chlorine concentration of about 60,000 ppm and a free residual chlorine concentration of about 60,000 ppm. (Item 46) A liquid chlorine oxide produced using the dry solid according to any one of items 1 to 7, (a) dissolving the dry solid in water to prepare a solution with an elevated pH; (b) adding a non-calcium inorganic alkaline agent to the solution prepared in step (a) while maintaining the pH of the solution to precipitate calcium salts, thereby forming a solid-liquid mixed phase comprising a liquid phase and a solid phase containing calcium salts, with the calcium ion concentration in the liquid phase being reduced; and (c) A step of extracting only the liquid phase from the solid-liquid mixed phase formed in step (b) to obtain liquid chlorine oxide. 1. A liquid chlorine oxide prepared by a method comprising: (Item 47) A liquid chlorine oxide produced using the dry solid according to any one of items 1 to 7, (a) dissolving the dry solid in water to prepare a solution having a pH of 10.0 or higher; (b) adding a non-calcium inorganic alkaline agent to the solution prepared in step (a) while maintaining the pH of the solution at 10.0 or higher to precipitate calcium salts, thereby forming a solid-liquid mixed phase comprising a liquid phase and a solid phase containing calcium salts, the calcium ion concentration in the liquid phase being 24 ppm or less; and (c) A step of extracting only the liquid phase from the solid-liquid mixed phase formed in step (b) to obtain liquid chlorine oxide. 1. A liquid chlorine oxide prepared by a method comprising: (Item 48) 48. The liquid or liquid chlorine oxide according to any one of items 8 to 14, 46 and 47, wherein the calcium concentration is substantially below the detection limit. (Item 49) 48. The liquid or liquid chlorine oxide according to any one of items 8 to 14, 46 and 47, wherein the calcium concentration is 24 ppm or less. (Item 50) Use of the dry solid according to any one of Items 1 to 7, the liquid according to any one of Items 8 to 14, or the liquid or liquid chlorine oxide according to any one of Items 46 to 49 as a germicidal disinfectant. (Item 51) Use of the dry solid according to any one of Items 1 to 7, the liquid according to any one of Items 8 to 14, the sterilizing disinfectant according to any one of Items 43 to 45, or the liquid or liquid chlorine oxide according to any one of Items 46 to 49 as a food additive. (Item 52) Use of the dry solid according to any one of Items 1 to 7, the liquid according to any one of Items 8 to 14, the sterilizing agent according to any one of Items 43 to 45, or the liquid or liquid chlorine oxide according to any one of Items 46 to 49, for sterilizing and disinfecting food. (Item 53) A method for producing a new drug from a solution containing hypochlorite ions, chlorate ions and chloride ions, comprising: Quantifying the concentration of hypochlorite ions, chlorate ions, and chloride ions in the solution; a first reaction step in which sulfuric acid is added to the solution to generate chlorine gas; A step of reacting the generated chlorine gas with sodium hydroxide or calcium hydroxide in a recovery liquid A to recover hypochlorite ions; adding sulfuric acid having a higher concentration than that in the first reaction step to the reaction mother liquor after the first reaction step; a second reaction step of generating chlorine dioxide gas; a step of reacting the produced chlorine dioxide gas with sodium hydroxide and hydrogen peroxide in a recovery liquid B to recover chlorite ions; A step of mixing recovered solution A and recovered solution B to obtain a new drug; The method includes: (Item 54) Item 54. The method according to Item 53, having one or more of the characteristics when the bactericidal disinfectant defined in Items 24 to 42 is replaced with a drug. (Item 55) 55. A medicament produced by the method according to item 53 or 54. (Item 56) Item 56. The agent according to item 55, having one or more of the characteristics when the bactericidal disinfectant defined in item 44 or item 45 is replaced by the agent. (Item 57) 57. Use of the agent according to item 55 or 56 as a bactericidal disinfectant. (Item 58) 57. Use of the agent according to item 55 or 56 as a food additive. (Item 59) 57. Use of an agent according to item 55 or 56 for sterilizing food. [Effects of the Invention]

[0026] This invention is an invention to obtain a useful new bactericidal disinfectant from sodium hypochlorite that has deteriorated in quality and generated chloride ions and chlorate ions, and is an invention to obtain a new bactericidal disinfectant that combines the properties of hypochlorite ions and chlorite ions and conforms to the standards of sodium hypochlorite or high-grade bleaching powder using sodium hypochlorite as a raw material. Furthermore, while a liquid containing both hypochlorite ions and chlorite ions has poor shelf life unless stored in a refrigerator, there is an advantage in that it can be stored for a long time by processing it into a dry granular solid.

[0027] Furthermore, the sodium hypochlorite and high-grade bleaching powder produced by this method have a weaker chlorine odor than liquids of the same concentration, which reduces the burden on workers and makes them easier to use. Even if a complex regeneration method is used, the manufacturing costs can be absorbed, making it possible to commercialize the products for sale. [Brief explanation of the drawings]

[0028] [Figure 1] Figure 1 shows the fading of potassium permanganate for a mixed solution of recovered liquid A and recovered liquid B (sodium hypochlorite standard), and from the left shows sodium hypochlorite only, sodium hypochlorite and sodium chlorite in an available chlorine ratio of 1:0.6, sodium hypochlorite and sodium chlorite in an available chlorine ratio of 1:0.7, and sodium chlorite only. [Figure 2] FIG. 2 shows the absorbance of sample 1 and sample 2 (for the mixed solution of recovery liquid A and recovery liquid B (sodium hypochlorite standard)). DETAILED DESCRIPTION OF THE INVENTION

[0029] The present invention will now be described with reference to the best mode thereof. Throughout this specification, singular expressions should be understood to include the plural concept unless otherwise specified. Therefore, singular articles (e.g., "a," "an," "the," etc. in English) should be understood to include the plural concept unless otherwise specified. Furthermore, terms used in this specification should be understood to have the meaning commonly used in the art unless otherwise specified. Therefore, unless otherwise defined, all technical and scientific terms used in this specification have the same meaning as commonly understood by those skilled in the art to which this invention belongs. In the event of conflict, the present specification (including definitions) will prevail.

[0030] (Definition of terms) The terms used in this specification are explained below.

[0031] In this specification, "a solution containing hypochlorite of deteriorated quality" means a solution of sodium hypochlorite in which chlorine has decomposed during storage, generating chloride ions and chlorate ions. In this specification, hypochlorite may be abbreviated to "hypochlorite".

[0032] In this specification, "low-salt sodium hypochlorite solution" means a sodium hypochlorite solution with a reduced amount of salt, and the chlorate ion content in a 12% low-salt sodium hypochlorite solution is 5000 to 6000 ppm, and at most 12000 ppm.

[0033] In this specification, "general-grade sodium hypochlorite solution" refers to a sodium hypochlorite solution in which the amount of salt has not been reduced, and in a 12% solution of general-grade sodium hypochlorite, approximately 14,000 to 26,000 ppm of chlorate ions are generated at the time of distribution.

[0034] In this specification, "available chlorine" or "available chlorine concentration" refers to the concentration of chlorine contained in disinfectants such as bleaching powder that is effective for bleaching. Available chlorine can be determined, for example, by adding potassium iodide to a sample of sodium hypochlorite, liberating iodine according to the formula Cl2 + KI → I2 + KCl (1), and then subjecting the liberated iodine to oxidation-reduction titration with sodium thiosulfate (I2 + 2Na2S2O3 → 2NaI + Na2S4O6 (2)).

[0035] In this specification, "free chlorine," "free chlorine concentration," or "free residual chlorine concentration" refers to a value measured by Appendix 3 of the "Testing Method for Free Residual Chlorine and Combined Chlorine Established by the Minister of Health, Labour and Welfare Pursuant to the Provisions of Article 17, Paragraph 2 of the Enforcement Regulations of the Water Supply Act" (hereinafter referred to as the colorimetric method (DPD indicator)), and is a value obtained by oxidizing the DPD indicator.

[0036] In this specification, "SO4-based components" refers to components derived from sulfuric acid, including sulfuric acid and sulfates.

[0037] In this specification, "hot air drying" refers to drying conditions in which the ambient temperature inside the cabinet is 50 to 60°C, the humidity inside the cabinet is 10% or less, and the air volume is 1.9 m 3 This is done by blowing warm air at / s.

[0038] As used herein, "chlorine oxide" refers to any oxide of chlorine. Examples include hypochlorous acid, chlorous acid, chloric acid, perchloric acid, and salts thereof. Also included are dichlorine heptaoxide, dichlorine hexaoxide, dichlorine trioxide, chlorine dioxide, and dichlorine monoxide.

[0039] In this specification, "high-grade bleached powder" means that it meets the standards for high-grade bleached powder set forth in the 8th edition of the Japanese Standards for Food Additives. Specifically, it meets the following: (1) Contains 60.0% or more of available chlorine, (2) There is a chlorine smell. (3) When 0.5 g of the solid is added to 5 ml of water and shaken, and red litmus paper is immersed in the mixture, the litmus paper turns blue and then fades. (4) When 2 ml of acetic acid (1 → 4) is added to 0.1 g of the solid, it dissolves and generates gas. When 5 ml of water is added to the solid and the filtered solution reacts to form calcium salts.

[0040] In this specification, "T.AL" refers to the alkalinity of a sample, measured by titrating the sample with 0.1 mol / L hydrochloric acid-acid standard solution until the pH reaches 4.0. When 1 mL of 0.1 mol / L hydrochloric acid is required to adjust the pH of 100 g of sample to 4.0, the alkalinity (T.AL) is defined as 1. pH 4.0 is the second neutralization point of sodium carbonate. High-grade bleaching powder has a wide range of specifications, and since chlorine oxide generally varies depending on the formulation of pH adjusters, etc., from manufacturer to manufacturer, T.AL is usually not listed in the specifications. However, because it contains chlorine, it shows a high T.AL value and is highly alkaline.

[0041] As used herein, the term "non-calcium inorganic alkaline agent" refers to a drug containing an inorganic alkaline substance having a cation other than calcium. It is understood that any inorganic alkaline substance containing a cation other than calcium can be used. Examples include, but are not limited to, sodium carbonate, disodium hydrogen phosphate, sodium sulfate, and sodium hydroxide.

[0042] As used herein, "divalent or higher inorganic alkaline agents" refers to non-calcium inorganic alkaline agents with a valence of divalent or higher. Sodium-containing alkaline agents are preferred, but are not limited to these. Divalent or higher inorganic alkaline agents are advantageously those capable of lowering the pH to 10 or less, as this lowers the pH of the high-grade bleaching powder. Examples include, but are not limited to, sodium carbonate, disodium hydrogen phosphate, and sodium sulfate. However, the present invention demonstrates that inorganic alkaline agents with a valence of less than divalent, such as sodium hydroxide, can also be used in some cases. The addition of sodium sulfate or other additives can also be advantageous. Without being bound by theory, the addition of sodium sulfate is preferred because it facilitates solidification and reduces floating in the precipitation tank after the reaction, improving workability. The amount of sodium sulfate added is typically approximately 0.1 times the amount of other inorganic alkaline agents added. Other amounts are acceptable as long as the intended purpose is achieved, but examples include 10% or less, preferably 5% or less, 2% or less, or 1% or less.

[0043] In this specification, "recovered liquid A" refers to the recovered liquid obtained by recovering the gas generated in the first reaction step in the method for treating a solution containing hypochlorite of the present invention. In this specification, "recovered liquid B" refers to the recovered liquid obtained by recovering the gas generated in the second reaction step in the method for treating a solution containing hypochlorite of the present invention.

[0044] DESCRIPTION OF THE PREFERRED EMBODIMENTS Preferred embodiments of the present invention will be described below. The embodiments provided below are provided for a better understanding of the present invention, and it is understood that the scope of the present invention should not be limited to the following description. Therefore, it is clear that those skilled in the art can make appropriate modifications within the scope of the present invention in light of the description in this specification. It is also understood that the following embodiments of the present invention can be used alone or in combination.

[0045] In one aspect, the present invention provides hypochlorite and a dry solid containing chlorite. Hypochlorite includes alkali metal or alkaline earth metal salts of hypochlorous acid, such as sodium, potassium, calcium, and magnesium salts. Chlorite includes alkali metal or alkaline earth metal salts of chlorite, such as sodium, potassium, calcium, and magnesium salts. The solid germicidal disinfectant of the present invention maintains its composition even when stored at room temperature, and when converted into a calcium salt, meets the food additive standard for high-grade bleaching powder. Salts such as potassium and magnesium salts can be obtained by using an alkaline solution of the corresponding alkali metal or alkaline earth metal in the recovery solution, or by exchanging the sodium or calcium salt for the corresponding metal.

[0046] In one embodiment, the solid is dry and granular.

[0047] In one embodiment, the solid comprises calcium hypochlorite.

[0048] In one embodiment, the solid is a powder as defined in the 8th edition of the Japanese Standards for Food Additives for High-grade bleached powder. Specifically, the solid satisfies the specifications set forth in the (1) Contains 60.0% or more of available chlorine, (2) There is a chlorine smell. (3) When 0.5 g of the solid is added to 5 ml of water and shaken, and red litmus paper is immersed in the mixture, the litmus paper turns blue and then fades. (4) When 2 ml of acetic acid (1 → 4) is added to 0.1 g of the solid, it dissolves and generates gas. When 5 ml of water is added to the solid and the filtered solution reacts to form calcium salts.

[0049] In one embodiment, the solid contains SO4-based components at a concentration between the detection limit and 8100 ppm. The SO4-based components may be 8000 ppm or less, 7000 ppm or less, 6000 ppm or less, 5000 ppm or less, 4000 ppm or less, 3000 ppm or less, 2000 ppm or less, or 1000 ppm or less. The SO4-based components may be 100 ppm or more, 200 ppm or more, 300 ppm or more, 400 ppm or more, 500 ppm or more, 600 ppm or more, 700 ppm or more, 800 ppm or more, 900 ppm or more, 1000 ppm or more, or 1100 ppm or more. These SO4-based components are entrained by sulfuric acid contained in the reaction tank, and the amount of SO4-based components can be one indicator of whether chlorine oxides have been produced by the present invention.

[0050] In one embodiment, the ratio of hypochlorite to chlorite in the solid is 1:5 to 25. This ratio is a value for a mixture obtained by pre-drying recovery liquid A and recovery liquid B used to obtain the solid to a moisture content of approximately 20%, respectively, and mixing the resulting mixture, followed by drying and solidification. In a solid product, the free residual chlorine concentration can be considered to be equal to the available chlorine concentration, so the concentration of hypochlorite ions can be derived from the free residual chlorine concentration. The chlorite ion concentration can be measured by ion chromatography. The ratio of hypochlorite to chlorite is derived from the ratio of each ion. The ratio of hypochlorite to chlorite in the solid can be 1:9 to 25. The ratio of hypochlorite to chlorite in the solid can be 1:5 to 9. The ratio of hypochlorite to chlorite in the solid can be any value or range between 5 and 25, with the hypochlorite being 1. For example, if hypochlorite is 1, chlorite can be 5, 6, 7, 8, 9, 10, 11, 12, 13, 14, 15, 16, 17, 18, 19, 20, 21, 22, 23, 24, or 25, or any value or range therebetween. As a specific example, the ratio of hypochlorite to chlorite in the solid is 1 to 5.53 to 23.59. The ratio of hypochlorite to chlorite in the solid can be 1 to 8.92 to 23.59. The ratio of hypochlorite to chlorite in the solid can be 1 to 5.53 to 8.92. A dry solid having such a ratio has high purity, long shelf life, high bactericidal effect, and little chlorine odor. In the case of calcium salts, it complies with the standard criteria for high-grade bleaching powder. If necessary, a solid with a value outside the above range may be prepared.

