KR100459988B1 - Apparatus And Method of Removing of Unburned Carbon In Fly ash by Corona-Electrostatic Field - Google Patents

Abstract

The present invention relates to a device and method for separating unburned carbon contained in fly ash discharged from a thermal power plant, and to improve separation efficiency, a bunker for collecting raw materials and a raw material collected in the bunker in a uniform thickness are supplied to the apparatus. A first rotatable by a chute and a motor, the drum for attaching and rotating the raw material supplied from the chute to an outer surface thereof, the first upper part of the drum and generating a static discharge by applying a first voltage to separate the raw material Discharge means, a second discharge means provided at an upper portion of the drum and generating a corona discharge by applying a second voltage to separate the raw material, a conductor separated from the raw material to the first and second discharge means, and an intermediate product. And an intermediate product supply means for supplying to the bunker an intermediate product collected by the collecting means and a collecting means for collecting the insulator respectively. .

By using the apparatus for separating unburned carbon powder in the fly ash by the composite corona-electrostatic field, the unburned carbon powder in the fly ash can be purified to about 3% or less, thereby improving the quality of the fly ash used as the concrete additive. The result is a fly ash supply system for homogeneous products.

Description

Apparatus And Method of Removing of Unburned Carbon In Fly ash by Corona-Electrostatic Field}

The present invention relates to an apparatus and a method for separating unburned carbon contained in fly ash discharged from a thermal power plant. Particularly, a dried powdery fly ash is passed through a composite corona-static discharge field to conduct conductive carbon powder and dielectric fly. An apparatus for separating ash and unburned carbon powder, and a method for separating the same.

Fly Ash is a by-product that remains in the form of spherical fine powder after coal (anthracite and bituminous coal) is burned in a coal-fired power plant. Such fly ash has been generally landfilled but its treatment is gradually As it became difficult, the developed countries have been actively researching and developing recycling technologies as part of coal ash disposal measures since the 1950s. As a result, fly ash is used in concrete to improve the properties of concrete and to effectively use industrial by-products. It became.

In general, the unburned carbon powder in fly ash reduces air embrittlement and decreases the effect of concrete admixtures such as precipitation agents, and thus increases the amount of admixtures and causes problems such as incongruity of concrete and coloring of concrete surfaces.

In Korea, a significant amount of coal ash was disposed of in coastal landfills before the 1980s, but recently, ready-mixed fly ash is used by the ready-mixed fly ash from the viewpoint of quality improvement, economic construction as a cement substitute, and recycling of industrial waste. .

In general, there are two types of processes for separating unburned carbon powder in fly ash, that is, wet process and dry process. The wet process includes a flotation screening method (US pat. 6,068,131, US pat. 5,936,216, US pat. 5,456,363, Korean Patent Publication No. 1996-033525) and a selective agglomeration method (US pat. 5,227,047, JP 05-138151). Electrostatic and triboelectric method of electrostatic separation method (US pat. 6,123,813, US pat. 6,074,458, US pat. 6,064,022, US pat. 5,967,331, US pat. 5,944,875, US pat. 5,513,755, Korean Patent Publication No. 1997-068549 , Korean Laid-Open Patent 1997-046374, Korean Laid-Open Patent 1996-027658, Korean Laid-Open Patent 1996-026663, Korean Laid-Open Patent 1996-026662), Grinding and Grain Size Classification (US pat. 6,038,987, US pat. 5,976,331, US pat. 5,887,724, US Pat. 5,299,692, Korean Patent Publication No. 1997-000749, Korean Patent Publication No. 1996-033525, and Oxidative Combustion Method (US pat. 5,868,084, US pat. 5,749,308, US pat. 5,735,403, US pat. 5,555,821, US pat. 5,399,194, Korean Patent Publication No. 1996-073565, Korean Patent Publication 1994-000209).

Among these methods, the structure shown in FIG. 5 is known as an example of the apparatus for commercially sorting the substance etc. which are currently commercialized and the fly ash contains. As shown in FIG. 5, the fly ash raw material in which unburned carbon, carbon, and other materials are mixed is stored in a fly ash storage tank 51 in a transport vehicle from a thermal power plant, and the transfer pipe communicated on an outlet of the storage tank. A blower fan 53 attached to one side of 52 is operated so that the high-pressure primary discharge air flows out into the transfer pipe and is transferred to the sorter 54 while containing the fly ash in the storage tank.

