KR101032478B1 - Water-treatment cohesive agents and Preparing method thereof - Google Patents

Abstract

The present invention relates to a water treatment flocculant and a method for manufacturing the same, and more specifically, the water treatment flocculant of the present invention comprising poly aluminum calcium chloride (PACCS), stably water treatment In addition to being possible, low alkali is also very suitable for the fluorine treatment present in raw water. In addition, the production method of the present invention is manufactured by passing through the intermediate, the yield of the polyaluminum calcium chloride silicate is not only high, there is a feature that can be manufactured under stable conditions of normal pressure.

Polyaluminum calcium chloride silicate, flocculant

Description

Water-treatment cohesive agents and preparing method

The present invention relates to a water treatment flocculant including polyaluminum calcium silicate and a method for producing the same, and the water treatment flocculant of the present invention is capable of stably treating the water and treating fluorine present in low alkalinity raw water with high efficiency. Is possible. In addition, since the water treatment flocculant is prepared using an intermediate in preparation, not only can be obtained with a high yield, but also can be prepared under stable conditions of normal pressure.

In water treatment, the role of flocculants in physical and chemical treatments is very important. Such flocculants include Al ₂ (SO ₄ ) ₃ · 16H ₂ O or Al ₂ (SO ₄ ) ₃ · 18H ₂ O is mainly used, despite the advantages of relatively inexpensive, there is a disadvantage in that the coagulation effect is low and the alkalinity and pH decrease after the treatment is large. The second generation coagulant, poly aluminum chloride (PAC), is widely used, and recently, poly aluminum sulfate (PAS), poly aluminum sulfate silicate (PASS), poly Flocculants such as poly alumium chloride silicate (PACS) are used. Unlike the first-generation flocculant, the second-generation flocculant has advantages of wide range of coagulation with respect to pH or turbidity, excellent cohesive force, low consumption of alkalinity, and low use amount of flocculent aid unlike the first flocculant. . However, there is a problem in that the basicity is not sufficient enough that the pH adjuster (alkaline) is unnecessary, and degradation may occur.

Accordingly, Korean Patent Application No. 10-1996-30191 discloses an invention for polyaluminum chloride. The known polyaluminum chloride has a high basicity, but is stable in treating wastewater containing fluorine and phosphorus. Has a problem that decreases and the fluorine treatment efficiency is not good, and in the manufacturing method, because the manufacturing in the harsh conditions under a very high pressure of about 12 atm, mass production is not easy due to the problem of the equipment and unsafe have.

Recently, the use of fluorine as a surface treatment and cleaning agent for semiconductors is gradually increasing, and the importance of countermeasures against water pollution caused by fluorine is increasing. In the environment industry, steel industry, semiconductor industry, foshan manufacturing industry, metal processing industry, etc. There is an increasing demand for developing flocculants for effective fluorine treatment.

In order to solve the above problems and problems of the existing flocculant, the present inventors have continuously studied and tried to find that the calcium content should be increased in order to increase the fluorine treatment efficiency of the polyaluminum chloride, which is a water treatment flocculant, In order to maintain the stability of the product, and to introduce a silicate, and to maintain the stability of the flocculant was found to have a high basicity of the polyaluminum calcium chloride silicate with an increased content of calcium and hydroxide ions. It is also an object of the present invention to provide a method for preparing the water treatment flocculant with high yield and economy.

Water treatment flocculant of the present invention for solving the above problems

It is characterized by including a polyaluminum calcium chloride silicate represented by the following formula (1).

Al ₂ Ca _x (OH) _y Cl _z (SiO ₂ ) _i

In Formula 1, x, y, and z are 6 + 2x = yzi, and are real numbers satisfying 1.0 ≦ x ≦ 2.2, 3 ≦ y ≦ 5.1, 3.4 ≦ z ≦ 5.5, and 0.0008 ≦ i ≦ 0.0832.

Moreover, the manufacturing method of the said water treatment flocculant of this invention is

A first step of preparing a mixed solution by mixing and stirring aluminum hydroxide (Al (OH) ₃ ), hydrochloric acid and water;

Reacting the mixed solution at 145 ° C. to 170 ° C. for 2 to 4 hours to prepare a solution containing an intermediate represented by Formula 2 below;

A third step of slowly adding and mixing the calcium silicate solution to the solution containing the intermediate at 50 ° C. to 80 ° C .;

And a fourth step of preparing a polyaluminum calcium chloride silicate represented by the following Chemical Formula 1 by aging the mixed solution of the third step.