[0051] In one embodiment, the available chlorine concentration in the solid is in the range of 600,000 ppm to 900,000 ppm, and the free residual chlorine concentration is in the range of 900 ppm to 60,000 ppm. The available chlorine concentration in the solid can be any value or range within the range of 600,000 ppm to 900,000 ppm. The available chlorine concentration in the solid can be 600,000 ppm, 650,000 ppm, 700,000 ppm, 750,000 ppm, 800,000 ppm, 850,000 ppm, 900,000 ppm, or any combination of these values. The free residual chlorine concentration in the solid can be any value or range within the range of 900 ppm to 60,000 ppm. The free residual chlorine concentration in the solid may be 900 ppm, 1,000 ppm, 2,000 ppm, 3,000 ppm, 4,000 ppm, 5,000 ppm, 6,000 ppm, 7,000 ppm, 8,000 ppm, 9,000 ppm, 10,000 ppm, 15,000 ppm, 20,000 ppm, 25,000 ppm, 30,000 ppm, 35,000 ppm, 40,000 ppm, 45,000 ppm, 50,000 ppm, 55,000 ppm, 60,000 ppm, or within any combination of these values. As a specific example, the available chlorine concentration in the solid is within the range of 606,811 ppm to 881,677 ppm, and the free residual chlorine concentration is within the range of 901 ppm to 58,728 ppm. The available chlorine concentration in the solid may be within the range of 606,811 ppm to 881,677 ppm. The available chlorine concentration in the solid may be 606,811 ppm, 616,877 ppm, 632,513 ppm, 647,265 ppm, 781,019 ppm, 782,210 ppm, 824,064 ppm, or 881,667 ppm. As a specific example, the free residual chlorine concentration in the solid may be within the range of 901 ppm to 58,728 ppm. The free residual chlorine concentration in the solid can be 901 ppm, 2,145 ppm, 2,625 ppm, 20,785 ppm, 49,314 ppm, 55,916 ppm, or 58,728 ppm.Dry solids with such concentrations have high purity, long shelf life, high bactericidal effect, and little chlorine odor. In the case of calcium salts, they meet the specifications for high-grade bleaching powder. If necessary, solids with values ​​outside the above range may be produced.

[0052] In one aspect, the present invention provides a liquid obtained by dissolving the dry solid. Examples of solvents for dissolving the dry solid include water, alcohol, and ether. Examples of water include tap water, well water, seawater, ion-exchanged water, and purified water.

[0053] In one embodiment, when diluted with water to a 1% available chlorine concentration, the ratio of hypochlorite ions to chlorite ions is 1 to 7 to 35, and when the hypochlorite ions are 1, the chlorite ions can be 7, 8, 9, 10, 11, 12, 13, 14, 15, 16, 17, 18, 19, 20, 21, 22, 23, 24, 25, 26, 27, 28, 29, 30, 31, 32, 33, 34, or 35, or any value or range of values ​​therebetween. As a specific example, when diluted with water to a 1% available chlorine concentration, the ratio of hypochlorite ions to chlorite ions is 1 to 7.16 to 34.36. When diluted with water to a 1% available chlorine concentration, the free residual chlorine concentration is in the range of 150 ppm to 900 ppm. The free residual chlorine concentration can be 150 ppm, 200 ppm, 250 ppm, 300 ppm, 350 ppm, 400 ppm, 450 ppm, 500 ppm, 550 ppm, 600 ppm, 650 ppm, 700 ppm, 750 ppm, 800 ppm, 850 ppm, or 900 ppm, or any value or range therebetween. As a specific example, when diluted with water to a 1% available chlorine concentration, the free residual chlorine concentration is in the range of 187.07 ppm to 836.70 ppm. Because free residual chlorine can be decomposed during operation, the ratio of hypochlorite ions to chlorite ions can vary depending on the degree of dilution. A liquid with such a ratio has high purity, a high disinfecting effect, and a low chlorine odor.

[0054] When diluted with water to an available chlorine concentration of 6%, the ratio of hypochlorite ions to chlorite ions is 1 to 6-30, and when the hypochlorite ions are 1, the chlorite ions can be 6, 7, 8, 9, 10, 11, 12, 13, 14, 15, 16, 17, 18, 19, 20, 21, 22, 23, 24, 25, 26, 27, 28, 29, 30, or any value or range of values ​​therebetween. As a specific example, when diluted with water to an available chlorine concentration of 6%, the ratio of hypochlorite ions to chlorite ions is 1 to 6.31-29.54. When diluted with water to a 6% available chlorine concentration, the free residual chlorine concentration is in the range of 1,000 ppm to 6,000 ppm. The free residual chlorine concentration can be 1,000 ppm, 1,500 ppm, 2,000 ppm, 2,500 ppm, 3,000 ppm, 3,500 ppm, 4,000 ppm, 4,500 ppm, 5,000 ppm, 5,500 ppm, or 6,000 ppm, or any value or range therebetween. As a specific example, when diluted with water to a 6% available chlorine concentration, the free residual chlorine concentration is in the range of 1,296.01 ppm to 5,624.20 ppm. Because free residual chlorine can be decomposed during operation, the ratio of hypochlorite ions to chlorite ions can vary depending on the degree of dilution. A liquid with such a ratio has high purity, a high disinfecting effect, and a low chlorine odor.

[0055] When diluted with water to an available chlorine concentration of 12%, the ratio of hypochlorite ions to chlorite ions is 1 to 6-30, and when the hypochlorite ions are 1, the chlorite ions can be 6, 7, 8, 9, 10, 11, 12, 13, 14, 15, 16, 17, 18, 19, 20, 21, 22, 23, 24, 25, 26, 27, 28, 29, 30, or any value or range of values ​​therebetween. As a specific example, when diluted with water to an available chlorine concentration of 12%, the ratio of hypochlorite ions to chlorite ions is 1 to 6.39-28.16. When diluted with water to a 12% available chlorine concentration, the free residual chlorine concentration is in the range of 2,500 ppm to 12,000 ppm, and the free residual chlorine concentration can be 2,500 ppm, 3,000 ppm, 3,500 ppm, 4,000 ppm, 4,500 ppm, 5,000 ppm, 6,000 ppm, 6,500 ppm, 7,000 ppm, 7,500 ppm, 8,000 ppm, 8,500 ppm, 9,000 ppm, 9,500 ppm, 10,000 ppm, 10,500 ppm, 11,000 ppm, 11,500 ppm, 12,000 ppm, or any value or range of values ​​therebetween. As a specific example, when diluted with water to a 12% available chlorine concentration, the free residual chlorine concentration is in the range of 2736.70 ppm to 11378.81 ppm. Because the free residual chlorine may be decomposed during operation, the ratio of hypochlorite ions to chlorite ions may change depending on the degree of dilution. A liquid with such a ratio has high purity, a strong disinfecting effect, and a low chlorine odor.

[0056] In one aspect, the present invention provides a method for producing a dry solid containing hypochlorite and chlorite, comprising the steps of: preparing a solution containing hypochlorite ions, chlorate ions, and chloride ions; a first reaction step of adding sulfuric acid to the solution to generate chlorine gas; a step of reacting the generated chlorine gas with sodium hydroxide or calcium hydroxide in recovered liquid A to recover hypochlorite ions; a second reaction step of adding sulfuric acid to the reaction mother liquor after the first reaction step at a concentration higher than that in the first reaction step to generate chlorine dioxide gas; a step of reacting the generated chlorine dioxide gas with sodium hydroxide and hydrogen peroxide in recovered liquid B to recover chlorite ions; a step of mixing recovered liquid A and recovered liquid B; and a step of drying and solidifying the resulting mixed solution. This method regenerates deteriorated sodium hypochlorite to produce a new and useful germicidal disinfectant. The solid bactericidal disinfectant produced and dried by this method does not change its composition even when stored at room temperature, and when converted into a calcium salt, it can meet the standards for high-grade bleached powder, a food additive. The dried solid produced by this method has the advantages of having a low chlorine odor, reducing the burden on workers, and being easy to use. Even if a complex regeneration method is used, the manufacturing costs can be absorbed, and it can be said that it can be commercialized for practical sale.

[0057] In one embodiment, the recovery solution A contains calcium hydroxide.

[0058] In one embodiment, the method further comprises adding hydrogen peroxide to the reaction mother liquor after the first reaction. This step of adding hydrogen peroxide makes it possible to suppress the generation of chlorine gas.

[0059] In one embodiment, in the step of mixing the recovery liquid A and the recovery liquid B, when the effective chlorine concentration of the recovery liquid A is 1, the effective chlorine concentration of the recovery liquid B is within the range of 9.6 to 33.95. With respect to the effective chlorine concentration of the recovery liquid A, 1, the effective chlorine concentration of the recovery liquid B may be 9.6 or more, 9.7 or more, 9.8 or more, 9.9 or more, 10.0 or more, 11 or more, 12 or more, 13 or more, 14 or more, 15 or more, 16 or more, 17 or more, 18 or more, 19 or more, 20 or more, 21 or more, 22 or more, 23 or more, 24 or more, 25 or more, 26 or more, 27 or more, 28 or more, 29 or more, 30 or more, 31 or more, 32 or more, 33 or more, and may be 33.95 or less, 33.9 or less, 33.8 or less. , 33.7 or less, 33.6 or less, 33.5 or less, 33.4 or less, 33.3 or less, 33.2 or less, 33.1 or less, 33 or less, 32 or less, 31 or less, 30 or less, 29 or less, 28 or less, 27 or less, 26 or less, 25 or less, 24 or less, 23 or less, 22 or less, 21 or less, 20 or less, 19 or less, 18 or less, 17 or less, 16 or less, 15 or less, 14 or less, 13 or less, 12 or less, 11 or less, 10 or less, 9.9 or less, 9.8 or less, 9.7 or less. The effective chlorine concentration of recovered solution B can be 9.6, 9.7, 9.8, 9.9, 10, 11, 12, 13, 14, 15, 16, 17, 18, 19, 20, 21, 22, 23, 24, 25, 26, 27, 28, 29, 30, 31, 32, or 33, relative to the effective chlorine concentration of recovered solution A. Preferably, the effective chlorine concentration of recovered solution B is 20% relative to the effective chlorine concentration of recovered solution A. If the effective chlorine ratio of recovered solution B is less than 9.6, the effective chlorine may fall below 60%, making it unsuitable for high-grade bleaching powder. This effective chlorine ratio is the lower limit. If the effective chlorine ratio of recovered solution B exceeds 33.95, it will not comply with the specifications for free residual chlorine and calcium.

[0060] In one embodiment, in the step of mixing the recovered liquid A and the recovered liquid B, the recovered liquid A and the recovered liquid B are each slurried and then mixed. By mixing the recovered liquid A and the recovered liquid B after forming a slurry and then drying them, the overall operation time can be shortened and loss of available chlorine and changes in composition can be prevented compared to the case where the recovered liquid A and the recovered liquid B are not slurried.

[0061] In one embodiment, the step of mixing the recovered liquid A and the recovered liquid B includes the steps of pre-drying the recovered liquid A to form granulation nuclei, slurriing the recovered liquid B, and then adding the dried recovered liquid A to the slurry of the recovered liquid B. Pre-drying to some extent improves workability and stability.

[0062] In one embodiment, the drying and solidification step includes a step of drying with hot air for 20 to 30 minutes. The drying conditions are an internal ambient temperature of 50 to 60°C and an internal humidity of 10% or less. The air volume is 1.9 m 3 / s sends out warm air.

[0063] In one embodiment, the drying and solidification step includes reducing the moisture content of each of recovered liquid A and recovered liquid B to 20% or less. In one embodiment, the moisture content may be 26% or less, 25% or less, 24% or less, 23% or less, 22% or less, 21% or less, 20% or less, 19% or less, 18% or less, 17% or less, 16% or less, 15% or less, 14% or less, 13% or less, 12% or less, 11% or less, or 10% or less. If the moisture content is 26% or more, the free residual chlorine (hypochlorite ions) in recovered liquid A reacts with chlorite ions, resulting in a decrease in the available chlorine concentration and an increase in chlorate ions, which in turn reduces the purity and drying rate. Furthermore, if the moisture content exceeds 30%, the self-decomposition of free residual chlorine (hypochlorite ions) becomes significant, resulting in a particular decrease in free residual chlorine (hypochlorite ions), which also reduces the purity and drying rate. It is preferable to reduce the amount of water to 20% or less, but an appropriate amount of water can be selected taking into consideration operability and cost.

[0064] In one aspect, the present invention provides a method for producing a new germicidal disinfectant from a solution containing hypochlorite ions, chlorate ions, and chloride ions, comprising the steps of: quantifying the concentrations of hypochlorite ions, chlorate ions, and chloride ions in the solution; a first reaction step of adding sulfuric acid to the solution to produce chlorine gas; a second reaction step of adding sulfuric acid to the reaction mother liquor after the first reaction step at a concentration higher than that in the first reaction step to produce chlorine dioxide gas; a second reaction step of reacting the chlorine dioxide gas with sodium hydroxide and hydrogen peroxide in a recovered liquid B to recover chlorite ions; and a third step of mixing recovered liquid A and recovered liquid B to obtain a new germicidal disinfectant. The mixture of recovered liquid A and recovered liquid B can be used as a germicidal disinfectant. This method regenerates deteriorated sodium hypochlorite to produce a new, useful germicidal disinfectant. The bactericidal disinfectant produced by this method, when converted into a sodium salt, can comply with the standards for sodium hypochlorite as a food additive.

[0065] In one embodiment, the solution containing hypochlorite ions, chlorate ions, and chloride ions is a solution containing degraded hypochlorite.

[0066] In one embodiment, the spoiled hypochlorite-containing solution is derived from a low-salt grade sodium hypochlorite solution.

[0067] In one embodiment, the spoiled hypochlorite-containing solution is derived from a general-grade sodium hypochlorite solution.

[0068] In the first reaction, it is important to control the chlorine dioxide gas mixed into the recovered liquid A by adjusting the sulfuric acid concentration, and it is important that the acidity of the reaction mother liquor during the first reaction does not decompose the chlorate ions.

[0069] The sulfuric acid concentration in the second reaction depends on two factors: the sulfuric acid concentration used and the sulfuric acid concentration in the reaction mother liquor during the second reaction. Also, the higher the sulfuric acid concentration used in the second reaction, the better, but the sulfuric acid concentration in the reaction mother liquor is not the only important factor in the second reaction.

