WO2017069545A1 - Method for preparing synthetic zeolite using pumice - Google Patents

Abstract

The present invention relates to a method for preparing synthetic zeolite using pumice and, more specifically, to a method for preparing synthetic zeolite, in which pulverized pumice and an alkaline substance are mixed in a powder form and then homogeneously fused by applying heat thereto, and the fused material in a fused powder form is mixed with water together with an aluminum-containing material and zeolite seeds to produce zeolite through aging, crystallization, and drying procedures, wherein the crystallization is carried out such that the pulverized pumice is mixed with the alkaline substance after the content of CaO as a crystallization inhibitor is reduced to a predetermined level or less, thereby improving the degree of crystallization, thus allowing the mass production and maintaining the quality of zeolite at a certain level.

Description

Synthetic zeolite manufacturing method using pumice

The present invention relates to a method for producing synthetic zeolite using pumice, and more particularly, to mix the pulverized pumice and alkali material in powder form and then apply heat to uniformly fuse the fused powder. The zeolite is mixed with water and mixed with water to produce zeolite through aging, crystallization, and drying, and the pulverized pumice reduces the CaO content, which is a crystallization inhibitor, to a predetermined level or less, and then mixes with alkaline material to make crystallization. The present invention relates to a method for producing a synthetic zeolite which can improve the crystallinity and thereby allow mass production and maintain the quality of the zeolite at a constant level.

Coal is a useful resource that has been used in various industries for a long time, such as thermal power plants, domestic fuels, and steel mill furnaces. The coal is mined and then subjected to the process of coal mining. The remaining waste other than coal used in the industry is called tailings. Among them, the rocks that are discarded because there is little coal component are called pumice (gane), and in other mineral mines other than coal mines. Contains rock that is discarded. In Korea's anthracite coal mines, discarded pumice is produced in an amount nearly equal to the amount of coal selected in the process of coal mining. Such pumice is a situation that is treated as a simple waste as a by-product of the coal mine difficult to treat.

However, the pumice generated during the mining process due to environmental pollution regulation is difficult to dispose of and left in the coal mine as it is, and the amount is hundreds of millions of tons.

Although there are some differences in the composition of pumice, except for carbon, it is approximately 40-50% of SiO ₂ , 15-25% of Al ₂ O ₃ , 2-10% of Fe ₂ O ₃ , other TiO ₂ , It consists of CaO, MgO, etc. In these components, SiO ₂ and Al ₂ O ₃ are useful raw materials for the synthesis of zeolites, so that coal mine wastes, especially discarded pumice, can be recycled as zeolites.

Although a number of cases have been proposed as the zeolite production method, the present invention relates to a zeolite manufacturing method using fly ash generated in a thermal power plant. In addition, in the production method of zeolite using existing fly ash, the fly ash has a relatively high CaO content of 20 wt.% Or more due to the effect of limestone introduced in the desulfurization process, and the zeolite synthesis and purity, yield, crystallinity, etc. are decreased due to CaO effect. There is a disadvantage that it is difficult to prepare the zeolite in the shape.

In addition, the existing zeolite manufacturing method is difficult to mass production because of the use of hydrothermal synthesis or alkaline solution in the manufacturing process and has the problems of equipment corrosion.

In addition, since the composition of pumice varies according to various regions, mass production of zeolites having a certain quality is difficult, and thus, research on a new method of manufacturing is required.

Korean Patent No. 10-0656177 (registered on Dec. 5, 2006; hereafter referred to as 'Previous Document 1') presented a method for synthesizing NaP1 zeolite using a thermal power plant flooring material. Prior art document 1 is a flooring material pre-treatment step of drying the flooring stacked on the boiler floor for thermal power plant 22 ~ 26 hours at 90 ~ 110 ℃, to crush the dried flooring to a particle size of less than 100㎛; Mixing the pretreated flooring material with NaOH solution of 2M ~ 3M to synthesize zeolite by normal temperature or atmospheric pressure or hydrothermal synthesis at 80 ℃ ~ 100 ℃; In addition, the synthesized zeolite is washed with distilled water and then dried at 70-90 ° C. for 11-13 hours. Since the prior document 1 synthesizes the zeolite by the hydrothermal synthesis method, it is not suitable for mass production because the high temperature and high pressure conditions should be made. In addition, although the content of CaO component, which is a crystallization hindering material rather than fly ash, is still higher than 9% by weight relative to the total weight, it is difficult to produce various types of zeolites by the crystallization hindering material at normal temperature and pressure.

Chinese Patent Publication No. 101850987 (published Oct. 6, 2010; hereafter referred to as 'Previous Document 2') has proposed a method for preparing nanoscale zeolite 4A using low-carbon as a raw material. The prior document 2 is to pulverize the low-carbon coal, the calcined powder is added to the NaOH solution and gelatinized, it is crystallized using this. This is also because it is difficult to uniformly mix the low-carbon coal pulverized with NaOH because the NaOH solution is used to make the reaction is made by adding an excess of NaOH, the excess of NaOH should be added to the recovery process. In addition, there is a need for a cooling device for removing heat due to the exothermic reaction generated during NaOH dissolution, and because of the high concentration of NaOH solution, problems such as device corrosion are inherent in mass production processes.

The synthetic zeolite production method of the present invention,

The purpose of the present invention is to prepare synthetic zeolite using pumice, which is a waste generated from coal mining, and to provide a method of maximizing crystallinity while simplifying the manufacturing process.

In addition, the present invention is to produce a zeolite using a pumice having a variety of component ratios, but the crystallization of the manufactured zeolite is made to a certain level or more to improve the productivity, can be applied to the production of zeolite A as well as various types of zeolite It is to provide a way to.

