KR102060501B1 - Synthesis method of energy reduction type zeolite using filtered waste liquid generated during synthesis of zeolite - Google Patents

Abstract

The present invention relates to an energy-saving zeolite synthesis method of reusing filter waste fluid generated during zeolite synthesis and, more specifically, to an energy-saving zeolite synthesis method of reusing filter waste fluid generated during zeolite synthesis to have high crystallinity, enable mass production, constantly maintain quality, and have high economic efficiency by increasing an alkali content by collecting filter waste fluid and significantly shortening aging time and crystallization time. The present invention includes: a first step of forming a first workpiece through a thermal treatment by mixing an alkali material with coal fly ash including SiO_2 and Al_2O_3; a second step of dissolving the first workpiece in water and forming a second workpiece by mixing at least one of an aluminum source, a silica source, and a zeolite seed; a third step of forming a third workpiece by aging the second workpiece for 20-40°C for 1-5 hours; a fourth step of forming a fourth workpiece by crystalizing the third workpiece at 70-100°C for 1-5 hours through a hydrothermal reaction; and a fifth step of synthesizing zeolite by collecting the filter waste fluid generated when filtering after crystallization to the second step and re-aging and recrystallizing so that a weight ratio of the alkali material to the coal fly ash is 0.1 or more under a condition in which a molar ratio of SiO_2 to Al_2O_3 is 2.5.

Description

Synthesis method of energy reduction type zeolite using filtered waste liquid generated during synthesis of zeolite}

The present invention relates to a method for synthesizing an energy-saving zeolite using recycled filtrate generated during zeolite synthesis, and more particularly, by recovering the filtrate and increasing alkali content to drastically shorten the aging time and crystallization time. The present invention relates to a method for synthesizing an energy-reduced zeolite that reuses a filter waste fluid generated during zeolite synthesis, which enables high-volume, high-volume production, constant quality, and high economic efficiency.

As the demand for energy increases due to the rapid industrialization, various energy sources such as coal, nuclear power, and renewable energy are used. Recently, a number of methods for synthesizing zeolites using wastes containing a large amount of silica (SiO ₂ ) and alumina (Al ₂ O ₃ ) as raw materials such as coal fly ash discharged from thermal power plants have been developed.

However, hydrothermal synthesis and molten coal fly ash, which are most used among the existing zeolite synthesis techniques, have a problem that it is difficult to mass-produce various zeolites by dissolving molten coal fly ash in water and then extracting the supernatant.

For example, the "zeolite synthesized from the waste containing silica and alumina (Registration No .: 10-1138854)" has a high mixing ratio with alkaline substances and takes a long crystallization time, and is difficult to mass-produce zeolite A type. There was a problem.

In another example, "The method for manufacturing synthetic zeolite using the bottom ash of thermal power plant (Registration No .: 10-1602933)" said that it is possible to produce zeolite with improved crystallinity by removing CaO, which is a crystallization obstacle, There is a problem that the economic efficiency is very low because the process is complicated and the production period is longer.

Therefore, it is time for new technology development research to synthesize zeolite with high economical efficiency by reusing the filter waste fluid generated during zeolite synthesis.

Registered Korean Patent Publication No. 10-1138854, registered on April 16, 2012. Registered Korean Patent Publication No. 10-1602933, registered on March 7, 2016.

The present invention has been invented to solve the above problems, by recovering the filtrate and increasing the alkali content to significantly shorten the aging time and crystallization time, high crystallinity is possible, mass production is possible and the quality can be kept constant It is also an object of the present invention to provide a method for synthesizing an energy-reduced zeolite, which reuses a filter waste liquid generated during the synthesis of zeolite to increase economical efficiency.

