KR20120021478A - Method of recycling cerium oxide abrasive material - Google Patents

Abstract

PURPOSE: A method for recycling cerium oxide abrasive is provided to get high purity cerium oxide abrasive because frit glasses and inorganic coagulants of abrasive wastes are removed environmentally-friendly by applying an acid treatment process and an ultrasonic and/or bubble treatment process together. CONSTITUTION: A method for recycling cerium oxide abrasive is as follows. Organic acid solution and abrasive wastes are mixed and stirred in a reactor(100) to change inorganic coagulants to ionic species by an acid treatment process and float frit glasses. The floated frit glasses are removed. The cerium oxide abrasive is obtained through cleaning and drying process. The ph of the organic acid is within 0.5-6.0.

Description

Method of recycling ceria-based abrasives {Method of recycling cerium oxide abrasive material}

The present invention relates to a method for regenerating ceria-based abrasives, and more particularly, to a method for regenerating ceria-based abrasives that can environmentally regenerate high-purity ceria-based abrasives from abrasive waste containing ceria-based abrasives, frit glasses, and inorganic flocculants. It is about.

Ceria-based abrasives containing ceria (CeO ₂ ) as a main component are used for polishing various glass materials. Recently, glass for magnetic recording media such as hard disks, glass substrates of liquid crystal displays (LCDs), glass substrates of plasma display panels (PDPs), and the like. It is also used for polishing of the same glass material, and its application field is gradually expanding.

In general, when polishing a glass material such as a glass substrate of LCD or PDP by using a ceria-based abrasive, a sandblasting process of spraying and polishing a ceria-based abrasive on the glass material using an abrasive powder spray nozzle or using a roll ( role floating process is used.

Abrasive wastes are produced during sandblasting or floating processes using ceria-based abrasives, which include impurities such as ceria-based abrasives, frit glass components and polishing pad components contained in glass materials. exist. The ceria-based abrasive accounts for about 10 wt% to 60 wt%, and the frit glass is present in the form of a powder mixed with the ceria-based abrasive or adsorbed on the ceria-based abrasive surface. The frit glass has SiO _{2 as a} main component.

Recently, the demand for display devices such as LCDs and PDPs is increasing rapidly. As a result, the amount of ceria-based abrasives is rapidly increasing, and the amount of abrasive waste is also rapidly increasing. Since the abrasive waste containing such ceria-based abrasives is entirely discarded, it may cause environmental pollution.

In the conventional method of treating the abrasive waste, the abrasive waste slurry containing the ceria-based abrasives having been polished is sent to a purification device, and the solidification particle is added by adding an aluminum (Al) or iron (Fe) flocculant in the purification device. Is precipitated and caked, the discharged liquid is chemically treated and discharged, and the caked abrasive waste is disposed of in its entirety.

However, in order to polish glass materials, a large amount of ceria-based abrasives are required, and in recent years, the price of ceria-based abrasives is also increasing. Ceria-based abrasives are rarely produced in Korea and almost all depend on imports. It is true. Therefore, the necessity of regenerating ceria-based abrasives has emerged. However, there has been little research on a method of regenerating ceria-based abrasives in spite of the necessity of regeneration thereof.

Korean Patent Application No. 10-2005-0037510 relates to the recycling method of CRT sludge by wet specific gravity method, and suggests how to separate and recycle CRT sludge by wet specific gravity screening method. It is a technique of separating and recovering each component in a different composition.

Korean Patent Application No. 10-2006-0103546 relates to a method of reclaiming waste abrasive for polishing a glass panel for display, and shows a method for separating the display abrasive sludge and adding a metal oxide to sinter and classify. As a technique for adding, sintering and pulverizing a metal oxide from an abrasive slurry to a sintering aid, a process is complicated and energy consumption is high.

The problem to be solved by the present invention is environmentally friendly recycling of ceria-based abrasives from abrasive waste containing ceria-based abrasives, frit glass and inorganic flocculant, obtains high purity ceria-based abrasives, yields a very high yield of ceria-based abrasives The present invention provides a method for reproducing.

