KR20210061793A - Method for manufacturing high crystalline cokes - Google Patents

Abstract

The present invention is to provide a method for manufacturing highly crystalline coke of a new concept. According to the present invention, the method for manufacturing highly crystalline coke comprises: a first step of pre-treating the coke; a second step of plating a transition metal on the surface of the pre-treated coke; and a third step of heating the transition metal-plated coke to a set temperature, and aligning the carbon component on the surface of the coke while repeating the penetration and separation of the carbon component into the transition metal to form graphite crystals on the surface of the coke.

Description

Method for manufacturing high crystalline cokes {Method for manufacturing high crystalline cokes}

The present invention relates to a method for producing highly crystalline coke.

In general, in order to produce heat and crucibles for semiconductors, casting dies for metallurgy, graphite electrodes, heat dissipation sheets and plates, electric discharge processing electrodes (EDM), etc. (hereinafter referred to as "high thermal conductivity products"), a binder pitch is applied to coke. The mixture was mixed to make a mixture, and the mixture was pressed and heated to form a molded body block, the molded body block was carbonized to form a carbonized body, and the carbonized body was graphitized.

At this time, the coke must have high crystallinity from the beginning, so that the thermal conductivity of the high thermal conductivity product increases. That is, when the physical properties of coke, which occupy about 80% of the total content, must be sufficiently secured, the thermal conductivity of the high thermal conductivity product is also improved.

To this end, in the prior art, before mixing the coke with the binder pitch, the coke was heated to 2600 to 2800°C to graphitize the entire coke. This is because the crystallinity is very good when coke is graphitized.

However, since the entire coke must be graphitized by applying such high heat, a lot of time and cost were consumed.

Korean Patent Publication (Patent 2000-0019095)

It is an object of the present invention to provide a new concept of a high crystalline coke manufacturing method capable of solving the above-described problems.

In order to achieve the above object, the method for producing highly crystalline coke,

A first step of pre-treating coke;

A second step of plating a transition metal on the surface of the pre-treated coke; And

It characterized in that it comprises a third step of heating the coke plated with the transition metal to a set temperature, aligning the carbon component on the surface of the coke while repeating penetration and separation of the transition metal, and making graphite crystals on the surface of the coke. .

In the present invention, only the surface of coke is graphitized by coating a transition metal on the surface of coke. For this reason, the heat treatment temperature (2600-2800°C) required to graphitize the entire coke can be significantly lowered to the catalytic graphitization temperature (1600-1800°C). Therefore, it is possible to significantly reduce the time and cost for heat treatment of coke.

1 is a flow chart showing a method of manufacturing highly crystalline coke according to an embodiment of the present invention.
2 is a graph showing the amount of nickel plating according to the plating temperature in a manner in which the plating solution is heated using a hot plate but no ultrasonic waves are applied.
3 is a photograph showing the result of EDS mapping on the surface of nickel-plated coke in a manner that heats a plating solution using a hot-plate but does not apply ultrasonic waves.
4 is a graph showing the amount of nickel plating according to the plating time in a method of heating and ultrasonic treatment of a plating solution using an ultra bath.
5 is a photograph showing the result of EDS mapping on the surface of nickel-plated coke by heating a plating solution using an ultra bath and performing ultrasonic treatment.
FIG. 6 is a graph showing differences in nickel plating amounts in a method of heating a plating solution using a hot-plate and ultrasonic treatment using a horn-sonic method, and a method of not performing the ultrasonic treatment.
7 is a photograph showing the result of EDS mapping on the surface of nickel-plated coke by heating a plating solution using a hot-plate and ultrasonicating with a horn-sonic method.
8 is a schematic diagram for explaining a third step of FIG. 1.
9 is a schematic diagram showing the interlayer structure of graphite crystals formed on the surface of coke after the third step of FIG. 1.
10 is a table summarizing the average height, interlayer distance, etc. of graphite crystals made by heat treatment after nickel plating on the surface of coke.
11 is a graph showing the Raman spectrum of graphite crystals made by heat treatment after nickel plating on the surface of coke.
12 is a table showing the average height, interlayer distance, etc. of graphite crystals made by heat treatment after nickel-cobalt plating on the surface of coke.
13 is a graph showing the Raman spectrum of graphite crystals made by heat treatment after nickel-cobalt plating on the surface of coke.