The present invention for achieving the above object, the first step of forming a primary treatment through heat treatment by mixing a coal fly ash (CFA) and an alkali containing SiO ₂ and Al ₂ O ₃ ; Dissolving the primary treatment product in water and mixing at least one of an aluminum source, a silica source, and a zeolite seed to form a secondary treatment product; A third step of aging the secondary treatment at 20-40 ° C. for 1-5 hours to form a tertiary treatment; A fourth step of forming the fourth treated material by crystallizing the third treated material through a hydrothermal reaction at 80 to 90 ° C. in 1 hour; And recovering the filtered waste liquid generated during the filtration after the crystallization in the second step so that the weight ratio of alkali material / coal fly ash is 0.6-1.8 under the condition that the SiO ₂ / Al ₂ O ₃ molar ratio is 2.5 to re-maturation and recrystallization. And a fifth step of synthesizing a Na-A zeolite having a square crystal structure. In the fifth step, the filtrate is reused when the weight ratio of the alkali material / coal fly ash is in the range of 0.6 to 1.5, and a zeolite seed is added. The technical gist of the energy-saving zeolite which recycles the filtration waste liquid which arises during the synthesis | combination of a zeolite characterized by synthesize | combining a square crystal structure of Na-A zeolite without a supply is made into a technical summary.

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Preferably, in the fifth step, it is characterized in that the re-maturation and recrystallization while adjusting to pH 10 or more by the addition of an aqueous alkali solution.

The synthesis | combining method of the energy reduction zeolite which recycled the filter waste liquid which arises in the zeolite synthesis | combination of this invention by the solution of the said subject has the following effects.

First, there is an effect of improving the structure and crystallinity of the zeolite by recovering the coal fly ash discharged from the thermal power plant by optimizing the alkali content, the crystallization temperature and the crystallization time of the synthetic variables in the zeolite synthesis.

Second, the zeolite synthesized at the optimum alkali content and SiO ₂ / Al ₂ O ₃ mole ratio has high crystallinity, and radioactive materials such as strontium (Sr), cesium (Cs), and lead (Pb), chromium (Cr), and nickel (Ni). ) Ion exchange ability with heavy metals such as cobalt (Co), copper (Cu) and zinc (Zn) is effective in removing radioactive materials and heavy metals.

1 is a flow chart according to a preferred embodiment of the present invention.
2 is an XRD graph of zeolite synthesized according to the alkali concentration of the present invention.
Figure 3 is an XRD graph of the zeolite synthesized according to the crystallization temperature and crystallization time of the present invention.
Figure 4 is a SEM photograph of the zeolite according to the crystallization time when the crystallization temperature of the present invention is 70 ℃.
Figure 5 is a SEM photograph of the zeolite according to the crystallization time when the crystallization temperature of the present invention 80 ℃ and 90 ℃.
Figure 6 is a graph of the crystallinity of the zeolite according to the alkali addition of the present invention.
Figure 7 is a SEM photograph of the zeolite according to the NaOH / CFA weight ratio control of the present invention.

Hereinafter, preferred embodiments of the present invention will be described in detail with reference to the accompanying drawings.

1 is a flow chart according to a preferred embodiment of the present invention. As shown in FIG. 1, the present invention recovers the filtrate generated during the synthesis of zeolite in a aging process to increase the alkali content, thereby drastically reducing the aging time and crystallization time, as compared to the conventionally known method. The present invention relates to a method for synthesizing zeolites capable of maintaining a constant and high quality as well as economical efficiency. The method comprises the following steps: a first step (S10), a second step (S20), a third step (S30), and a fourth step (S40). ) And the fifth step (S50), the characteristics of each step are as follows.

First, a first step is a step of forming a primary treatment through heat treatment by mixing a coal fly ash (CFA) and an alkali material containing silica (SiO ₂ ) and alumina (Al ₂ O ₃ ) ( S10).

In other words, in the first step, the coal fly ash is mixed with the alkali material by mixing the turbid fly ash and the alkaline material discharged from the thermal power plant and classified as waste, thereby forming a fusion fly ash as the primary treatment product.