[0070] In one embodiment, the solution containing the deteriorated hypochlorite is derived from a low-salt sodium hypochlorite solution, the sterilizing disinfectant is a solid product, the sulfuric acid concentration in the reaction mother liquor in the first reaction step is 4.00 to 6.37%, the sulfuric acid concentration in the reaction mother liquor in the second reaction step is 30.00 to 40.00%, and the sulfuric acid concentration used in the second reaction step is 50.0 w / w% to 70.0 w / w%. In a further embodiment, when the sterilizing disinfectant is a solid product, the sulfuric acid concentration in the reaction mother liquor in the first reaction step can be 4.00%, 4.10%, 4.20%, 4.30%, 4.40%, 4.50%, 4.60%, 4.70%, 4.80%, 4.90%, 5.00%, 5.10%, 5.20%, 5.30%, 5.40%, 5.50%, 5.60%, 5.70%, 5.80%, 5.90%, 6.00%, 6.10%, 6.20%, 6.30%, or 6.37%, and the sulfuric acid concentration in the reaction mother liquor in the second reaction step can be 30.0%, 31.0%, 32.0%, 33.0%, 34. 0%, 35.0%, 36.0%, 37.0%, 38.0%, 39.0% or 40.0%, and the sulfuric acid concentration used in the second reaction step is 50.0 w / w%, 51.0 w / w%, 52.0 w / w%, 53.0 w / w%, 54.0 w / w%, 55.0 w / w%, 56.0 w / w%, 57.0 w / w%, 58.0 w / w%, 59.0 w / w%, 60.0 w / w%, 61.0 w / w%, 62.0 w / w%, 63.0 w / w%, 64.0 w / w%, 65.0 w / w%, 66.0 w / w%, 67.0 w / w%, 68.0 w / w%, 69.0 w / w%, or 70.0 w / w%.

[0071] In one embodiment, the solution containing the deteriorated hypochlorite is derived from a low-salt sodium hypochlorite solution, the sterilizing disinfectant is a liquid product, the sulfuric acid concentration in the reaction mother liquor in the first reaction step is 4.00 to 6.37%, the sulfuric acid concentration in the reaction mother liquor in the second reaction step is 30.00 to 59.04%, and the sulfuric acid concentration used in the second reaction step is 50.0 w / w% to 70.0 w / w%. In a further embodiment, the sterilizing disinfectant is a liquid product, and the sulfuric acid concentration in the reaction mother liquor in the first reaction step is 4.00, 4.10%, 4.20%, 4.30%, 4.40%, 4.50%, 4.60%, 4.70%, 4.80%, 4.90%, 5.00%, 5.10%, 5.20%, 5.30%, 5.40%, 5.50%, 5.60%, 5.70% , 5.80%, 5.90%, 6.00%, 6.10%, 6.20%, 6.30% or 6.37%, and the sulfuric acid concentration in the reaction mother liquor in the second reaction step is 30.0%, 31.0%, 32.0%, 33.0%, 34.0%, 35.0%, 36.0%, 37.0%, 38.0%, 39.0%, 40.0%, 41.0%, 42.0%, 43.0%, 44.0% , 45.0%, 46.0%, 47.0%, 48.0%, 49.0%, 50.0%, 51.0%, 52.0%, 53.0%, 54.0%, 55.0%, 56.0%, 57.0%, 58.0%, 59.0% or 59.04%, and the sulfuric acid concentration used in the second reaction step is 50.0 w / w%, 51.0 w / w%, 52.0 w / w%, 53.0 w / w% , 54.0 w / w%, 55.0 w / w%, 56.0 w / w%, 57.0 w / w%, 58.0 w / w%, 59.0 w / w%, 60.0 w / w%, 61.0 w / w%, 62.0 w / w%, 63.0 w / w%, 64.0 w / w%, 65.0 w / w%, 66.0 w / w%, 67.0 w / w%, 68.0 w / w%, 69.0 w / w%, or 70.0 w / w%.

[0072] In one embodiment, the solution containing degraded hypochlorite is derived from a general-grade sodium hypochlorite solution, the sulfuric acid concentration in the reaction mother liquor in the first reaction step is 4.00-4.50%, the sulfuric acid concentration in the reaction mother liquor in the second reaction step is 25.00-30.00%, and the sulfuric acid concentration used in the second reaction step is 65 w / w%. In a further embodiment, the sulfuric acid concentration in the reaction mother liquor in the first reaction step is 4.00%, 4.10%, 4.20%, 4.30%, 4.40%, or 4.50%, the sulfuric acid concentration in the reaction mother liquor in the second reaction step is 25.0%, 26.0%, 27.0%, 28.0%, 29.0%, or 30.00%, and the sulfuric acid concentration used in the second reaction step is 65 w / w%.

[0073] In one embodiment, in the first reaction, when the chloride concentration in the raw material is X% and the sulfuric acid concentration in the reaction mother liquor is Y%, (1) Y = -1.2676X + 9.84393 (2) X≦4 This formula is derived by taking into account the condition that the chlorate ions in the raw material are not decomposed or increase as the upper limit, and that the chlorate ions increase by 110% or more in consideration of a safety factor, and that if the chloride concentration in the raw material is high, the concentration of sulfuric acid that can be added will decrease.

[0074] In one embodiment, the recovery solution A contains sodium hydroxide or calcium hydroxide.

[0075] In one embodiment, recovery solution B contains sodium hydroxide and hydrogen peroxide.

[0076] The reaction step can be carried out while blowing air into the reaction vessel, which helps to prevent the chlorine gas and chlorine dioxide gas generated in the reaction vessel from returning to the solution and causing reverse reaction products.

[0077] In one embodiment, the first reaction step is carried out while blowing air.

[0078] In one embodiment, the second reaction step is carried out while blowing air.

[0079] In one embodiment, an intermediate trap tank containing hydrogen peroxide is provided between the reaction tank and the recovery tank containing recovery liquid B. The intermediate trap tank prevents chlorine gas from being mixed into recovery liquid B.

[0080] In one embodiment, the method further comprises a step of adding hydrogen peroxide to the reaction mother liquor after the first reaction. By adding hydrogen peroxide during the second reaction, the generation of chlorine gas is suppressed.

[0081] In one embodiment, in the step of mixing the recovery liquid A and the recovery liquid B, the effective chlorine concentration of the recovery liquid A is taken as 1, and the effective chlorine concentration of the recovery liquid B is 0.43 to 0.6. In one embodiment, the effective chlorine concentration of the recovered liquid A is 1, and the effective chlorine concentration of the recovered liquid B is 0.43 or more, 0.44 or more, 0.45 or more, 0.46 or more, 0.47 or more, 0.48 or more, 0.49 or more, 0.5 or more, 0.51 or more, 0.52 or more, 0.53 or more, 0.52 or more, 0.53 or more, 0.54 or more, 0.55 or more, 0.56 or more, 0.57 or more, 0.58 or more, 0.59 or more, 0.6 or less, 0.59 or less, 0.58 or less, 0.57 or less, 0.56 or less, 0.55 or less, 0.54 or less, 0.53 or less, 0.52 or less, 0.51 or less, 0.50 or less, 0.49 or less, 0.48 or less, 0.47 or less, 0.46 or less, 0.45 or less, 0.44 or less It can be any numerical range. When the concentration is within this range, the mixture of recovered solution A and recovered solution B can meet the food additive standard for sodium hypochlorite.

[0082] In one embodiment, the germicidal disinfectant comprises sodium hypochlorite.

[0083] In one embodiment, the sterilizing disinfectant is a product that complies with the standards for food additive sodium hypochlorite. (1) Contains 4.0% or more of available chlorine, (2) There is a chlorine smell. (3) Reaction with sodium salts and reaction with hypochlorites; (4) When 4 ml of this aqueous solution (1→25) is added to 100 ml of phosphate buffer solution (pH 8), the maximum absorption occurs at wavelengths of 291 to 294 nm. (5) When red litmus paper is immersed in this product, the paper turns blue and then fades.

[0084] In one embodiment, the germicidal disinfectant contains SO4-based components at a detection limit of 8100 ppm or less. The SO4-based components may be 8000 ppm or less, 7000 ppm or less, 6000 ppm or less, 5000 ppm or less, 4000 ppm or less, 3000 ppm or less, 2000 ppm or less, or 1000 ppm or less. The SO4-based components may be 100 ppm or more, 200 ppm or more, 300 ppm or more, 400 ppm or more, 500 ppm or more, 600 ppm or more, 700 ppm or more, 800 ppm or more, 900 ppm or more, 1000 ppm or more, or 1100 ppm or more. These SO4-based components are entrained by sulfuric acid contained in the reaction tank, and the amount of SO4-based components can be one indicator of whether chlorine oxides have been produced by the present invention.

[0085] In one embodiment, the ratio of hypochlorite ions to chlorite ions in the disinfectant is 1:0.24 to 0.3. In the case of liquid products, it is difficult to identify substances and determine their concentrations from the free residual chlorine concentration. Therefore, chlorite ions from recovered liquid B were determined by ion chromatography, converted to available chlorine, and subtracted from the total available chlorine. The remaining available chlorine was then defined as available chlorine from recovered liquid A, and multiplied by a coefficient to determine the hypochlorite ions, resulting in the final ion ratio. The ratio of hypochlorite ions to chlorite ions in the disinfectant may be any value or range between 0.24 and 0.3, where chlorite is 1. For example, when hypochlorite is 1, chlorite is 0.24, 0.25, 0.26, 0.27, 0.28, 0.29, or 0.30. A disinfectant having such a ratio has high purity, high sterilization effect, and a low chlorine odor.

[0086] In one embodiment, the disinfectant has an available chlorine concentration of about 60,000 ppm and a free residual chlorine concentration within the range of about 60,000 ppm. The available chlorine concentration of the disinfectant may be 55,000 ppm, 56,000 ppm, 57,000 ppm, 58,000 ppm, 59,000 ppm, 60,000 ppm, 61,000 ppm, 62,000 ppm, 63,000 ppm, 64,000 ppm, 65,000 ppm, or any combination thereof. Specific examples include the available chlorine concentration of 60,114 ppm and 60,814 ppm. The free residual chlorine concentration in the disinfectant may be 55,000 ppm, 56,000 ppm, 57,000 ppm, 58,000 ppm, 59,000 ppm, 60,000 ppm, 61,000 ppm, 62,000 ppm, 63,000 ppm, 64,000 ppm, or 65,000 ppm, or any combination thereof. A specific example is 58,157 ppm or 59,380 ppm. Disinfectants with such concentrations have high purity, strong sterilization effects, and little chlorine odor.

[0087] In one aspect, the present invention provides a germicidal disinfectant produced by any of the above methods.

[0088] In one embodiment, the ratio of hypochlorite ions to chlorite ions in the germicidal disinfectant is 1 to 0.24 to 0.3. The ratio of hypochlorite ions to chlorite ions in the disinfectant may be any value or range between 0.24 and 0.3, where 1 is the ratio of hypochlorite. For example, where 1 is the ratio of hypochlorite, 0.24, 0.25, 0.26, 0.27, 0.28, 0.29, or 0.30 is the ratio of chlorite. A disinfectant having such a ratio has high purity, a high disinfecting effect, and a low chlorine odor.

[0089] In one embodiment, the disinfectant has an available chlorine concentration of about 60,000 ppm and a free residual chlorine concentration of about 60,000 ppm. The available chlorine concentration of the disinfectant may be 55,000 ppm, 56,000 ppm, 57,000 ppm, 58,000 ppm, 59,000 ppm, 60,000 ppm, 61,000 ppm, 62,000 ppm, 63,000 ppm, 64,000 ppm, 65,000 ppm, or any combination thereof. Specific examples include 60,114 ppm and 60,814 ppm. The free residual chlorine concentration in the disinfectant may be 55,000 ppm, 56,000 ppm, 57,000 ppm, 58,000 ppm, 59,000 ppm, 60,000 ppm, 61,000 ppm, 62,000 ppm, 63,000 ppm, 64,000 ppm, or 65,000 ppm, or any combination thereof. A specific example is 58,157 ppm or 59,380 ppm. Disinfectants with such concentrations have high purity, strong sterilizing effects, and little chlorine odor.

[0090] In one embodiment, a liquid chlorine oxide is produced using the dry solid. The liquid chlorine oxide is prepared by a process comprising the steps of: (a) dissolving the dry solid in water to prepare a solution with an elevated pH; (b) adding a non-calcium inorganic alkaline agent to the solution prepared in step (a) while maintaining the pH of the solution to precipitate calcium salts, thereby forming a solid-liquid mixed phase containing a liquid phase and a solid phase containing calcium salts, the liquid phase having a reduced calcium ion concentration; and (c) isolating only the liquid phase from the solid-liquid mixed phase formed in step (b) to obtain liquid chlorine oxide. The pH in step (a) may be 10.0 or higher. The pH in step (b) may be 10.0 or higher. This method may be the method disclosed in Japanese Patent No. 5931253. When the dry solid is liquefied and used, calcium salts may remain as residue, raising concerns about food contamination at end-user food processors. Furthermore, processing large amounts of calcium salts is extremely time-consuming. This liquid chlorine oxide is useful because calcium has been removed. This method has the effect of preventing calcium salt precipitation even during long-term storage. Furthermore, the product produced by this method has a lower chlorine odor than sodium hypochlorite solution of the same concentration, which has the advantage of reducing the burden on workers and making it easier to use. It is now possible to manufacture industrial chemical products using high-grade bleaching powder, a raw material that can be stored for long periods of time. Furthermore, since calcium salts do not precipitate in products produced and distributed by this method and the chlorine odor is also greatly reduced, end consumers can use them with peace of mind.

[0091] In one embodiment, the liquid or liquid chlorine oxide is provided having a calcium concentration substantially below the detection limit. Preferably, the calcium concentration in the chlorine oxide-containing liquid is 24 ppm or less. Alternatively, the calcium concentration in the chlorine oxide-containing liquid is more preferably 23 ppm or less, 22 ppm or less, 21 ppm or less, 20 ppm or less, 19 ppm or less, 18 ppm or less, 17 ppm or less, 16 ppm or less, 15 ppm or less, 14 ppm or less, 13 ppm or less, 12 ppm or less, 11 ppm or less, 10 ppm or less, 9 ppm or less, 8 ppm or less, 7 ppm or less, 6 ppm or less, 5 ppm or less, 4 ppm or less, 3 ppm or less, 2 ppm or less, 1 ppm or less, 0.9 ppm or less, 0.8 ppm or less, 0.7 ppm or less, 0.6 ppm or less, 0.5 ppm or less, 0.4 ppm or less, 0.3 ppm or less, 0.2 ppm or less, 0.1 ppm or less, or 0.01 ppm or less. When these concentrations are achieved, the chlorine odor is reduced to an unproblematic level, and preferably to a level where the chlorine odor is substantially undetectable (a slight chlorine odor (for example, 0.1 ppm or less)).

[0092] In one embodiment, there is provided use of the dry solid, the liquid, or the liquid or liquid chlorine oxide as a sterilizing and disinfecting agent. In one embodiment, there is provided use of the dry solid, the liquid, the sterilizing and disinfecting agent, or the liquid or liquid chlorine oxide as a food additive. In one embodiment, there is provided use of the dry solid, the liquid, the sterilizing and disinfecting agent, or the liquid or liquid chlorine oxide for sterilizing food.

[0093] In one embodiment, a method for producing a new drug from a solution containing hypochlorite ions, chlorate ions, and chloride ions is provided, the method comprising the steps of: quantifying the concentration of hypochlorite ions, chlorate ions, and chloride ions in the solution; a first reaction step of adding sulfuric acid to the solution to generate chlorine gas; a second reaction step of adding sulfuric acid with a higher concentration than that in the first reaction step to the reaction mother liquor after the first reaction step to generate chlorine dioxide gas; and a second reaction step of reacting the generated chlorine dioxide gas with sodium hydroxide and hydrogen peroxide in a recovery liquid B to recover chlorite ions; and a step of mixing the recovery liquid A and the recovery liquid B to obtain a new drug. This method may have one or more of the characteristics of the above-defined sterilizing disinfectant replaced with a drug. In one embodiment, a drug produced by this method is provided. This agent may have one or more of the characteristics of the agent when the agent is substituted for the sterilizing disinfectant defined above. Use of this agent as a sterilizing disinfectant, a food additive, and a food sterilizing disinfectant may be provided.

