KR20220106716A - A method to reduce residual aluminum - Google Patents

Abstract

The present invention relates to a method for reducing aluminum, and specifically, to a method for reducing aluminum, which can reduce aluminum without materials or additional equipment by treating a coagulant containing sulfate ion, hydrochloric acid ion and aluminum oxide in a certain ratio alone, or treating the coagulant together with an inorganic coagulant and/or an organic coagulant to maximize the removal of residual aluminum by solving a problem of the residual aluminum in a conventional coagulant.

Description

A method to reduce residual aluminum

The present invention relates to a method for reducing aluminum, and a method for reducing aluminum by treating a coagulant containing sulfate ions, hydrochloric acid ions and aluminum oxide in a certain ratio alone or in combination with an inorganic coagulant and/or an organic coagulant will be.

Aluminum accounts for about 8% by weight of soil components, and is a silvery-white soft metal constituting the tissues of rocks and animals and plants. It is a metal capable of forming aluminate by dissolving in alkali to generate hydrogen. Aluminum tends to form precipitates in water or is adsorbed in the form of hydroxides and carbonates, so aluminum is used as a coagulant in water purification plants.

As a coagulant containing aluminum, there are aluminum sulfate (Aluminum Sulphate), sodium aluminate (Sodium Aluminate), aluminum ammonium Sulphate (Aluminum ammonium Sulphate), potassium alum (Potash alum), etc. Poly Aluminum Chloride, Poly Aluminum Sulfate, Poly Aluminum Sulfate Silicate, Poly Aluminum Hydroxy Chloro Sulfate, and the like.

Regarding aluminum, there are reports that, although controversial, it is associated with Alzheimer's disease, a type of dementia. Accordingly, it has been pointed out that the total aluminum level, including monomer aluminum and other forms of aluminum in water, should be less than 200 mg per liter. In drinking water quality standards, etc., the maximum recommended value of aluminum in drinking water is set at 0.2 mg per liter.

In the case of Korea, since there has been little rain for the past 5 years, the pH of raw water has risen nationwide, and in spring and autumn, the pH rises to 9.5. are doing It is inevitable to use aluminum-based coagulants such as aluminum sulfate in water purification facilities, and many high-salinity coagulants are used for efficient water treatment such as turbidity and organic matter removal. In addition, due to the problem of residual aluminum, sulfuric acid or hydrochloric acid is simply added or a CO ₂ treatment facility is used, but there are limitations due to non-reaction of hazardous chemicals, design cost, and design capacity. In particular, in the case of sulfuric acid and hydrochloric acid, if it is 10% or more, it is a hazardous chemical, and if it is used for water treatment, there may be a problem for the safety of workers. Therefore, most water treatment plants use 9% hydrochloric acid and sulfuric acid to lower the pH. As low concentrations of hydrochloric acid and sulfuric acid are used, the amount of input increases, resulting in many difficulties in storage tank management.

Conventional aluminum sulfate (Aluminum Sulfate) exists in a solid or liquid phase, and the aluminum oxide content is 16% or more in the solid phase and 8% or more in the liquid phase. A liquid phase is mainly used for the ease of quantitative input, and the aggregation reaction is performed in the following manner.

Al ₂ (SO ₄ ) + 2H ₂ PO ₄ ^- + 4HCO ₃ ^- → 2AlPO ₄ + 3SO ₄ ^2- + 4H ₂ CO ₃

In addition, conventional poly aluminum chloride (Poly Aluminum chloride) has different basicity depending on the degree of polymerization and has different characteristics depending on the manufacturing process, but mainly the content of aluminum oxide is 10 to 18% by weight, and the basicity is 35% or more. Polyaluminum chloride is known to have excellent aggregation ability due to its excellent electrical neutralization ability and OH crosslinking action, and the aggregation reaction is performed in the following manner.

[Al ₂ (OH) ₃ Cl ₃ ] _n + 2H ₂ PO ₄ ^- + HCO ₃ ^- → 2AlPO ₄ + 3Cl ^- + +2H ₂ O + H ₂ CO ₃

In this regard, Korean Patent No. 10-0318661 on a wastewater treatment agent containing calcium carbonate and calcium chloride, Korean Patent Publication No. 1999-0014376 on a wastewater treatment agent containing a large amount of fluorine, and a coagulant composition for water treatment containing zirconium There are domestic registered patents No. 10-1016392, etc., and Korean Patent Publication No. 2019-0115868 discloses an aluminum sulfate-based inorganic coagulant using a spent sulfuric acid solution, and domestic registered patent No. 10-1159236 has a low-base poly _A method for manufacturing an aluminum _chloride coagulant and a water treatment method using the same, which can prevent eutrophication such as green algae, and can be stored for a long time. A coagulant is disclosed, and Korean Patent Registration No. 10-1640368 discloses a method for manufacturing a coagulant that maintains a low saltity of 7 to 15 wt% of Al ₂ O ₃ and 1 to 5 wt% of Fe, and a method for treating wastewater through it. has been disclosed.

In general, inorganic coagulants are mostly aluminum-based coagulants, and as a coagulant is added rather than aluminum contained in raw water, aluminum remaining after binding with colloids is dissolved in water, causing a problem in eluting aluminum.

In particular, the problem of aluminum elution starts to occur when the pH of the raw water is 7.5 or higher, and the higher the pH of the raw water, the bigger the problem of aluminum elution. Even if the minimum amount of coagulant is input for coagulation, if the pH of the raw water is high, aluminum is detected above the standard value in the treated water even if coagulation is made, and the higher the input amount, the higher the residual aluminum is detected. Efforts are made to reduce aluminum, but there is no effect of reducing residual aluminum in raw water with high pH.

In addition, as a pH control method to solve the problem of aluminum dissolution, a method of using carbon dioxide or injecting an excessive amount of coagulant is tried, but when carbon dioxide is injected, it is difficult in terms of operation management, cost, efficiency, etc. in the actual process There is a problem that, when an excessive amount of coagulant is used, the amount of sludge generated increases, and the amount of residual aluminum may further increase as the input amount increases.

Accordingly, the present inventors have made efforts to solve the above problem, and as a result of using a conventional coagulant, if a certain amount of the composition according to the present invention is added to lower the pH to 7.5 or less, the generation of residual aluminum is reduced, and less input than sulfuric acid or hydrochloric acid The present invention was completed by revealing that it is possible to lower the pH to 7.5 or less, the residual aluminum is detected lower, and the aggregation efficiency can be expected while reducing the residual aluminum even if it is added alone.

Republic of Korea Patent Publication No. 1999-0014376 Republic of Korea Patent Publication No. 2019-0115868 Republic of Korea Patent No. 10-1016392 Republic of Korea Patent No. 10-0318661 Republic of Korea Patent No. 10-1640368

Konkuk University master's thesis, Youngsong Ko et al., 1993.02, A study on factors affecting the minimization of residual aluminum concentration in water treatment

In the present invention, when using a conventional coagulant, in order to solve the problem of an increase in residual aluminum as a coagulant is added in raw water having a high pH, a method capable of reducing aluminum while using an inorganic coagulant and/or an organic coagulant as it is.

In order to solve the above problem, the present invention

In a system for reducing aluminum in the sewage treatment process of a water purification plant,

an aluminum-based flocculant storage tank in the system;

Sulfuric acid, hydrochloric acid, or aluminum-based coagulant injection piping;

water storage and supply tanks;

a reactor for stirring the reactants;

Including a flocculating unit for receiving a coagulant and coagulating with wastewater

It includes a reaction unit for reacting aluminum hydroxide, sulfuric acid, hydrochloric acid, aluminum sulfate or aluminum hydrochloride in the reaction tank at 20 to 200 ℃,

It provides an aluminum reduction system, characterized in that 10 to 100 ppm of the coagulant is added in the agglomeration part to reduce aluminum to 0.15 mg/l or less.