In the case of coal fly ash, it is produced after burning coal as fuel in a thermal power plant, such as 15 to 40 wt% (particularly 15 to 30 wt%) of alumina (Al ₂ O ₃ ) and 40 to 70 wt% (particularly, 40 to 55 wt%). %) Of silica (SiO ₂ ).

In the case of an alkaline substance, although the kind is not specifically limited, it is preferable to include a sodium (Na) component, For example, it may be sodium hydroxide (NaOH). In addition, alkali materials including potassium, calcium, barium, and the like may be used, such as sodium carbonate, potassium hydroxide, potassium carbonate, calcium hydroxide, barium hydroxide, and the like. For reference, the alkaline material may be used in a solid state, but in order to facilitate mixing with coal fly ash, it is preferable to use the powder in a solid state rather than a solid state.

Although the weight ratio of the coal fly ash and the alkali substance may vary depending on the component ratio of the zeolite finally required, it is preferably made of a weight ratio of 1: 0.1 ~ 1.8. In particular, when the alkali material is less than 0.5 weight ratio to 1 weight ratio of the coal fly ash, the alkali content is low so that a large amount of aqueous alkali solution may be required in order to increase the alkali content again, and when it exceeds 1.8 weight ratio, fusion with the coal fly ash is made stable. Can't.

The heat treatment is preferably performed at 450 to 600 ° C., but only at 450 to 600 ° C., coal fly ash and alkali material discharged from the thermal power plant are uniformly melted and fused to each other to form an advantageous structure for zeolite synthesis. In other words, the main component of coal fly ash is Na ₂ SiO _{3 which} is well soluble in water or NaAlSiO ₄ which is well soluble in aqueous alkali solution. Form a circle. For this reason, it is sufficient if the heat treatment at 450 ~ 600 ℃ within 30 minutes ~ 3 hours. This is because even after 30 minutes of heat treatment, the coal fly ash and the alkali substance are sufficiently and uniformly dissolved.

For example, when the alkali material is sodium hydroxide (NaOH), the weight ratio of coal fly ash and sodium hydroxide may be 1: 0.1 to 1.8, and heat treatment may be performed at 500 to 550 ° C.

As another example, when the alkali material is sodium carbonate (Na ₂ CO ₃ ), if a certain amount of coal fly ash and sodium carbonate are mixed and heat treated at 500 to 550 ° C., the quartz or aluminum silicate contained in the coal fly ash is 50%. As it remains as above, the zeolite synthesis does not work well, and there is a hassle of high temperature heat treatment to 800-900 ° C. in order to change into an amorphous or water-soluble form which is easy to be used as a raw material for zeolite synthesis. For this reason, it is more preferable to use sodium hydroxide than sodium carbonate.

Next, the second step is a step of dissolving the primary treatment in water (water), and mixing any one or more of the aluminum source, silica source and zeolite seed to form a secondary treatment (S20).

First, the water used to dissolve the molten fusion fly ash, which is the primary treatment in the second step, may be 200 to 1,000 parts by weight based on 100 parts by weight of the primary treatment. If the water is less than 200 parts by weight, the alkali concentration becomes too high and stable. When the structure is changed to Na-P1 or Sodalite, which is less used, and when it exceeds 1,000 parts by weight, the crystallization rate is slowed during the reaction, and the reactor or plant size for mass synthesis is not only large, but the waste water is generated and the treatment cost is increased. Inefficient in terms of productivity. Therefore, the water is preferably used 200 to 1,000 parts by weight, more preferably 400 to 600 parts by weight.