[0094] The chlorine oxide produced by the present invention uses degraded sodium hypochlorite as a raw material, so the raw material may contain various components. Furthermore, during the treatment of the degraded sodium hypochlorite, various reactions may occur, producing various components, including various chlorine oxides. Therefore, although recovered solution A and recovered solution B may contain hypochlorite and chlorite as their main components, not all components can be identified. Therefore, the bactericidal disinfectant of the present invention, produced by mixing recovered solution A and recovered solution B, may contain unidentified components, although it meets the standards for sodium hypochlorite and high-grade bleaching powder. It is possible that these unidentified components contribute to improved bactericidal effect and stability, and it is expected that a different effect will be obtained than when simply combining hypochlorite and chlorite.

[0095] It should be understood that all references cited herein, including scientific literature, patents, patent applications, and the like, are incorporated by reference in their entirety to the same extent as if each were specifically set forth.

[0096] The present invention has been described above by showing preferred embodiments for ease of understanding. The present invention will be described below based on examples. However, the above description and the following examples are provided for illustrative purposes only and are not intended to limit the present invention. Therefore, the scope of the present invention is not limited to the embodiments or examples specifically described herein, but is limited only by the claims. [Example]

[0097] The amount of sulfate ions was measured by the following test method (ion chromatography). Preparation of sample solution The sample is diluted with water to adjust the sulfate ion concentration to 0 to 40 mg / L. Preparation of standard solutions for the calibration curve The reagent anion mixed standard IV manufactured by Kanto Chemical Co., Ltd. is used as the standard solution. (1 mL of this solution contains approximately 40 μg of sulfate ions). Measurement conditions Measurement is performed using an ion chromatograph (suppressor type) with an electric conductivity detector under the following conditions. Packing material: Ethylene vinyl benzene-divinyl benzene polymer anion exchange resin Column tube: inner diameter 4.0 mm, length 250 mm Eluent: A mixture of 12 mmol / L sodium carbonate and 5 mmol / L sodium bicarbonate Column temperature: room temperature Flow rate: 1.0mL / min Sample injection volume: 250 μL Calibration curve Accurately inject 250 μL of the standard solution into the ion chromatograph, and create a calibration curve for sulfate ions from the obtained peak areas. quantitative The concentration (A) of sulfate ions in the sample solution is determined using the peak area obtained from the sample solution and the calibration curve, and the content (X) [mg / L] of sulfate ions in the sample stock solution is calculated using the following formula. (X)=A×K A: Concentration of sulfate ions in the sample solution (mg / L) K: Dilution ratio when preparing the sample solution

[0098] (Deterioration of quality of sodium hypochlorite) There are two main types of 12% sodium hypochlorite solution available as a food additive: low-salt and standard-grade. The amount of chlorate ions generated by the low-salt grade is approximately 20,000-25,000 ppm, while the amount of chlorate ions generated by the standard grade is approximately 30,000-42,000 ppm. Theoretically, the amount of chlorate ions is thought to increase by approximately 3,500 ppm for every 1% decrease in available salt, but it was found that depending on the quality of the sodium hypochlorite, the initial value of chlorate ions may be higher, and even more than the theoretical value may be generated.

[0099] Furthermore, when acid was added to a 12% sodium hypochlorite solution to forcibly eliminate the available chlorine, the amount of chlorate ions produced was approximately 58,000 to 66,000 ppm, so it was also found that no more chlorate ions could be produced from a 12% sodium hypochlorite solution.

[0100] [Table 1]

[0101] (Reaction of degraded hypochlorous acid 1) Degraded sodium hypochlorite contains hypochlorite ions, chloride ions, and chlorate ions, but we first carried out a preliminary verification of the reaction of chlorate ions, which are expected to be difficult to decompose, with sulfuric acid. In addition, a sodium chlorate group was set up to compare reactivity.

[0102] As a result, sodium chlorate easily generates chlorine dioxide gas by reacting with sulfuric acid, and chlorite ions can be obtained through sodium hydroxide. In addition, the yield of chlorite ions was improved by adding hydrogen peroxide to sodium hydroxide.

[0103] On the other hand, it was not possible to recover chlorite ions from deteriorated sodium hypochlorite, and only chloride ions could be recovered. Furthermore, adding hydrogen peroxide to sodium hydroxide resulted in an increase in the amount of chloride ions recovered.

[0104] This is thought to be because when deteriorated sodium hypochlorite is reacted with sulfuric acid, chlorine gas is first produced from the highly reactive hypochlorite ions, which then react with hydrogen peroxide in the recovered liquid, resulting in an increase in chloride ions.

[0105] Furthermore, if the hydrogen peroxide in the recovered liquid is reduced by the chlorine gas, the recovery rate of chlorite ions in the recovered liquid will decrease and chlorate ions will be generated.

[0106] From this, it was found that although the present manufacturing method uses deteriorated sodium hypochlorite as the reaction mother liquor, it is necessary to carry out two consecutive reactions from this single reaction mother liquor, in which chlorine gas is recovered as the first reaction and then chlorine dioxide gas is recovered, and furthermore, it is necessary to separate and recover these gases and then combine them.

[0107] Therefore, it was found that it was necessary to consider two-stage reaction conditions for the reaction model: the first reaction is to generate chlorine gas from the reaction mother liquor by adding deteriorated sodium hypochlorite and sulfuric acid solution, and then recover hypochlorite ions using sodium hydroxide or calcium hydroxide; the second reaction is to generate chlorine dioxide gas and recover chlorite ions using sodium hydroxide and hydrogen peroxide.

[0108] ·Cl2+2NaOH→NaCl+NaClO+H2O····(1) ·Cl2+2NaOH+H2O2→NaCl+NaClO+H2O NaClO+H2O2→NaCl+H2O+O2····(2) ·2ClO2+2NaOH→NaClO2+NaClO3+H2O····(3) ·2ClO2+2NaOH+H2O2→2NaClO2+O2+2H2O····(4)

[0109] [Table 2]

[0110] (Reaction of degraded hypochlorous acid 2) Because the amount of chlorite ions in the degraded sodium hypochlorite was small, simply adding sulfuric acid dropwise would result in poor reactivity. Therefore, we considered conducting a batch reaction, increasing the sulfuric acid concentration to 65 w / w%, and increasing the reaction temperature to generate chlorine gas and chlorine dioxide gas in stages. We also prepared two recovery solutions, A and B, and considered recovering hypochlorite ions in Recovery Solution A during the first reaction. After the first reaction, we switched the piping and recovered chlorite ions in Recovery Solution B. As a result, chlorine dioxide began to be generated and chlorite ions were successfully recovered, demonstrating the importance of temperature and acidity in the reaction mother liquor. However, the majority of chlorite ions were recovered in Recovery Solution A, which did not contain added hydrogen peroxide, resulting in poor yield. Furthermore, the absence of hydrogen peroxide resulted in the generation of chlorite ions, resulting in the generation of chlorine gas and chlorine dioxide gas. Therefore, we determined the conditions for further staged generation and bubbled them into the respective recovery solutions.

[0111] [Table 3-1] [Table 3-2]

[0112] (Reaction of degraded hypochlorous acid 3) In order to confirm the sulfuric acid concentration required to generate chlorine gas preferentially during the first reaction, the sulfuric acid concentration was set to 50 w / w%. The sulfuric acid concentration in the reaction mother liquor at this time was 25.0%.

[0113] As a result, it was possible to control the recovery of chlorine gas in the first reaction and the recovery of chlorine dioxide gas in the second reaction in a more stepwise manner. Furthermore, an improvement in the recovery rate of chlorite ions was observed in recovery liquid B, to which sodium hydroxide and hydrogen peroxide were added. However, chlorite ions were also recovered in recovery liquid A, possibly due to the presence of chlorine dioxide gas, and chlorate ions were also generated because hydrogen peroxide could not be added. Therefore, it was found that it was necessary to consider not only the concentration of sulfuric acid but also the method of adding sulfuric acid.

[0114] [Table 4-1] [Table 4-2]

[0115] (Reaction of degraded hypochlorous acid 4) In order to react depleted sodium hypochlorite and recover it from the reaction mother liquor in two stages, the reaction temperature and the acidity of the sulfuric acid are important. However, if the initial sulfuric acid concentration is too high, both chlorine gas and chlorine dioxide gas are generated, making it impossible to switch the recovery solution. Therefore, we not only lowered the sulfuric acid concentration but also added it in two separate additions. Although there was no significant change in yield, we found that the amount of chlorine dioxide gas generated in the first reaction was greater when 100 g of 65 wt.% sulfuric acid was added in two separate additions than when 200 g of 50 wt.% sulfuric acid was added. This indicates that the sulfuric acid concentration in the reaction mother liquor during the first reaction was still excessive, and that the reactivity also differed depending on the sulfuric acid concentration at the time of addition.

[0116] [Table 5-1] [Table 5-2]

[0117] (Reaction of degraded hypochlorous acid 5) The sulfuric acid concentration, amount, and temperature were set for the first and second reactions, and the sulfuric acid was added twice to investigate the possibility of recovering chlorine gas and chlorine dioxide gas separately. The sulfuric acid concentration used in the first reaction was 50 w / w%, and the amount added was 25 g, resulting in a sulfuric acid concentration of 5.6% in the reaction mother liquor. In the second reaction, the sulfuric acid concentration was 65 w / w%, and the amount added was 250 g, resulting in a sulfuric acid concentration of 36.8% in the reaction mother liquor. As a result, the amount of chlorine dioxide gas mixed into recovered liquid A could be reduced, and the amounts of chlorite ions and chlorate ions could also be reduced.

[0118] In addition, the amount of chlorite ions recovered in recovered liquid B increased by 20% compared to the previous amount, reaching more than 60% of the expected value. In other words, it was found that it is important to control the chlorine dioxide gas mixed into recovered liquid A by adjusting the sulfuric acid concentration in the first reaction, and that it is important for the acidity of the reaction mother liquor during the first reaction not to decompose chlorite ions.

[0119] [Table 6-1] [Table 6-2]

[0120] (Reaction of degraded hypochlorous acid 6) As the sulfuric acid concentration and amount during the first and second reactions became clear, the change in recovery rate when the treatment volume was increased five-fold was confirmed. Furthermore, spare recovery tanks were set up for recovery liquids A and B to check for any gas leaks. Furthermore, the timing of air injection was advanced, so that air was injected into the reaction tank immediately after the raw materials were added, and the amount of air was gradually increased.

[0121] As a result, even when the treatment volume was increased five times, only hypochlorite ions were recovered in recovered liquid A, and the amounts of chlorite ions and chlorate ions produced remained small. In addition, the amount of chlorite ions in recovered liquid B also increased, reaching 87.42%. The reason why this increase in recovery rate was due to the timing of air injection during the second reaction is thought to be because if the chlorine gas and chlorine dioxide gas generated in the reaction tank were left to recover naturally, they would return to the solution and the reverse reaction would occur.

[0122] However, gas is generated in the reaction tank during the reaction, and the internal pressure rises due to the air being blown in, so backflow occurs when the gas and air blowing weakens. The test results this time showed that although the recovery rate was good, backflow occurred and sulfate ions were detected in the recovered liquid, so a retest is necessary, and a trap tank to prevent backflow and release pressure must be installed between the reaction tank and the recovery tank. This trap tank will prevent backflow, prevent droplets from being entrained from the reaction liquid, and also serve as a gas recovery tank.

[0123] [Table 7-1] [Table 7-2]

[0124] (Reaction of degraded hypochlorous acid 7) After installing the trap tank and making no other major changes, we re-examined whether the recovery rate could be improved by changing the timing of air injection, and found that injecting air from the early stage of the reaction resulted in a better recovery rate of available chlorine.In addition, since recovered liquid A had reduced chlorite ions and chlorate ions, and recovered liquid B had reduced chloride ions, it became possible to separate recovered liquids A and B.

[0125] In the first reaction, when depleted sodium hypochlorite and 50 wt% sulfuric acid were added, chlorine gas was generated so rapidly that there was no need to blow air into the reactor. After the reaction slowed down 1 hour 25 minutes later, air was blown in for 2 hours 50 minutes, for a total reaction time of 4 hours 15 minutes. In the second reaction, when 1000g of 65 wt% sulfuric acid was added to the reaction mother liquor, chlorine dioxide gas was generated rapidly, but after 20 minutes the reaction began to slow down, so air was gradually increased and blown in for 3 hours 50 minutes, for a total reaction time of 4 hours 5 minutes. From the above, it was found that the recovery rate was significantly improved by actively blowing air into the reactor and forcibly blowing chlorine dioxide gas into the recovery liquid, especially in the second reaction.

[0126] [Table 8-1] [Table 8-2]

[0127] (Reaction of degraded hypochlorous acid 8) In order to re-examine the difference in recovery rate depending on the timing of the start of air, we decided to check the recovery rate when the start time of air was deliberately delayed.

[0128] Therefore, in the second reaction, a natural reaction was carried out for 2 hours and 30 minutes, and when the foaming and gas generation had decreased, air was blown in. This method was also used in the early stages of the research.

[0129] As a result, it was found that the recovery rate had dropped significantly, and it was reaffirmed that the recovery rate could be increased by proactively injecting air from the early stages of the reaction. Furthermore, the sudden foaming caused by the generation of chlorine dioxide gas during the second reaction affects the production volume, but this lasts within about 15 minutes, so in order to improve the recovery rate, it was found that it was necessary to inject air into the reaction tank up to this point and gradually increase the amount of air.

[0130] [Table 9-1] [Table 9-2]

[0131] (Reaction of degraded hypochlorous acid 9) When considering effective disinfectants, chemical concentration is important. Up until now, the recovery solution has been set to an approximately equal volume to the input amount of deteriorated sodium hypochlorite, the raw material. However, a concentration recovery test was conducted to check whether the recovery rate would decrease even if the volume of the recovery solution was halved.

[0132] As a result, the concentration of available chlorine derived from hypochlorous acid was around 3%, but it was 8.38%, and the concentration of available chlorine derived from chlorous acid was around 3.5%, but it was 4.96%. However, while concentrated recovery of recovery solution A was relatively easy, the recovery rate of recovery solution B was poor, and only 63.04% of the expected recovery value was recovered.

[0133] Furthermore, measurements were also taken of the reaction mother liquor after recovery A and the reaction mother liquor after recovery B. It was found that the chlorate ion concentration in the reaction mother liquor after the first reaction had increased from 24,378.5 ppm to 33,990.4 ppm. Conversely, it was also found that the chloride ion concentration had decreased from 50,079.5 ppm to 23,532.4 ppm. This increase in chlorate ion was thought to be due to the re-disproportionation reaction in the strong acidification caused by the addition of sulfuric acid, and furthermore, it was thought that the decrease in chloride ion when sulfuric acid was added was due to the generation of hydrochloric acid, which contributed to the reaction.

[0134] These reactions can be explained by the following chemical formula: chloride ions produced in deteriorated sodium hypochlorite produce hydrochloric acid in the presence of sulfuric acid, and then in the second reaction, chlorine dioxide gas is produced from the hydrochloric acid and chloric acid.