The present invention relates to a method for regenerating a ceria-based abrasive from an abrasive waste comprising a ceria-based abrasive, a frit glass, and an inorganic flocculant, wherein the organic acid solution and the abrasive waste that do not form a salt by reacting with the ceria-based abrasive in a reaction tank. By adding and stirring, the inorganic flocculant is changed into ionic species by acid treatment with the organic acid, and the frit glass is suspended, the suspended frit glass is removed, and the washing and drying process is performed. Comprising a step of obtaining an abrasive, the organic acid provides a ceria-based abrasive regeneration method characterized in that the pH range of 0.5-6.

In the method for regenerating the ceria-based abrasive, ultrasonic waves are applied through an ultrasonic horn installed in the reaction tank while stirring with a stirrer installed in the reaction tank, and the chemical reaction of the organic acid and the inorganic coagulant is promoted by the ultrasonic waves, A sonication step is performed in which the generated bubbles swell violently and burst due to the high pressure, and the shock wave when the bubbles explode acts on the abrasive waste, causing the frit glass attached to the ceria-based abrasive surface to peel off from the ceria-based abrasive surface. It may further include.

In the method of regenerating the ceria-based abrasive, air is injected by using a bubble generator provided in the lower part of the reactor while stirring with a stirrer installed in the reactor, thereby generating bubbles and by the force of the shock waves or bubbles that rise. The method may further include a bubble treatment step of removing the frit glass from the ceria-based abrasive surface to float.

The method of regenerating the ceria-based abrasive may further include performing a wet vibrating sifting to filter foreign matter and the suspended frit glass mixed during the regeneration process after the acid treatment, wherein the wet vibrating sifting is performed. It is preferable to sift with 50-2000 mesh sieve.

The method of regenerating the ceria-based abrasive may further include performing an alkali treatment by adding an alkali solution to dissolve the frit glass remaining in the ceria-based abrasive, after removing the frit glass. At least one alkali compound selected from sodium, potassium hydroxide, ammonia, primary amines having 1 to 10 carbon atoms, secondary amines and tertiary amines is used, and the alkali treatment has a pH in the range of 9 to 13 It is preferable to selectively remove the frit glass by adding the alkali solution so that the weight ratio of the ceria-based abrasive to the alkali solution is in the range of 1: 0.5 to 10.

The inorganic flocculant may be composed of aluminum sulfate, polyaluminum chloride, ammonium alum, sodium aluminate, ferrous sulfate, ferric sulfate or ferric chloride.

The organic acid solution preferably includes at least one acid selected from acetic acid, lactic acid, citric acid and oxalic acid.

The regeneration method of the ceria-based abrasive may further include performing a second acid treatment using an organic acid solution different from the organic acid solution after acid treatment with the organic acid solution.

According to the present invention, the ceria-based abrasive can be separated and recovered with high purity from the ceria-based abrasive waste which is entirely disposed of in landfill, and can be recycled, thus replacing the ceria-based abrasive depending on the total amount of import.

By applying the acid treatment process, which is a chemical method, and the ultrasonic and / or bubble treatment process, which are physical methods, it is possible to obtain high purity ceria-based abrasives by eco-friendly and easy removal of frit glass and inorganic flocculant present in the abrasive waste. The yield is very high.

In addition, the expensive ceria-based abrasive recycled from the abrasive waste can be used again in the industrial field, which can greatly reduce the industrial cost and production cost, and can suppress environmental pollution by not discarding the abrasive waste.