[Formula 1]

Al ₂ Ca _x (OH) _y Cl _z (SiO ₂ ) _i

In Formula 1, x, y, and z are 6 + 2x = yzi, and are real numbers satisfying 1.0 ≦ x ≦ 2.2, 3 ≦ y ≦ 5.1, 3.4 ≦ z ≦ 5.5, and 0.0008 ≦ i ≦ 0.0832.

Al ₂ (OH) _{0.5 ~ 1.0} Cl _{5.0 ~ 5.5}

The water treatment flocculant of the present invention is not only capable of stably treating the water, but also capable of treating fluorine present in the low alkalinity raw water with high efficiency, and the water treatment flocculant manufacturing method of the present invention provides a water treatment flocculant to be produced at a high yield. In addition to being able to obtain a low pressure without the installation of the equipment is characterized by an economical and mass production method.

The present invention will be described in detail below.

As a general fluorine treatment method, the most widely used method is calcined lime (calcium hydroxide, Ca (OH) ₂ ) as shown in Chemical Formula 3 below. It is precipitated in the form of calcium fluoride (Calcium fluoride, CaF ₂ ). The slaked lime injected for fluorine removal not only supplies calcium ions but also adjusts the pH at the same time, so that the raw water is suitable when the raw water is acidic. When the reaction pH is increased to 9 or more, since carbon dioxide in the air is present in the form of carbonate in water, calcium ions present in the reaction solution are removed with CaCO ₃ . Therefore, the fluorine removal efficiency is reduced under the condition of pH 9 or more. Therefore, in order to increase the fluorine removal efficiency, there is a need for a method for increasing calcium concentration in wastewater while reducing the pH increase due to the addition of extra lime.

In view of this, the inventor has invented a water treatment flocculant with an increased calcium content.

2F ^- + _{Ca (OH) 2 → CaF 2} + 2OH -

The present invention relates to a water treatment flocculant,

It is characterized by including a polyaluminum calcium chloride silicate represented by the following formula (1).

[Formula 1]

Al ₂ Ca _x (OH) _y Cl _z (SiO ₂ ) _i

In Formula 1, x, y, and z are 6 + 2x = yzi, and are real numbers satisfying 1.0 ≦ x ≦ 2.2, 3 ≦ y ≦ 5.1, 3.4 ≦ z ≦ 5.5, and 0.0008 ≦ i ≦ 0.0832.

In Chemical Formula 1, when the x value is less than 1, a low basicity may cause a decrease in pH and a small amount of calcium ions, which may cause a problem of decreasing water treatment. Can be. In addition, when the y value is less than 3, the basicity may be 50 or less, which may cause a problem in that the pH decreases. When the y value is greater than 5.1, the stability of the product may occur with a basicity of 85% or more. In addition, if the z value is less than 3.4, it may cause stability problems of the product, and if it exceeds 5.5, the residual Cl ⁻ may be high, so that the problem of the effect of equipment corrosion upon water treatment may occur. In addition, when the i value is less than 0.0008, a problem of stability (precipitate generation) of the product may occur, and a problem of stability (precipitate generation) of the product may occur when more than 0.0832.

According to the component analysis, the polyaluminum chloride silicate used in the present invention as a water treatment flocculant is characterized by Al ₂ O ₃ 8 to 12% by weight, Ca 4 to 9.5% by weight, SiO ₂ 0.01 to 2% by weight, Cl 10 to 15% by weight. , And H ₂ O 69 ~ 72.5% by weight is characterized by consisting of a content ratio.

Here, when the Al ₂ O ₃ is less than 8% by weight may cause problems of reduction of fluorine treatment efficiency and economics, and when it exceeds 12% by weight, problems of product stability (precipitate) may occur, and when Ca is less than 4% by weight. The problem of fluorine treatment efficiency may occur, and if it exceeds 9.5 wt%, product stability (precipitate generation) may occur. And when the SiO ₂ is less than 0.01% by weight product stability (precipitate generation) problem may occur, when more than 2% by weight, product stability (precipitate generation) problem occurs, and when the Cl component is less than 10% by weight product stability Problems may arise, and if the amount of residual Cl exceeds 15% by weight, the problem of the effect of equipment corrosion on water treatment may occur. Next, when the H ₂ O component is less than 69% by weight, the Al ₂ O ₃ content is 12% or more, which may cause stability (precipitate generation) problems of the product, and when it exceeds 72.5% by weight, Al ₂ O _{3 is} 8% or less. As the content is reduced, problems of reduced fluorine treatment efficiency and economics may occur.