[0135] 2NaClO + H2SO4 → Na2SO4 + Cl2 + H2O (5) First reaction 2NaCl + H2SO4 → 2HCl + Na2SO4 (6) First and second reactions NaClO + 2HCl → NaCl + Cl2 + H2O (7) First reaction 3NaClO → 2NaClO + NaClO3 (8) First reaction 2NaClO3 + H2SO4 → 2HClO3 + Na2SO4 (9) Second reaction HClO3+HCl→HClO2+HClO····(10) Second reaction HClO3 + HClO2 → 2ClO2 + H2O (11) Second reaction

[0136] [Table 10-1] [Table 10-2]

[0137] (Reaction of degraded hypochlorous acid 10) In order to confirm the upper limit of sulfuric acid concentration in the reaction mother liquor in the first and second reactions, tests were conducted in which the acidity was adjusted and the sulfuric acid concentration in the reaction mother liquor was set to 6.37% and 37.03%. Concentration recovery was also carried out.

[0138] As a result, the recovery rate of recovered liquid A was 69.87%, but since some generation of chlorite ions and chlorate ions had also progressed, it was found that it was not appropriate to further increase the acidity in the first reaction.

[0139] In addition, the recovery rate of recovered solution B increased from 63.04% to 74.48% for available chlorine and from 71.03% to 78.91% for chlorite ions, suggesting that the acidity was insufficient for the upper limit. In addition, in this test, it was confirmed that the reaction mother liquor after the first reaction had an increased amount of chlorate ions and a decreased amount of chloride ions.

[0140] [Table 11-1] [Table 11-2]

[0141] (Reaction of degraded hypochlorous acid 11) In the conventional reaction method, the second reaction was carried out using sulfuric acid solution of approximately the same weight as the deteriorated sodium hypochlorite. However, although the amount of chlorate ions generated in the deteriorated sodium hypochlorite increased after the first reaction, the concentration was insufficient to increase reactivity.

[0142] Therefore, we decided to verify the difference in yield when the second reaction was carried out with a sulfuric acid concentration of 50% or more in the reaction mother liquor. At this time, the sulfuric acid used was 70 w / w% sulfuric acid, and the sulfuric acid concentration in the reaction mother liquor was set to 58.47% or more, and the second reaction was carried out to confirm the recovery rate.

[0143] Furthermore, since it was found that chloric acid was regenerated after the first reaction was completed, we confirmed whether the recovery rate would improve by adding hydrogen peroxide as a reducing agent to the reaction mother liquor after adding sulfuric acid.

[0144] As a result, when 70 w / w% sulfuric acid was used and the sulfuric acid concentration in the reaction mother liquor was increased to 58.47% or more, it was confirmed that the chlorate ions in the reaction mother liquor were completely decomposed and the recovery rate of available chlorine was significantly increased. The recovery rate of available chlorine was 83.46%, and the recovery rate of chlorite ions was 99.63%. Therefore, it was found that the concentration of sulfuric acid added in the second reaction should be 65 w / w% or more, preferably 70 w / w%, and that favorable results can be obtained when the sulfuric acid concentration in the reaction mother liquor is up to 59.39%.

[0145] However, a large amount of chloride ions are produced in recovered liquid B, more than chlorite ions. This result is not a problem for liquid products such as sodium hypochlorite, but when processing into powder products such as high-grade bleaching powder, the concentration rate decreases as the amount of inorganic salts increases, making it impossible to obtain a high concentration of available chlorine.

[0146] On the other hand, it was confirmed that when sulfuric acid was added to the raw material, degraded sodium hypochlorite, and then hydrogen peroxide was added, the recovery rate dropped significantly. This is thought to be due to the following chemical reaction, where the hydrochloric acid produced by the reaction of sulfuric acid and chloride ions was decomposed and did not contribute to the reaction.

[0147] H2O2+2HCl→2H2O+Cl2····(12) It was also found that if the generated hydrochloric acid is decomposed before the reaction, not only will the recovery rate decrease, but the generated chlorine gas will be mixed into recovered liquid B and decomposed by the hydrogen peroxide in recovered liquid B, resulting in the generation of a large amount of chloride ions.

[0148] [Table 12-1] [Table 12-2]

[0149] (Reaction of degraded hypochlorous acid 12) In order to confirm the lower limit of the sulfuric acid concentration in the reaction mother liquor during the second reaction, the sulfuric acid concentration in the reaction mother liquor was increased to 35.7%, and the recovery rate was confirmed again. In addition, the reaction mother liquor after the completion of the reaction was measured, and the residual components after the completion of the first and second reactions were confirmed.

[0150] As a result, due to the high chloride ion content in recovered solution B, the recovery rate was high, although it was limited to sodium hypochlorite standards.

[0151] [Table 13-1] [Table 13-2]

[0152] (Reaction of degraded hypochlorous acid 14) Using low-salt sodium hypochlorite as the raw material, the sulfuric acid concentration added to the reaction mother liquor in the first and second reactions was all 70 w / w%, and the sulfuric acid concentration in the reaction mother liquor in the first reaction was set to 6.37%, and the sulfuric acid concentration in the second reaction was set to 35.7%.

[0153] As a result, it was considered that the sulfuric acid concentration in the first reaction was not related to the concentration of sulfuric acid added, but was dependent on the sulfuric acid concentration in the reaction mother liquor in the first reaction.

[0154] In addition, it was found that the sulfuric acid concentration during the second reaction depends on two factors: the sulfuric acid concentration used and the sulfuric acid concentration in the reaction mother liquor during the second reaction. It was also found that the higher the sulfuric acid concentration used during the second reaction, the better, and that 70% w / w or at least 65% w / w or more is best, and it was found that the sulfuric acid concentration in the reaction mother liquor alone is not important in the second reaction.

[0155] The recovery rate of recovery solution B was very good, exceeding 80%, but the concentration of chloride ions was higher than that of chlorite ions, and this composition could only be used for sodium hypochlorite standards.

[0156] [Table 14-1] [Table 14-2]

[0157] (Reaction of degraded hypochlorous acid 15) The reactivity and recovery rate of this manufacturing method were confirmed using not only low-salt sodium hypochlorite but also degraded sodium hypochlorite, a 12% solution of general-grade sodium hypochlorite that has been degraded in quality.

[0158] Furthermore, the characteristics of general-grade sodium hypochlorite are that it has a lower chemical unit price than low-salt sodium hypochlorite, has a higher amount of chloride ions in its composition, and tends to have a higher amount of chlorate ions from the start.

[0159] Therefore, in the test, since there was an excess of chloride ions in the raw material, the sulfuric acid concentration of the reaction mother liquor in the first reaction was set low at 4.47%, and furthermore, in order to completely decompose the chlorate ions in the reaction mother liquor in the second reaction, additional sodium chloride was added to actively promote the production of hydrochloric acid.

[0160] Then, 10% calcium hydroxide was used as recovered liquid A, and since it was confirmed that the chloride ions in recovered liquid B tended to increase when the recovery rate of recovered liquid B was overestimated, recovered liquid B was passed through an intermediate trap tank (containing hydrogen peroxide). There were two possible reasons for the chloride ions at this time: either hydrochloric acid was splashed in from the reaction tank, or chlorine gas was mixed in.

[0161] As a result, the recovery rate of recovered liquid A was good, but despite the reduction in the sulfuric acid concentration in the reaction mother liquor during the first reaction, both chloride ions and chlorate ions decreased, which was different from the result when low-salt sodium hypochlorite was used as the raw material.

[0162] In addition, the recovery rate of recovered liquid B was in the 20% range, and a large amount of chloride ions was recovered in the chloride ion recovery trap tank (containing hydrogen peroxide). The chloride ion content in recovered liquid B also showed a high value.

[0163] These are thought to be caused by the excessive production of hydrochloric acid during strong acidification. Normally, strongly acidic conditions make it easier to decompose chloric acid and produce chlorine dioxide gas, but in this case, a large amount of chloride ions had already been produced in the general-grade degraded sodium hypochlorite, which in the presence of strong sulfuric acid caused excessive production of hydrochloric acid. As a result, it was found that a side reaction that produces chlorine gas occurs when sodium chlorate is decomposed, causing the main reaction to proceed very little and significantly reducing the recovery rate. For this reason, when using general-grade degraded sodium hypochlorite, the addition of additional sodium chloride is unnecessary, and it is assumed that the large amount of chloride ions produced in recovered solution B is due to the inclusion of chlorine gas as a result of the side reaction.

[0164] Therefore, the reaction of decomposing chlorate ions consists of a main reaction and a side reaction, and the reaction ratio changes depending on the reaction conditions. In particular, as the reaction approaches the end point and the amount of chlorate ions decreases, the side reaction is thought to be more likely to proceed.

[0165] 2NaClO3 + 4HCl → 2ClO2 + Cl2 + 2NaCl + 2H2O (13) Main reaction NaClO3 + 6HCl → 3Cl2 + NaCl + 3H2O (14) Side reaction *In particular, in the case of general-grade hypochlorous acid degradation reactions, the progress of the main and side reactions is likely to change depending on the acidity and the amount of hydrochloric acid produced.

[0166] [Table 15-1] [Table 15-2]

[0167] (Reaction of degraded hypochlorous acid 16) It has been confirmed that when using standard-grade degraded sodium hypochlorite, the progression of the main and side reactions is more likely to reverse than when using low-salt degraded sodium hypochlorite. For example, chlorate ions already tend to decompose at the first reaction stage, which is caused by the excess production of hydrochloric acid due to the reaction between the large amount of chloride ions produced in the degraded sodium hypochlorite and sulfuric acid, but it is difficult to remove the chloride ions produced in the raw material beforehand.

[0168] Therefore, for the reaction of general-grade deteriorated sodium hypochlorite, we decided to conduct a preliminary test in which hydrogen peroxide was added in advance during the second reaction, and then sulfuric acid was added. This was to add a route for chlorine dioxide gas generation through the reaction of chlorate ions and hydrogen peroxide in the presence of sulfuric acid, and to prevent chlorate ions from generating chlorine gas through side reactions by decomposing and chlorinating the excess hydrochloric acid produced.

[0169] In addition, in the preliminary test, sulfuric acid was added twice during the second reaction to check the composition change of the reaction mother liquor during the reaction, and analysis was carried out during the second reaction. The final sulfuric acid concentration in the second reaction was set at 37.37%.

[0170] As a result, it was found that even with the sulfuric acid concentration (21.57%) of the second reaction (1), more than 80% of the chlorate ions in the reaction mother liquor were decomposed in about 1 hour. However, in the equipment environment of the preliminary test, gas recovery was not successful, and the recovery rate could not be verified, but in the second reaction, more than 80% of the chlorate ions were decomposed in about 1 hour, and the composition was chlorite ions > chloride ions, so it was possible to confirm the tendency for the chlorite ion generation ratio to increase as the main reaction progresses.

[0171] However, when 65 w / w% sulfuric acid was subsequently added to bring the sulfuric acid concentration in the reaction mother liquor to a final 37.37% and the reaction was continued, almost only chloride ions were recovered, and the purity of recovered liquid B as chlorite ions dropped dramatically.From the above, it was found that when general-grade deteriorated sodium hypochlorite is used, the chlorate ions are decomposed in a short time due to the excessive production of hydrochloric acid, so it is important to prioritize the progress of the main reaction during this reaction time.

[0172] [Table 16-1] [Table 16-2]

[0173] (Reaction of degraded hypochlorous acid 17) To confirm the sulfuric acid conditions for the first reaction of general-grade deteriorated sodium hypochlorite, the sulfuric acid concentration in the reaction mother liquor was set to 4.0%. This is because it was thought that if the sulfuric acid concentration was set to 4.5%, a slightly excessive amount of hydrochloric acid would be generated at the time of the first reaction, resulting in the decomposition of chlorate ions.

[0174] In addition, the sulfuric acid concentration in the reaction mother liquor during the second reaction was set to 30%. This was because when the sulfuric acid concentration was around 20%, about 20% of the chlorate ions remained, preventing complete decomposition. As in the previous experiment, hydrogen peroxide was added before adding sulfuric acid. Hydrogen peroxide is often added to suppress the generation of chlorine dioxide, or to generate chlorine dioxide gas at low sulfuric acid concentrations, and its reaction often varies depending on the conditions. This time, hydrogen peroxide was added to suppress side reactions caused by the addition of hydrogen peroxide.

[0175] Furthermore, we decided to send in a large amount of air immediately after adding sulfuric acid, and prioritized filling the empty trap tank (backflow prevention / gas recovery tank) with gas, because we were concerned that if the reaction tank was left filled with gas, it might return to the solution or cause a reverse reaction.

[0176] In addition, the available chlorine in recovered liquid B was measured every hour, and a graph of the available chlorine recovery was created, while at the same time, changes in the composition of recovered liquid B were confirmed.

[0177] As a result, it was confirmed that chlorite ions were completely decomposed after one hour of the second reaction, and the recovery rate of available chlorine at that time was 57.7%. Since the recovery rate did not change after two hours, it was confirmed that the second reaction was completed in approximately two hours. Therefore, even taking into account the presence of residual gas in the equipment and piping, it was found that the second reaction would be completed if the reaction and recovery were carried out for a maximum of about two and a half hours. Furthermore, even under the test conditions used in this study, the composition of recovered liquid B was chlorite ions > chloride ions, indicating that the main reaction proceeded preferentially.

[0178] Therefore, the important thing about the second reaction is to increase purity by allowing the main reaction to proceed preferentially and preventing the production of chloride ions. For this reason, it can be said that the recovery rate improved as a result of the main reaction proceeding in this test, but the sulfuric acid concentration at which chlorate ions are completely decomposed is not necessarily the same as the sulfuric acid concentration at which the main side reaction changes. The same applies to the addition and amount of hydrogen peroxide.

[0179] [Table 17-1] [Table 17-2]

[0180] [Table 18]

[0181] (Reaction of degraded hypochlorous acid 18) In the case of general-grade sodium hypochlorite, since it contains a large amount of chloride ions, if the reaction conditions become too extreme, the main and side reactions are likely to be reversed.

[0182] Therefore, when the sulfuric acid concentration in the reaction mother liquor during the second reaction was set to 40.0%, it was confirmed whether the main reaction or the side reaction would proceed preferentially.

[0183] As a result, when the sulfuric acid concentration in the reaction mother liquor during the second reaction was increased to 40.0%, chloride ions were generated in recovered liquid B, and since chloride ions exceeded chlorite ions, it was thought that side reactions proceeded preferentially. In addition, the recovery rate also decreased significantly, so it was found that even if hydrogen peroxide was added, chlorine gas would be generated and side reactions would proceed if the sulfuric acid concentration in the reaction mother liquor was increased to 40.0%.

[0184] [Table 19-1] [Table 19-2] [Table 20]

[0185] (Reaction of degraded hypochlorous acid 19) When the sulfuric acid concentration in the reaction mother liquor during the second reaction was 40.0%, a side reaction proceeded, producing a large amount of chloride ions derived from chlorine gas, resulting in a deterioration in the recovery rate.

[0186] Next, a test was conducted in which the sulfuric acid concentration in the reaction mother liquor was set to 30.0% and hydrogen peroxide was not added in advance. In this test, by not suppressing chlorine gas in the second reaction, the total reactivity improved, but on the other hand, it was predicted that a large amount of chloride ions would be produced.