Hereinafter, a method for producing highly crystalline coke according to an embodiment of the present invention will be described in detail.

As shown in Figure 1, the method for producing highly crystalline coke according to an embodiment of the present invention,

A first step of pre-processing coke (S11);

A second step (S12) of plating a transition metal on the surface of the pre-treated coke;

The transition metal-plated coke is heated to a set temperature, and the carbon component on the surface of the coke is aligned while repeating penetration and separation of the transition metal, and a third step (S13) of making graphite crystals on the surface of the coke is performed.

The first step S11 will be described.

Coke is pretreated through steps 1 to 9 below.

1) After adding 10g coke to 100 ml of 5M HCl aqueous solution, magnetically agitate for 30 minutes.

2) After self-stirring sample is filtered through vacuum distillation, it is washed several times with distilled water.

3) After washing with water, dry the sample in an oven at 80℃ for 30 minutes.

_{4) Add 100ml of 0.1M SnCl 2} + 0.1M HCl aqueous solution to the dried sample and magnetically stir for 30 minutes. (This is a sensitization process)

5) After filtering the acid-treated sample through vacuum distillation, neutralize it by washing with distilled water several times.

6) After washing with water, dry the sample in an oven at 80℃ for 20 minutes.

7) Put the dried sample into 0.0014 M PdCl ₂ +0.25 M HCl aqueous solution and magnetically stir for 30 minutes. At this time, the palladium catalyst is attached to the surface of the coke. The degree of impregnation of the catalyst is controlled by the acid treatment time of coke. In addition, the catalyst is impregnated after the coke is acid-treated, and the degree of impregnation of the catalyst is controlled by the loading time of the coke in the catalyst solution.

8) After filtering the acid-treated sample through vacuum distillation, wash it several times with distilled water.

9) After washing with water, dry the sample in an oven at 80℃ for 1 hour.

After going through steps 1) to 9), coke is pretreated.

The second step (S12) will be described.

In this embodiment, a nickel (Ni) or nickel cobalt (Ni-Co) alloy is used as the transition metal. Transition metals are plated on the pretreated coke by the following three electroless plating methods. Hereinafter, the case where the transition metal is nickel will be described.

1. A method that heats the plating solution using a hot-plate but does not apply ultrasonic waves.

1) Use commercial plating solutions ENF-M and ENF-A to prepare Ni plating solutions.

2) Prepare a 100ml plating solution with a composition of 84 vol.% of distilled water, 10 vol.% of ENF-M, and 6 vol.% of ENF-A.

3) Heat the plating solution to 60°C, 70°C, or 80°C by boiling water with a hot-plate.

4) Keep the temperature of the plating solution, put the pre-treated coke powder into the plating solution, and plate for 15 minutes.

Through steps 1) to 4), nickel is plated on the surface of the pretreated coke.

As shown in FIG. 2, as the plating temperature (60°C, 70°C, 80°C) increases, the nickel plating amount (3.3wt.%, 30.7wt.%, 50.6wt.%) increases. In this way, the plating amount can be controlled by the plating temperature.

As shown in FIG. 3, as a result of EDS mapping the surface of nickel-plated coke, it can be seen that nickel is evenly distributed as the plating temperature (60°C, 70°C, 80°C) increases. (In FIG. 3, the red color is carbon and the green color is nickel.) In this way, the plating distribution can be adjusted by the plating temperature.

2. A method of heating and ultrasonicating plating solution using an ultra bath

1) Use commercial plating solutions ENF-M and ENF-A to prepare Ni plating solutions.

2) Prepare a 100 ml plating solution with a composition of 84 vol.% of distilled water, 10 vol.% of ENF-M, and 6 vol.% of ENF-A.

3) Heat the plating solution to 60℃ using an ultra bath.

4) Keep the temperature of the plating solution, put the pre-treated coke powder into the plating solution, and apply ultrasonic waves to plate.

Through steps 1) to 4), nickel is plated on the surface of the pretreated coke.

As shown in FIG. 4, as the plating time (15min, 30min) increases, the nickel plating amount (11.3wt.%, 43.4wt.%) increases. In this way, the plating amount can be controlled by the plating time.