Since the water treatment flocculant of the present invention has a basicity of 50 to 85%, it is stable and has excellent flocculation effect.

The present invention is very excellent in the removal efficiency of the fluorine present in the raw water, it is characterized in that can remove 70% or more, preferably 70% to 98% fluorine.

Hereinafter, the manufacturing method of the water treatment flocculant of this invention is demonstrated.

The method for producing a water treatment flocculant of the present invention

A first step of preparing a mixed solution by mixing and stirring aluminum hydroxide (Al (OH) ₃ ), hydrochloric acid and water;

A second step of reacting the mixed solution at 145 ° C. to 170 ° C. for 2 to 4 hours to prepare a solution containing an intermediate represented by Formula 2 below;

A third step of adding and mixing the calcium silicate solution to the solution containing the intermediate at 50 ° C. to 80 ° C., followed by reaction;

And a fourth step of preparing a polyaluminum calcium chloride silicate represented by the following Chemical Formula 1 by aging the mixed solution of the third step.

[Formula 1]

Al ₂ Ca _x (OH) _y Cl _z (SiO ₂ ) _i

In Formula 1, x, y, and z are 6 + 2x = yzi, and are real numbers satisfying 1.0 ≦ x ≦ 2.2, 3 ≦ y ≦ 5.1, 3.4 ≦ z ≦ 5.5, and 0.0008 ≦ i ≦ 0.0832.

[Formula 2]

Al ₂ (OH) _{0.5 ~ 1.0} Cl _{5.0 ~ 5.5}

In the intermediate represented by Formula 2, the number of moles of OH is preferably 0.5 to 1.0 and the number of moles of Cl is 5.0 to 5.5. If the number of moles is outside the range of moles, it is difficult to prepare polyaluminum calcium chloride silicate having Formula 1 to be prepared. there is a problem.

In the second step, when preparing a solution containing the intermediate, the mixture of the first step is prepared by reacting for 2 to 4 hours at 145 ℃ ~ 170 ℃, wherein, if the temperature is less than 145 ℃ Al (OH) ₃ There is a problem that can not obtain the intermediate material because it is not completely dissolved, there is a problem that can not be made to the desired intermediate material by polymerizing by increasing the OH increases more than 170 ℃, the intermediate when reacting in less than 2 hours When the yield is lowered and more than 4 hours OH is increased a lot of polymerization may cause a problem that can not produce the desired intermediate, it is preferable to prepare a solution containing the intermediate in the reaction conditions within the above range.

When the mixed solution of the first step is reacted under the above conditions, it is possible to obtain a solution containing _{0.5 to 1.0} Cl _{5.0 to 5.5} of Al ₂ (OH) containing 95 wt% or more.

In the third step, it is preferable to slowly add the calcium silicate solution when adding, and to mix with stirring at high speed. In addition, it is preferable to react with the mixture at a temperature in the range of 50 ℃ to 80 ℃, this time, when the reaction is less than 50 ℃ may occur a problem that takes a long time for aging, the molecular structure is destroyed when it exceeds 80 ℃ Since this may cause a problem of deterioration, it is preferable to mix and react at a temperature within the above range.

The calcium hydroxide solution may be prepared by mixing calcium hydroxide, sodium silicate (Na ₂ SiO ₃ ) and water, using a mixture concentration of calcium hydroxide and sodium silicate contained in the calcium silicate solution 20 to 58.5% by weight Good to do. Here, if the concentration of the mixture of calcium hydroxide and sodium silicate is less than 20% by weight, there is a problem that the x value of the prepared Al ₂ Ca _x (OH) _y Cl _z is less than 1, the problem of stability of the product when the concentration is more than 58.5% by weight Occurs. In addition, the sodium silicate (Na ₂ SiO ₃ ) may be prepared by using a silicon oxide (SiO ₂ ) in a concentration of 10 to 40% by weight, the sodium silicate is 0.05 to the total weight of the polyaluminum calcium chloride silicate Weight percent to 5 weight percent may be used.

The fourth step is a step of ripening the third step reactant, it is preferable to ripen for about 1 to 3 hours. After sufficient aging, the polyaluminum calcium chloride silicate is separated from the solution and dried to obtain the water treatment flocculant of the present invention.

In the third to fourth steps, the calcium hydroxide hydroxide solution and the mixed solution of the second step are reacted as shown in Scheme 1, thereby preparing polyaluminum calcium chloride silicate represented by Chemical Formula 1.