[0187] As a result, after 24 minutes into the second reaction, the hydrogen peroxide in recovered liquid B became insufficient, and additional hydrogen peroxide had to be added. This is thought to be because more chlorine gas or chlorine dioxide gas than expected was recovered in recovered liquid B, and as a result of the lack of hydrogen peroxide, chlorine gas became chloride ions, and chlorine dioxide gas was recovered as chlorite ions. In addition, since the recovered composition was chloride ions > chlorite ions, it was thought that most of the chlorine gas was mixed in as a side reaction proceeded.

[0188] Furthermore, although there was a recovery loss due to a lack of hydrogen peroxide in recovered liquid B, the increased reactivity resulted in a tendency for the recovery rate of chlorite ions to increase. However, although the recovery rate of chlorite ions increased, a large amount of chloride ions was also generated at the same time, resulting in a decrease in purity. Furthermore, without a certain level of purity, it becomes difficult to recover a high concentration when dried and concentrated, making it impossible to process high-grade bleached powder. In any case, hydrogen peroxide is added during the second reaction to suppress the generation of chlorine gas, and an intermediate trap tank is also required to prevent chlorine gas from mixing into recovered liquid B.

[0189] [Table 21-1] [Table 21-2] [Table 22]

[0190] (Reaction of degraded hypochlorous acid 20) To confirm the reaction conditions when using general-grade sodium hypochlorite, the first reaction was carried out using general-grade deteriorated sodium hypochlorite as the raw material, 50 w / w% sulfuric acid, and the sulfuric acid concentration in the reaction mother liquor was set to 4.0%, while air was introduced. The reaction time was 1 hour. Then, recovery liquid A was recovered using sodium hydroxide (or calcium hydroxide).

[0191] In the second reaction, hydrogen peroxide solution is added to the reaction mother liquor after the first reaction to suppress chloride ion formation. Then, using 65 wt% sulfuric acid, the sulfuric acid concentration in the reaction mother liquor is set to 30.0%, and the second reaction is carried out while raising the temperature to 60-70°C and introducing air. The reaction time is 2-2.5 hours. The solution passes through an intermediate trap tank containing hydrogen peroxide, and is recovered as recovered solution B using sodium hydroxide and hydrogen peroxide. Furthermore, passing the hydrogen peroxide solution through the intermediate trap tank performs chlorine gas washing, which serves to remove chloride ions. As a result, highly pure recovered solution B is recovered, which can then be concentrated to a high concentration by a subsequent drying process.

[0192] In the present invention, as shown in reaction formulas (13) and (14), both chlorine dioxide gas and chlorine gas are always produced, but even if the chlorine gas is washed away and chlorine dioxide gas is passed through the intermediate trap tank using hydrogen peroxide, only about half of the amount of chlorine gas produced can be removed, as shown in reaction formulas (15) and (16). If chlorine gas is removed at a high level using another method, chlorine dioxide gas, which is also an oxidizing agent, will also react, and the recovered liquid in the present invention, which uses sodium hypochlorite as a raw material, will always contain chloride ions.

[0193] 2NaClO3 + 4HCl → 2ClO2 + Cl2 + 2NaCl + 2H2O (13) Main reaction NaClO3 + 6HCl → 3Cl2 + NaCl + 3H2O (14) Side reaction Cl2+3H2O2→2HCl+2H2O+2O2····(15) 2HCl+H2O2→2H2O+Cl2 (16)

[0194] [Table 23-1] [Table 23-2] [Table 24]

[0195] (Reaction of degraded hypochlorous acid 21) Until now, the second reaction was carried out at a temperature of 60-70°C. However, when general-grade sodium hypochlorite was used, the reactivity was high, and under the same reaction conditions as low-salt-grade sodium hypochlorite, a large amount of chloride ions were generated, resulting in an excess, making it necessary to adjust the concentration of sulfuric acid in the reaction mother liquor, for example.

[0196] Therefore, we decided to check the reactivity at room temperature (without temperature control) during the second reaction.

[0197] As a result, it was found that when general-grade sodium hypochlorite was used as the raw material, the recovery rate did not change significantly even if the temperature during the second reaction was not particularly adjusted.

[0198] [Table 25-1] [Table 25-2]

[0199] (Reaction of degraded hypochlorous acid 22) The amount of sodium hydroxide in the recovered solution B in the second reaction is examined. The amount of alkali in the second reaction is better to have an excess amount of alkali to prevent leakage, but if there is a lot of inorganic alkali salt, the concentration rate when dried will decrease, which will also lead to a decrease in the final concentration.

[0200] Therefore, we decided to change the sodium hydroxide in recovery solution B to 0.5N and check the change in recovery rate.

[0201] As a result, it was found that the T.AL of recovered liquid B before the second reaction was 515.46, and after the reaction was completed it was 149.25, meaning that 366.21 T.AL was consumed in the reaction. Although the recovery rate of recovered liquid B tends to decrease slightly, the drying efficiency increases, making it possible to dry it into a powder containing a very high concentration of available chlorine.

[0202] However, since the concentration of chlorate ions contained in the deteriorated sodium hypochlorite is low and chloride ions are also produced as a by-product, it is impossible to achieve the theoretical recovery rate. In order to dry and concentrate the recovered liquid obtained from this to a high concentration, it is necessary to concentrate it by about 35 times, and as a result, the remaining alkali and chloride ions will also be concentrated by 35 times.

[0203] To achieve the above, it is necessary to control the amount of alkali and chloride ions in the recovered solution. However, when sodium hypochlorite is used as the raw material, a certain amount of chloride ions will always be generated relative to the chlorite ions, so it is important to control the residual alkali and inorganic salts in recovered solution B.

[0204] [Table 26-1] [Table 26-2] [Table 26-3]

[0205] (Reaction of degraded hypochlorous acid 23) In order to conduct a test to verify whether the sulfuric acid concentration in the first and second reactions is determined by the raw material composition, the reaction conditions were verified using low-salt sodium hypochlorite from another manufacturer, which has a high chloride content.In addition, the chloride concentration in the raw material was measured using the Mohr method to separately quantify the chloride ions in the sodium hypochlorite, and the reaction conditions for the chloride concentration and sulfuric acid concentration were confirmed.

[0206] As a result, when the available chlorine in the raw material was 50,511 ppm and the chloride concentration was 42,186 ppm, the sulfuric acid concentration in the reaction mother liquor was set to 6.37%, and the available chlorine was reduced to 598 ppm, and chlorine was recovered in recovered liquid A. However, at the same time, the chlorate ions were decomposed and reduced, and it was found that there was an excess of sulfuric acid. Furthermore, when the sulfuric acid concentration in the reaction mother liquor of the second reaction was set to 58.00%, chloride ions derived from chlorine were generated in recovered liquid B, and it was thought that a side reaction was mainly proceeding. Therefore, it was found that setting the sulfuric acid concentration to 58.00% and running the second reaction was too much, given that the chloride concentration in the reaction mother liquor after the first reaction was 15,523 ppm.

[0207] [Table 27-1] [Table 27-2]

[0208] (Reaction of degraded hypochlorous acid 24) The first reaction conditions were set to be the same as those in (Reaction of Degraded Hypochlorite 23) to confirm reproducibility, and the sulfuric acid concentration in the reaction mother liquor during the second reaction was set to 30.0%.

[0209] As a result, after the first reaction, chlorate ion was decomposed by 5.15%, and it was confirmed that there was still an excess of sulfuric acid for the chloride concentration of 43,429 ppm in the raw material, and that there was some variation in the decomposition rate of chlorate ion. For the second reaction, the chloride concentration in the reaction mother liquor after the first reaction was 18,225 ppm, and the reaction was carried out with a sulfuric acid concentration of 30%, but since almost no chloride ion or chlorate ion was produced in recovered liquid B, it was possible to mainly react in the main reaction, and recover high purity.

[0210] [Table 28-1] [Table 28-2]

[0211] (Reaction of degraded hypochlorous acid 25) The chloride concentration in the raw material was 41,983 ppm, and the sulfuric acid concentration in the reaction mother liquor during the first reaction was set to 4.00% for production.

[0212] As a result, 14,397 ppm of available chlorine remained in the reaction mother liquor after the first reaction was completed, and although the chlorate ions increased by 13.82%, the reaction was insufficient for the available chlorine.

[0213] Furthermore, if a large amount of available chlorine exists in the reaction mother liquor, there is a concern that chloride ions will be generated in the recovered liquid B. However, in reality, the amount of chloride ions was small, and the recovered liquid B was highly pure. In addition, the recovery rate also increased due to the influence of the increase in chlorate ions in the reaction mother liquor after the completion of the first reaction.

[0214] [Table 29-1] [Table 29-2]

[0215] (Reaction of degraded hypochlorous acid 26) The chloride concentration in the raw material was 41,416 ppm, and the sulfuric acid concentration in the reaction mother liquor during the first reaction was set to 5.00%, and production was carried out. As a result, after the first reaction was completed, 13,281 ppm of available chlorine remained in the reaction mother liquor, and the chlorate ion had decreased by 1.36%, which confirmed that there was a slight excess.

[0216] [Table 30-1] [Table 30-2]

[0217] (Reaction of degraded hypochlorous acid 27) The chloride concentration in the raw material was 41,416 ppm, and the sulfuric acid concentration in the reaction mother liquor during the first reaction was set to 6.00%, and production was carried out. As a result, after the first reaction was completed, 13,281 ppm of available chlorine remained in the reaction mother liquor, and the chlorate ion was reduced by 3.6%, confirming that it was excessive. In addition, the recovery rate of recovered liquid B also decreased due to the decrease in chlorate ion.

[0218] [Table 31-1] [Table 31-2]

[0219] (Reaction of degraded hypochlorous acid 28) The chloride concentration in the raw material was 42614 ppm, and the sulfuric acid concentration in the reaction mother liquor during the first reaction was set to 4.50%. In addition, since it was predicted that available chlorine would remain in the reaction mother liquor after the first reaction was completed, the reaction time, including air, was set to 2 hours.

[0220] As a result, it was confirmed that 13,333 ppm of available chlorine remained in the reaction mother liquor after the first reaction was completed, and that chlorate ions had increased by 12.56%. Up until now, the decomposition of available chlorine in the raw material and the increase or decrease in chlorate ions have been confirmed by using sulfuric acid concentrations of 4.0%, 4.5%, 5.0%, 6.0%, and 6.37% in the reaction mother liquor for the raw material of the same lot. For a chloride concentration of about 42,000 ppm in the raw material, chlorate ions increased up to 4.0% and 4.5%, but chlorate ions began to decrease rapidly from 5.0%.

[0221] From these facts, the concentration of sulfuric acid that can be added is determined by the chloride concentration in the raw material, and if sulfuric acid is added to completely decompose the available chlorine in the raw material, the chlorate ion may decrease depending on the chloride concentration, and the subsequent yield will decrease. Therefore, the sulfuric acid concentration at the time of the first reaction is determined by the chloride concentration in the raw material, and if the chloride concentration is excessive, it is not possible to add a large amount of sulfuric acid even if the available chlorine concentration is high.

[0222] [Table 32-1] [Table 32-2]

[0223] (Reaction of degraded hypochlorous acid 29) Previously, it was thought that a sulfuric acid concentration of 4.5% was within the appropriate range for a chloride concentration of approximately 42,000 ppm in the raw material, but a reaction test was conducted using a different lot of raw material with a chloride concentration of approximately 35,000 ppm. Furthermore, since 42,000 ÷ 35,000 = 1.2, the appropriate sulfuric acid concentration was calculated to be 4.5% × 1.2 = 5.4%, but this condition increases chlorate ions by approximately 110% or more, which is a safe value that takes into account the variability of the reaction. For this reason, the initial reaction was conducted at a concentration of 6.0%.

[0224] As a result, it was confirmed that the chlorate ion concentration after the primary reaction was approximately 104%, which is within the appropriate range where chlorate ion does not decrease, but is below 110%. It was also confirmed that recovered liquid B after the secondary reaction was highly pure with few chloride ions.

[0225] [Table 33-1] [Table 33-2]

[0226] (Reaction of degraded hypochlorous acid 30) The formula for adding sulfuric acid in the reaction mother liquor during the first reaction was set so that the upper limit was set so that the chlorate ions in the raw material were not decomposed or increased, and in consideration of a safety factor, the chlorate ions increased by 110% or more.

[0227] If the chloride concentration in the raw material is high, the concentration of sulfuric acid that can be added will decrease, so the calculation formula is as follows: (2) The reason why X≦4 is set is to prevent excessive available chlorine from remaining in the raw material. (1) Y = -1.2676X + 9.84393 (2) X≦4 (Y: sulfuric acid concentration in the reaction mother liquor, X: chloride concentration in the raw material) Therefore, the test was carried out by adding 5.4% sulfuric acid according to the calculation formula during the first reaction, and by adding 40.0% sulfuric acid during the second reaction.

[0228] As a result, the chlorate ion concentration after the first reaction had increased to 118.24%, and the recovery rate of recovered liquid B after the second reaction was also 93.7%. The chloride ion concentration in recovered liquid B had increased to 3827 ppm, confirming that increasing the sulfuric acid concentration to improve the recovery rate would result in the by-production of chloride ions. If the final product were a sodium hypochlorite solution, a high chloride concentration in recovered liquid B would be acceptable, but in the case of high-concentration bleached powder, if the chloride concentration exceeded 4000 ppm, the concentration rate during drying would decrease, and as a result, it would become impossible to produce high-concentration high-concentration bleached powder.

[0229] [Table 34-1] [Table 34-2]

[0230] (Reaction of degraded hypochlorous acid 31) Using low-salt sodium hypochlorite as the raw material, the sulfuric acid concentration in the reaction mother liquor during the second reaction was set to 45.0%, and the reaction was carried out. As a result, chloride ions in recovered liquid B began to increase, and the recovery rate also decreased. This indicates that when chlorate ions in the reaction mother liquor are decomposed, a side reaction to produce chlorine gas begins to progress. From the above, it was found that when the sulfuric acid concentration in the second reaction exceeds 45%, chlorine gas is rapidly produced, and the concentration rate decreases when producing a solid product.

[0231] [Table 35-1] [Table 35-2]

[0232] (Reaction of degraded hypochlorous acid 32) The reaction was carried out using low-salt sodium hypochlorite as the raw material, with the sulfuric acid concentration in the reaction mother liquor during the second reaction set at 40.0%.

[0233] When this manufacturing method is carried out using low-salt sodium hypochlorite, the chloride concentration in the raw material is already too high for the reaction, so even if chlorine gas generation is prevented by using hydrogen peroxide, chloride ions derived from chlorine gas will be generated in recovered liquid B. This phenomenon occurs when the sulfuric acid concentration is high or when the chloride concentration in the raw material is high, but when producing a solid product using this method, the chloride ions in recovered liquid B must be around 4000 ppm in order to be concentrated to a high concentration, so 40.0% is the upper limit. (However, when producing a liquid product, there is no need to consider the concentration rate, so this is not the case and it can be up to 59.4%.)

[0234] [Table 36-1] [Table 36-2]

[0235] (Sulfuric acid concentration during reaction) The raw material, degraded sodium hypochlorite, comes in two types: low-salt grade and general grade, each with different chloride ions and chloride concentrations, and the appropriate sulfuric acid concentration changes depending on the concentration.

[0236] The appropriate sulfuric acid concentration in the first reaction is such that available chlorine is converted into chlorine gas without decomposing chlorate ions in the raw material, and the sulfuric acid concentration in the reaction mother liquor is determined by measuring the chloride concentration in the raw material.