FIG. 1 is a view schematically showing a reaction tank in which bubbles are raised and filtered while generating bubbles by a bubble treatment step.
Figure 2 is a graph showing the particle size distribution of commercially available ceria-based abrasives.
3 is a graph showing the particle size distribution of the ceria-based abrasive recycled according to Example 1. FIG.
4 to 6 are graphs showing the particle size distribution of the ceria-based abrasive obtained by pulverizing the ceria-based abrasive recycled according to Example 1 using an ultrasonic vibrating body.
7a and 7b is a scanning electron microscope (Scanning Electron Microscope) photograph of the regular product.
8A and 8B are scanning electron microscope (SEM) photographs of abrasive waste.
9A to 9C are scanning electron microscope (SEM) photographs of ceria-based abrasives obtained by pulverizing a ceria-based abrasive recycled according to Example 1 using an ultrasonic vibrating body.
FIG. 10 is a graph showing X-ray diffraction patterns of commercially available ceria-based abrasives.
FIG. 10 is a graph showing an X-ray diffraction pattern of a ceria-based abrasive obtained by pulverizing a ceria-based abrasive recycled according to Example 1 using an ultrasonic vibrating body. FIG.

Hereinafter, preferred embodiments of the present invention will be described in detail with reference to the accompanying drawings. However, the following embodiments are provided to those skilled in the art to fully understand the present invention, and may be modified in various forms, and the scope of the present invention is limited to the embodiments described below. It doesn't happen. Like numbers refer to like elements in the figures.

The present invention provides a method for regenerating ceria-based abrasives in abrasive waste containing ceria abrasives.

When polishing a glass material such as a glass substrate of LCD or PDP by using a ceria abrasive, a sandblasting process or a roll is performed by spraying a ceria-based abrasive onto a glass material using an abrasive powder spray nozzle. Using a floating (role floating) process.

Abrasive wastes are generated in a sandblasting process or a floating process using ceria-based abrasives, which include frit glass components contained in ceria-based abrasives and glass materials. The ceria-based abrasive accounts for about 10 wt% to 60 wt%, and the frit glass is present in the form of a powder mixed with the ceria-based abrasive or adsorbed on the ceria-based abrasive surface. The frit glass has SiO _{2 as a} main component.

Abrasive wastes, which are abrasive by-products of glass materials, are caked by adding inorganic flocculants such as aluminum (Al) or iron (Fe) flocculants to precipitate solid particles and drain the liquid.

Examples of the aluminum flocculant include aluminum sulfate (Al ₂ (SO ₄ ) _{3 to} 18 H 20), polyaluminum chloride (PAC), ammonium alum (Al ₂ (SO ₄ ) _{3 to} (NH ₄ ) ₂ SO _{4 to} 24H ₂ O), Sodium aluminate (NaAlO ₂ ) and the like are used, and as iron-based coagulant, ferrous sulfate (FeSO ₄ -7H ₂ O), ferric sulfate (Fe ₂ (SO ₄ ) ₃ ), ferric chloride (FeCl ₃ ? 6H ₂ O) and the like are used. The aluminum salt or iron salt used as the inorganic flocculant is easily hydrolyzed in water to become a polymerization polyvalent cation, and consumes alkali or generates CO ₂ in the reaction to lower the pH. For example, aluminum sulfate reacts with alkali in water to form aluminum hydroxide, causing agglomeration, and in the process, CO _{2 is} also generated, resulting in a decrease in pH, and ferric sulfate in alkali. It reacts with to form a hydroxide to generate CO ₂ , Ferric Chloride is also known to reduce the pH by generating hydrochloric acid or CO ₂ .

Thus, the abrasive waste which is a by-product used for polishing the glass material contains oxide fine particles and inorganic coagulant components such as ceria abrasive and frit glass used for polishing the glass material.

The specific gravity difference between the ceria-based abrasive and the frit glass shows a large variation, but the average particle diameter does not show a variation. In addition, since the ceria-based abrasive and the frit glass have a maximum particle size of 10 µm or less, it is not easy to selectively remove the frit glass and the inorganic flocculant through the general classification process, and the method described in the preferred embodiment of the present invention. It must be removed through the same special process.

Hereinafter, a method of regenerating a ceria-based abrasive according to a preferred embodiment of the present invention will be described.

An acid treatment method using an organic acid solution can selectively classify ceria-based abrasives from abrasive waste containing ceria-based abrasives.

An acid slurry is prepared to selectively classify only ceria-based abrasives.