Also, the present invention

A) A1) sulfuric acid; aluminum hydroxide; and water to prepare a coagulant; A2) an aluminum sulfate-based composition; aluminum hydroxide; And preparing a coagulant by mixing water, 5 to 35% by weight of sulfuric acid, 0.5 to 7% by weight of aluminum hydroxide, and 35 to 80% by weight of water relative to the total weight of the flocculant to prepare a flocculant; and

b) b1) the coagulant obtained in step a) is added alone; b2) adding the coagulant obtained in step a) in combination with at least one coagulant selected from the group consisting of inorganic coagulants and organic coagulants;

After the step b), the aluminum concentration is 0.15 mg / l or less, providing a method for reducing aluminum in the water purification plant.

Also, the present invention

c) c1) hydrochloric acid; aluminum hydroxide; and water to prepare a coagulant; C2) an aluminum hydrochloride-based composition; aluminum hydroxide; and water to prepare a coagulant, but 5 to 35% by weight of hydrochloric acid, 0.5 to 7% by weight of aluminum hydroxide, and 35 to 80% by weight of water relative to the total weight of the flocculant to prepare a flocculant; and

d) d1) adding the coagulant obtained in step c) alone; d) adding the coagulant obtained in step c) in combination with at least one coagulant selected from the group consisting of inorganic coagulants and organic coagulants;

After the step d), the aluminum concentration is 0.15 mg/l or less, providing a method for reducing aluminum in the water purification plant.

Also, the present invention

a) a sulfuric acid or aluminum sulfate-based composition; hydrochloric acid or hydrochloric acid-based composition; aluminum hydroxide; And a coagulant is prepared by mixing two or more selected from the group consisting of water, but 0.5 to 35 wt% of hydrochloric acid, 0.5 to 35 wt% of sulfuric acid, 0.5 to 15 wt% of aluminum hydroxide, and 35 to 80 wt% of water based on the total weight of the coagulant preparing a coagulant; and b1) adding the coagulant obtained in step a) alone; b2) adding the coagulant obtained in step a) in combination with at least one coagulant selected from the group consisting of an inorganic coagulant and an organic coagulant;

In one aspect of the present invention, the aluminum hydroxide in step a) is 1 to 80% of aluminum oxide.

In one aspect of the present invention, the aluminum hydroxide in step a) is to be mixed with 0.5 to 12% by weight based on the total weight of the coagulant.

In one aspect of the present invention, the aluminum sulfate-based composition of step a) includes an aluminum oxide concentration of 0.5 to 8% by weight, a sulfate ion concentration of 10 to 40% by weight, and the remainder of water.

In one aspect of the present invention, the aluminum sulfate-based composition of step a) includes an aluminum oxide concentration of 1 to 5% by weight, a sulfate ion concentration of 15 to 38% by weight, and the remainder of water.

In one aspect of the present invention, the aluminum hydrochloride-based composition of step a) includes an aluminum oxide concentration of 0.5 to 7% by weight, a hydrochloride ion concentration of 10 to 35% by weight, and the remainder of water.

In one aspect of the present invention, the aluminum hydrochloride-based composition of step a) includes an aluminum oxide concentration of 1 to 5% by weight, a hydrochloride ion concentration of 28 to 30% by weight, and the remaining amount of water.

In one aspect of the present invention, the coagulant of step a) comprises 0.5 to 8% by weight of aluminum oxide, 10 to 40% by weight of the sum of sulfate ions and hydrochloric acid ions, based on the total weight.

In a specific embodiment of the present invention, the coagulant of step a) comprises 0.5 to 5% by weight of aluminum oxide, 10 to 35% by weight of the sum of sulfate ions and hydrochloric acid ions, based on the total weight.

In one aspect of the present invention, the coagulant of step a) is sulfide, chloride, silicate, oxide; And it may further include one or more compounds selected from the group consisting of salts thereof.

In one embodiment of the present invention, the coagulant of step a) further comprises at least one compound selected from the group consisting of a group 2A compound, a group 3A compound, a group 4A compound, a group 3B compound, a group 4B compound, and salts thereof. can

In one embodiment of the present invention, the coagulant of step a) is a group 2A chloride, a group 2A sulfide, a group 3B chloride, a group 3B sulfide, a group 4B chloride, a group 4B sulfide, sodium silicate (Na ₂ SiO ₃ ) and salts thereof It may further include one or more compounds selected from the group consisting of.

In one aspect of the present invention, the coagulant of step a) is calcium chloride (CaCl ₂ ), gallium sulfate (Ga ₂ (SO ₄ ) ₃ ), sodium silicate (Na ₂ SiO ₃ ), zirconium chloride (ZrCl ₄ ), yttrium chloride (YCl ₄ ) and one or more compounds selected from the group consisting of salts thereof may be further included.

In one aspect of the present invention, the inorganic coagulant in step b2) is an aluminum-based coagulant, an iron salt-based coagulant, or a mixed coagulant thereof.

In one aspect of the present invention, the inorganic coagulant of step b2) is aluminum chloride, aluminum sulfate, polyaluminum sulfate, polyaluminum chloride, polyaluminum silicate, polyaluminum chloride silicate, polyhydroxychlorinated aluminum silicate, polysilicic acid polysulfate and It is at least one selected from the group consisting of polyhydroxychlorinated aluminum sulfate.

In one aspect of the present invention, the organic coagulant of step b2) is polyacrylamide-based, polyvinylamine-based, polyallylamine-based, polyethyleneamine-based, polyamine-based, polyacrylic ester-based, polyethyleneimine-based, polydead film and It is at least one selected from the group consisting of these mixed coagulants.

In one aspect of the present invention, in the method for reducing aluminum, the residual aluminum is 40 to 80% compared to the case where the coagulant is not added.

In one aspect of the present invention, in the aluminum reduction method, the aluminum concentration after treatment is 0.2 mg/l or less.

In one aspect of the present invention, the pH of the treated water after the aluminum reduction method treatment is 6 to 8.

In addition, the present invention is a) sulfuric acid or aluminum sulfate-based composition; hydrochloric acid or hydrochloric acid-based composition; aluminum hydroxide; And a coagulant is prepared by mixing two or more selected from the group consisting of water, but 0.5 to 35 wt% of hydrochloric acid, 0.5 to 35 wt% of sulfuric acid, 0.5 to 15 wt% of aluminum hydroxide, and 35 to 80 wt% of water based on the total weight of the coagulant preparing a coagulant; and

b1) adding the coagulant obtained in step a) alone;

b2) adding the coagulant obtained in step a) in combination with at least one coagulant selected from the group consisting of an inorganic coagulant and an organic coagulant;

The present invention is a method capable of reducing residual aluminum through treatment of hydrochloric acid, sulfuric acid, and aluminum oxide, and can reduce aluminum compared to a conventional coagulant, and thus no additional material or equipment is required to reduce aluminum. There is this.

Hereinafter, the present invention will be described in detail.

the present invention

A) A1) sulfuric acid; aluminum hydroxide; and water to prepare a coagulant; A2) an aluminum sulfate-based composition; aluminum hydroxide; And preparing a coagulant by mixing water, 5 to 35% by weight of sulfuric acid, 0.5 to 7% by weight of aluminum hydroxide, and 35 to 80% by weight of water relative to the total weight of the flocculant to prepare a flocculant; and

b) b1) the coagulant obtained in step a) is added alone; b2) adding the coagulant obtained in step a) in combination with at least one coagulant selected from the group consisting of inorganic coagulants and organic coagulants;

After the step b), the aluminum concentration is 0.15 mg / l or less, it relates to a method for reducing aluminum in the water purification plant.