In the case of an aluminum source, it means a material including aluminum, and is finally added to adjust the composition ratio of the zeolite required. That is, it is possible to adjust the SiO ₂ / Al ₂ O ₃ molar ratio of the zeolite finally synthesized by the addition of an aluminum source. NaAlO ₂ may be used as the aluminum source, and other aluminum-based flocculants may be used. Although the amount of aluminum source depends on the composition ratio of the zeolite and the chemical composition of the coal fly ash and the primary treatment, which is finally required, 5 to 25 parts by weight may be added based on 100 parts by weight of the primary treatment. When added, it is difficult to adjust the SiO ₂ / Al ₂ O ₃ molar ratio of the zeolite to 2.5, and when it exceeds 25 parts by weight, the SiO ₂ / Al ₂ O ₃ molar ratio exceeds 2.5, so 5 to 10 parts by weight is more preferable. However, in the present invention, since the filtered waste liquid is recovered by the aging process of the third step to increase the alkali content, in some cases, the aluminum source does not need to be added.

In the case of a silica source, it means a material containing silica, and it is possible to add insufficient silica to the primary treatment, and may be added in some cases so as to optimize the SiO ₂ / Al ₂ O ₃ molar ratio to 2.5. It is not limited to the amount.

In the case of the zeolite seed, it serves as a template for determining the form of the finally synthesized zeolite, and may be mixed in an amount of 0.1 to 1 parts by weight based on 100 parts by weight of the primary treatment product. If the zeolite seed is added less than 0.1 part by weight, the zeolite form is not stable even when the synthesis of the zeolite is completed, and if it is more than 1 part by weight, the effect is not more excellent than that in the case where the amount is less than 1 part by weight. There is no need to mix. Therefore, the zeolite seed is preferably 0.1 to 1 parts by weight, more preferably 0.1 to 0.5 parts by weight.

Next, the third step is a step of forming the third treatment by aging the secondary treatment for 1 to 5 hours at 20 ~ 40 ℃ (S30).

That is, the third step is a process of ripening the secondary treatment completed in the second step for 20 minutes to 40 ℃ conditions for 1 to 5 hours, especially when the filtrate of the fifth step is recovered later, the aging time due to the increase of alkali content It can be greatly reduced within this hour.

Next, the fourth step is to form a fourth treatment by crystallizing the third treatment by hydrothermal reaction at 70 ~ 100 ℃ (S40).

In other words, the fourth step is carried out by a hydrothermal reaction in which heat required for the reaction is transferred by the aqueous medium at 70-100 ° C., which is usually performed in an autoclave, but in the present invention, an atmospheric pressure reactor. .

This crystallization may be performed for 30 minutes to 12 hours when there is no energy source other than hydrothermal, but by 1 to 6 hours, there is an effect that is time intercepted.

Finally, the fifth step recovers the filtered waste solution generated during the crystallization after the crystallization to the second step so that the weight ratio of alkali material / coal fly ash is at least 0.1 in the condition that the SiO ₂ / Al ₂ O ₃ molar ratio is 2.5 or more re-aging and Recrystallization is a step of synthesizing zeolite (S50).

In the fifth step, it is preferable to adjust the weight ratio of the alkali material / coal fly ash to be in the range of 0.1 to 1.8 when recovering the liquid filtrate separated from the solids of the fourth treatment through filtration and washing of the fourth treatment.

In particular, when only the wastewater collected in the second stage has to be adjusted for the number of times of reuse of the wastewater and the amount of water used, and it is difficult to maintain a constant alkali concentration upon each reuse. It is preferable to adjust so that.

Thus, in the fifth step, when the filtrate separated from the zeolite synthesized in the fourth step is recovered in the second step and undergoes re-aging and recrystallization, Na-A zeolite having a stable square crystal structure does not need to be additionally supplied with zeolite seed. There is an effect that can be synthesized.

Hereinafter, an embodiment according to the method for synthesizing the energy-reducing zeolite using the filter waste fluid generated during the synthesis of the zeolite of the present invention will be described. However, the following examples are only illustrated to aid the understanding of the present invention, and the scope of the present invention is not limited thereto.

<Example 1>

Synthesis of Zeolite According to Alkali Addition

In order to find out whether the zeolite is synthesized according to the amount of alkali added using coal fly ash discharged from the thermal power plant, the zeolite was synthesized by maintaining the aging temperature at 5 hours and stirring at 80 ° C for 5 hours.