In detail, an acidic solution containing an organic acid and an abrasive waste containing an organic acid that does not form a salt by reacting with a ceria-based abrasive is added to a reaction tank, and then stirred with a stirrer to give an acid having a solid content of about 0.1 to 50% by weight. By forming a slurry, the frit glass contained in the abrasive waste is suspended and an acid treatment treatment process is performed in which the inorganic flocculant is converted into ionic species.

It is preferable that the stirring speed in preparing the acid slurry is about 50 to 2000 rpm so that the frit glass and the inorganic flocculant mixed in the abrasive waste are sufficiently dispersed and reacted.

The organic acid solution is an acid solution that does not form a salt by reacting with a ceria-based abrasive, and includes at least one selected from acetic acid, lactic acid, citric acid, and oxalic acid. It is preferable to use the above organic acid. Inorganic acids such as nitric acid, sulfuric acid, and hydrochloric acid may melt the ceria-based abrasive, and therefore, it is preferable to use an organic acid. The concentration of the organic acid solution is preferably about 0.1 ~ 30wt%.

The acid treatment process using the organic acid solution is preferably carried out for 30 minutes to 48 hours at room temperature (eg, 10 ~ 30 ℃) to 100 ℃. The polishing waste and the organic acid are preferably mixed in a weight ratio of about 1: 0.1-10 (polishing waste: organic acid). If the content of the organic acid is too small, the inorganic coagulant may not be sufficiently converted into ionic species. If the content of the organic acid is too high, it may be difficult to expect the effect of changing the inorganic coagulant to the ionic species any more. Not

The organic acid is added to change the pH in the range 0.5-6.0, more preferably in the range 2.0-4.0. If the pH controlled by the addition of the organic acid is less than 0.5, the acidity of the acidic slurry is not only too high and unstable, but the stability of the subsequent work may be reduced by the high acidity. The effect of changing the flocculant into ionic species may be weak.

As the pH of the inorganic flocculant and the flotation of the frit glass were observed as the pH was changed by adding the organic acid, the effect of changing the inorganic flocculant into the ionic species when the pH was 0.5 to 6.0 due to the addition of the organic acid was observed. The fritted glass was also suspended and separated from ceria abrasives.

As described above, by the organic acid treatment method, the inorganic flocculant is transformed into ionic species and dispersed in the organic acid solution in a dissolved state, and the frit glass forms a complex compound and floats on the organic acid solution.

Ceria-based abrasives sink because their specific gravity is relatively greater than that of frit glass and is insoluble in organic acids and heavy. Due to the difference in specific gravity, the ceria-based abrasive having a higher specific gravity sinks, and the frit glass having a smaller specific gravity is separated from the ceria-based abrasive and suspended.

While stirring the slurry using a stirrer, an ultrasonic treatment may be performed by injecting ultrasonic waves into the slurry using an ultrasonic wave oscillator. The sonication process removes the frit glass adhering to the ceria-based abrasive surface from the ceria-based abrasive surface. The frit glass component contained in the abrasive waste is separated from the ceria-based abrasive by the ultrasonic treatment process. The frequency of the injected ultrasound can be about 28 to 40 kHz, and the ultrasound time is 30 minutes? It is preferable to apply about 6 hours. In general, ultrasound refers to sound waves having a frequency of 20kHz or more. When ultrasonic waves are injected into the slurry, gas molecules (bubbles) in the slurry expand violently, and the gas molecules have a very high pressure and burst at their limits. When the bubble bursts, the shock wave acts on the abrasive waste to exfoliate the surrounding frit glass from the ceria-based abrasive. In addition, when the ultrasonic wave is injected into the slurry, the chemical reaction between the inorganic flocculant and the organic acid is promoted.

Instead of the sonication process or together with the sonication process, air is injected using a bubble generator provided in the lower part of the reaction tank to generate air bubbles, and the frit glass is generated by the force of the shock waves or bubbles that rise. A bubble treatment process may be performed to remove the surface of the abrasive and float it. The frit glass mixed in the abrasive waste has a specific gravity of about 1.4 and the ceria-based abrasive has a specific gravity of about 7, and the specific gravity difference between the frit glass and the ceria-based abrasive shows a large deviation. The frit glass can be selectively removed by classifying from the ceria-based abrasive.