[0237] At this time, if the raw material contains a high concentration of chlorides, the amount of sulfuric acid added cannot be increased because chlorate ions are decomposed, and as a result, available chlorine remains, but if too much sulfuric acid is added to reduce the available chlorine, the chlorate ions are decomposed, resulting in a decrease in the yield of the subsequent recovered liquid B. However, if too much available chlorine remains, chloride ions will be generated in the recovered liquid B in the next stage, reducing the purity, so in this case it is necessary to extend the air time to 2 hours and remove available chlorine from the reaction mother liquor.

[0238] Based on the test data obtained up to now, the calculation formula at this time is as follows, and the addition formula is one that takes into account a safety factor so that the chlorate ion concentration increase rate after the first reaction is 110% or more. Also, (2) X≦4 is set to prevent excessive amounts of available chlorine from remaining in the raw material. (1) Y = -1.2676X + 9.84393 (2) X≦4 (Y: sulfuric acid concentration in the reaction mother liquor, X: chloride concentration in the raw material)

[0239] Next, for the second reaction, the reaction mother liquor after the completion of the first reaction is used as the raw material, but the raw material contains enough chloride for the reaction, and in many cases there is a slight excess. If the sulfuric acid concentration in the reaction mother liquor is too high, a side reaction will proceed, producing only chlorine gas, and a large amount of chloride ions will be generated in the recovered liquid B. The same thing happens if the sulfuric acid concentration is too low.

[0240] Therefore, the appropriate sulfuric acid concentration during the second reaction must be such that the chlorate ions in the reaction mother liquor are completely decomposed, side reactions are controlled, and a large amount of chloride ions are not produced in the recovered liquid B.

[0241] However, there is no close relationship between the chlorate ion, chloride concentration and sulfuric acid concentration in the reaction mother liquor after the completion of the first reaction. For example, although the chloride ion content of low-salt sodium hypochlorite and general-grade sodium hypochlorite after the completion of the first reaction is 3 to 7.5 times higher, both have good recovery rates at a sulfuric acid concentration of 30%.

[0242] Therefore, based on the data obtained so far, the sulfuric acid concentration in the reaction mother liquor of the second reaction is as follows:

[0243] [Table 37-1] *For general-grade sodium hypochlorite, a chlorine gas removal process using an intermediate trap is required. (Reaction condition data list) [Table 37-2]

[0244] (Mixed solution of recovery liquid A and recovery liquid B (sodium hypochlorite standard)) Degraded sodium hypochlorite was used as a raw material and reacted again to obtain recovered liquids A and B while preventing the regeneration of chlorate ions. However, in order to mix these and meet the standards for sodium hypochlorite as a food additive, the effective chlorine concentration must be 4% or more and other confirmation tests must be passed.

[0245] Therefore, we decided to check the available chlorine ratio when recovered liquid A and recovered liquid B were mixed.

[0246] As a result, it was found that the effective chlorine concentration of recovered solution A was 1, and the effective chlorine concentration of recovered solution B was 0.6 as the upper limit, and 0.7 was not compliant with the hypochlorous acid (3) item of the confirmation test (1). From this, considering the configuration from the purpose of the present invention, it is desirable to combine them at an effective chlorine concentration ratio of 0.43 to 0.6. Furthermore, the bactericidal disinfectant produced with this effective chlorine concentration ratio was also analyzed by an external organization and was found to comply with the standard criteria for sodium hypochlorite.

[0247] [Table 38]

[0248] Similarly, the effective chlorine concentration and free residual chlorine concentration of the final liquid product were measured when the following ratios were combined. [Table 39]

[0249] The free residual chlorine concentration was measured using DPD reagent, and was found to be 58,157 to 59,380 ppm, which is close to the available chlorine concentration, suggesting that a reaction with substances other than hypochlorous acid was occurring.

[0250] In the case of liquid products, since it is difficult to determine the concentration from the free residual chlorine concentration, the chlorite ion concentration from recovered liquid B was determined by ion chromatography, converted to the available chlorine concentration, and subtracted from the total available chlorine concentration.Furthermore, the remaining available chlorine concentration was determined as the available chlorine concentration from recovered liquid A, and multiplied by a coefficient to determine the hypochlorite ion concentration, which was used as the final ion ratio.

[0251] [Table 40] * Calculated using the following conversion formula (conversion formula) Available chlorine concentration x 0.476 = chlorite ion concentration (ClO2 - ) Available chlorine concentration x 0.726 = hypochlorite ion concentration (ClO - ) This conversion formula was obtained by using known concentrations of chlorite ions or hypochlorite ions to derive the relationship to available chlorine concentration.

[0252] (Storage of the mixed solution) The shelf life of the bactericidal disinfectant (food additive, sodium hypochlorite compliant product) manufactured using this method was confirmed.

[0253] As a result, a bactericidal disinfectant was produced with an initial effective chlorine concentration of approximately 6.94%, but even at refrigerated temperature (6°C), the effective chlorine concentration had decreased to approximately 5% (approximately 72%) at D+30, and at 40°C, the effective chlorine concentration had decreased to approximately 3.8% (approximately 54%) at D+3.This shows that bactericidal disinfectant (liquid) containing both hypochlorite ions and chlorite ions has very poor shelf life and is difficult to sell at room temperature, and it is preferable to sell it refrigerated.

[0254] [Table 41]

[0255] (Study on the composition of the recovered liquid during the first reaction) We decided to investigate how to improve storage stability and effective chlorine concentration by converting the recovered solution from the first reaction into calcium hydroxide, drying it, and solidifying it. As a result, no significant difference in recovery rate was observed when recovering 1 part 20% calcium hydroxide to 1 part degraded sodium hypochlorite, and when recovering 1 part 20% calcium hydroxide to 2 parts degraded sodium hypochlorite, and it was found that concentrated recovery was possible.

[0256] The highest recovery rate was achieved when 10% calcium hydroxide was used in a ratio of 1 part depleted sodium hypochlorite to 1 part depleted sodium hypochlorite, which was thought to be due to the high fluidity of the calcium hydroxide slurry. For this reason, it was found that it is preferable to concentrate the available chlorine in the subsequent drying process rather than concentrating it at the recovered liquid stage.

[0257] [Table 42]

[0258] (Mixed solution of recovery solution A and recovery solution B (high-grade bleaching powder)) Degraded sodium hypochlorite was used as a raw material and reacted again to obtain recovered solution A and recovered solution B in order to prevent the generation of chlorate ions. However, these solutions must be mixed together to comply with the standards for high-grade bleaching powder, which is a food additive; the effective chlorine concentration must be 60% or more, and the solution must also pass other confirmation tests.

[0259] To achieve this, the effective chlorine concentration of recovered liquid A is set to 1, and the effective chlorine concentration of recovered liquid B is adjusted to a ratio of 9.6 to 33.95, and then the drying process is carried out. Due to the characteristics of this product, to avoid the ratio of recovered liquid B becoming too high, the main blend is recovered liquid A: 1 to recovered liquid B: 9.6.

[0260] Furthermore, it was found that the yield deteriorated depending on the drying process and the order of addition, and since free residual chlorine is particularly susceptible to decomposition, granulation nuclei were formed in advance using only recovered liquid A, and then recovered liquid B was concentrated to a certain extent to form a slurry. If the two were mixed and dried in this state, decomposition of the free residual chlorine was unlikely to occur, and a dry solid could be obtained with very little change in composition before and after drying.

[0261] The dried solid produced by the above method was found to meet the specifications for high-grade bleached powder by external analysis.

[0262] Since the high-grade bleached powder produced by this method has a unique composition compared to the high-grade bleached powders generally available on the market, we believe it would be preferable to sell it as a disinfectant (food additive preparation) or a disinfectant preparation rather than as high-grade bleached powder alone.

[0263] (Standard composition ratio of recovered solution A and recovered solution B) When recovered liquid A and recovered liquid B are mixed and dried, the concentration rate at the time of drying differs, making it impossible to measure the effective chlorine ratio in the final product. Therefore, in order to confirm the lower limit of the effective chlorine ratio of recovered liquid A and recovered liquid B, recovered liquid A and recovered liquid B were dried separately as a preliminary test, and the effective chlorine concentration of each was measured and samples were prepared.

[0264] [Table 43]

[0265] [Table 44]

[0266] (drying process) The drying conditions are an ambient temperature of 50-60°C and humidity of 10% or less. Warm air is blown in at a rate of 1.9 m3 / s. The warm air does not need to be blown directly onto the liquid in the drying chamber; its purpose is to maintain the temperature and humidity inside the chamber.

[0267] Furthermore, the yield and content composition after drying are more stable if the granulation nuclei of recovered liquid A and the slurry of recovered liquid B are formed separately and then mixed. In particular, when hypochlorite ions and chlorite ions are mixed, the available chlorine decomposes, and at the same time, chloride ions and chlorate ions are produced. In this case, not only will the available chlorine concentration of the final product be lower, but the purity will also be reduced due to the secondary components.

[0268] [Table 45]

[0269] (Yield changes due to differences in drying process) Compared to Method No. 1, Method No. 2 reduces free residual chlorine to an extremely small extent, and also generates less of the secondary components chloride ions and chlorate ions.

[0270] [Table 46] (Yield changes due to differences in moisture content during the drying process) [Table 47]

[0271] The stability of liquid A and B when mixed and dried was affected by two factors: the amount of water retained before drying, and the available chlorine ratio when recovered liquid A and recovered liquid B were mixed.

[0272] In this manufacturing method, granulation nuclei are formed in recovered liquid A and slurry is formed in recovered liquid B, and we have found that drying them to a certain extent beforehand improves workability and stability. As a guideline, it is best to pre-dry each until the total moisture content before drying is 20% or less.

[0273] At this time, if the moisture content is 26% or more, the free residual chlorine (hypochlorite ions) in recovered liquid A will react with chlorite ions, reducing the available chlorine concentration and increasing chlorate ions, resulting in a decrease in purity and drying rate. Also, if the moisture content exceeds 30%, the self-decomposition of free residual chlorine (hypochlorite ions) will become significant, resulting in a particular decrease in free residual chlorine (hypochlorite ions), and also a decrease in purity and drying rate.

[0274] Furthermore, when mixing recovered liquid A and recovered liquid B, the effective chlorine ratio is 1:20, which produces the least amount of secondary components and has the highest purity. Therefore, when drying recovered liquid A and recovered liquid B while keeping them stable, it is best to set the effective chlorine ratio to 1:20 and keep the moisture content below 20%.

[0275] (Calculated value of solid matter at 20% moisture content after pre-drying) [Table 48] In addition, the available chlorine ratio and ion ratio after drying were calculated from the measured values ​​of the solid product in the 20% moisture content group after pre-drying. The hypochlorite ion:chlorite ion ratio was 1:5.53 to 23.18.

[0276] (Composition of recovered liquids A and B and combined drying results (1:9.61)) This is the measurement result when recovery liquid A is mixed with recovery liquid B at an effective chlorine ratio of 1 and 9.61, and then dried. With this effective chlorine ratio, the following reaction occurs in excess, producing chloride and chlorate ions. ClO - +ClO2 - → ClO3 - + Cl -

[0277] Therefore, if the effective chlorine ratio is higher than this, the effective chlorine may fall below 60%, making it incompatible with high-grade bleaching powder, so this effective chlorine ratio is the lower limit.

[0278] [Table 49]

[0279] (Composition of recovered liquids A and B and combined drying results (1:33.95)) This is the measurement result when recovered liquid A was mixed with recovered liquid B at an effective chlorine ratio of 33.95 and dried, but if the effective chlorine ratio of recovered liquid B becomes too high, it is expected that it may not comply with the standards for free residual chlorine and calcium. With this ratio, the calcium ion concentration after drying is 5.64%, which is at the lower limit of the conditions for the amount of calcium in high-grade bleached powder, so this effective chlorine ratio is almost at the upper limit.

[0280] [Table 50]

[0281] (Composition of recovered liquids A and B and combined drying results (list)) In the case of (1), if there is a lot of free residual chlorine, hypochlorite ions and chlorite ions react, reducing the available chlorine and generating chloride ions and chlorate ions. In this case, not only is the available chlorine decomposed, but secondary components that do not contribute to the available chlorine are also generated, which reduces the drying concentration rate and results in the lowest available chlorine concentration.

[0282] On the other hand, in areas (4), (5), and (6), despite the initial amount of free residual chlorine added being reduced, the generation ratio of both the by-produced chloride ions and chlorate ions was high.The reason for this is unknown, but in the ratio of available chlorine to hypochlorite ions, when the hypochlorite ions were high, the available chlorine decomposed and did not meet the standard.On the other hand, even when the hypochlorite ions were low, the proportion of chlorine that changed to secondary components such as chloride ions and chlorate ions increased, reducing purity and hindering drying and concentration.

[0283] [Table 51]

[0284] In addition, since this process is carried out by reacting chlorine gas, it contains sulfate ions of about 1140 ppm or more. These sulfate ions are entrained by the sulfuric acid contained in the reaction tank, and since calcium hydroxide is present in excess in the recovered liquid, they are mainly in the form of sodium sulfate.

[0285] [Table 52]

[0286] (When dissolving solids) Based on the recipe below, ion-exchanged water was added so that the effective chlorine concentration after dilution would be 1%, 6%, or 12%, and the mixture was stirred with a stirrer for 15 minutes to ensure that no residue remained. The mixture was then left to stand in a 10°C incubator for 1 hour (to obtain a clear supernatant), and the supernatant was collected without absorbing any precipitate. The free residual chlorine concentration, effective chlorine concentration, and various ion concentrations (ion chromatography) of the supernatant were then measured.

[0287] [Table 53]

[0288] When the solid product was diluted with ion-exchanged water and liquefied, the decomposition of free residual chlorine was promoted to some extent, resulting in a decrease, but the available chlorine ratio and ion ratio were as shown in the separate table.

[0289] [Table 54-1]

[0290] (Composition when calcium is removed from solid product) Based on the recipe below and the Ca removal equation (*), ion-exchange water was added to the recovered solution after Ca removal so that the effective chlorine concentration after dilution would be 1%, 6%, or 12%, and the solution was stirred with a stirrer for 15 minutes to ensure that no residue remained. (A 20% sodium carbonate solution calculated from the equation was added and stirred for 1 minute.) The solution was then left to stand in a 10°C incubator for 19 hours (obtaining a clear supernatant), and the supernatant was collected without absorbing any sediment. The supernatant's free residual chlorine concentration, effective chlorine concentration, and various ion concentrations (ion chromatography) were then measured. *Calcium ion concentration (%) in high-grade bleached powder <x1>and the amount of 20% sodium bicarbonate solution added (g) <y1>The relation (1) is Y1=14.042X1+0.0185

[0291] Calcium ions were measured using an NN indicator and titrated with EDTA solution. 1 ml of 0.05 mol / L EDTA solution = 3.705 mg Ca(OH)2 x molecular weight of calcium ion (40.08) / molecular weight of calcium hydroxide (74.08) = 0.05 mol / 1 ml of EDTA solution = 2.005 mg Ca 2+

[0292] [Table 54-2] When the solid product was diluted with ion-exchanged water and the calcium ions were removed according to the relational equation to liquefy it, the decomposition of free residual chlorine was inhibited by the increase in alkalinity, and the available chlorine ratio and ion ratio were as shown in the table below.