Also, the present invention

c) c1) hydrochloric acid; aluminum hydroxide; and water to prepare a coagulant; C2) an aluminum hydrochloride-based composition; aluminum hydroxide; and water to prepare a coagulant, but 5 to 35% by weight of hydrochloric acid, 0.5 to 7% by weight of aluminum hydroxide, and 35 to 80% by weight of water relative to the total weight of the flocculant to prepare a flocculant; and

d) d1) adding the coagulant obtained in step c) alone; d) adding the coagulant obtained in step c) in combination with at least one coagulant selected from the group consisting of inorganic coagulants and organic coagulants;

After the step d), the aluminum concentration is 0.15 mg / l or less, it relates to a method for reducing aluminum in the water purification plant.

the present invention

a) sulfuric acid or aluminum sulfate-based flocculants; hydrochloric acid or hydrochloric acid-based coagulant; aluminum hydroxide; And a coagulant is prepared by mixing two or more selected from the group consisting of water, but 0.5 to 35 wt% of hydrochloric acid, 0.5 to 35 wt% of sulfuric acid, 0.5 to 15 wt% of aluminum hydroxide, and 35 to 80 wt% of water based on the total weight of the coagulant preparing a coagulant; and

b1) adding the coagulant obtained in step a) alone;

b2) adding the coagulant obtained in step a) in combination with at least one coagulant selected from the group consisting of an inorganic coagulant and an organic coagulant;

In this specification, a compound has the same meaning as commonly understood in the technical field to which the present invention pertains. In addition, in the present specification, water treatment is a process of removing contaminants in raw water, and has the same meaning as commonly understood in the technical field to which the present invention pertains.

In this specification, % means % by weight unless otherwise defined.

In the present invention, the steps b1) and b2) may be performed sequentially or each step may be performed alone or together, and the order of each step is not limited. In the present invention, when the organic coagulant or inorganic coagulant is used alone, aluminum appears remarkably high, so it is used in combination with the coagulant of the present invention so that water treatment efficiency such as phosphorus and sulfur removal is possible, and aluminum can be reduced, so additional facilities or equipment are required. not required

In the present invention, when one or more coagulants selected from the group consisting of an inorganic coagulant and an organic coagulant are used in combination in step b2), this means that 'the coagulant of step a), an inorganic coagulant and an organic coagulant' are used in combination. case, and 'the coagulant and inorganic coagulant of step a)' or 'the coagulant and the organic coagulant of step a)' are used in combination.

In addition, when used in combination in the present invention, it includes not only the case of using each of the separate flocculants separately, but also mixing each flocculant and using it as a single flocculant. For example, the coagulant of step a) and aluminum hydroxide chloride may be mixed to exist as one solution or powder form, or if they are added to raw water, they are used together at the time of each use, or both.

In the present invention, the aluminum reduction method may be capable of improving turbidity and reducing pH.

In an example of the present invention, hydrochloric acid, sulfuric acid, and aluminum hydroxide may be mixed with water, and when hydrochloric acid, sulfuric acid or aluminum hydroxide is mixed with water in a state of dissolving it in water, a range other than the above concentration may be used. For example, when a sulfuric acid concentration of 70% is used, the coagulant can be prepared by increasing the input amount compared to the case where the sulfuric acid concentration is 97%. However, when the sulfuric acid concentration is 95% or more, the coagulant can be generated within a short time through an exothermic reaction with aluminum hydroxide.

In one aspect of the present invention, the coagulant of step a) may be to prepare a coagulant by mixing sulfuric acid, hydrochloric acid, aluminum hydroxide and water.

Further, in one aspect of the present invention, the coagulant of step a) may be prepared by mixing sulfuric acid, an aluminum hydrochloride-based coagulant and water to prepare a coagulant.

Further, in one aspect of the present invention, the coagulant in step a) may be prepared by mixing an aluminum sulfate-based coagulant, hydrochloric acid, and water.

Also, in one aspect of the present invention, the coagulant of step a) may be to prepare a coagulant by mixing an aluminum sulfate-based coagulant, an aluminum hydrochloride-based coagulant, and water.

In one aspect of the present invention, the aluminum hydroxide in step a) is 1 to 80% of aluminum oxide.

In one aspect of the present invention, the aluminum hydroxide in step a) is to be mixed with 0.5 to 12% by weight based on the total weight of the coagulant.

In one aspect of the present invention, the aluminum sulfate-based composition of step a) includes an aluminum oxide concentration of 0.5 to 7% by weight, a sulfate ion concentration of 10 to 40% by weight, and the remainder of water.

In a specific aspect of the present invention, the aluminum sulfate-based composition of step a) may have an aluminum oxide concentration of 1 to 7%, more specifically 1 to 5%, based on the total weight. In addition, in the aluminum sulfate-based composition of step a), the concentration of sulfate ions may be 10 to 39%, more specifically, 15 to 38%, and 16 to 36%, based on the total weight.

In one aspect of the present invention, the aluminum hydrochloride-based composition of step a) includes an aluminum oxide concentration of 0.5 to 7% by weight, a hydrochloride ion concentration of 10 to 40% by weight, and the remainder of water.

In a specific aspect of the present invention, the aluminum hydrochloride-based composition of step a) has an aluminum oxide concentration of 1 to 7%, more specifically 1 to 5%, based on the total weight. In addition, in the aluminum hydrochloride-based composition of step a), the concentration of hydrochloric acid ions may be 10 to 40%, more specifically, 28 to 32%, 28 to 30%, and 29 to 30% of the total weight.

In an example of the present invention, when aluminum sulfate and sulfuric acid are mixed to prepare the aluminum sulfate-based composition in step a), the aluminum sulfate concentration is 5 to 10%, more specifically 7 to 8%, sulfuric acid Aluminum sulfate having an ion concentration of 19 to 27%, more specifically 20 to 25%, may be used, and the aluminum sulfate-based composition in the above range may be prepared by mixing it with sulfuric acid.

In one aspect of the present invention, the coagulant of step a) comprises 0.5 to 8% by weight of aluminum oxide, 10 to 40% by weight of the sum of sulfate ions and hydrochloric acid ions, based on the total weight.

In a specific embodiment of the present invention, the coagulant of step a) comprises 0.5 to 5% by weight of aluminum oxide, 10 to 35% by weight of the sum of sulfate ions and hydrochloric acid ions, based on the total weight.

In the present invention, as the total weight % of hydrochloric acid ions and sulfate ions is adjusted, the aluminum reduction effect is excellent. In addition, since it contains both hydrochloric acid ions and sulfate ions, the aluminum reduction effect is excellent compared to conventional coagulants containing sulfuric acid or hydrochloric acid alone.

Specifically, when the sum of the contents of hydrochloric acid ions and sulfate ions is less than 10%, it is not enough to dissolve aluminum oxide, so that the coagulant is not made and Al is not removed, and the sum of the contents of hydrochloric acid ions and sulfate ions is more than 40%. In this case, unreacted sulfate ions may remain and may be toxic, and additional treatment may be required. In addition, when the concentration of aluminum oxide is less than 0.5%, there is no cohesive ability, and when it is 6% or more, the residual aluminum increases, which may cause an effect different from the object of the present invention.

In one aspect of the present invention, the coagulant of step a) is sulfide, chloride, silicate, oxide; And it may further include one or more compounds selected from the group consisting of salts thereof.

In one embodiment of the present invention, the coagulant of step a) further comprises at least one compound selected from the group consisting of a group 2A compound, a group 3A compound, a group 4A compound, a group 3B compound, a group 4B compound, and salts thereof. can

In addition, in one embodiment of the present invention, the coagulant of step a) is a group 2A chloride, a group 2A sulfide, a group 3B chloride, a group 3B sulfide, a group 4B chloride, a group 4B sulfide, sodium silicate (Na ₂ SiO ₃ ) and these It may further include one or more compounds selected from the group consisting of salts.

In one aspect of the present invention, the coagulant of step a) is calcium chloride (CaCl ₂ ), gallium sulfate (Ga ₂ (SO ₄ ) ₃ ), sodium silicate (Na ₂ SiO ₃ ), zirconium chloride (ZrCl ₄ ), yttrium chloride (YCl ₄ ) and one or more compounds selected from the group consisting of salts thereof may be further included.