1 shows a reaction tank 100 in which bubbles are raised and filtered while generating bubbles by a bubble treatment process.

In the reaction tank 100, a stirrer 120 including a motor M and a rotary blade 110 rotated by the motor M is installed, and the rotary blade 110 of the stirrer 120 is provided. Rotate at 50 to 2000 rpm. In addition, an ultrasonic horn H is installed in the reactor 100, and the ultrasonic horn H is connected to an ultrasonic wave generator (not shown). The ultrasonic waves oscillated by the ultrasonic generator are applied to the ultrasonic horn H to generate ultrasonic waves in the reaction tank. The ultrasonic waves applied to the ultrasonic horn H serve to separate the frit glass adhered to the ceria-based abrasive surface in the reaction tank 100 from the ceria-based abrasive surface. In addition, the lower surface in the reaction tank 100 is provided with a perforated plate 130 having a plurality of fine pores, and functions to generate air bubbles when passing through the perforated plate 130 by injecting air from the lower perforated plate 130.

The slurry including the frit glass, the inorganic flocculant, and the ceria-based abrasive is not precipitated by the rotation of the stirrer 120 to prevent the pores of the perforated plate 130 from being blocked. In addition, as air is injected from the injection hole below the perforated plate 130, bubbles are generated through the perforated plate 130, and the frit glass floats together with the bubbles.

On the other hand, the ceria-based abrasive has a large specific gravity and cannot remain on the bubble and remains on the bottom surface of the reactor 100. Bubbles generated through the stirring process in the reaction tank 100 cling to the surface of the frit glass to increase the buoyancy, so the frit glass quickly rises above the water surface. At this time, when the rotational speed of the stirrer 120 is too large, the vortex occurs largely, so that the ceria-based abrasive may also float along the wall surface of the reactor 100 by the vortex, and the rotational speed of the stirrer 120 is too small. Since the frit glass does not float and coexists with the ceria-based abrasive, sufficient separation is difficult, so that the rotation speed of the stirrer 120 is about 50 to 2000 rpm.

After performing the acid treatment step, the wet vibration sieve classification method described later may be used. The sieve used for the wet vibrating sieve has a 50 to 2000 mesh size. The floated frit glass has a particle size of about 10 μm or more in agglomerated form, and the ceria-based abrasive has a particle size of less than 10 μm so that the frit glass can be selectively removed by using a wet vibrating sifting. Specifically, the wet vibrating sifting process may be performed by sieving while vibrating the slurry in which the acid treatment process is performed with a sieve of a target mesh to selectively separate the ceria-based abrasive from the slurry. The frit glass having a large particle size does not pass through the sieve, and the ceria-based abrasive having a small particle size passes through the sieve, whereby the floated frit glass is selectively classified from the ceria-based abrasive.

The reaction vessel in which the ceria-based abrasive is settles down to remove impurities such as floating frit glass and polishing pad components. At this time, the ceria-based abrasive remains in the bottom of the reactor. As described above, the frit glass may be easily removed by pouring the frit glass suspended in the reactor. Inorganic flocculant converted to ionic species is dispersed in the organic acid solution, so it is removed together in the process of pouring the frit glass.

The acid treatment process using the organic acid solution may be repeatedly performed at least one or more times using different organic acids. For example, primary acid treatment may be performed using acetic acid, and secondary acid treatment may be performed using oxalic acid. By performing the two-step acid treatment process as described above, there is an advantage that the frit glass and the inorganic flocculant can be more completely removed.