In other words, 10g of coal fly ash discharged from thermal power plant and 12g of sodium hydroxide are mixed and melted, and then aged at 30 ℃ for 5 hours, and then experimented with the effects of crystallization time for 1 to 5 hours at the crystallization temperature of 70 ~ 90 ℃. saw.

12 g of sodium hydroxide was pulverized and mixed with 10 g of coal fly ash, which was melted at 550 ° C. for 3 hours, and the fused fly ash was dissolved in 100 g of water (5 g of ultrapure water / 1 g of fusion fly ash), and the molar ratio of SiO ₂ / Al ₂ O ₃ (mol / mol) 1.0 g of NaAlO ₂ was added to maintain 2.5, and then 0.1 g of zeolite 4A (commercial catalyst) was added to aid the growth of zeolite, and aged with stirring at room temperature for 5 hours.

In order to determine the effect of alkali addition amount, fused fly ash is dissolved in 0.5 M or 1.0 M aqueous NaOH solution instead of 100 g of water, and 1.0 g of NaAlO ₂ is added to maintain SiO ₂ / Al ₂ O ₃ molar ratio at 2.5 and then zeolite. 0.1 g of zeolite 4A (commercial catalyst) was added thereto to help growth of the cells, and aged at room temperature with stirring for 5 hours. After aging was completed, the temperature was raised to the desired crystallization temperature at a rate of 10 ° C./min to 80 ° C. After crystallization, the zeolite synthesized after the hydrothermal reaction for 5 hours at 80 ° C. was filtered and washed several times, and dried at 90˜100 ° C. to synthesize the zeolite.

2 is an XRD graph of a zeolite synthesized according to the alkali concentration of the present invention. In order to determine the effect of the amount of alkali added, NaOH / CFA weight ratio was adjusted to 1: 0.1 to 1.8, and then NaOH aqueous solution (including filtrate) was added instead of water by 0.0M, 0.5M, 1.0M and then aged and crystallized. XRD patterns of zeolites are shown in FIGS. 2- (a), 2- (b) and 2- (c), respectively.

2- (a) is a hydrothermal synthesis using water instead of aqueous NaOH solution, the NaOH / CFA weight ratio of 0.1 and 0.3 zeolite showed almost no peak of zeolite SiO ₂ and Al ₂ O ₃ contained in coal fly ash as a zeolite It was judged that it was not synthesized. However, the NaOH / CFA weight ratio of 0.6 or more was confirmed that the peak of the zeolite appears at the same 2θ position as the commercial zeolite Z-CS. This peak showed a similar tendency for the height of the peak even though the NaOH / CFA weight ratio increased from 0.6 to 1.8.

2- (b) shows the XRD pattern of the zeolite synthesized by fusion hydrothermal synthesis by adding an aqueous solution of NaOH 0.5M concentration in place of water to increase the amount of alkali in the case of reuse of the filtrate. When the NaOH aqueous solution was added, it was confirmed that zeolite was produced when the NaOH / CFA weight ratio was 0.1. As the NaOH / CFA weight ratio was increased, the zeolite peak was increased. However, when the NaOH / CFA weight ratio is more than 1.2, a different type of zeolite peak appeared.

2- (c) shows the XRD pattern of the zeolite synthesized by fusion-melting by adding 1.0 M aqueous NaOH solution instead of water. When the NaOH / CFA weight ratio was 0.1, zeolite was formed, and the NaOH / CFA weight ratio was shown. It can be seen that the peak of the zeolite increases as it increases to 1.2. However, when the NaOH / CFA weight ratio is more than 1.2 it can be seen that other forms of zeolite peaks.