Synthetic zeolite production method of the present invention for achieving the above object,

A first step of pulverizing the selected pumice stone into powder of 30 mesh or less using a continuous crusher; A second step of injecting the pumice crushed material of the first step into a water bath to elute and remove the CaO component, which is a crystallization inhibitor; A third step of subjecting the pumice pulverized product from which the CaO component is removed in the second step to a heat treatment tank for heat treatment to burn off carbon and other impurities remaining in the pumice pulverized product; A fourth step of adding the pumice powder and powdery alkali material heat-treated in the third step to a stirrer and stirring the mixed powder evenly; A fifth step in which the mixed powder uniformly stirred through the fourth step is introduced into a heating bath and heated, and the alkali material melted by heat is fused with the pumice powder; A sixth step of mixing the fusion material which has undergone the fusing step in the fifth step with water, an aluminum source and zeolite seed; A seventh step of aging by stirring the mixture of the sixth step while heating at a low temperature to 20 ~ 60 ℃; An eighth step of crystallizing the heating temperature of the mixture aged in the seventh step to 80 to 100 ° C. to synthesize and grow the zeolite crystals; And a ninth step of forming the product by filtration, washing with water, and drying the zeolite synthesized in the eighth step.

The pumice may be a pumice pumice generated from a waste mine.

In addition, the second step includes a step 2-1 of injecting pumice powder into a water bath to elute and remove a CaO component which is a crystallization-interrupting substance; It may be made, including; step 2-2 to dehydrate the pumice pulverized to reduce the CaO component.

In addition, in the second step 2-2, the step 2-2a of compressing and dehydrating the pumice pulverized product having reduced crystallization-interrupting substance into a cake, and the step of putting the pumice pulverized cake agglomerated in a cake state into a stirrer and crushing it in powder form Step 2-2b; may be further made.

In the step 2-1, the step 2-1a may be performed in which the pulverized pumice is soaked in hot water at 50 to 80 ° C. for 0.5 to 2 hours and stirred to lower the CaO content of the pulverized pumice to 0.5 to 5% by weight. Can be.

In addition, in the step 2-1, through the plurality of micro-pores formed on the inner surface of the tank, the high-pressure air is injected into the tank to generate a plurality of small air bubbles in the tank, and the rising air bubbles are raised to form an upward flow. The upstream may be further mixed with the swirling flow of the stirrer to generate the mixed turbulence.

In step 2-1, when the step 2-1a or step 2-1b is performed, the CaO content is measured, and the measured value is equal to or greater than the allowable error range according to the remaining process execution time in comparison with the CaO content setting value. In step 2-1a, the process is converted to step 2-1b to be discharged and then discharged. In step 2-1b, the CaO content measurement and automatic conversion process is performed to be discharged after the step 2-1a is again performed. Step 2-1c may be further performed.

In the fifth step, an alkali material is selected from sodium hydroxide (NaOH) and sodium carbonate (Na ₂ CO ₃ ), and the powdered alkaline material selected from 100 parts by weight of the pulverized pumice powder is 50 to 200. The mixture may be mixed in parts by weight and heat treated at 500 to 900 ° C. for 0.5 to 3 hours to allow the pumice pulverized material and the alkaline material to be fused.

The sixth process may be mixed with 200 to 1000 parts by weight of water, 5 to 25 parts by weight of aluminum source and 0.5 to 5 parts by weight of zeolite seed, based on 100 parts by weight of the pumice fusion produced in the fifth process. The aluminum source may be NaAlO ₂ .

In addition, the seventh process may be stirred for 3 to 12 hours at a temperature of 20 ~ 60 ℃.

In addition, the eighth process may allow crystallization to be performed for 2 to 72 hours in a batch reactor at 80 to 100 ° C. and atmospheric pressure.

Synthetic zeolite production method of the present invention by the above solution means,

Synthetic zeolite is prepared using discarded pumice, and the pulverized pumice powder and alkali material are mixed and mixed in a powder form and mixed at high temperature, mixed as uniformly as possible, and then reacted with an aluminum-containing material to make crystallization. Zeolites can be produced. In particular, by lowering the CaO component to less than 5% by weight from the pumice having a large amount of CaO component and to perform the zeolite synthesis reaction, it is possible to improve the purity while enabling the production of various types of zeolite.

In addition, since there is no hydrothermal reaction, it can be manufactured in a batch reactor under atmospheric pressure, which enables mass production by a continuous process to reduce production costs, and prevents environmental pollution by leachate and fine dust scattering due to discarded pumice loading. It is now possible to provide useful methods.

1 is a manufacturing process flow chart according to an embodiment of the present invention.

2 is a manufacturing process flow chart according to another embodiment of the present invention.

Figure 3 is an analysis of zeolite 4A prepared by the production method of the present invention.

Figure 4 is a SEM photograph of zeolite 4A prepared by the production method of the present invention.

Figure 5 is an analysis of zeolite NaP1 prepared by the production method of the present invention.