After performing the acid treatment process, an alkali treatment process may be performed to remove frit glass remaining in the ceria-based abrasive using an alkaline solution. As the alkaline solution, at least one alkali compound selected from sodium hydroxide, potassium hydroxide, ammonia, a primary amine having 1 to 10 carbon atoms, a secondary amine, and a tertiary amine may be used. The alkaline solution serves to dissolve the frit glass. It is preferable that the alkali treatment is performed at a pH of 9 to 13, more preferably at a range of 9.5 to 12. When the pH controlled by the alkaline solution exceeds 13, not only is it unstable, but it is difficult to expect the frit glass melting effect any longer, and when the pH is less than 9, the effect of melting the frit glass may be weak. As a result of observing the effect of melting the frit glass by changing the pH by adding the alkaline solution, the effect of melting the frit glass was the highest when the pH by the addition of the alkaline solution was in the range of 9-13. The alkali treatment process is preferably carried out for 30 minutes to 48 hours at a temperature of about room temperature (for example, 10 ~ 30 ℃) to 100 ℃. The acid treated ceria-based abrasive and the alkali solution are preferably mixed in a weight ratio of about 1: 0.5 to 10 (ceria-based abrasive: alkali solution). If the content of the alkaline solution is too small, the frit glass cannot be sufficiently dissolved, and if the content of the alkaline solution is too large, it is not economical as waste of raw materials. The concentration of the alkaline solution is preferably about 0.1 ~ 30wt%.

It is preferable to wash the ceria-based abrasive with water (H ₂ O) at least once after performing an acid treatment process or an alkali treatment process.

After washing, a drying process is performed. The drying process may be performed through a general drying process such as hot air drying, vacuum drying, spray drying or freeze drying, and may obtain a ceria-based abrasive after the drying process.

Since the ceria-based abrasive particles are entangled with each other and aggregated, the ceria-based abrasive particles may be pulverized or pulverized to separate the particles from each other and to be refined. The pulverization or pulverization may use a generally known ultrasonic sieving method, a ball mill method, or the like.

Hereinafter, embodiments of the present invention will be described in more detail, and the present invention is not limited to the following examples.

≪ Example 1 >

An acid slurry was prepared. Specifically, 12 kg of abrasive waste comprising 1 kg of oxalic acid, ceria-based abrasives, frit glass, and poly aluminum chloride inorganic flocculant, and 22 kg of water (H ₂ O) are 75 l dissolver ( High-speed stirrer), and then stirred to form an acidic slurry to carry out the first acid treatment process. The pH of the slurry was about 1.5.

While stirring the slurry using a stirrer, a bubble treatment process was performed to float the aggregated frit glass. The apparatus for the bubble treatment process, as shown in Figure 1 is provided with a reaction tank 100, the reaction tank 100 in the rotary blade 110 that is rotated by a motor (M) and the motor (M). The stirrer 120 is configured to be installed, the ultrasonic wave horn (H) is installed in the reaction tank 100, the ultrasonic horn 50 is an ultrasonic wave generator (ultrasonic wave generator) Is connected to, the lower surface of the reaction tank 100 is provided with a perforated plate 130 formed with a plurality of holes, by injecting air from the lower perforated plate 130 to generate bubbles when passing through the perforated plate 130 It was. While stirring the stirrer 120 slowly, air was injected from the lower inlet, and the frit glass was floated together with the bubbles by bubbles generated while passing through the perforated plate 130 having fine pores. Ceria-based abrasives are large, the specific gravity was not raised by bubbles and remained on the bottom surface of the reactor (100). While performing the bubble treatment process, an ultrasonic wave of 28 Hz was applied to the ultrasonic horn to perform an ultrasonic treatment process for 4 hours. The rotary blade 30 of the stirrer 120 was rotated at 1000rpm, the stirring temperature was 25 ℃, the stirring time was 4 hours.

After performing the first acid treatment process, wet vibrating sifting was performed to remove suspended frit glass and foreign matter. The wet vibrating sifting sifted the frit glass suspended in a 100 mesh sieve, causing the ceria-based abrasive to disintegrate by vibration. After the wet vibration sieve was classified with a 100 mesh sieve, the second wet vibration sieve was classified using a 300 mesh sieve.

After removing the floating frit glass by wet vibration sifting, 2.4 kg of citric acid and 30 kg of water (H ₂ O) were added to the abrasive wastes subjected to primary acid treatment and wet vibration sifting. By stirring, a second acid treatment process was performed. The pH of the acid slurry by citric acid was about 1.5.