As shown in FIG. 2, it can be seen that as the NaOH / CFA weight ratio is increased in the melt hydrothermal synthesis process, more green-green Si and Al are eluted on the surface of the calcined material. To increase alkali content in FIG. 2- (b), when zeolite was synthesized by adding 0.5 M NaOH aqueous solution instead of water and re-aging and recrystallization, NaOH / CFA weight ratio was 0.1 or higher, and Na- Na / CFA weight ratio was increased. The tendency of the peak of A-type zeolite to become high was confirmed. However, when the zeolite was synthesized by re-aging and recrystallization by adding an aqueous NaOH solution of 0.1 M instead of water to increase alkali content as shown in FIG. 2- (c), the NaOH / CFA weight ratio was higher than 0.1. As the Na-A zeolite peaks, the peak tends to increase. However, as NaOH / CFA weight ratio increases, other types of zeolite peaks appear.

<Example 2>

Synthesis of Zeolite According to Crystallization Time and Crystallization Temperature

After 10g of fly ash discharged from the thermal power plant and 12g of sodium hydroxide were mixed regularly, it was aged for 5 hours at 30 ℃ of aging temperature, and then 1 to 5 hours of crystallization time at 70 ~ 90 ℃ for crystallization time. Experiments were conducted by crystallization time.

12 g of sodium hydroxide was pulverized and mixed with 10 g of coal fly ash, which was melted at 550 ° C. for 1 hour, and the fused fly ash was dissolved in 100 g of ultrapure water (5 g of ultrapure water / 1 g of fusion fly ash), and the molar ratio of SiO ₂ / Al ₂ O ₃ was 2.5. 1.0 g of NaAlO ₂ was added to maintain the solution, and 0.1 g of zeolite 4A (commercial catalyst) was added thereto to aid the growth of the zeolite, and aged with stirring at room temperature for 5 hours. After aging is completed, the mixture is heated to a desired crystallization temperature at a rate of 10 ° C./min up to 90 ° C., and then, after crystallization of the zeolite after hydrothermal reaction at 90 ° C. for 1 hour to 5 hours, the synthesized zeolite is filtered and washed several times and dried at 90-100 ° C. After the zeolite was synthesized.

3 is an XRD graph of zeolites synthesized according to the crystallization temperature and crystallization time of the present invention. Referring to FIG. 3, it is shown whether zeolite is synthesized according to crystallization time and crystallization temperature in order to shorten the zeolite synthesis time.

3- (a) shows the XRD pattern of the crystallized zeolite after 1 hour, 3 hours, and 5 hours at 70 ° C. after aging for 5 hours at 30 ° C., and FIG. 3- (b) Shows the XRD pattern of the crystallized zeolite after 1 hour, 3 hours, 5 hours at 80 ℃ after aging and maintained for 5 hours at a temperature of 30 ℃, Figure 3- (c) is at a temperature of 30 ℃ After aging for 5 hours, 1 hour, 3 hours, and 5 hours at 90 ° C. showed XRD patterns of crystallized zeolite.

Referring to FIG. 3, after the aging temperature is maintained at 30 ° C. for 5 hours, the zeolite is synthesized when the crystallization time reaches 1 hour or more as shown in the zeolite XRD pattern according to the crystallization time at 90 ° C. I could see that. And it was confirmed that the zeolite peak was almost similar even though the crystallization time was longer.

Figure 4 is a SEM photograph of the zeolite according to the crystallization time when the crystallization temperature of the present invention is 70 ℃. Figure 4 is synthesized by crystallization at 70 ℃ after passing the temperature of 30 ℃ and 5 hours under a condition that fixed the molar ratio of silica (SiO ₂ ) and alumina (Al ₂ O ₃ ) 2.5 and NaOH / CFA weight ratio to 1.2 SEM photographs of zeolites are shown.

Figure 4 (a) shows a zeolite that passed through a 1 hour crystallization time at a crystallization temperature of 70 ℃, Figure 4- (b) shows a zeolite that passed through a 3 hour crystallization time at a crystallization temperature of 70 ℃, Figure 4 -(c) shows the zeolite which passed the crystallization time for 5 hours at the crystallization temperature of 70 degreeC.