In one aspect of the present invention, the inorganic coagulant in step b2) is an aluminum-based coagulant, an iron salt-based coagulant, or a mixed coagulant thereof.

The aluminum-based coagulant is, for example, aluminum sulfate (Alum), poly aluminum chloride, etc., and the iron salt-based coagulant is ferric chloride (FeCl ₃ ), ferrous chloride (FeCl ₂ ), sulfuric acid. Ferric sulfate (Fe ₂ (SO ₄ ) ₃ ), ferrous sulfate (Fe(SO) ₄ ), polyferric chloride (PFC), polyferric sulfate (PFS), polyferric silicate ( polysilicate iron) and the like, and in the present invention, the aluminum-based coagulant and the iron salt-based coagulant are not limited to the above examples. In addition, these mixed coagulants refer to coagulants having both aluminum-based and iron salt-based compounds, and for example, polyaluminum iron chloride, aluminum iron, polychlorinated aluminum iron sulfate, and the like.

In one aspect of the present invention, the inorganic coagulant of step b2) is aluminum chloride, aluminum sulfate, polyaluminum sulfate, polyaluminum chloride, polyaluminum silicate, polyaluminum chloride silicate, polyhydroxychlorinated aluminum silicate, polysilicic acid polysulfate and It is at least one selected from the group consisting of polyhydroxychlorinated aluminum sulfate.

In one aspect of the present invention, the inorganic coagulant in step b2) may have an aluminum oxide content of 5 to 15% based on the total weight. In a specific aspect of the present invention, the inorganic coagulant of step b2) may use an aluminum-based coagulant, and the content of aluminum oxide may be 8 to 12%.

In one aspect of the present invention, in step b2), the organic coagulant is polyacrylamide-based, polyvinylamine-based, polyallylamine-based, polyethyleneamine-based, polyamine-based, polyacrylic ester-based, polyethyleneimine-based, polydead film and at least one selected from the group consisting of a mixed coagulant thereof.

In one aspect of the present invention, in the method for reducing aluminum, the residual aluminum is 40 to 80% compared to the case where the coagulant is not added. In addition, in the aluminum reduction method, the residual aluminum is 40 to 90% compared to the case in which the conventional coagulant is added. In addition, more specifically, in the reduction method, the aluminum concentration may be less than 90%, less than 85%, less than 80%, or less than 78% compared to the case of administering sulfuric acid or hydrochloric acid alone. In addition, more specifically, the reduction method includes sulfuric acid or hydrochloric acid, and compared to a coagulant containing aluminum oxide, the aluminum concentration may be less than 98%, 96%, 95%, 94%, 93%, 92%.

In one aspect of the present invention, in the aluminum reduction method, the aluminum concentration after treatment is 0.2 mg/l or less. In a specific aspect of the present invention, the aluminum reduction method is 0.19 mg/l or less, more specifically, 0.18 mg/l or less, 0.17 mg/l or less, 0.16 mg/l or less, 0.15 mg/l or less. In a more specific aspect of the present invention, the aluminum reduction method is 0.14 mg/l or less, 0.13 mg/l or less, 0.12 mg/l or less, 0.11 mg/l or less, 0.10 mg/l or less.

In one aspect of the present invention, the pH of the treated water after the aluminum reduction method treatment is 6 to 8. In addition, in the aluminum reduction method, the pH of the treated water after treatment is 6.5 to 7.5.

In one aspect of the present invention, in the aluminum reduction method, the coagulant may be added at 10 to 100 ppm, more specifically 10 to 70 ppm.

In addition, the aluminum reduction method in the present invention may be used in a water purification plant.

In addition, the present invention is a) sulfuric acid or aluminum sulfate-based composition; hydrochloric acid or hydrochloric acid-based composition; aluminum hydroxide; And a coagulant is prepared by mixing two or more selected from the group consisting of water, but 0.5 to 35 wt% of hydrochloric acid, 0.5 to 35 wt% of sulfuric acid, 0.5 to 15 wt% of aluminum hydroxide, and 35 to 80 wt% of water based on the total weight of the coagulant preparing a coagulant; and

b1) adding the coagulant obtained in step a) alone;

b2) adding the coagulant obtained in step a) in combination with one or more coagulants selected from the group consisting of inorganic coagulants and organic coagulants; relates to a method for adjusting pH.

Hereinafter, the present invention will be described in detail by way of Examples and Experimental Examples.

However, the following Examples and Experimental Examples are merely illustrative of the present invention, and the content of the present invention is not limited to the following Examples and Experimental Examples.

<1-1> Preparation of aluminum reducing coagulant (1)

A mixture of 0.5 to 12% by weight of aluminum hydroxide (Al(OH) ₃ ), which is 63% of aluminum oxide based on the weight of the final coagulant, and water was transferred to the reactor. After that, 35% hydrochloric acid and 98% sulfuric acid were added to the mixture in an amount of 10 to 35% by weight based on the weight of the coagulant, and the mixture was reacted at a temperature of 30 to 150° C. for 30 to 100 minutes. Specifically, the amounts of aluminum hydroxide, hydrochloric acid, sulfuric acid and water used in the preparation are as shown in Tables 1 and 2.

After collecting the reactants, sulfuric acid, hydrochloric acid and aluminum hydroxide were added according to the pH, and when the pH adjustment was completed, 30 to 45 wt% of water was added to adjust the concentration, and then filtered to prepare a coagulant. At this time, according to the amount of water to be added, the properties of the coagulant were prepared as shown in Tables 3 to 8 below.

<1-2> Preparation of aluminum reducing coagulant (2)

Prepared by the same method as <1-1>, but the reactants used are AlCO-C (Al ₂ O ₃ 1 to 5%, Cl ^- 29 to 30%) and AlCO-S (Al ₂ O ₃ 1 to 5%) , SO ₄ ² - 17 to 36%) was prepared by mixing.

Example 1 Example 2 Example 3 Product properties Al ₂ O ₃ (%) 5 One 3 SO ₄ ^2- (%) 30 0.5 33 Cl ^- (%) 5 29 One composition ratio division Concentration used composition ratio Concentration used composition ratio Concentration used composition ratio aluminum hydroxide 63% 7.94 55% 1.82 40% 7.50 Hydrochloric acid 35% 14.69 35% 82.19 17% 6.05 sulfuric acid 98% 31.25 45% 1.13 80% 42.11 water - 46.13 - 14.86 - 44.34

Example 4 Example 5 Example 6 Product properties Al ₂ O ₃ (%) One 5 One SO ₄ ^2- (%) 33 5 20 Cl ^- (%) One 27 15 composition ratio division Concentration used composition ratio Concentration used composition ratio Concentration used composition ratio aluminum hydroxide 25% 4.00 67% 7.46 35% 2.86 Hydrochloric acid 10% 10.28 34% 81.65 30% 51.41 sulfuric acid 75% 44.92 50% 10.21 60% 34.03 water - 40.80 - 0.68 - 11.7

Example 7 Example 8 Example 9 Product properties Al ₂ O ₃ (%) 0.5 3 0.5 SO ₄ ^2- (%) 0.5 5 30 Cl ^- (%) 29 27 5 composition ratio division Concentration used composition ratio Concentration used composition ratio Concentration used composition ratio aluminum hydroxide 10% 5.00 60% 5.00 30% 1.67 Hydrochloric acid 35% 85.19 35% 79.32 20% 25.71 sulfuric acid 10% 5.11 35% 12.76 75% 40.83 water - 4.7 - 2.92 - 31.79