After performing the secondary acid treatment process, the reaction vessel in which the ceria-based abrasive was settled was tilted to pour out the floating frit glass. At this time, the ceria-based abrasive remains in the bottom of the reactor. As described above, the frit glass may be easily removed by pouring the frit glass suspended in the reactor. Inorganic flocculant converted to ionic species is dispersed in the organic acid solution, so it is removed together in the process of pouring the frit glass.

After tilting the reactor to pour the suspended frit glass, 3 kg of 10% sodium hydroxide (NaOH) and 30 kg of water (H ₂ O) were added to the polishing waste subjected to the secondary acid treatment, followed by stirring to give alkali. The treatment process was carried out. The pH of the alkali slurry with sodium hydroxide was brought to about 11.5.

After performing the alkaline treatment process, wet sifting was performed using a 1450 mesh sieve to remove frit glass or foreign matter.

The result of the wet sifting was washed twice with 30 kg of water (H ₂ O).

A drying process was performed to dry the washed resultant. The drying process was using a hot air dryer, and dried at 90 ℃ for 24 hours to obtain a high purity ceria-based abrasive.

FIG. 2 is a graph showing a particle size distribution of commercially available ceria-based abrasives (hereinafter referred to as 'regular article'), and FIG. 3 is a ceria-based abrasive (hereinafter referred to as 'regenerated dried article') recycled according to Example 1 This graph shows the particle size distribution of. 4 to 6 are graphs showing the particle size distribution of the ceria-based abrasive (regenerated crushed product) obtained by pulverizing the ceria-based abrasive recycled according to Example 1 using an ultrasonic vibrating body. In the disintegration process using the ultrasonic vibrating body, the feeding speed is 10 kg / kg (FIG. 4), 30 kg / kr (FIG. 5), 50 kg / hr (FIG. 6), and the applied voltage of the ultrasonic wave is 36 kHz. The vibrating body was performed with 500 mesh. Since the ceria-based abrasive recycled in accordance with Example 1 is weakly aggregated, only the disintegration process such as an ultrasonic vibrating body can release the intergranulation.

Compared to FIG. 2 and FIG. 3, the regenerated dried product showed almost the same particle size distribution as compared to the regular product, and compared to FIG. 4 to FIG.

Table 1 below shows the results of particle size analysis of regular products, regenerated dried products and remanufactured products.

subject D _{10 (} μm) D ₅₀ (㎛) D ₉₀ (㎛) D ₁₀₀ (㎛) Regular article 0.725 1.689 3.704 8.71 Recycled dry goods 0.800 2.029 5.448 34.674 Recycled crushed products1 0.639 1.478 3.515 8.71 Recycled crushed products2 0.646 1.554 3.625 8.71 Recycled shreds 3 0.751 1.767 3.855 8.71

Table 2 below shows the results of X-ray fluorescence (X-ray fluorescence) analysis of regular products, regenerated dry products and remanufactured products.

Regular article Abrasive waste Recycled F 10.4 7.31 7.38 Mg 0.0015 0.254 0.0160 Al 0.0284 8.22 0.0343 Si 0.0631 1.61 0.0913 P 0.0038 0.397 0.0318 S 0.0504 0.436 0.0188 K 0.0149 0.0198 0.0074 Ca 0.157 0.236 0.151 Fe 0.0482 0.898 0.111 Cu 0.0185 0.0190 Sr 0.0477 0.0522 Zr 0.0185 0.0076 La 30.4 26.9 30.6 Ce 55.5 50.6 57.4 Pr 3.11 2.78 3.53 Nd 0.160 0.259 0.395 Ag 0.105

As shown in Table 2, Al and Si components were almost absent in the regular products, and the abrasive waste was found to contain a large amount of Si as the main components of Al and frit glass, which are inorganic coagulants. In addition, it is seen that the regenerated disintegrated product obtained through the present invention has almost no Al and Si components in the same way as the regular product, and the main components of the regular product are also kept the same.