According to FIG. 4, SEM of zeolite according to crystallization time at a crystallization temperature of 70 ° C. was maintained at a aging temperature of 30 ° C. for 5 hours under conditions fixed at a SiO ₂ / Al ₂ O ₃ molar ratio of 2.5 and a NaOH / CFA weight ratio of 1.2. In the photograph, when the crystallization time was 1 hour, almost no square grain structure, which is a typical crystal structure of Na-A zeolite, was observed. However, it was confirmed that when the crystallization time is 3 hours and 5 hours, a square grain structure, which is a typical crystal structure of Na-A zeolite, is synthesized. Therefore, it was found that Na-A zeolite was synthesized when the aging time was maintained at 30 ° C. for 5 hours and the crystallization time was 3 hours or longer at 70 ° C ..

5 is a SEM photograph of the zeolite according to the crystallization time when the crystallization temperature of the present invention is 80 ℃ and 90 ℃. Fig. 5- (a) shows a 1 hour crystallization time at a crystallization temperature of 80 ° C. after a temperature of 30 ° C. and 5 hours of aging under a condition that the SiO ₂ / Al ₂ O ₃ molar ratio is 2.5 and the NaOH / CFA weight ratio is 1.2. 5- (b) shows 90 ° C. after a temperature of 30 ° C. and 5 hours of aging under a condition in which the molar ratio of SiO ₂ / Al ₂ O ₃ is 2.5 and the NaOH / CFA weight ratio is fixed at 1.2. It shows the zeolite which passed the crystallization time for 1 hour at the crystallization temperature of.

According to FIG. 5, it was found that Na-A zeolite was synthesized when the aging temperature was maintained at 30 ° C. for 5 hours and the crystallization time was at least 1 hour at 80 ° C. and 90 ° C., respectively.

In particular, in the case of the zeolite synthesized from the waste containing silica and alumina (Registration No .: 10-1138854), which is a patent for synthesizing zeolite using existing fly ash or waste, it is maintained at 80-100 ° C. and atmospheric pressure for 2 hours or more. Although the zeolite was synthesized, in the present invention, the zeolite synthesis peak appears within 1 hour when the crystallization temperature is in the 80 ~ 90 ℃ range, the zeolite synthesis peak appears when the crystallization time exceeds 1 hour when the crystallization temperature is 70 ℃ can confirm.

From these results, it is confirmed that mass production of zeolites is possible because the actual temperature of the zeolite synthesis using the coal fly ash discharged from the thermal power plant can be shortened and the synthesis time can be shortened.

Experimental Example 1

Crystallinity of Zeolite According to Alkali Content

In Experimental Example 1, the crystallinity of the zeolite was tested according to the amount of alkali added.

6 is a graph showing the crystallinity of the zeolite according to the alkali addition of the present invention. Referring to FIG. 6, when the NaOH / CFA weight ratio adjusted by adding the NaOH weight recovered during the aging process and the NaOH weight added during the melting process increases, the degree of crystallinity increases, but the NaOH / CFA weight ratio ranges from 0.6 to 1.5. It can be seen that even if the increase has a similar crystallinity, it can be reused in this range. It was found that the zeolite crystallinity was lowered when the NaOH / CFA weight ratio was 1.5 or more. However, if the NaOH / CFA weight ratio is less than 0.6, the performance may not come out well may be limited in reuse.

Figure 7 is a SEM photograph of the zeolite according to the NaOH / CFA weight ratio control of the present invention. 7- (a) is a SEM image of zeolite when the adjusted NaOH / CFA weight ratio is 0.1, and FIG. 7- (b) is a SEM image of zeolite when the adjusted NaOH / CFA weight ratio is 0.6, and FIG. 7- ( c) is a zeolite SEM picture when the adjusted NaOH / CFA weight ratio is 0.9, Figure 7- (d) is a zeolite SEM picture when the adjusted NaOH / CFA weight ratio is 1.2, Figure 7- (e) is the control Zeolite SEM photograph when the NaOH / CFA weight ratio is 1.8, Figure 7- (f) is a zeolite SEM photograph when the adjusted NaOH / CFA weight ratio is 2.2.