Example 10 Example 11 Example 12 Example 13 Product properties Al ₂ O ₃ (%) 5 4 0.5 One SO ₄ ^2- (%) 20 6 18 0.5 Cl ^- (%) 0.5 5 3 10 composition ratio division Concentration used composition ratio Concentration used composition ratio Concentration used composition ratio Concentration used composition ratio aluminum hydroxide 67% 7.46 65% 6.15 One% 50.00 60% 1.67 Hydrochloric acid One% 51.41 25% 20.56 30% 10.28 35% 29.38 sulfuric acid 80% 25.52 30% 20.42 55% 33.41 One% 51.04 water - 15.61 - 52.87 - 6.31 - 17.92

Example 14 Example 15 Example 16 Example 17 Product properties Al ₂ O ₃ (%) 5 5 One One SO ₄ ^2- (%) 0 35 0 30 Cl ^- (%) 30 0 30 0 composition ratio division Concentration used composition ratio Concentration used composition ratio Concentration used composition ratio Concentration used composition ratio aluminum hydroxide 60% 8.33 50% 10.00 60% 1.67 40% 2.50 Hydrochloric acid 35% 88.13 - 0 33% 93.47 - 0 sulfuric acid - 0 50% 71.46 - 0 40% 76.56 water - 3.54 - 18.54 - 4.86 - 20.94

Example 18 Example 19 Example 20 Example 21 Product properties Al ₂ O ₃ (%) 3 One 5 One SO ₄ ^2- (%) 34 34 0 35 Cl ^- (%) 0 0 29 0 composition ratio division Concentration used composition ratio Concentration used composition ratio Concentration used composition ratio Concentration used composition ratio aluminum hydroxide 45% 6.67 5% 20.00 65% 7.69 50% 2.00 Hydrochloric acid - 0 - 0 35% 85.19 - 0 sulfuric acid 90% 38.56 95% 36.54 - 0 70% 51.04 water - 54.77 - 43.46 - 7.12 - 46.96

Example 22 Example 23 Example 24 Product properties Al ₂ O ₃ (%) 0.5 3 0.5 SO ₄ ^2- (%) 0 0 35 Cl ^- (%) 30 30 0 composition ratio division Concentration used composition ratio Concentration used composition ratio Concentration used composition ratio aluminum hydroxide 55% 0.91 50% 6.00 One% 50.00 Hydrochloric acid 34% 90.72 35% 88.13 - 0 sulfuric acid - 0 - 0 90% 39.70 water - 8.37 - 5.87 - 10.30

Example 25 Example 26 Example 27 Example 28 Product properties Al ₂ O ₃ (%) 5 4 0.5 One SO ₄ ^2- (%) 20 0 20 0 Cl ^- (%) 0 11 0 20 composition ratio division Concentration used composition ratio Concentration used composition ratio Concentration used composition ratio Concentration used composition ratio aluminum hydroxide 30% 16.67 67% 5.97 One% 50.00 30% 3.33 Hydrochloric acid - 0 15% 75.40 - 0 35% 58.75 sulfuric acid 30% 68.06 - 0 60% 34.03 - 0 water - 15.28 - 18.63 - 15.97 - 37.91

<Experimental Example 1> Residual aluminum reduction effect of coagulant

The aluminum reduction coagulant prepared in Example 1 was collected from water from the A purification plant, and a coagulation experiment using Jar-test was performed. The properties of the raw water used in the coagulation experiment, the amount of coagulant input, and the input results are as shown in Table 3.

Example 1 Example 1-1 Example 14 Example 15 sulfuric acid 9%
PAC 10ppm Dosage (ppm) 25 25 25 25 80 pH 7.02 7.01 7.10 7.02 7.06 Turbidity (NTU) 0.612 0.613 0.816 0.801 0.815 Al (mg/l) 0.017 0.016 0.019 0.019 0.154 note - Raw water phase: pH 8.51, turbidity 1.96NTU, Al 0.027mg/l
- Example 1-1 was prepared by the manufacturing method of <1-2>, and the properties of the coagulant were the same.
→ Manufacturing method: Prepared by mixing 17 g of AlCO-C (Al ₂ O ₃ 5%, Cl ^- 30%) and 83 g of AlCO-S (Al ₂ O ₃ 5%, SO ₄ ^2- 36%).
- AlCO-C : Al ₂ O ₃ 5%, Cl ^- 30%
- AlCO-S : Al ₂ O ₃ 5%, SO ₄ ^2- 35%

With respect to Table 9, the results of using 9% sulfuric acid and PAC to reduce aluminum using 9% sulfuric acid and PAC, which are currently used for aluminum reduction in water purification plants, are experimental results compared with the examples of the present invention. As shown in the results of Table 9, when the coagulant prepared according to Example 1 was added alone, despite the addition of a smaller amount than that used by mixing 9% sulfuric acid and PAC, the residual aluminum was significantly less It was confirmed that when 9% sulfuric acid and PAC were used, turbidity removal was similar to Example 14 or Example 15, but the residual aluminum showed a result of eluting residual aluminum compared to raw water, but the present invention is more removed than raw water was confirmed. In addition, it was confirmed that the coagulant of the present invention containing both hydrochloric acid and sulfuric acid exhibits the same aluminum properties, but the aluminum removal effect is superior to that of Example 14 or Example 15 containing hydrochloric acid or sulfuric acid alone.

<Experimental Example 2> Residual aluminum reduction effect when coagulant is used in combination

The hydrochloric acid-based coagulant prepared by the method of Example 1 was collected in water from the water purification plant B, and a coagulation experiment using Jar-test was performed. The effect of reducing residual aluminum was confirmed by using it in combination with an aluminum-based coagulant, and the properties of raw water used in the coagulation experiment, properties of the coagulant, the amount of coagulant input, and the input results are shown in Tables 10 to 12.

Example 2 Example 2-1 Example 16 Example 17 sulfuric acid 9% not input Dosage (ppm) 20 20 20 20 75 - flocculant High alkalinity aluminum coagulant Dosage (ppm) 13 pH 7.11 7.08 7.13 7.10 7.12 7.93 Turbidity (NTU) 0.221 0.223 0.263 0.261 0.381 0.633 Al (mg/L) 0.094 0.096 0.102 0.099 0.163 0.192 note - Raw water phase: pH 8.22, turbidity 2.11NTU, Al 0.021mg/l
- Example 2-1 was prepared by the manufacturing method of <1-2>, and the properties of the coagulant were the same.
→ Manufacturing method: Prepared by mixing 97 g of AlCO-C (Al ₂ O ₃ 1%, Cl ^- 30%) and 3 g of AlCO ^- S (Al ₂ O ₃ 1%, SO ₄ 2-17%).
- High basicity aluminum coagulant : Al ₂ O ₃ 10.5% Basicity 70%

Example 3 Example 3-1 Example 18 sulfuric acid 9% not input Dosage (ppm) 15 15 15 70 - flocculant aluminum sulfate Dosage (ppm) 20 pH 7.03 7.04 7.03 7.05 7.79 Turbidity (NTU) 0.341 0.340 0.386 0.488 0.891 Al (mg/L) 0.101 0.103 0.102 0.178 0.221 note - Raw water phase: pH 8.21, turbidity 2.22NTU, Al 0.021mg/l
- Example 3-1 was prepared by the manufacturing method of <1-2>, and the properties of the coagulant were the same.
→ Manufacturing method: Manufactured by mixing 3 g of AlCO-C (Al ₂ O ₃ 3%, Cl ^- 30%) and 97 g of AlCO-S (Al ₂ O ₃ 3%, SO ₄ ² - 34.5%).
- Aluminum sulfate: Al ₂ O ₃ 8%

Example 4 Example 4-1 Example 19 sulfuric acid 9% not input Dosage (ppm) 20 20 20 70 - flocculant Low basicity aluminum-based coagulant Dosage (ppm) 13 pH 7.01 7.02 7.02 7.05 8.02 Turbidity (NTU) 0.303 0.300 0.338 0.446 0.746 Al (mg/l) 0.096 0.098 0.103 0.181 0.235 note - Raw water phase: pH 8.32, turbidity 2.36NTU, Al 0.022mg/l
- Example 4-1 was prepared by the manufacturing method of <1-2>, and the properties of the coagulant were the same.
→ Manufacturing method: Manufactured by mixing 3 g of AlCO-C (Al ₂ O ₃ 1%, Cl ^- 30%) and 97 g of AlCO-S (Al ₂ O ₃ 1%, SO ₄ ² - 34.5%).
- Low basicity aluminum coagulant : Al ₂ O ₃ 11.5% Basicity 15%

As shown in Table 10, when the coagulant prepared according to Example 1 was used in combination with a high alkalinity aluminum-based coagulant, it was confirmed that, despite the addition of less than 9% sulfuric acid, the residual aluminum was significantly reduced. In addition, it was confirmed that the coagulant of the present invention containing both hydrochloric acid and sulfuric acid showed the same aluminum properties, but the aluminum removal effect was superior to that of Example 16 or Example 17 containing hydrochloric acid or sulfuric acid alone.