The present invention comprises a first step of grinding the selected pumice stone into a powder form of 30mesh or less using a continuous crusher; A second step of injecting the pumice crushed material of the first step into a water bath to elute and remove the CaO component, which is a crystallization inhibitor; A third step of subjecting the pumice pulverized product from which the CaO component is removed in the second step to a heat treatment tank for heat treatment to burn off carbon and other impurities remaining in the pumice pulverized product; A fourth step of adding the pumice powder and powdery alkali material heat-treated in the third step to a stirrer and stirring the mixed powder evenly; A fifth step in which the mixed powder uniformly stirred through the fourth step is introduced into a heating bath and heated, and the alkali material melted by heat is fused with the pumice powder; A sixth step of mixing the fusion material which has undergone the fusing step in the fifth step with water, an aluminum source and zeolite seed; A seventh step of aging by stirring the mixture of the sixth step while heating at a low temperature to 20 ~ 60 ℃; An eighth step of crystallizing the heating temperature of the mixture aged in the seventh step to 80 to 100 ° C. to synthesize and grow the zeolite crystals; And a ninth step of forming the product by filtration, washing with water, and drying the zeolite synthesized in the eighth step.

Hereinafter, the present invention will be described in more detail with reference to the accompanying drawings. However, the accompanying drawings are only examples for easily describing the content and scope of the technical idea of the present invention, and thus the technical scope of the present invention is not limited or changed. In addition, it will be apparent to those skilled in the art that various modifications and changes can be made within the scope of the present invention based on these examples.

1 and 2 are a manufacturing process flow chart according to a preferred embodiment of the present invention.

Synthetic zeolite manufacturing method using pumice according to the present invention, the first step of the grinding step, the second step of removing the crystallization-interrupting substance, the third step of the heat treatment step, the fourth step of the mixing powder stirring step, the second step of the fusion step It includes five steps, a sixth step of mixing, a seventh step of aging, an eighth step of crystallization, and a ninth step of commercialization.

The first step is to grind the pumice, and can be used to grind various mineral pumice. Preferably, the pumice is waste pumice which is a rock mass collected and discarded in a coal mine area, and the remaining pumice or coal-free pumice generated in the mining process after the coal mining process is performed in the coal mine area. It is a process of receiving and grinding.

In the first step, carbon powder or impurities may remain in the pumice in the form of rock, and therefore, it is preferable to crush the powder as much as possible. The apparatus used for the crushing may be pulverized using a continuous crusher (Hammer crusher or Scutter crusher) that can be continuously supplied by a conveyor belt. At this time, the grinding degree is pulverized to 30 mesh (mesh) or less, preferably pulverized into a powder of 30 ~ 60 mesh.

Next, as shown in FIG. 2, a second process of removing the CaO component, which is a crystallization inhibitor, is performed.

The second step is a step of removing the CaO component which is an obstacle to the zeolite crystallization, can be divided into a 2-1 step of removing the CaO component, and a 2-2 step of dehydration, the CaO removal process Step 2-1 is step 2-1a, which is a hot water stirring step, step 2-1b, which is an air injection mixing step of injecting air injection to generate mixed turbulence, and step 2-1c, which measures CaO content. The second and second dehydration processes may be subdivided into a second-2a process of forming a cake and a second-2b process of pulverizing the cake.

In the step 2-1, the content of CaO is lowered to 5 wt% or less, preferably 3 wt% or less, to increase the zeolite crystallization rate, thereby enabling various types of zeolite synthesis. Removing the CaO component as much as possible is advantageous in improving reactivity, but considering economics, it is preferable to lower the content to 1 to 3% by weight relative to the total pumice powder weight and then perform a subsequent reaction step. In particular, when a continuous zeolite synthesis is performed using a high content of CaO component, the CaO component should be lowered through a second process and then crystallized.

Step 2-1a of the step 2-1, the pumice crushed material is soaked for 0.5 to 2 hours in a tank containing high temperature water of 50 ~ 80 ℃ to facilitate the elution of CaO component from the pumice crushed, stirring Through the component dissolution is more easily made to finally lower the CaO content to at least 5% by weight or less preferably 3% by weight or less.

The pumice powder can be CaO component elution by a variety of ways. For example, a batch type of agitation type that is put into a water tank and agitated, a conveyor type that is settled on a conveyor belt and passes through a water tank, a horizontal water tank rotating method that forms a spiral vane on the inner surface of a horizontal water tank and moves it in one direction to discharge it. Multiple discharges can be applied by parallel connection.

In the step 2-1b, the step 2-1b is an air injection mixing step for generating mixed turbulence. For example, a large number of micro-pores are formed on the inner surface of the tank and high pressure air is injected into the tank to generate a large number of small air bubbles, and the upward flow generated by the generated air bubbles ascending, the spiral flow in the stirrer or the spiral in the tank By mixing with the flow by vanes to generate turbulence, CaO and water react with calcium hydroxide by increasing the contact frequency of the surface of pumice crushed powder containing calcium oxide (CaO) and water with low concentration of calcium hydroxide (Ca (OH) ₂ ). The frequency of dissolution can be increased. In addition, as small air bubbles rise while passing through the stacked pumice grinds, the pumice grinds stacked up or down may be mixed or diffused to increase the frequency of contact with water, thereby making it easier to dissolve CaO. In this case, various gases such as hydrogen carbon dioxide may be selected and injected into the gas to be injected.

Steps 2-1a and 2-1b may be sequentially performed, or only one of them may be selectively performed.

In addition, it is possible to selectively perform steps 2-1a and 2-1b according to the CaO content of the pumice pulverization through the 2-1c process, which is a CaO content measuring process.

For example, if the CaO content is higher than the target content by measuring the CaO content of the pumice crushed powder, which has been subjected to the 2-1a process through the 2-1c process, the process may be newly performed or the 2-1a process is performed. In the process of performing the CaO content periodically measured if the measured CaO content is higher than the target content can be adjusted to increase the time to pass through the tank so that the CaO content at the discharge side is lower than the target content.