7 shows that the SiO ₂ / Al ₂ O ₃ molar ratio of 2.5, the aging temperature and the aging time was maintained at 30 ℃ and 5 hours, respectively, the crystallization temperature and crystallization time at 90 ℃ and 5 hours, respectively In the SEM photograph of the zeolite synthesized according to the NaOH / CFA weight ratio, the crystal structure of Na-A zeolite was not observed at 0.1 adjusted NaOH / CFA weight ratio, but Na-A zeolite at NaOH / CFA weight ratio of 0.6-1.8. It was confirmed that the tetragonal crystal structure of was obtained, but it was found that the Na-A type zeolite particle size decreased as the NaOH / CFA weight ratio increased. However, when the NaOH / CFA weight ratio was 2.2, it was observed that the crystal structure was changed to a form other than Na-A zeolite.

Therefore, in the present invention, in order to mass-produce zeolites having excellent crystallinity, it is necessary to control NaOH / CFA weight ratio, and a problem arises in that the manufacturing cost increases depending on the amount of alkali added. NaOH consumption can be lowered and zeolite synthesis is possible without the need for the supply of zeolite seeds.

When operating the actual zeolite synthesis process by recovering and recycling the coal fly ash discharged from the thermal power plant from the above-described results, it is possible to shorten the temperature and the zeolite synthesis time compared to the existing methods, and to recover and reuse the filtered waste liquid to recover the alkali content. It is important to simplify the process and to be environmentally friendly, as well as to enable mass production of zeolites, since the zeolite seed supply can be omitted.

The above description is merely illustrative of the technical idea of the present invention, and those skilled in the art to which the present invention pertains may make various modifications and changes without departing from the essential characteristics of the present invention.

Therefore, the embodiments disclosed in the present invention are not intended to limit the technical idea of the present invention, but to describe the present invention, and the scope of the technical idea of the present invention is not limited by these embodiments.

The scope of protection of the present invention should be interpreted by the claims, and all technical ideas within the scope equivalent thereto should be construed as being included in the scope of the present invention.

Claims (4)

A first step of forming a primary processed material through heat treatment by mixing a coal fly ash (CFA) and an alkali material including SiO ₂ and Al ₂ O ₃ ;
Dissolving the primary treatment product in water and mixing at least one of an aluminum source, a silica source, and a zeolite seed to form a secondary treatment product;
A third step of aging the secondary treatment at 20-40 ° C. for 1-5 hours to form a tertiary treatment;
A fourth step of forming the fourth treated material by crystallizing the third treated material through a hydrothermal reaction at 80 to 90 ° C. in 1 hour; And
After the crystallization, the filtration waste solution generated during the filtration is recovered in the second step so that the weight ratio of the alkali material / coal fly ash is 0.6-1.8 under the condition that the SiO ₂ / Al ₂ O ₃ molar ratio is 2.5. And a fifth step of synthesizing a Na-A zeolite having a crystal structure.
In the fifth step,
When the weight ratio of the alkali material / coal fly ash is 0.6 to 1.5, the filter waste liquid is reused,
A method for synthesizing an energy-reduced zeolite by reusing a filter waste fluid generated during zeolite synthesis, comprising synthesizing a Na-A zeolite having a square crystal structure without additional supply of zeolite seed. delete delete The method of claim 1,
In the fifth step,
A method for synthesizing an energy-reduced zeolite by reusing a filtrate solution generated during zeolite synthesis, wherein the mixture is re-matured and recrystallized while being adjusted to pH 10 or more by addition of an aqueous alkali solution.

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