In addition, as shown in Tables 11 and 12, even when the coagulant of the present invention is used in combination with aluminum sulfate or a low-base aluminum-based coagulant, it was confirmed that the aluminum removal effect was excellent despite a small amount of the coagulant.

In the case of Tables 10 to 12, it is an experimental result confirming the aluminum removal effect when used in combination with a generally used aluminum-based coagulant. When used in combination with an aluminum coagulant, residual aluminum is 0.192, 0.221, and 0.235 mg/l (not added), respectively, which sometimes exceeds 0.2 mg/l of the discharge standard. As shown in Tables 10 to 12, even when used in combination with 9% sulfuric acid, the aluminum results were lower than 0.163, 0.178, and 0.181 mg/l, and higher than 0.15 mg/l. (In general, aluminum concentration is operated at 0.15 mg/l or less due to concerns about effluent quality accidents.) On the other hand, when treated with the coagulant of the present invention, aluminum results of 0.15 mg/l or less are obtained, indicating that the aluminum reduction effect is excellent. Confirmed.

<Experimental Example 3> Residual aluminum reduction effect of coagulant containing additives

An additive (polyvinylamine as an organic coagulant) was further included in the coagulant prepared by the method of Example 1, and water was collected from the C water purification plant and an agglomeration experiment using Jar-test was performed. The properties of raw water used in the coagulation experiment, properties of the coagulant, the amount of coagulant input, and the input results are as shown in Table 13.

Example 5 Example 5-P Example 20 sulfuric acid 9%
PAC 10ppm Dosage (ppm) 25 25 25 80 pH 7.02 7.05 7.08 7.07 Turbidity (NTU) 0.721 0.511 0.911 0.908 Al (mg/l) 0.019 0.017 0.020 0.165 note - Raw water phase: pH 8.51, turbidity 2.35NTU, Al 0.025mg/l
- Example 5-P added 3% by weight of polyamine to Example 5

As shown in Table 13, it was confirmed that, despite the addition of less than 9% sulfuric acid in the coagulant prepared according to Example 1 and the coagulant containing the additive in Example 1, the amount of residual aluminum was significantly reduced. In addition, Example 20, wherein the coagulant of the present invention containing both hydrochloric acid and sulfuric acid shows the same aluminum properties, but contains hydrochloric acid or sulfuric acid alone It was confirmed that the aluminum removal effect was more excellent. When 9% sulfuric acid and 10 ppm of PAC were added, turbidity was similar to that of Example 20, but it was confirmed that aluminum appeared to be about 5 times higher than 0.025 mg/l of raw water. In addition, when 9% sulfuric acid and 10 ppm of PAC were used, the result was higher than 0.1 mg/l, but on the contrary, it was confirmed that the aluminum result was 0.1 mg/l or less when treated with the coagulant of the present invention. .

<Experimental Example 4> Residual aluminum reduction effect when used in combination with a coagulant containing additional additives

By further including an additive (Group 2A, Group 3A, Group 3B, Group 4A, Group 4B material and/or a poly-dead membrane) in the coagulant prepared by the method of Example 1, the water of the D water purification plant was collected and Jar-test An aggregation experiment using The properties of the raw water used in the coagulation experiment, the properties of the coagulant, the amount of coagulant input, and the input results are as shown in Tables 14 to 16.

Example 6 Example 6-2A Example 6-3A Example 21 sulfuric acid 9%
PAC 10ppm Dosage (ppm) 20 20 20 20 80 flocculant High alkalinity aluminum-based coagulant Dosage (ppm) 13 pH 7.08 7.07 7.08 7.04 7.09 Turbidity (NTU) 0.233 0.228 0.227 0.283 0.281 Al (mg/l) 0.095 0.090 0.089 0.099 0.186 note - Raw water phase: pH 8.33, turbidity 3.21NTU, Al 0.027mg/l
- Example 6-2A: 0.5% by weight of the group 2A material (CaCl ₂ ) was added to Example 6
- Example 6-3A: 0.5% by weight of the group 3A material (Ga ₂ (SO ₄ ) ₃ ) in Example 6 was added
- High basicity aluminum coagulant : Al ₂ O ₃ 10.5% Basicity 70%

Example 7 Example 7-4A Example 7-4B Example 22 sulfuric acid 9%
PAC 10ppm Dosage (ppm) 20 20 20 20 75 flocculant High alkalinity aluminum-based coagulant Dosage (ppm) 13 pH 7.10 7.09 7.08 7.07 7.11 Turbidity (NTU) 0.246 0.232 0.231 0.291 0.465 Al (mg/l) 0.101 0.091 0.091 0.112 0.214 note - Raw water phase: pH 8.18, turbidity 4.21NTU, Al 0.025mg/l
- Example 7-4A: 0.5% by weight of the group 4A material (Na ₂ SiO ₃ ) in Example 7 was added
- Example 7-4B: 0.5% by weight of the group 4B material (ZrCl ₄ ) was added to Example 7
- High basicity aluminum coagulant : Al ₂ O ₃ 10.5% Basicity 70%

Example 8 Example 8-3A-P Example 8-3B-P Example 23 sulfuric acid 9%
PAC10ppm Dosage (ppm) 20 20 20 20 75 pH 7.08 7.07 7.08 7.10 7.06 Turbidity (NTU) 0.911 0.900 0.904 1.21 2.08 Al (mg/l) 0.020 0.018 0.018 0.023 0.157 note - Raw water phase: pH 8.31, turbidity 2.11NTU, Al 0.029mg/l
- Example 8-3A-P: 0.5% parts by weight of a group 3A material (Ga ₂ (SO ₄ ) ₃ ) and 3% parts by weight of a polyDADMAC in Example 8
- Example 8-3B-P: 0.5% parts by weight of a group 3B material (YCl ₃ ) and 3% by weight of a polyDADMAC (PolyDADMAC) were added in Example 8

As shown in Table 14, when the coagulant prepared according to Example 1 and the coagulant further containing additives were used in combination with the high-base aluminum-based coagulant, the aluminum residual was significantly reduced despite the addition of less than 9% sulfuric acid. It was confirmed that it appeared to be less. In addition, it was confirmed that the present invention flocculant containing both hydrochloric acid and sulfuric acid and the present invention flocculant containing additional additives exhibited the same aluminum properties, but had better aluminum removal effect than Example 21 containing sulfuric acid alone.

In addition, as shown in Table 15, when the flocculant prepared according to Example 1 and the coagulant further containing additives were used in combination with the high-base aluminum-based coagulant, despite the addition of less than 9% sulfuric acid, residual aluminum It was confirmed that this was significantly reduced. In addition, the present invention flocculant containing both hydrochloric acid and sulfuric acid and the present invention flocculant containing further additives exhibit the same aluminum properties, but in Example 22 containing hydrochloric acid alone It was confirmed that the aluminum removal effect was more excellent.

In addition, as shown in Table 16, it was confirmed that the aluminum removal effect was excellent even when the present invention coagulant and the present invention coagulant further containing additives were used alone.