Next, as fly ash flowed into the classifier 54 is returned from the high-pressure air stream due to the secondary discharge air supply, unburned carbon or carbon is dropped into the waste powder storage tank 55, and the purified fly ash is again a cyclone, which is a dust collector. (56) introduces mixed air from a conduit installed in a tangential direction with respect to the fuselage part of the cyclone, for example, and collects the fly ash purified by giving a swirling motion to the mixed air. . The air at this time constitutes a series of waste cycles which are again conveyed to the other side of the blower fan and removes unburned carbon of the fly ash, and then the purified fly ash is stored in the output storage unit 57.

However, the conventional method having the above configuration has a problem that the screening efficiency is lowered.

In addition, as a process currently in operation, the particle size classification method is known as the most economical method, although the separation efficiency is not good. However, in recent years, the specification of fly ash requires that the carbon content is about 3% or less, and in order to satisfy this, it is difficult to achieve the purpose of the particle size classification alone.

In addition, the above-mentioned electrostatic separation method has an electrostatic induction type, a contact and a triboelectric charge type according to the charging method of the particles, and in any of these methods, there is a problem in that the separation efficiency varies depending on the water content, the electrical properties, etc. .

In addition, a technique disclosed in Korean Patent Publication No. 10-0216901 is known as an example of a technique for solving the above problems.

That is, in the above publication, the fly ash is supplied from the raw material supply device and dispersed through the air suction method to separate the unburned carbon and the pure fly ash into a classifier and a fly ash that has passed through the classifier. Cyclone dust collector that precipitates fly ash powder, Bag filter that refines residual fly ash containing air passed through dust collector into fine powder of 2㎛ or less of representative particle size, Pure fly ash purified through dust collector and bag filter A transfer device for transferring the discharged air to the coal ash storage bin, a waste discharger for storing and discharging the unburned carbon separated through the classifier, and a double for discharging the collected pure fly ash powder collected at the discharge part of the dust collector and the bag filter in the transfer process. A coal ash recovery device consisting of a buffer is described.

In addition, the technique disclosed in Korean Laid-Open Patent Publication No. 1999-24969 is known as an example of a technique for solving the problem of having to undergo a dehydration and drying process before combustion in the above-described conventional wet process.

In other words, the publication includes an electrostatic precipitator hopper, a vibrator for conveying coal ash, a diaphragm for supplying an appropriate amount of coal ash by a vibrator, a coal ash pressurized nozzle using the principle of a venturi tube, and an air blower for supplying high pressure air to the pressurized nozzle. Coal ash supply unit, the frictional charging unit in the cyclone to charge the coal ash containing unburned carbon supplied by the coal ash supply unit by the rapid catalyst, and the unburned in the coal ash containing unburned carbon charged by the friction charging unit electrically Cyclone consisting of electrostatic separator with positive (+) (-) electrode to generate electric field to separate and dust removal vibration to remove coal ash and unburned carbon attached to positive (+) (-) electrode in electrostatic separator An electrostatic separator is described.

However, fly ash is composed of mineral particles with dielectric properties (such as alumina silicate, quartz, iron calcium and magnesium silicate) and carbon particles with conductive properties. And depending on the combustion conditions, but in the range of about 5 to 10% and there are a number of problems in the concrete admixture as described above, in recent years there is a demand for a product having reduced the content to less than about 3%, In the apparatus according to the technique described in the publication, there is a problem that the production efficiency for the fly ash is not high and its processing cost becomes expensive.

An object of the present invention is to solve the above problems, to provide an apparatus and a method for separating unburned carbon powder in fly ash by a composite corona-electrostatic field.

Another object of the present invention is to reduce the carbon content in the fly ash to less than about 3% and to separate the unburned carbon so that the recovery rate is about 90% by adopting the method of separating the carbon powder by the composite corona-electrostatic separation method during the dry separation process It is to provide a device and a method of separation.

It is still another object of the present invention to provide an apparatus and a separation method for separating unburned carbon powder by a composite corona-electrostatic field which not only improves the quality of the fly ash but also has high production efficiency and low processing cost.

1 is an explanatory view showing a charging method of separated particles for explaining the unburned carbon powder separating apparatus and separating method in fly ash by a composite corona-electrostatic field according to the present invention

2 is an explanatory diagram of various electric fields of a drum type separator for explaining unburned carbon powder separating apparatus and separating method in fly ash by a composite corona-static field according to the present invention.