In addition, when the CaO content measured from the pumice pulverized matter which performed step 2-1a through the measurement of CaO content is higher than the target content, the step 2-1b is performed to mix the stirring method and the air injection method. CaO content can be reduced. The pumice pulverized material, which has performed step 2-1b, may also measure CaO content through a CaO content measurement process, and if the measured CaO content is higher than the target content, perform step 2-1a or 2-1b again. Can be.

The CaO content measurement of the 2-1c process may be continuously measured in a continuous manner, or measured by a predetermined time unit to adjust the device speed. In this way, if the CaO content measurement process is additionally performed, even if the CaO content of the input material is changed, the CaO content of the pumice pulverized material discharged by the automatic control in this process can be lowered to a certain level or less, thus maintaining the quality of the final zeolite uniformly. It provides the effect. In the step 2-1c, which is a CaO content measuring step, the CaO content is preferably set to 5% by weight or less relative to the total mixture, and more preferably 3% by weight or less to improve the crystallinity.

In addition, the step of removing the CaO component was to complete any one of steps 2-1a and 2-1b and to perform an additional step according to the CaO content, in addition to the stirrer 2-1a process In the process of performing the stirring process by measuring the CaO content periodically, if the measured CaO content value is out of the range of 1% by weight compared to the set CaO content value can perform the step 2-1b to increase the CaO removal rate per hour.

For example, if the 2-1 step of removing the CaO component is performed for 1 hour, the CaO component is removed by the water tank stirring method of the 2-1a process, and the value measured by measuring the CaO content is measured at 30 minutes. When a difference of 1% by weight or more from the set value occurs, pumice pulverized material having a CaO content or less set within the set time may be provided by a method of injecting air to perform the step 2-1b.

Here, the determination of switching to step 2-1b during the process of step 2-1a is made by a difference between the CaO content set value and the CaO content measured value, and the error range with the CaO content set value is determined in the remaining time. It can be set to vary according to the data, it can be made to automatically convert according to the CaO content measurement results by the data.

That is, in the CaO content measurement process (Step 2-1c), when the remaining time for performing the CaO component removal process (Step 2-1) is 30 minutes, the error range between the set value and the measured value is 1% by weight, and the remaining time. In the case of 15 minutes, the error range between the set value and the measured value is converted into 0.4% by weight, and it is determined whether the measured CaO content measured at each time point is within the error range. An automatic operation setting process may be included to automatically set whether to switch to the process to quickly remove the CaO component.

When the automatic operation setting is included in this way, the zeolite produced even when the pumice having various CaO contents is added can be produced by similar crystallinity, so that the productivity can be maintained uniformly.

On the other hand, in the batch method and the horizontal water tank rotating method, by adding vibration or microwave to the water tank container, the CaO component is further eluted by increasing the contact frequency of the low calcium hydroxide (Ca (OH) ₂ ) water and pumice powder in the water tank. Can be promoted.

Next, the dehydration step 2-2 is a step of dewatering the pumice crushed material which has undergone the 2-1 step of removing the CaO component, and centrifugal force or a pressurization method may be applied.

This 2-2 process includes a 2-2a process of compressing and dehydrating pumice crushed material having reduced crystallization-interrupting material and converting the cake into a cake, followed by a 2-2b process of crushing the cake.

For example, the cake of the 2-2a process may be dewatered by pressurization using a continuous filter press.

In addition, step 2-2b is a step of crushing the compressed cake. Step 2-2b is a step of crushing the caked agglomerated pumice crushed by pressing into a stirrer including a crusher. At this time, the drying may be performed at the same time by applying heat in the crushing process to make the dry powder. Here, the stirrer is composed of a heating jacket to crush the pumice pulverized agglomerates by heat supply and at the same time to evaporate the water to powder the powder, or to dry the pulverized pumice pulverized by the crushing roll generated by heat transfer. Can be made at the same time. In addition, in the second-2b process, only the cake crushing process may be performed, and drying by heat may be performed together with combustion in the following heat treatment process.

Next, a third heat treatment process is performed. The third step is a step of injecting the powdered pumice crushed material discharged from the second step into a heat treatment tank by using a transfer means to dry the water by evaporation and to calcinate carbon and other flammable impurities remaining in the pumice crushed product. The conveying means may be conveyed by a variety of known methods such as a conveyor belt or a free fall method. The heat treatment temperature applied in the third step is in the range of 700 ~ 800 ℃.

At this time, the heat treatment tank (firing furnace) may be heated while the pumice pulverized material is moved by the conveyor belt, or may be heated in a batch type firing furnace to heat the heat. At this time, the heat treatment temperature is formed in the range of 700 to 900 ° C. If the temperature is less than 700 ° C, the combustion and removal of carbon powder or other impurities remaining in the pumice crushed product are not completely performed, and thus the purity of the zeolite is acted as an impurity. When the heating temperature is higher than 900 ° C., the heat treatment effect due to the temperature increase is insignificant, but the energy consumption is increased, so the heat treatment is preferably performed in the above range.

In addition, the pumice pulverized is sufficiently dried by calcination is made by preheating at a low temperature of 100 ~ 300 ℃ and then calcining at a high temperature rather than directly put into a firing furnace of 700 ~ 900 ℃ calcination is made Efficient removal of impurities can be achieved while shortening the time. In other words, when there is no low temperature preheating, a calcination time of 70 to 100 minutes is required. However, when low temperature preheating is performed, only a calcination time of 50 to 60 minutes is required.

The fourth step of stirring the mixed powder is a step of mixing and stirring the light component chain heat-treated in the third step with a powdered alkali material.