In addition, when 9% sulfuric acid and 10 ppm of PAC were used, both results were higher than 0.15 mg/l, but on the contrary, it was confirmed that aluminum results of 0.15 mg/l or less were obtained when treated with the coagulant of the present invention. did.

<Experimental Example 5> Residual aluminum reduction effect when used in combination with a coagulant containing additional additives

An additive (group 3B, group 4A material) was further included in the coagulant prepared by the method of Example 1, and water was collected from the E water purification plant, and an agglomeration experiment using Jar-test was performed. The properties of raw water used in the coagulation experiment, properties of the coagulant, the amount of coagulant input, and the input results are as shown in Table 17.

Example 9 Example 9-3B Example 9-4A Example 24 sulfuric acid 9% not input Dosage (ppm) 20 20 20 20 75 - flocculant polyaluminum chloride Dosage (ppm) 13 polymer Polyvinylamine Dosage (ppm) 3 pH 7.05 7.08 7.09 7.06 7.07 8.30 Turbidity (NTU) 0.317 0.298 0.297 0.483 0.689 0.821 Al (mg/l) 0.088 0.086 0.085 0.093 0.176 0.228 note - Raw water phase: pH 8.44, turbidity 2.51NTU, Al 0.023mg/l
- Example 9-3B: 0.5% parts by weight of the group 3B material (YCl ₃ ) was added to Example 9
- Example 9-4A: 0.5% by weight of the group 4A material (Na ₂ SiO ₃ ) was added to Example 9

As shown in Table 17, when the coagulant further containing the coagulant and additives prepared in Example 1 is used in combination with the aluminum-based coagulant as well as the organic coagulant, despite the addition of less than 9% sulfuric acid, the residual It was confirmed that significantly less aluminum appeared. In addition, it was confirmed that the present invention flocculant containing both hydrochloric acid and sulfuric acid and the present invention flocculant containing additional additives exhibited the same aluminum properties, but had superior aluminum removal effect than Example 24 containing sulfuric acid alone.

In addition, when 9% sulfuric acid was used, the result was higher than 0.15 mg/l, but on the contrary, it was confirmed that the aluminum result was 0.15 mg/l or less when treated with the coagulant of the present invention.

<Experimental Example 6> Residual aluminum reduction effect of coagulant (single input)

The aluminum-reducing coagulant prepared in Example 1 was collected in water from the E water purification plant, and a coagulation experiment using Jar-test was performed. The properties of the raw water used in the coagulation experiment, the amount of coagulant input, and the input results are as shown in Table 18.

Example 10 Example 10-1 Example 25 sulfuric acid 9%
PAC10ppm Dosage (ppm) 45 45 45 80 pH 7.01 6.98 7.00 7.07 Turbidity (NTU) 0.498 0.502 0.661 0.674 Al (mg/l) 0.021 0.020 0.023 0.178 note - Raw water phase: pH 9.11, turbidity 3.28NTU, Al 0.033mg/l
- Example 10-1 was prepared by the manufacturing method of <1-2>, and the properties of the coagulant were the same.
→ Manufacturing method: Prepared by mixing 4.8 g of AlCO-C (Al ₂ O ₃ 5%, Cl ^- 10.5%) and 95.2 g of AlCO-S (Al ₂ O ₃ 5%, SO ₄ ^2- 21%).

As shown in Table 18, when the coagulant prepared according to Example 1 was added alone, it was confirmed that the aluminum removal effect was superior to that in which 9% of sulfuric acid was included.

In addition, when 9% sulfuric acid and 10 ppm of PAC were used, the result was higher than 0.1 mg/l, but, on the contrary, it was confirmed that the aluminum result was 0.1 mg/l or less when treated with the coagulant of the present invention. .

<Experimental Example 7> Residual aluminum reduction effect of coagulant (single input)

The aluminum-reducing coagulant prepared in Example 1 was collected in water from the E water purification plant, and a coagulation experiment using Jar-test was performed. The properties of the raw water used in the coagulation experiment, the amount of coagulant input, and the input results are as shown in Table 19.

Example 11 Example 11-1 Example 26 sulfuric acid 9%
PAC10ppm Dosage (ppm) 70 70 70 85 pH 7.00 7.02 7.02 7.05 Turbidity (NTU) 0.312 0.336 0.558 0.555 Al (mg/l) 0.022 0.024 0.025 0.176 note - Raw water phase: pH 9.22, turbidity 3.09NTU, Al 0.038mg/l
- Example 11-1 was prepared by the manufacturing method of <1-2>, and the properties of the coagulant were the same.
→ Manufacturing method: Prepared by mixing 40 g of AlCO-C (Al ₂ O ₃ 4%, Cl ^- 12.5%) and 60 g of AlCO ^- S (Al ₂ O ₃ 4%, SO ₄ 2-10%).

As shown in Table 18, even when the pH of the raw water exceeds 9, when the coagulant prepared according to Example 1 was added alone, it was confirmed that the aluminum removal effect was superior to that in which 9% of sulfuric acid was included.

In addition, when 9% sulfuric acid and 10 ppm of PAC were used, the results were higher than 0.1 mg/l, but, on the contrary, it was confirmed that the aluminum results were 0.1 mg/l or less when treated with the coagulant of the present invention.

<Experimental Example 8> Residual aluminum reduction effect of coagulant (injection in combination)

The aluminum-reducing coagulant prepared in Example 1 was collected in water from the F water purification plant, and a coagulation experiment using Jar-test was performed. The properties of the raw water used in the coagulation experiment, the amount of coagulant input, and the input results are shown in Table 20.

Example 12 Example 12-1 Example 27 sulfuric acid 9% not input Dosage (ppm) 40 40 40 80 - flocculant High alkalinity aluminum coagulant Dosage (ppm) 13 pH 7.05 7.03 7.02 7.07 8.16 Turbidity (NTU) 0.231 0.230 0.271 0.277 0.274 Al (mg/l) 0.093 0.095 0.102 0.175 0.212 note - Raw water phase: pH 9.07, turbidity 3.51NTU, Al 0.025mg/l
- Example 12-1 was prepared by the manufacturing method of <1-2>, and the properties of the coagulant were the same.
→ Manufacturing method: Prepared by mixing 25 g of AlCO-C (Al ₂ O ₃ 0.5%, Cl ^- 12%) and 75 g of AlCO-S (Al ₂ O ₃ 0.5%, SO ₄ ^2- 24%).
- High basicity aluminum-based coagulant: Al ₂ O ₃ 10.5% Basicity 70%

As shown in Table 18, even when the pH of the raw water exceeds 9, when the coagulant prepared according to Example 1 was co-injected, it was confirmed that the aluminum removal effect was superior to that in which 9% of sulfuric acid was included.

In addition, when 9% sulfuric acid was used, the result was higher than 0.15 mg/l, but on the contrary, it was confirmed that the aluminum result was 0.15 mg/l or less when treated with the coagulant of the present invention.

<Experimental Example 9> Residual aluminum reduction effect of coagulant (combined input)

The aluminum-reducing coagulant prepared in Example 1 was collected in water from the F water purification plant, and a coagulation experiment using Jar-test was performed. The properties of the raw water used in the coagulation experiment, the amount of coagulant input, and the input results are as shown in Table 21.

Example 13 Example 13-1 Example 28 sulfuric acid 9% not input Dosage (ppm) 65 65 65 78 - flocculant aluminum sulfate Dosage (ppm) 20 pH 7.03 7.01 7.03 7.06 7.96 Turbidity (NTU) 0.316 0.318 0.351 0.492 0.912 Al (mg/l) 0.082 0.081 0.088 0.189 0.225 note - Raw water phase: pH 9.32, turbidity 3.42NTU, Al 0.026mg/l
- Example 13-1 was prepared by the manufacturing method of <1-2>, and the properties of the coagulant were the same.
→ Manufacturing method: Prepared by mixing 95.2 g of AlCO-C (Al ₂ O ₃ 1%, Cl ^- 10.5%) and 4.8 g of AlCO-S (Al ₂ O ₃ 1%, SO ₄ ² - 10.4%).
- High alkalinity aluminum-based coagulant: Al ₂ O ₃ 8%

As shown in Table 18, even when the pH of the raw water exceeds 9, when the coagulant prepared according to Example 1 was co-injected, it was confirmed that the aluminum removal effect was superior to that in which 9% of sulfuric acid was included.