Al ₂ (OH) _a Cl _b + Ca (OH) ₂ + Na ₂ SiO ₃ → Al ₂ Ca _x (OH) _y Cl _z (SiO ₂ ) _i + 2NaCl ↓

A, b, x, y, z and i are the same as a, b, x, y, z and i of Chemical Formulas 1 and 2 described above.

The water treatment flocculant of the present invention described above is suitable for the water treatment of raw water having a pH of 3.0 to 9.0, and is particularly preferably applied in the water treatment of raw water having a high fluorine content.

Hereinafter, the present invention will be described in more detail with reference to Examples. However, the scope of the present invention is not limited by the following examples.

Preparation of Water Treatment Coagulant

Example 1

24.5 kg of aluminum hydroxide [Al (OH) ₃ ] and 20.5 kg of water were mixed, and 55 kg of hydrochloric acid (HCl 35%) was mixed thereto to prepare a mixed solution. The mixture was reacted at 160 ° C. for about 3 hours to obtain a solution containing Al ₂ (OH) _0.6 Cl _5.4 (intermediate) having 15% Al ₂ O ₃ and 10% basicity. 13 kg of solid calcium hydroxide, 2.25 kg of sodium silicate (Na ₂ SiO ₃ ), and 34.75 kg of water were mixed to form an aqueous calcium silicate hydroxide solution having a concentration of 30.5% by weight of a mixture of calcium hydroxide and silicon oxide and an intermediate at a temperature of about 55 ° C. To 100 kg of solution containing calcium hydroxide aqueous solution was added slowly and reacted using a high speed mixer (homogenizer). After completion of the reaction, the _{mixture was} aged for 2 hours and had a basicity of 55% polyaluminum calcium chloride silicate (Al ₂ Ca _1.2125 (OH) _3.3 Cl _5.1 (SiO ₂ ) _0.025 ; PACCS) 150 kg was prepared. The polyaluminum calcium silicate prepared as a result of the component analysis, Al ₂ O ₃ 10% by weight, Ca 4.5% by weight, SiO ₂ 0.1% by weight, It was confirmed that the content of Cl 12.5% by weight.

Examples 2 to 3

Example 2 was carried out in the same manner as in Example 1, except that 21 kg of solid calcium hydroxide, 2.25 kg of sodium silicate, and 26.75 kg of water were mixed, using an aqueous calcium silicate hydroxide solution having a mixture concentration of 46.5% by weight of calcium hydroxide and sodium silicate. To prepare a water treatment flocculant as shown in Table 1.
Example 3 was carried out in the same manner as in Example 1, except that 27 kg of solid calcium hydroxide, 2.25 kg of sodium silicate and 23 kg of water were mixed, using an aqueous calcium silicate solution having a concentration of 58.5% by weight of a mixture of calcium hydroxide and sodium silicate. To prepare a water treatment flocculant as shown in Table 1.

Examples 4-5

In the same manner as in Example 1, the intermediate was prepared by reacting at 170 ℃ for 3 hours to use a solution containing Al ₂ (OH) _0.7 Cl _5.3 , Example 5 was prepared at 150 ℃ for 3 hours Reaction was carried out to prepare a polyaluminum calcium chloride silicate as shown in Table 1 using a solution containing Al ₂ (OH) _0.5 Cl _5.5 .

Comparative Examples 1 and 2

In the same manner as in Example 1, a calcium hydroxide solution having a concentration of 14.5% by weight of a mixture of calcium hydroxide and sodium silicate was used. When the intermediate was prepared, the reaction was performed at 190 ° C. for about 3 hours to prepare a polyaluminum chloride as shown in Table 1 using a solution containing Al ₂ (OH) _1.9 Cl _4.1 .

Comparative Example 3

In the same manner as in Comparative Examples 1 and 2, the solution containing the intermediate and the calcium hydroxide solution were mixed and reacted at about 90 ° C to 105 ° C.