The mixed alkali material may be selected from sodium hydroxide (NaOH) and sodium carbonate (Na ₂ CO ₃ ). In addition to the alkali material containing a sodium component; Alkali materials containing potassium and calcium or barium, such as potassium hydroxide, potassium carbonate, calcium hydroxide and barium hydroxide, may be selected and used.

It is preferable that such an alkali material is also pulverized to 30 to 60 mesh like the pumice crushed powder to be mixed in a powder form to enable uniform mixing.

The mixing ratio is preferably 50 to 200 parts by weight of the powdered alkali material selected relative to 100 parts by weight of the pulverized pumice crushed powder. When the alkali material is mixed in an amount of 50 parts by weight or less, the formation of the aluminate ion source and the silicate ion source is inadequate, resulting in low crystallization. When the mixture is mixed in an amount of 200 parts by weight or more, the aluminate ion source and the silicate ion source It is preferable to mix within the above range because the degree of formation enhancement is insufficient.

In addition, the mixer used for mixing is preferably mixed uniformly using a ribbon mixer, it is possible to apply the CSTR method for a continuous process, for example, a plurality of ribbon mixers are installed in series and stay in each ribbon mixer. By controlling the time to make the continuous mixing can be possible. The stirring time of the mixing powder stirring step is made for 5 minutes to 60 minutes, preferably stirring for 10 to 20 minutes that can be sufficiently uniformly mixed with pumice powder and alkali material.

The fifth step, the fusion process, is a process in which a uniformly stirred mixed powder is introduced into a heating bath and heated to fuse the alkali material and the pumice powder. In the fifth process, the alkali material in the mixed powder is melted by the supplied heat to fuse with the pumice powder. Therefore, when the alkali material and pumice powder are uniformly mixed in powder form, the molten alkaline material and pumice powder are fused 1: 1 to form a structure that is advantageous for the synthesis of zeolite.

That is, by heating, SiO ₂ in the main component of pumice is changed into Na ₂ SiO _{3 which} is well soluble in water or NaAlSiO ₄ which is soluble in an alkaline aqueous solution, thereby forming an aluminate ion source and a silicate ion source required for zeolite synthesis.

The heat treatment temperature in this fusion step is formed to 500 ~ 900 ℃, it is preferable to be made for 30 to 180 minutes. In other words, the alkali material does not melt well below 500 ° C., so that fusion with the pumice crushed material is not made well. Above 900 ° C., the alkali material is excessively melted and agglomerated with adjacent alkali materials to form agglomerates. It is preferable to apply heat.

At this time, when using sodium hydroxide (NaOH) as the alkali material, it is preferable to mix the 100 to 120 parts by weight with respect to 100 parts by weight of pumice crushed, in the fusion step is preferably to be fused at a temperature of 500 ~ 550 ℃.

In addition, in the case of using sodium carbonate (Na ₂ CO ₃ ) as an alkaline material, it is preferred to mix 50 to 200 parts by weight with respect to 100 parts by weight of pumice crushed matter, and to be fused at a temperature of 800 ~ 900 ℃ in the fusion step. Do. When the fusion is performed by applying heat below 600 ° C. using sodium carbonate, the yield is lowered because more than 50% of quartz or aluminum silicate contained in the pumice powder remains and does not participate in crystallization to zeolite. Therefore, it is desirable to be able to change the amorphous or water-soluble form which is easy to be used as a zeolite raw material by adjusting the heat treatment temperature according to the alkali material to be added.

Next, a mixing process, which is a sixth process, is performed. The sixth step is a step of mixing the pumice pulverized material and the pumice fused material of the alkaline material, the water, the aluminum source and the zeolite seed, which have been subjected to the fusion step in the previous fifth step.

The mixing ratio is 200 to 1000 parts by weight of water, 5 to 25 parts by weight of aluminum source and 0.5 to 5 parts by weight of zeolite seed with respect to 100 parts by weight of the pumice fusion produced in the fusion process.

When the water is mixed at 200 parts by weight or less, the amount of zeolite is lowered. When the mixture is mixed at 1000 parts by weight or more, the crystallization rate is slowed, so that the plant size increases during mass production. More preferably, it mixes 400-500 weight part. In addition, by adjusting the mixing amount of the water to increase the concentration of alkali in the mixture to produce a NaP1 zeolite having a stable structure, or to produce sodalite.

In addition, the aluminum source is added to control SiO ₂ / Al ₂ O _3, which is a composition ratio of the finally required synthetic zeolite. As the aluminum source, an aluminum waste coagulant (Al content of 5 to 40% by weight) is used, and NaAlO ₂ is typically used.

In addition, the zeolite seed serves to determine the shape of the final synthetic zeolite. In particular, the present invention may further include a circulation step in the process so that some of the produced zeolite can be reused as a seed because of high purity.

In order to perform the mixing process of the sixth process, a plurality of synthesis reactors accommodating each mixture may be formed, and may be installed in series so that the mixing may be performed while sequentially passing each synthesis reaction tank, or a plurality may be installed in parallel. It can be applied in such a way that each of them is fed separately, each reacts independently, and then a sequential release occurs.

The seventh step is a step of aging by stirring the mixture of the sixth step at 20 ~ 60 ℃ low temperature heating.

This process is a step of stirring so that the pumice fusion is sufficiently dissolved in water, it is preferable to make the stirring for 3 to 12 hours. When the aging time is less than 3 hours, the pumice fusion is not sufficiently dissolved in water, and thus the amount synthesized in the crystallization step is lowered. When the aging time is more than 12 hours, the degree of crystallization is insufficient. It is desirable to make it.