3 is a view showing a device for separating unburned carbon powder in fly ash by a composite corona-electrostatic field according to the present invention.

Figure 4 is a fly ash separation process in the unburned carbon powder separating apparatus in fly ash by the composite corona-electrostatic field according to the present invention

Figure 5 is a process chart for explaining the conventional coal ash recovery method

<Description of the symbols for the main parts of the drawings>

One ; Bunker 2; Chute 3; Corona electrodes

4 ; Drum 5; Brush 6; Displacement electrode

7; Separator 8; Chamber 9; Electric heater

The unburned carbon powder separator of the present invention for achieving the above object is a device for separating unburned carbon contained in the fly ash, which is a raw material discharged from a thermal power plant, the bunker for collecting the raw material, the raw material collected in the bunker A chute for supplying a uniform thickness into the apparatus, a drum rotatable by a motor, a drum for attaching and rotating a raw material supplied from the chute to an outer surface thereof, and a first drum provided inside the drum for heating the drum. Electrical heating means, first discharging means provided at the top of the drum and applying a first voltage to separate the raw material to generate an electrostatic discharge, and second provided at the top of the drum and separating the raw material Second discharging means for generating a corona discharge by applying a voltage of the first and second discharging means, And collecting means for collecting the separated conductor, the intermediate product, and the insulator, respectively, and intermediate product supplying means for supplying the intermediate product collected by the collecting means to the bunker.

In the unburned carbon powder separator of the present invention, the outer surface of the drum is chromium plated, and the chute is provided with second electric heating means for heating the chute.

In the unburned carbon powder separator of the present invention, the load voltage H = 5kv / cm is applied to the anode (+) of the first discharge means as the first voltage, and to the anode (+) of the second discharge means. As a second voltage, a voltage of H = 4 kv / cm is applied.

In addition, the unburned carbon powder separator of the present invention further includes a brush provided in contact with the drum to remove the insulator continuously attached to the outer surface of the drum without being separated by the first and second discharge means.

In addition, the unburned carbon powder separation method of the present invention for achieving the above object is a bunker for collecting the raw material, the raw material collected in the bunker to separate the unburned carbon contained in the fly ash, which is a raw material discharged from the thermal power plant A method for separating unburned carbon powder in a fly ash, comprising: a chute for supplying a uniform thickness and a drum for attaching and rotating a raw material supplied from the chute to an outer surface thereof, wherein the raw material is removed while the raw material is moved in the chute. A step of heating, a step of supplying an electrostatic discharge to the raw material supplied from the chute and attached to the drum, a step of heating the raw material by the heat of the drum and supplying the electrostatic discharge and at the same time supplying the corona discharge, the electrostatic discharge Conductor, intermediate product, insulation separated from the raw material by supply and the corona discharge Collecting each of the sieves, and re-feeding the intermediate product not separated into a conductor and an insulator by the respective steps.

In the separation step of the unburned carbon powder separation method of the present invention, four-step electrostatic separation is performed, and electrostatic separation is performed by applying a load voltage of H = 5 kv / cm to the anode of the displacement electrode for electrostatic discharge.

In addition, the method for separating unburned carbon powder of the present invention further includes a step of classifying the carbon products of the conductors electrostatically separated by the respective steps to 0.06 mm and adding a portion of 0.06 mm or less to the ash product to increase the recovery rate. .

Hereinafter, the present invention will be described in detail with reference to the drawings. In addition, in the figure, the same code | symbol is attached | subjected to the same part, and the repeated description is abbreviate | omitted.

First, the concept of the corona-electrostatic field according to the present invention will be described.

In general, corona discharge refers to a partial discharge that occurs when the electric field strength reaches the local breakdown strength at the end of a small radius of curvature, such as a sharp part of an object charged over several kilowatts. In addition, electrostatic discharge is an insulation breakdown of a gas caused by collision of electrons accelerated by an electrostatic field and ionization, and refers to a discharge that occurs when the electric field strength due to charged charge reaches the dielectric breakdown strength.

In the present invention, unlike the electrostatic induction or triboelectric method described above, the electric field for separating the carbon particles in the fly ash is divided into an electrostatic field, a corona discharge field, and a composite corona-electrostatic field. The separation method using the electrostatic field is adopted, and the conductor is separated from the complex electric field simultaneously applying the corona-static field.