7A and 7B are scanning electron microscope (SEM) images of regular products, FIGS. 8A and 8B are scanning electron microscope (SEM) images of abrasive waste, and FIGS. 9A to 9C are scanning of remanufactured products. SEM photographs.

Referring to FIGS. 7A to 9C, it can be seen that even when scanning electron micrographs of the normal product and the remanufactured product are compared, they have almost the same particle distribution and size.

FIG. 10 is a graph showing an X-ray diffraction (XRD) pattern of a regular product, and FIG. 11 is a graph showing an X-ray diffraction (XRD) pattern of a remanufactured product.

Referring to FIGS. 10 and 11, it can be seen that the same diffraction peak pattern is shown even when comparing the X-ray diffraction patterns of the regular product and the remanufactured product.

As mentioned above, although preferred embodiment of this invention was described in detail, this invention is not limited to the said embodiment, A various deformation | transformation by a person of ordinary skill in the art within the scope of the technical idea of this invention is carried out. This is possible.

100: reactor 110: rotary wing
120: stirrer 130: perforated plate
M: Motor H: Ultrasonic Horn

Claims (8)

A method of regenerating a ceria-based abrasive from an abrasive waste comprising a ceria-based abrasive, a frit glass and an inorganic flocculant,
Adding and stirring an organic acid solution which does not form a salt by reacting with the ceria-based abrasive and the polishing waste to a reaction tank, and the inorganic flocculant is changed into ionic species by acid treatment with the organic acid, and the frit glass is suspended. ;
Removing the floated frit glass; And
Performing a cleaning and drying process to obtain a ceria-based abrasive;
Ceria-based abrasive regeneration method, characterized in that the pH of the organic acid ranges from 0.5 to 6.0.
The bubble of claim 1, wherein ultrasonic waves are applied through an ultrasonic horn installed in the reactor while stirring with a stirrer installed in the reactor, and the ultrasonic reaction promotes a chemical reaction between the organic acid and the inorganic coagulant and is generated by the ultrasonic wave. Further expands violently and bursts at its threshold due to high pressure and the shock wave when the bubble bursts acts on the abrasive waste to cause the frit glass attached to the ceria-based abrasive surface to peel off from the ceria-based abrasive surface. Regeneration method of ceria abrasives.
The method of claim 1, wherein the air is injected by using a bubble generator provided in the lower portion of the reactor while stirring with a stirrer installed in the reaction tank to generate bubbles and the frit glass by the force of the shock wave or bubbles to rise bubbles A method of regenerating a ceria-based abrasive further comprising a bubble treatment step of removing the ceria-based abrasive from the surface.
The method according to claim 1, wherein after the acid treatment,
Performing a wet vibratory sifting to filter foreign matter incorporated during the regeneration process and the suspended frit glass;
The wet vibration sieve classification method is a regeneration method of the ceria-based abrasive, characterized in that the sieve 50 ~ 2000 mesh sieve.
The method of claim 1, wherein after removing the frit glass:
Further comprising the step of alkali treatment by adding an alkaline solution to melt the frit glass remaining in the ceria-based abrasive,
The alkaline solution uses at least one alkali compound selected from sodium hydroxide, potassium hydroxide, ammonia, primary amines having 1 to 10 carbon atoms, secondary amines and tertiary amines, and the alkali treatment has a pH in the range of 9-13. The method for regenerating ceria-based abrasives, characterized in that to remove the frit glass selectively by adding the alkaline solution so that the weight ratio of the ceria-based abrasives and the alkali solution is in the range of 1: 0.5 to 10.
The method of claim 1, wherein the inorganic flocculant comprises aluminum sulfate, polyaluminum chloride, ammonium alum, sodium aluminate, ferrous sulfate, ferric sulfate, or ferric chloride.
The method of claim 1, wherein the organic acid solution comprises at least one acid selected from acetic acid, lactic acid, citric acid, and oxalic acid.
The method of claim 1, wherein after acid treatment with the organic acid solution,
And performing a secondary acid treatment using an organic acid solution different from the organic acid solution.

Images