The eighth step is a step of increasing the heating temperature to 80 ~ 100 ℃ to the mixture aged through the seventh step to the synthesis and growth of zeolite crystals.

The eighth process of the present crystallization can be carried out in a hydrothermal reactor, but can also be carried out in a general batch reactor. Therefore, by installing a plurality of batch reactors in parallel to perform the crystallization reaction by the time difference in order to achieve a sequential discharge can be produced crystallized zeolite similar to the continuous process.

This eighth process is carried out for 2 to 72 hours to allow crystallization to occur, preferably to allow the crystallization to proceed in the reaction tank for 3 hours or more, and can be controlled within the above range to perform the crystallization according to the type of zeolite have.

The ninth process is a process in which the zeolite synthesized through crystallization in the eighth process is filtered, washed with water and dried to produce a commercially used product.

That is, the zeolite crystallized in the eighth step is filtered and washed with distilled water to remove the mother liquor and metal ions on the zeolite, and dehydrated through a continuous filter press. In addition, wastewater generated during the dehydration process may be used in place of water mixed with the pumice fusion in the mixing step.

The drying is made in the range of 90 ~ 100 ℃, it can be made through the continuous tunnel drying continuous drying.

In addition, the dried zeolite may be commercialized in a powder state, or may be used by further firing, or may be used by hot firing after molding in pellet or bead form.

The present invention will be described in more detail with reference to the following Examples.

1. Preparation of Zeolite of the Present Invention

-Pumice receiving and grinding process (1st process)

The discarded pumice was received near the coal mine in Gangwon-do.

The received pumice was powdered up to 30 mesh (about 600 μm) through a crusher.

The powdered pumice crushed powder is analyzed using XRF and shown in Table 1 below.

TABLE 1

As shown in Table 1, it can be seen that the CaO content is about 8% by weight. In addition, since the sum of SiO ₂ and Al ₂ O ₃ is about 81%, the purity of the zeolite synthesis is also expected to be 81% or more.

CaO removal process (2nd process)

Pumice pulverized material was added to 90 ℃ hot water of the batch water tank and stirred for 1 hour to lower the CaO component to less than 7% by weight of the total weight.

The pumice pulverized material having low CaO content was dehydrated by a compression method, and the compressed cake was crushed and supplied to a heat treatment process.

-Heat treatment process (3rd process)

The pumice pulverized material subjected to the CaO removal process was put into a calcination furnace and heat treated at 800 ° C. At this time, the heating was preheated at 200 ℃ for 10 minutes, and then heated up at 50 ℃ heat treatment for 50 minutes.

When the preheating process was performed, the combustion of residual carbon and volatile materials was completed in the same manner as the heat treatment at 800 ° C. for 100 minutes without preheating, thereby reducing the heating time. Therefore, in the present invention, the heat treatment was performed by a method including a preheating process for shortening the time.

-Mixed powder stirring process and fusion process (4th and 5th process)

100 g of the heat treated pumice powder was collected and introduced into a mixer, and powdered sodium hydroxide was selected as an alkaline material, and 120 g was added to the mixer, followed by stirring for 10 minutes to uniformly prepare a mixed powder.

The mixed powder of pumice powder and sodium hydroxide was introduced into a heating bath, and heated at 500 ° C. for about 1 hour to be fused.

-Mixing process, aging process and crystallization process (6th, 7th and 8th process)

100 g of fused pumice fusion, 500 mL of water, and 1 g of zeolite 4A seed were added to the synthesis reactor.

In addition, since the molar ratio of SiO ₂ / Al ₂ O _{3 in} the pumice is 2.9, 20 g of NaAlO ₂ selected as an aluminum source is further added to adjust the molar ratio of SiO ₂ / Al ₂ O ₃ to 2.0.

The mixture was heated to a low temperature of 30 ° C. for 5 hours with stirring to allow the pumice fusion to be sufficiently dissolved in water.

The heating temperature of the mixture after aging was raised to 90 ° C. and stirred for 5 hours to proceed with crystallization.

-Zeolite commercialization process (9th process)

After crystallization of the zeolite was filtered, washed with deionized water and dehydrated, the zeolite was dried at 100 ° C. in a dry oven to produce a powdered zeolite 4A.

2. Manufacture of zeolite 4A

1) Example 1 - Zeolite 4A was prepared by the above method, but the CaO content was adjusted to 7 wt% or less based on the total weight of the pumice powder by changing the process run time in the CaO removal process.

2) Example 2 - Zeolite 4A was prepared by the preparation method, but the CaO component content was adjusted to 6 wt% or less based on the total weight of the pumice crushed material in the CaO removal process.

3) Example 3 - Zeolite 4A was prepared by the preparation method, but the CaO component content was adjusted to 5 wt% or less with respect to the total weight of the pumice crushed material in the CaO removal process.

4) Example 4 - Zeolite 4A was prepared by the preparation method, but the CaO component content was adjusted to 4 wt% or less with respect to the total weight of the pumice crushed material in the CaO removal process.

5) Example 5 - Zeolite 4A was prepared by the preparation method, but the CaO component content was adjusted to 3% by weight or less based on the total weight of the pumice powder in the CaO removal process.

6) Example 6 - Zeolite 4A was prepared by the preparation method, but the CaO content was adjusted to 2 wt% or less based on the total weight of the pumice crushed material in the CaO removal process.

7) Example 7 - Zeolite 4A was prepared by the above method, but the content of CaO component was adjusted to 1% by weight or less based on the total weight of the pumice powder in the CaO removal process.

8) Example 8 - Zeolite 4A was prepared by the preparation method, but the CaO content was adjusted to 0.5 wt% or less based on the total weight of the pumice crushed powder in the CaO removal process.