That is, the dried powdery fly ash is passed through the composite corona-electrostatic discharge field to separate the conductive carbon powder and the dielectric fly ash, and the carbon products are again sized and the fine particles are mixed with the fly ash product to electrostatic separation and particle size. Adopting a combined process provides a separation process with a carbon content of about 3% or less and a recovery rate of about 89-92% or more.

In the present invention, the international test method (ISO) was applied as a method for measuring moisture and carbon content, and the ISO for determination of moisture, ash and carbon content is as follows.

1 g sample was dried at -110 ° C to determine moisture (W ^a )

Determination of ash (A ^a ) by burning 1 g of sample at -815 ± 10 ° C

-Determination of total carbon amount (C _t ^a ) by burning a certain amount of sample at the electric furnace temperature of 815 ℃

Under these conditions the following reactions occur.

C + O ₂ → CO ₂

CaCO ₃ → CaO + CO ₂

MgCO ₃ → MgO + CO ₂

FeCO ₃ + O ₂ → (Fe ₂ O ₃ , Fe ₃ O ₄ ) + CO ₂

The generated CO ₂ gas is measured by weighing it by absorbing it into a reagent called “asskarit”. Carbonate carbonate (C ^a co ₂ ) is determined by acid treatment of a certain amount of sample measuring a certain volume of generated CO ₂ .

MCO ₂ + HCl → MCl ₂ + H ₂ O + CO ₂

Content of organic carbon (C ^a _o) is the difference between the total amount of carbon (C _t ^a) and carbonate carbon (C ^a co _2).

(C ^a _o ) = (C _t ^a )-(C ^a co ₂ )

Korean measurement method (KSA0021) was also applied to measure loss of burning (LOI) and moisture (B).

1 is an explanatory diagram showing a charging method of separated particles for explaining the unburned carbon powder separating apparatus and the separating method in the fly ash by the composite corona-electrostatic field according to the present invention, Figure 2 is a composite corona-electrostatic according to the present invention It is explanatory drawing of the various electric field of the drum type | mold separator for demonstrating the apparatus and the separation method of unburned carbon powder in fly ash by the chapter.

In FIG. 1, a is a diagram illustrating a process in which a conductor and a dielectric are ionized by corona discharge, b is a diagram illustrating triboelectricity of a conductor and a dielectric, and c is an induction of the conductor and the dielectric. Is a view showing that the conductor and the dielectric are in contact with the charged electrode.

In Fig. 2, a is a view showing a state of separation by an electrostatic field when the carbon particles are separated, b is a view showing a state of separation by a corona charge field when the carbon particles are separated, c is a carbon particle Shows the state of separation by a corona-static field during

3 is a view showing a device for separating unburned carbon powder in fly ash by a composite corona-static field according to the present invention.

In Fig. 3, reference numeral 1 denotes a bunker for collecting raw materials, and reference numeral 2 denotes a uniform thickness by means of an electric vibrator in which the raw materials are embedded from the bunker 1 so that the flow of particles in the non-uniform electric field of the corona discharge. It is suit to let in. An electric heating device (not shown) is built in the chute 2.

(3) is a corona positive electrode according to the present invention, and (4) is a drum to which a motor (not shown) is attached and used as a ground electrode. The drum 4 is a hollow metal cylinder, which is chrome plated on its outer surface, and has an electric heater 9 fixed therein, and is rotated by a DC motor through a pulley.

Denoted at 5 is a brush for removing the insulator particles attached to the drum 4, and at 6 is a displacement electrode.

Denoted at 7 is a separator provided to separate the raw material separated by the corona electrode 3 and the displacement electrode 6, and 8 is a chamber for collecting the separated raw material. The chamber 8 is divided into a conductor chamber 8a for collecting carbon as a conductor, an intermediate chamber 8b for collecting intermediate products, and an insulator chamber 8c for collecting insulators.

In the separator shown in Fig. 3, the size of the separated particles was 0.04 to 3 mm, the treatment capacity of the apparatus was about 90 kg / h, and the rotation speed of the drum was 30 to 90 rpm. The separator was continuously heated and the drum temperature was about 30 to 100 캜, the bunker was about 30 to 150 캜 and the chute was about 30 to 100 캜. Corona and induction electrode potentials were 30 mA or more and the maximum current was 1 mA.

Briefly explaining the process of Figure 3 under the above conditions are as follows.