division basicity(%) Al ₂ O ₃
weight% Ca
weight% SiO ₂
weight% Chemical formula of the prepared polyaluminum calcium silicate Example 1 55 10 4.5 0.1 Al ₂ Ca _1.2125 (OH) _3.3 Cl _5.1 (SiO ₂ ) _0.025 Example 2 70 10 7.5 0.1 Al ₂ Ca _1.5125 (OH) _4.2 Cl _4.8 (SiO ₂ ) _0.025 Example 3 85 10 9.5 0.1 Al ₂ Ca _1.9125 (OH) _5.1 Cl _4.7 (SiO ₂ ) _0.025 Example 4 57 10 4.5 0.1 Al ₂ Ca _1.2125 (OH) _3.4 Cl _5.0 (SiO ₂ ) _0.025 Example 5 53 10 4.5 0.1 Al ₂ Ca _1.2125 (OH) _3.2 Cl _5.2 (SiO ₂ ) _0.025 Comparative Example 1 55 10 2.5 - Al ₂ Ca _0.7 (OH) _3.3 Cl _4.1 Comparative Example 2 70 10 4.0 - Al ₂ Ca _0.9 (OH) _4.2 Cl _3.6 Comparative Example 3 55 10 2.5 - Al ₂ Ca _0.7 (OH) _3.3 Cl _4.1

Experimental Example 1 and Comparative Experimental Example 1

Fluorine treatment efficiency measurement experiment

The fluorine treatment efficiency of Examples 1 to 5 and Comparative Examples 1 to 3 was measured using raw water having a fluorine concentration of 53 ppm, pH 6.8, and a water temperature of 5.1 ° C. In the experiment, 25% caustic soda was used for pH control, and the residual fluorine measurement was performed using the lanthanum-alizarin complexson method.

Looking at the fluorine removal efficiency of Table 2, in the case of the experimental examples of the present invention Examples 1 to 5, it can be seen that the fluorine removal efficiency is very high as 70% or more, unlike the comparative experimental example.

Experimental Example 2 and Comparative Experimental Example 2

Stability Test of Water Treatment Coagulant

Stability test of the water treatment flocculant of the above Examples and Comparative Examples by adjusting to a low temperature thermostat (20 ° C.) was visually observed at room temperature (20 ° C.) for up to 30 days to check whether or not a precipitate occurred, and the results are shown in Table 3 below. Shown in

The stability test results of the water treatment flocculant of Table 3 shows that the water treatment flocculent of the present invention is much more stable than the comparative examples 1 to 3, which are due to the introduction of SiO ₂ .

Claims (7)

A water treatment flocculant comprising polyaluminum calcium chloride silicate represented by the following formula (1); [Formula 1] Al ₂ Ca _x (OH) _y Cl _z (SiO ₂ ) _i In Formula 1, x, y, and z are 6 + 2x = yzi, and are real numbers satisfying 1.0 ≦ x ≦ 2.2, 3 ≦ y ≦ 5.1, 3.4 ≦ z ≦ 5.5, and 0.0008 ≦ i ≦ 0.0832. According to claim 1, The aluminum calcium silicate silica is Al ₂ O ₃ 8-12 wt%, Ca 4 ~ 9.5 wt%, SiO ₂ 0.01-2 wt%, Cl 10-15 wt% according to the component analysis, and Water treatment flocculant, characterized in that the content ratio of H ₂ O 69 ~ 72.5% by weight. The water treatment flocculant of claim 1, wherein the polyaluminum calcium chloride silicate has a basicity of 50 to 85%. The water treatment flocculant of any one of Claims 1-3 whose fluorine removal efficiency with respect to raw water is 70 to 98%. A first step of preparing a mixed solution by mixing and stirring aluminum hydroxide (Al (OH) ₃ ), hydrochloric acid and water; Reacting the mixed solution at 145 ° C. to 170 ° C. for 2 to 4 hours to prepare a solution containing an intermediate represented by Formula 2 below; A third step of adding and mixing the calcium silicate solution to the solution containing the intermediate at 50 ° C. to 80 ° C., followed by reaction; A fourth step of preparing a polyaluminum calcium chloride silicate represented by the following Chemical Formula 1 by aging the mixed solution of the third step; a water treatment flocculant manufacturing method comprising a; [Formula 1] Al ₂ Ca _x (OH) _y Cl _z (SiO ₂ ) _i In Formula 1, x, y, and z are 6 + 2x = yzi, and are real numbers satisfying 1.0 ≦ x ≦ 2.2, 3 ≦ y ≦ 5.1, 3.4 ≦ z ≦ 5.5, and 0.0008 ≦ i ≦ 0.0832. [Formula 2] Al ₂ (OH) _{0.5 ~ 1.0} Cl _{5.0 ~ 5.5} The method of claim 5, wherein the calcium hydroxide solution has a concentration of 20 to 58.5 wt% of the mixture of calcium hydroxide and sodium silicate. The method of claim 5 or 6, wherein the calcium hydroxide solution is prepared by mixing calcium hydroxide, sodium silicate and water.