9) Comparative Example 1 did not run the CaO step of removing the zeolite 4A prepared by the above method.

Experimental Example 1) Crystallinity Measurement

XRD was measured using the zeolite produced in Examples 1 to 8 and Comparative Example 1 to calculate the crystallinity.

[Equation 1]

Here, the product is a zeolite prepared in Examples 1 to 6, and the reference product is a commercial zeolite 4A or a commercial zeolite NaP1 manufactured by Wako.

The chemical composition of the commercial zeolite 4A was 47.32 wt% SiO _2, 34.87 wt% Al ₂ O ₃ , 17.66 wt% Na ₂ O, 0.07 wt% CaO, 0.03 wt% SO _3, 0.03 wt% Fe ₂ O ₃ , and other components. 0.02% by weight.

In addition, the crystallinity is a relative value when the crystallinity of the reference substance is 100%.)

In Example 1 to Comparative Example 1, the CaO component content and the crystallinity of the zeolite prepared by using the same as the total weight of the pumice powder before the heat treatment process are summarized in Table 2 below.

TABLE 2

As shown in Table 2, Examples 1 to 8 showed higher overall crystallinity than Comparative Example 1, but Examples 1 to 2 were almost similar, and thus the degree of improvement in crystallinity was insufficient. It can be seen that the crystallinity was greatly improved from Example 3 with CaO component fragrance less than 5% by weight, and in particular, Example 5 having 3% by weight or less showed a sharp improvement in crystallinity.

However, as in Example 8, in order to lower the CaO content to less than 0.5% by weight relative to the total weight, the stirring time in the water tank was increased by twice as much as in Example 5. That is, in order to numerically obtain an improvement in crystallinity, the CaO content is set at 0.5 to 5% by weight relative to the total weight in the CaO component removal process, and preferably, the CaO content is set at 1 to 3% by weight to achieve high crystallinity. Most preferably, the CaO content is set to 3% by weight to operate to obtain a high degree of crystallinity over time to improve productivity.

3 is an analysis of zeolite 4A prepared using pumice according to the preparation method of the present invention (Example 5; Zeolite AG) and commercial zeolite 4A (Zeolite A-ref.), And FIG. SEM photograph of zeolite 4A prepared by the preparation method of FIG. 5. As can be seen it can be seen that the synthetic zeolite prepared by the production method of the present invention has a peak close to the commercial zeolite.

Experimental Example 2) CaO Content Measurement after CaO Removal

1 kg of pumice crushed powder having the content shown in Table 1 was added to a batch tank containing 30 L of hot water, and a CaO removal process was performed.

The batch type water tank has a structure in which a plurality of air injection hoses are communicatively coupled from the outside to supply high pressure air in the form of small droplets through the inner side and the bottom surface, and an agitating method using an agitator and an air injection method for forming air bubbles are selected. Can be carried out.

10) Example 9 -The stirrer was stirred for 30 minutes, and the stirrer was stirred for another 30 minutes, after which the CaO content was measured.

11) Example 10 - Air bubbles floating method was performed for 30 minutes, air injection method was further performed for 30 minutes, and after completion of CaO content was measured.

12) Example 11 -After stirring the stirrer method for 30 minutes, the air injection method was carried out for 30 minutes, CaO content was measured after completion.

13) Example 12 -The stirrer was stirred for 30 minutes, and then the stirrer was stirred for 30 minutes, and the CaO content was measured.

The CaO content measured by Examples 9 to 12 is shown in Table 3 below.

TABLE 3

When the CaO removal process is performed at the same time as referring to Table 3, it can be seen that the stirring method is more effective in reducing the CaO content than the air injection method. This is because when pneumatic injection is not carried out, a number of air injection holes may be closed due to the inflow of pumice powder into the air injection hole when the air injection is not performed. It seems to be.

In addition, it can be seen that the CaO content effect shows a high removal rate when the mixture of the stirring method and the air injection method of Example 12 is executed, and Example 9, which is performed only by the stirring method, also shows a high removal rate. However, in Example 10 and Example 11 performed by air injection alone, the CaO content was relatively low.

Therefore, when the mixing method of stirring and air injection of Example 12 is applied in the CaO removal process, the CaO removal process time can be shortened. However, it is desirable to reduce the CaO component to the desired target value in a short time by applying the case where the gap is large compared to the target CaO content value by increasing the energy consumption since the air injection method is additionally performed.

3. Preparation of Zeolite NaP1 by the Production Method of the Present Invention

15) Example 13 - Zeolite NaP1 was prepared by the method of the present invention.

In the second step (CaO removal step), the content of CaO component to the total weight of the pumice crushed product was adjusted to 7% by weight or less.

Sodium carbonate was selected as the alkaline substance added in the fourth step (mixed powder stirring step).

In the fifth step (fusion process), the mixed powder of pumice crushed powder and sodium carbonate was introduced into a heating bath, and heated at a temperature of 850 ° C. for about 2 hours to be fused.

100 g of the pumice fusion fused in the sixth step, 500 mL of water, and 1 g of zeolite NaP1 seed were added to the synthesis reactor.

At this time, since the molar ratio of SiO ₂ / Al ₂ O ₃ was 2.9, NaAlO ₂ selected as an aluminum source was not added separately because the molar ratio of zeolite NaP ₁ was equal to 2.9.

In the eighth step (crystallization step), crystallization was performed while stirring at 90 ° C. for 18 hours.

After crystallization of the zeolite was filtered, washed with deionized water, and dehydrated, the zeolite was dried at 100 ° C. in a dry oven to produce zeolite NaP1 in powder form.