In addition, when 9% sulfuric acid was used, the result was higher than 0.15 mg/l, but on the contrary, it was confirmed that the aluminum result was 0.15 mg/l or less when treated with the coagulant of the present invention.

Claims (21)

In a system for reducing aluminum in the sewage treatment process of a water purification plant,
an aluminum-based flocculant storage tank in the system;
Sulfuric acid, hydrochloric acid, or aluminum-based coagulant injection piping;
water storage and supply tanks;
a reactor in which the reactants are stirred;
Including a flocculating unit for receiving a coagulant and coagulating with wastewater
It includes a reaction unit for reacting aluminum hydroxide, sulfuric acid, hydrochloric acid, aluminum sulfate or aluminum hydrochloride in the reaction tank at 20 to 200 ℃,
Aluminum reduction system, characterized in that 10 to 100 ppm of the coagulant is added in the agglomeration part to reduce the aluminum to 0.15 mg/l or less.
A) A1) sulfuric acid; aluminum hydroxide; and water to prepare a coagulant; A2) an aluminum sulfate-based composition; aluminum hydroxide; And preparing a coagulant by mixing water, 5 to 35% by weight of sulfuric acid, 0.5 to 7% by weight of aluminum hydroxide, and 35 to 80% by weight of water relative to the total weight of the flocculant to prepare a flocculant; and
b) b1) the coagulant obtained in step a) is added alone; b2) adding the coagulant obtained in step a) in combination with at least one coagulant selected from the group consisting of inorganic coagulants and organic coagulants;
After the step b), the aluminum concentration is 0.15 mg / l or less, the aluminum reduction method in the water purification plant.
c) c1) hydrochloric acid; aluminum hydroxide; and water to prepare a coagulant; C2) an aluminum hydrochloride-based composition; aluminum hydroxide; and water to prepare a coagulant, but 5 to 35% by weight of hydrochloric acid, 0.5 to 7% by weight of aluminum hydroxide, and 35 to 80% by weight of water relative to the total weight of the flocculant to prepare a flocculant; and
d) d1) adding the coagulant obtained in step c) alone; d) adding the coagulant obtained in step c) in combination with at least one coagulant selected from the group consisting of inorganic coagulants and organic coagulants;
After the step d), the aluminum concentration is 0.15 mg / l or less, the aluminum reduction method in the water purification plant.
a) a sulfuric acid or aluminum sulfate-based composition; hydrochloric acid or hydrochloric acid-based composition; aluminum hydroxide; And a coagulant is prepared by mixing two or more selected from the group consisting of water, but 0.5 to 35 wt% of hydrochloric acid, 0.5 to 35 wt% of sulfuric acid, 0.5 to 15 wt% of aluminum hydroxide, and 35 to 80 wt% of water based on the total weight of the coagulant preparing a coagulant; and
b1) adding the coagulant obtained in step a) alone;
b2) adding the coagulant obtained in step a) in combination with at least one coagulant selected from the group consisting of an inorganic coagulant and an organic coagulant;
5. The method of claim 4,
The aluminum hydroxide of step a) is aluminum oxide 1 to 80%, aluminum reduction method.
5. The method of claim 4,
The aluminum hydroxide of step a) is to mix 0.5 to 12% by weight based on the total weight of the coagulant, aluminum reduction method.
5. The method of claim 4,
The aluminum sulfate-based composition of step a) includes an aluminum oxide concentration of 0.5 to 7% by weight, a sulfate ion concentration of 15 to 40% by weight, and the remaining amount of water.
5. The method of claim 4,
The aluminum hydrochloride-based composition of step a) includes an aluminum oxide concentration of 0.5 to 7% by weight, a hydrochloride ion concentration of 25 to 35% by weight, and the remaining amount of water.
5. The method of claim 4,
The coagulant of step a) comprises 0.5 to 8% by weight of aluminum oxide, 10 to 40% by weight of the sum of sulfate ions and hydrochloric acid ions, based on the total weight, aluminum reduction method.
5. The method of claim 4,
The coagulant of step a) comprises 0.5 to 5% by weight of aluminum oxide, 10 to 35% by weight of sulfate ions and hydrochloric acid ions, based on the total weight, aluminum reduction method.
5. The method of claim 4,
The coagulant of step a) is sulfide, chloride, silicate, oxide; And one or more compounds selected from the group consisting of salts thereof, the aluminum reduction method.
5. The method of claim 4,
The coagulant of step a) further comprises at least one compound selected from the group consisting of a group 2A compound, a group 3A compound, a group 4A compound, a group 3B compound, a group 4B compound, and salts thereof.
5. The method of claim 4,
The coagulant of step a) is one selected from the group consisting of Group 2A chloride, Group 2A sulfide, Group 3B chloride, Group 3B sulfide, Group 4B chloride, Group 4B sulfide, sodium silicate (Na ₂ SiO ₃ ) and salts thereof. The method for reducing aluminum, further comprising the above compounds.
5. The method of claim 4,
The coagulant of step a) is calcium chloride (CaCl ₂ ), gallium sulfate (Ga ₂ (SO ₄ ) ₃ ), sodium silicate (Na ₂ SiO ₃ ), zirconium chloride (ZrCl ₄ ), yttrium chloride (YCl ₄ ), and their The method for reducing aluminum, further comprising one or more compounds selected from the group consisting of salts.
5. The method of claim 4,
The inorganic coagulant of step b2) is an aluminum-based coagulant, an iron salt-based coagulant, or a mixed coagulant thereof.
5. The method of claim 4,
In step b2), the inorganic coagulant is composed of aluminum chloride, aluminum sulfate, polyaluminum sulfate, polyaluminum chloride, polyaluminum silicate polysulfate, polyaluminum chloride silicate, aluminum polyhydroxychloride silicate, aluminum polysulfate aluminum silicate and polyhydroxychlorinated aluminum sulfate. At least one selected from the group, aluminum reduction method.
5. The method of claim 4,
In step b2), the organic coagulant is composed of polyacrylamide-based, polyvinylamine-based, polyallylamine-based, polyethyleneamine-based, polyamine-based, polyacrylic ester-based, polyethyleneimine-based, polydead film, and mixed coagulants thereof. At least one selected from the group, aluminum reduction method.
5. The method of claim 4,
The aluminum reduction method is an aluminum reduction method, characterized in that the residual aluminum is 40 to 80% compared to the case where the coagulant is not added.
5. The method of claim 4,
The aluminum reduction method is an aluminum reduction method, characterized in that the aluminum concentration is 0.2 mg / l or less after treatment.
5. The method of claim 4,
After the aluminum reduction method treatment, the pH of the treated water is 6 to 8, the aluminum reduction method.
a) a sulfuric acid or aluminum sulfate-based composition; hydrochloric acid or hydrochloric acid-based composition; aluminum hydroxide; And a coagulant is prepared by mixing two or more selected from the group consisting of water, but 0.5 to 35 wt% of hydrochloric acid, 0.5 to 35 wt% of sulfuric acid, 0.5 to 15 wt% of aluminum hydroxide, and 35 to 80 wt% of water based on the total weight of the coagulant preparing a coagulant; and
b1) adding the coagulant obtained in step a) alone;
b2) adding the coagulant obtained in step a) in combination with at least one coagulant selected from the group consisting of inorganic coagulants and organic coagulants; a method for adjusting pH.