The raw material is introduced into the bunker 1 and then into a uniform thickness through the chute 2, and the flow of particles enters into the uneven electric field of the corona discharge. Particles with high electrical conductivity in the raw material are discharged out of the corona discharge zone in contact with the drum 4 and particles with lower conductivity are discharged therein, and the insulator particles are attached to the drum 4 so that the brush 5 is removed. Is removed by

That is, as shown in Figure 3, in the present invention is separated by the corona, static electricity and their composite electric field, the separation product is divided into three types of conductor chamber (8a), intermediate chamber (8b) and insulator chamber Each of (8c) is separated into a conductor product (carbon powder), an intermediate product, and an insulator (batch product). This separation depends on the electro-physical properties of the raw material to be separated depending on the charged electrode by the corona, electrostatic or corona electrostatic field.

The intermediate product collected in the intermediate chamber 8c is fed to the bunker 1 for recirculation, and the final product is separated into a batch of carbonaceous product and a conductive portion containing a lot of carbon particles. The most effective electrostatic separation occurs when the carbon content in the fly ash is in the form of discrete particles and when the carbon content is low.

Table 1 shows the results of the quality analysis of the fly ash sample before the electrostatic separation K1, K2, K3, K4. Sample K1 selected about 15 kg of raw material, sample K2 selected LOI 5.5% raw material, K3 selected LOI 6.0% raw material, and K4 selected LOI 6.5% raw material. According to this table, products with ignition loss ≤ 3% can be obtained by simple particle size classification. In this table, most of the carbon powder is distributed in the particle size of 0.063 mm or more, and the carbon content is relatively small in the particle size of 0.063 mm or less.

However, electrostatic separation methods should be employed to obtain high recoveries of products with a carbon content of less than about 3%. Attempting to separate the carbon powder from the various electric fields mentioned above, it was confirmed that the most effective method of electrostatic separation is the separation method by the mixed corona-static field.

Table 1. Quality Analysis of Fly Ash Samples

Sample Name Classification particle size mm Distribution ratio Analytical Value, Weight% W ^a A ^a C _t ^d C ^a co ₂ LOI K1 all 100 0.25 92.20 7.25 0.07 7.37 0.1 or more 6.40 1.18 61.48 36.66 - 35.80 0.1-0.063 7.70 0.96 70.38 28.17 - 24.70 0.063 or less 85.9 0.23 96.51 2.97 0.05 3.05 K2 all 100 0.46 93.97 5.18 0.15 5.31 0.1 or more 3.69 0.72 73.60 24.10 - 23.40 0.1-0.063 6.97 0.61 83.88 13.55 - 11.80 0.063 or less 89.34 0.31 95.80 3.46 0.13 3.29 K3 all 100 0.34 93.95 5.26 0.14 5.38 0.1 or more 4.58 0.56 72.70 23.80 - 22.00 0.1-0.063 7.46 0.28 83.90 14.07 - 13.70 0.063 or less 87.96 0.26 95.93 3.41 0.12 3.40 K4 all 100 0.33 94.05 5.16 0.10 5.22 0.1 or more 3.96 0.73 74.50 22.80 - 21.90 0.1-0.063 7.06 0.58 84.10 15.86 - 13.60 0.063 or less 88.98 0.24 95.96 3.53 0.08 3.60

In Table 1, W ^a = moisture, A ^a = ash, C _t ^d = total carbon content, C ^a co ₂ = carbonate carbon, and LOI = thermal loss, respectively. In Table 1, moisture (W ^a ), ash (A ^a ), total carbon content (C _t ^d ), and carbonate carbon (C ^a co ₂ ) are determined by the ISO-625 method, and the value is fly ash. It was calculated as a dry matter of (C ^d t, C ^d co ₂ ).

Next, the electrostatic separation process of the fly ash according to the present invention will be described in detail with reference to FIG. 4.

Figure 4 is a fly ash separation process in the unburned carbon powder separating apparatus in fly ash by the composite corona-electrostatic field according to the present invention.

That is, Figure 4 shows the most effective separation of the separation process in the composite electric field shown in Figure 3, after the raw material is put into the bunker (1), the electrostatic separation four times by the electrostatic separator of Figure 3, At this time, the carbon product C = 12-15% by applying a load voltage of H = 5 kv / cm to the anode (+) of the displacement electrode 6.

Again, the carbon product C = 15-25% by applying a load voltage of H = 5 kv / cm to the anode (+) of the displacement electrode 6 and H = 4kv / cm to the anode (+) of the corona electrode 3. The recovery rate of the ash product (LOI = 2.5-2.7%) is 78-84%.