16) Examples 14 to 20 -Prepared in the same manner as in Example 13, except that the CaO content of 6, 5, 4, 3, 2, 1, The amount was adjusted to 0.5 wt% or less.

17) Comparative Example 2 -Prepared in the same manner as in Example 13, but without performing the second step (CaO removal step), the CaO component content to the total weight of the pumice crushed product is about 8% by weight as shown in Table 1 .

In Examples 13 to 20 and Comparative Example 2, the molar ratio of SiO ₂ / Al ₂ O ₃ was adjusted to 2.9 using NaAlO ₂ selected as the aluminum source in the sixth step.

Experimental Example 3 Measurement of Zeolite NaP1 Crystallinity

The crystallinity calculation was applied to the equation (1) of Experimental Example 1. The reference product here is Wako's commercial zeolite NaP1.

The measured binding degrees are shown in Table 4 below.

TABLE 4

As shown in Table 4, the zeolite NaP1 also showed a higher crystallinity from Example 15, which lowered the CaO content in the pumice grind to 5 wt% or less, as in zeolite 4A. It can be seen that the degree of crystallinity of more than 80% by weight.

In addition, the lower the CaO content in the pumice pulverized it can be seen that the crystallinity is higher, but the second process (CaO component removal process) takes a long time to lower the CaO content as in the production of zeolite 4A Because of this, it is preferable to perform the zeolite manufacturing process by setting to 3% by weight level.

The analysis of the zeolite NaP1 prepared by the preparation method of Example 17 can be seen as shown in FIG.

Claims (9)

A first step of pulverizing the selected pumice stone into powder of 30 mesh or less using a continuous crusher; A second step including a step 2-1 of injecting the pumice crushed material of the first step into a water tank to elute and remove the CaO component, which is a crystallization-interrupting substance, and a step 2-2 of dewatering the pumice crushed material having the reduced CaO component 2 step; A third step of subjecting the pumice powder having reduced CaO component to the heat treatment tank in the second step to heat-treat the carbon and other impurities remaining in the pumice powder to burn out; A fourth step of adding the pumice powder and powdery alkali material heat-treated in the third step to a stirrer and stirring the mixed powder evenly; A fifth step in which the mixed powder uniformly stirred through the fourth step is introduced into a heating bath and heated, and the alkali material melted by heat is fused with the pumice powder; A sixth step of mixing the fusion material which has undergone the fusing step in the fifth step with water, an aluminum source and zeolite seed; A seventh step of aging by stirring the mixture of the sixth step while heating at a low temperature to 20 ~ 60 ℃; An eighth step of crystallizing the heating temperature of the mixture aged in the seventh step to 80 to 100 ° C. to synthesize and grow the zeolite crystals; Including the ninth step of forming the product by filtration, washing and drying the zeolite synthesized in the eighth step; Step 2-1 of the second step, Immersing the pulverized pumice in hot water at 50-80 ° C. for 0.5-2 hours and stirring to lower the CaO content of the pulverized pumice to 0.5-5 wt%; High pressure air is injected into the tank through a plurality of micro-holes formed in the inner surface of the tank to generate a plurality of small air bubbles in the tank, and the rising air bubbles are raised to form an upward flow, and the upward flow is mixed with the swirling flow of the stirrer. 2-1b to generate a mixed turbulence; When performing the step 2-1a or step 2-1b to measure the CaO content, compared to the set value of the CaO content, if the value is more than the allowable error range according to the remaining process execution time, the second step 2-1a -2b process to be discharged and then discharged, and in step 2-1b, step 2-1c, which is a CaO content measurement and automatic conversion process, to be performed again after the process 2-1a is performed; Synthetic zeolite production method, characterized in that made. The method of claim 1, The pumice is synthetic zeolite manufacturing method, characterized in that the waste pumice is discarded in the waste mine. The method of claim 1, In the second step Method for producing a synthetic zeolite, characterized in that to remove the CaO component so that the CaO component in the range of 1 to 3% by weight relative to the total pumice powder weight. The method of claim 1, In step 2-2, A 2-2a step of compressing and dehydrating pumice crushed material having reduced crystallization-blocking substance to cake into a cake; 2-2b step of pulverizing the pumice pulverized in the cake state into a stirrer and crushed into a powder state; further comprising a synthetic zeolite production method. The method of claim 1, The fifth step, As an alkaline substance, select one kind from sodium hydroxide (NaOH), sodium carbonate (Na ₂ CO ₃ ), 50 to 200 parts by weight of the powdered alkali material selected for 100 parts by weight of the pulverized pumice powder, A method of producing a synthetic zeolite, characterized in that the pumice pulverized product and the alkali material are fused by heat treatment at 500 to 900 ° C. for 0.5 to 3 hours. The method of claim 1, The sixth step, Synthetic zeolite manufacturing method characterized in that the mixture of 200 to 1000 parts by weight of water, 5 to 25 parts by weight of aluminum source and 0.5 to 5 parts by weight of zeolite seed with respect to 100 parts by weight of the pumice fusion produced in the fifth step. The method of claim 6, The aluminum source is a method of producing a synthetic zeolite, characterized in that NaAlO ₂ . The method of claim 1, The seventh step, Synthetic zeolite production method characterized in that the stirring for 3 to 12 hours at a temperature of 20 ~ 60 ℃. The method of claim 1, The eighth step, Synthetic zeolite production method characterized in that the crystallization is carried out for 2 to 72 hours in a batch reactor at 80 ~ 100 ℃ and atmospheric pressure conditions.

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