[0293] [Table 54-3]

[0294] [Table 54-4] <Standards for Foods, Food Additives, etc., Part 2, Additives, D, Ingredient Standards and Storage Standards, Calcium Hydroxide> Quantitative method Accurately weigh out approximately 2 g of this product, dissolve in 30 ml of hydrochloric acid (1 → 4), add water to make exactly 250 mL, and use this as the test solution. Quantify using Method 1 of the Calcium Salt Determination Method. 0.05mol / L EDTA solution 1ml=3.705mgCa(OH)2 <Standards for Foods, Food Additives, etc., Part 2: Food Additives, B: General Test Methods, 8. Quantitative Analysis of Calcium Salts> Calcium salt determination is a method for quantifying the content of calcium salts using disodium ethylenediaminetetraacetic acid (EDTA). There are two methods: direct titration with EDTA solution (Method 1) and back titration (Method 2), in which excess EDTA is added and then titrated with zinc acetate solution. How to operate Unless otherwise specified, any of the following methods shall be used. Law 1 Accurately measure 10 ml of the test solution specified separately, add 50 ml of water, add 10 ml of potassium hydroxide solution (1 → 10), and leave for about 1 minute. Then add about 0.1 g of NN indicator and immediately titrate with 0.05 mol / LEDTA solution. The endpoint is when the reddish-purple color of the solution has completely disappeared and turned blue. Second law Accurately measure 20 ml of the test solution specified separately, accurately measure 25 ml of 0.02 mol / L EDTA solution, add 50 ml of water and 5 ml of ammonia-ammonium chloride buffer (pH 10.7), and let stand for approximately 1 minute. Then add 0.025 g of eriochrome black T-sodium chloride indicator, and immediately titrate the excess EDTA with 0.02 mol / L zinc acetate solution. The endpoint is when the blue color of the solution changes to blue-purple. Perform a separate blank test. 1 ml of 0.05 mol / L EDTA solution = 3.705 mg Ca(OH)2 × molecular weight of calcium ion (40.08) / molecular weight of calcium hydroxide (74.08) =0.05mol / L EDTA solution 1ml=2.005mgCa 2+

[0295] (Saved data) For comparison purposes, we conducted storage tests at 25°C and 40°C on a commercially available high-grade bleached powder ("Toyokuron-PTGIII") and high-grade bleached powder produced using this method ("High-grade bleached powder A"). The storage test consisted of official standard tests for "high-grade bleached powder," and included measuring the presence of bubbles (free residual chlorine) caused by reactions with moisture and hydrogen peroxide, as well as expansion.

[0296] As a result, there was almost no decrease in the available chlorine at either the 25°C or 40°C storage temperature range, and the product complied with the official standard test for "high-grade bleaching powder." Furthermore, the generation of bubbles due to hydrogen peroxide was confirmed, confirming that no change in composition was observed even after storage.

[0297] Furthermore, it was confirmed that it has superior preservation properties compared to commercially available "advanced bleaching powder."

[0298] The specimen was prepared by pre-drying recovered liquid A to form granulation nuclei, which were then mixed with pre-dried recovered liquid B and dried.

[0299] [Table 55-1] [Table 55-2] [Table 55-3]

[0300] (oxidation-reduction potential, chlorine gas concentration) The ORP (oxidation-reduction potential) and chlorine gas concentration were measured for the prepared mixed solutions (sodium hypochlorite standard), specimens (1) and (2). A sodium hypochlorite solution of the same concentration was also used as a control for comparison. The results showed that while the ORP (oxidation-reduction potential) of sodium hypochlorite did not change when diluted, the oxidizing power of specimens (1) and (2) increased when diluted. Furthermore, the chlorine gas concentration was confirmed to be superior, with almost no chlorine gas being released when the specimens came into contact with organic matter, with only approximately 1 / 31 to 1 / 50 of the measured concentration.

[0301] [Table 56] <Equipments and supplies used> Gas sampler GV-100S manufactured by Gastec Corporation Gastec Corporation detector tube No. 8LL: Measurement range 0.025 to 2.0 ppm Gastec Corporation detector tube No. 8La: measurement range 0.1 to 16 ppm Gastec Corporation detector tube No. 8H: Measurement range 25 to 1000 ppm

[0302] (Chlorine gas concentration in dissolved powder) Using the prepared high-grade bleaching powder liquid, the chlorine gas concentration was measured when it came into contact with organic matter, compared to sodium hypochlorite of the same concentration. The results showed that the high-grade bleaching powder liquid did not rapidly generate chlorine gas when it came into contact with organic matter, and only about 1 / 1000 to 1 / 6000 of the chlorine gas was measured. This also leads to a reduction in the chlorine odor that adheres to foods being sterilized. <Test area> Sodium hypochlorite 200ppm, 1000ppm High-grade bleaching powder liquid product 200ppm, 1000ppm 50g of each of the above liquids was measured and soaked with 5g of cut cabbage (liquid ratio 1:10), and then sealed. After soaking for 1 hour at 25°C, the chlorine gas concentration was measured.

[0303] [Table 57] <Equipments and supplies used> Gas sampler GV-100S manufactured by Gastec Corporation Gastec Corporation detector tube No. 8LL: Measurement range 0.025 to 2.0 ppm Gastec Corporation detector tube No. 8La: measurement range 0.1 to 16 ppm Gastec Corporation detector tube No. 8H: Measurement range 25 to 1000 ppm

[0304] (Confirmation of sterilization effect) The liquid product (sodium hypochlorite standard) and solid product (high-grade bleaching powder standard) prepared according to the present invention were used to confirm the sterilization effect on green onions, which are known to have a high bacterial count.

[0305] Compared to the control, sodium hypochlorite, the liquid product was confirmed to have a superior bactericidal effect on both general viable bacteria counts and coliform bacteria counts, and its bactericidal effect on coliform bacteria was particularly notable.

[0306] Furthermore, when the solid product was checked in two areas before and after calcium removal from the high-grade bleaching powder, the bactericidal effect against coliform bacteria was confirmed, confirming that the overall characteristic of the bactericide of this invention is its high bactericidal effect against coliform bacteria.

[0307] [Table 58-1] [Table 58-2]

[0308] (Difference in reaction with R2 method 1) Although the raw material is not degraded sodium hypochlorite, a similar reaction method is the R2 method.

[0309] The R2 method involves the batch reaction of sodium chlorate and sodium chloride under highly acidic conditions (8N-11N) using sulfuric acid to obtain chlorine dioxide gas. If the R2 method were used to react with degraded sodium hypochlorite, chlorate ions would be generated in recovered solution A, which is contrary to the objective of this method. Furthermore, in this method, both chlorate ions and chloride ions are naturally generated in the degraded sodium hypochlorite used as the raw material, and the amounts of chlorate ions and chloride ions increase or decrease during the first reaction. Furthermore, the amount of chloride ions in the degraded sodium hypochlorite is already excessive to generate hydrochloric acid, so it is necessary to control the excessive generation of hydrochloric acid by chloride ions.

[0310] However, it is possible that the recovery rate can be improved by adding sodium chloride to the reaction mother liquor, as in Method R2. If this is the case, it may be possible to reduce the cost of using sulfuric acid. Therefore, a second reaction was carried out using the reaction mother liquor (degraded sodium hypochlorite + sulfuric acid) after the first reaction, and 50% sulfuric acid and sodium chloride were added to confirm the decomposition rate of chlorate ions and the recovery rate in recovery solution B.

[0311] As a result, when 50% sulfuric acid and sodium chloride were added and the second reaction was carried out with the sulfuric acid concentration in the reaction mother liquor at around 17%, the decomposition rate of chlorate ions in the reaction mother liquor improved as sodium chloride was added and the reaction proceeded, but the chloride ions increased. Furthermore, the recovery rate of chlorite ions in recovered liquid B was low, and an increase in chloride ions was observed.

[0312] From these results, it was found that the low acidity of the reaction mother liquor due to sulfuric acid caused a side reaction to proceed, generating chlorine gas by decomposing chloric acid, and the amount of chloride ions in the reaction mother liquor increased. In addition, the amount of chloride ions in recovered liquid B increased as chlorine gas was decomposed by hydrogen peroxide, and the main reaction did not proceed, resulting in a decrease in the generation of chlorine dioxide and the recovery rate of chlorite ions.

[0313] [Table 59-1] [Table 59-2]

[0314] (Difference in reaction with R2 method 2) It was found that by adding sodium chloride to the reaction mother liquor after the completion of the first reaction, the decomposition rate of chlorate ions could reach 100% without adding an excess amount of sulfuric acid. Although the decomposition rate of chlorate ions improved, it also worsened the yield.

[0315] Therefore, a reaction test was carried out using 50% w / w sulfuric acid with sulfuric acid concentrations in the reaction mother liquor of 25.0% and 27.28%.

[0316] As a result, the main reaction proceeded under strongly acidic conditions, and the recovery of chlorite ions accompanied by the generation of chlorine dioxide gas progressed. However, a large amount of chloride ions was still recovered in recovered liquid B, which was thought to be due to the contamination of chlorine gas accompanying the progress of a side reaction.

[0317] From the above, it was found that side reactions are more likely to proceed when the acidity due to sulfuric acid is low, but when the sulfuric acid concentration is excessive, the production of hydrochloric acid increases and the side reaction also proceeds, so focusing on the decomposition of chloric acid will lead to the progression of side reactions and will not lead to an improvement in the recovery rate. Furthermore, in the reaction of deteriorated sodium hypochlorite, which already contains a sufficient amount of chloride ions, it is more important to prevent the progression of side reactions by controlling the excess hydrochloric acid produced.

[0318] [Table 60-1] [Table 60-2]

[0319] (Difference in reaction from R2 method 3) It was found that adding sodium chloride to the reaction mother liquor after the first reaction produced hydrochloric acid, and the decomposition rate of chlorate ions reached 100% without adding an excess of sulfuric acid.

[0320] However, even if the decomposition rate of chlorate ions is 100%, the recovery rate of chlorous acid does not improve because the decomposition reaction of chloric acid has two main and side reactions, and the progress changes depending on the reaction conditions, and it was found that the chloride ions in recovered liquid B are caused by the generation of chlorine gas due to the decomposition of chlorate ions. Therefore, if the chlorate ions are completely decomposed due to the excessive generation of hydrochloric acid, a large amount of chloride ions will be generated, which will lead to a deterioration in the recovery rate and a decrease in purity.

[0321] [Table 61-1] [Table 61-2]

[0322] (Basic test 1 to confirm the conditions for the first reaction and the increase in chlorate ions) We checked the increase or decrease in chloride ions and chlorate ions after the first reaction using deteriorated sodium hypochlorite. The first reaction is usually carried out at room temperature, 20 to 30°C, and at most 40°C due to the heat generated during the reaction.

[0323] Then, when they experimentally performed only the primary reaction, they confirmed a decrease in chloride ions and an increase in chlorate ions, and found that the chlorate ions continued to increase up to about 40°C.

[0324] However, if the primary reaction is carried out at 40°C, chlorite ions are detected in the recovered liquid, so it was found that the preferable temperature condition for the primary reaction is room temperature, around 30°C. In addition, raising the temperature too much generates steam, which increases the entrainment of sulfuric acid, hydrochloric acid, etc. into the recovered liquid, so this is also thought to be undesirable.

[0325] [Table 62-1] [Table 62-2]

[0326] (Basic test 2 to confirm the conditions for the first reaction and the increase in chlorate ions) This was a re-examination of the previous test, and the effect of acidity on the first reaction was confirmed by adding 65 w / w% sulfuric acid.

[0327] As a result, the increase in chlorate ions was greater when the acidity was increased than when the temperature was increased. However, on the other hand, it is thought that the generation of hydrochloric acid will also progress, and as a result, chlorite ions and chlorate ions will be detected in the recovered liquid A, and the recovery rate may also decrease. Therefore, it is not preferable to excessively increase the sulfuric acid concentration in the reaction mother liquor in the first reaction.

[0328] [Table 63-1] [Table 63-2]

[0329] (Exam explanation) The technology of remanufacturing degraded sodium hypochlorite, which is sodium hypochlorite that has deteriorated in quality, by re-reacting it is not a new technology in itself, but there is a problem in that the cost of remanufacturing cannot be added to the unit price of the product.

[0330] Therefore, we focused on the chloride ions and chlorate ions that are generated in deteriorated sodium hypochlorite, and investigated whether it would be possible to produce a bactericidal disinfectant containing a complex of various chlorine oxide ions by reacting these ions.

[0331] As a result, it was confirmed that when attempting to react deteriorated sodium hypochlorite to recover both chlorine gas and chlorine dioxide gas using a single liquid, there are drawbacks, such as the decomposition into chloride ions and the generation of chlorate ions. It was found that in order to recover them separately, reaction conditions are required that allow chlorine gas and chlorine dioxide gas to be extracted in stages from the reaction mother liquor consisting of deteriorated sodium hypochlorite and sulfuric acid.

[0332] It was also found that the reaction conditions differ depending on the grade of sodium hypochlorite used as raw material (low-salt grade or general grade).

[0333] Next, the recovered liquid is recovered using only sodium hydroxide or calcium hydroxide in the first reaction, and recovered by adding hydrogen peroxide to sodium hydroxide in the second reaction.

[0334] Furthermore, during the second reaction and recovery, an intermediate tank should be provided between the reaction tank and the recovery tank to prevent backflow, and in the case of general-grade sodium hypochlorite in particular, it is advisable to add hydrogen peroxide water to prevent chlorine gas from being mixed in.

[0335] These will lead to an increase in purity by removing residual alkali components and chloride ions during subsequent granular drying.

[0336] The mixing ratio of recovered liquid A to recovered liquid B must conform to the specifications for the food additives sodium hypochlorite and high-grade bleaching powder, and in the case of sodium hypochlorite, the available chlorine in recovered liquid A must be 1, and the available chlorine in recovered liquid B must not exceed 0.6, and in view of the characteristics of the present invention, it is desirable to adjust it within the range of 0.43 to 0.6. Similarly, in the case of high-grade bleaching powder, the available chlorine in recovered liquid A must be 1, and the available chlorine in recovered liquid B must be 33.95 or less, but in view of the characteristics of the present product, a ratio of 1:9.6 is desirable.

[0337] Furthermore, when concentrating by drying, it is faster to mix and dry each liquid to a certain degree of slurry rather than combining the two liquids at the solution stage, as this will prevent the loss of available chlorine and changes in composition. The dried solid produced by these methods has very little decomposition of free residual chlorine, and becomes a chlorine oxide solid that maintains the composition of the content liquid for a long period of time.

[0338] As is clear from the above tests, this invention not only allows degraded sodium hypochlorite to be used as a raw material and restored to inexpensive sodium hypochlorite, but also to be recycled into a bactericidal disinfectant that adds value to end consumers.

[0339] While the present invention has been illustrated using preferred embodiments thereof, it should be understood that the scope of the present invention should be construed solely in accordance with the claims. This application claims priority to Japanese Patent Application No. 2018-71515 (filed April 3, 2018), the contents of which are incorporated herein by reference in their entirety. It is understood that the patents, patent applications, and other documents cited herein are incorporated herein by reference in their entirety as if the contents themselves were specifically set forth herein. [Industrial Applicability]

[0340] The composition of the present invention is useful as a germicidal disinfectant. The method of the present invention regenerates deteriorated sodium hypochlorite to produce a new, useful germicidal disinfectant.

Claims

[Claim 1] The method described in the specification.

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