Next, by reducing the particle size classification to less than 0.06 mm, the recovery rate of the ash product is 78 to 84%, the carbon product C = 27 to 43%, the recovery rate is 8 to 11%, and the ash product (LOI = 2.7 to 2.95). %) Is 89 to 92%.

Table 2 shows the results of the process according to FIG. 4 as described above, and a product having a carbon content of about 3% or less of the final ash refined product was obtained as a recovery rate of about 89 to 92%.

Table 2. Carbon powder separation experiment results by the process of FIG.

fair Initial sample Ash product, wt% Carbon products, wt% Recovery rate LOI Recovery rate LOI 4 K1 91.1 2.95 8.9 42.6 K2 89.6 2.76 10.4 27.3 K3 91.5 2.67 8.5 28.9 K4 88.8 2.81 11.2 26.5

As mentioned above, although the invention made by this inventor was demonstrated concretely according to the said Example, this invention is not limited to the said Example and can be variously changed in the range which does not deviate from the summary.

Although the structure shown in FIG. 3 and the process shown in FIG. 4 have been described with respect to four stages of electrostatic separation, the present invention is not limited thereto and may be processed in three or less stages or five or more stages as necessary.

In addition, in the structure illustrated in FIG. 3, a description of a structure in which an intermediate product is fed back to the bunker 1 is omitted for convenience of drawing, but such a structure may be achieved by a conventional feedback system.

As described above, according to the present invention, a method for separating unburned carbon powder in fly ash by a composite corona-electrostatic field and a method of separating unburned carbon powder in fly ash to about 3% or less are used as concrete additives. By improving the quality of the ash, a fly ash supply system of homogeneous products can be achieved. Therefore, high quality ready-mixed concrete can be supplied and effective utilization of waste resources can be expected.

In addition, according to the present invention, the unburned carbon powder separating apparatus and the separating method in the fly ash by the composite corona-electrostatic field not only improve the quality of the fly ash, but also produce the effect of high production efficiency and low processing cost. .

Claims (7)

In the device for separating unburned carbon contained in the fly ash, a raw material discharged from the thermal power plant, A bunker for collecting the raw material, A chute for supplying the raw material collected in the bunker to the apparatus at a uniform thickness, A drum rotatable by a motor, for attaching and rotating a raw material supplied from the chute to an outer surface thereof; First electric heating means provided inside the drum for heating the drum, First discharging means provided on an upper portion of the drum to generate an electrostatic discharge by applying a first voltage to separate the raw material; Second discharge means provided at an upper portion of the drum to generate a corona discharge by applying a second voltage to separate the raw material; Collecting means for collecting conductors, intermediate products, and insulators separated from the raw materials by the first and second discharge means, respectively; And an intermediate product supply means for supplying the intermediate product collected by the collecting means to the bunker. The method of claim 1, The outer surface of the drum is chromium plated, and the chute is provided with a second electric heating means for heating the chute. The method of claim 1, A load voltage H = 5kv / cm is applied to the anode (+) of the first discharge means as a first voltage, and H = 4kv / cm as a second voltage to the anode (+) of the second discharge means. Unburned carbon powder separator characterized in that the voltage is applied. The method of claim 1, And a brush provided in contact with the drum to remove the insulator that is not separated by the first and second discharge means and is still attached to the outer surface of the drum. In order to separate unburned carbon contained in fly ash, a raw material discharged from a thermal power plant, a bunker for collecting the raw material, a chute for supplying the raw materials collected in the bunker in a uniform thickness, and a raw material supplied from the chute. In the method for separating the unburned carbon powder in the fly ash by having a drum attached to the outer surface to rotate, Heating the raw material while the raw material is moving in the chute; Supplying an electrostatic discharge to the raw material supplied from the chute and attached to the drum, Heating the raw material by the heat of the drum and supplying the electrostatic discharge and at the same time supplying the corona discharge, Collecting conductors, intermediate products, and insulators separated from the raw materials by the electrostatic discharge supply and the corona discharge; And re-supplying said intermediate product which is not separated into a conductor and an insulator by said each process to said bunker. The method of claim 5, In the separation step, the four-stage electrostatic separation is performed, and the electrostatic separation is performed by applying a load voltage of H = 5 kv / cm to the anode of the displacement electrode for electrostatic discharge. The method of claim 5, And classifying the carbon product of the conductor electrostatically separated by the respective steps into a particle size of 0.06 mm and adding a portion of 0.06 mm or less to the ash product to increase the recovery rate.