On the other hand, as shown in FIG. 2, it can be seen that the plating amount increased to 11.3 wt% when ultrasonic waves were applied compared to 3.3 wt% of the plating amount when the plating temperature was 60° C. and the plating time was 15 min without ultrasonic waves. The amount of plating can be increased by applying ultrasonic waves in this way.

As shown in FIG. 5, as a result of EDS mapping the surface of nickel-plated coke, it can be seen that the longer the plating time (15min, 30min), the rougher the nickel plating surface. (In FIG. 5, black is carbon and blue-green is nickel) In this way, the roughness of the plated surface can be adjusted according to the plating time.

3. Heating the plating solution using a hot plate and ultrasonicating it with a horn-sonic

1) Use commercial plating solutions ENF-M and ENF-A to prepare Ni plating solutions.

2) Prepare a 100 ml plating solution with a composition of 84 vol.% of distilled water, 10 vol.% of ENF-M, and 6 vol.% of ENF-A.

3) Heat the plating solution to 80℃ using a hot-plate.

4) Maintaining the temperature of the plating solution, put the pre-treated coke powder into the plating solution, and apply it by ultrasonic treatment for 15 minutes in a horn type.

Through steps 1) to 4), nickel is plated on the surface of the pretreated coke.

As shown in FIG. 6, it can be seen that the nickel plating amount is 73.323 wt.% when ultrasonic waves are applied, but the nickel plating amount is reduced to 50.6 wt.% when ultrasonic waves are not present. The amount of plating can be increased by applying ultrasonic waves in this way.

On the other hand, as shown in FIG. 7, as a result of EDS mapping the surface of nickel-plated coke, it can be seen that the nickel plating size has become very large in units of um, and the reason is that the plating is very accelerated by the horn ultrasonic treatment. Because it became.

On the other hand, compared to heating the plating solution using an ultra bath and giving ultrasonic waves, the power of the ultrasonic waves applied by the horn ultrasonic waves to the plating solution is stronger, so that the palladium catalyst impregnated on the coke surface can be removed before reaction. I can. In this case, the nickel plating layer may not be sufficiently bonded to the coke surface and thus may be peeled off. To prevent this, after a waiting time of about 5 minutes until the catalyst is activated, the second step (S12) is performed.

The third step (S13) will be described.

The coke plated with a transition metal shown in FIG. 8(a) is heated as shown in FIG. 8(b). The heating temperature is 1600~1800℃. Thereafter, transition metals such as nickel (melting point: 1455°C) and cobalt (melting point: 1495°C) are melted and penetrate into the coke.

As shown in Figs. 8(b) and 8(c), the carbon components on the surface of coke are aligned while repeating the penetration and separation of the transition metal. Then, as shown in Fig. 8(c), graphite crystals having a thin thickness are formed on the surface of the coke. Then, the transition metal penetrates into the coke. The black arrow shown in FIG. 8(b) represents the carbon component penetrating into the transition metal, and the black arrow shown in FIG. 8(c) represents the carbon component released from the transition metal.

As shown in Fig. 9, the graphite crystal made on the surface of coke is composed of a plurality of layers. Lc is the average height of the graphite crystal, and d002 is the interlayer distance.

K: Scherrer constant (K=0.89)

β : Half width (radian)

θ: angle at the maximum peak during XRD measurement

λ : 1.542 Å of wavelength used for XRD measurement

λ : 1.542 Å of wavelength used for XRD measurement

θ: angle at the maximum peak during XRD measurement

The larger the Lc value, the more layers the graphite crystal is formed, and the smaller the d002 value, the smaller the interlayer distance. In order to obtain the highly crystalline coke to be made in the present invention, the larger the Lc value of the graphite crystal formed on the surface of the coke and the smaller the d002 value, the better.

Through the first step (S11) to the third step (S13), high crystalline coke is manufactured. Highly crystalline coke is used as a raw material for high thermal conductivity products.

Experimental Example 1 (nickel plating)

As an example shown in FIG. 10, in the case of H18-Ni-D5-S10 (heat treatment at 1800°C, nickel plating solution, immersion time in the plating solution 5 minutes, ultrasonic input time 10 minutes during plating), the distance of the layer forming the graphite crystal is It can be seen that the average height of the graphite crystal is 3.38Å and 341.47Å. On the other hand, when the coke was heat-treated at 1800°C without nickel plating, the distance of the layer forming the graphite crystal was 3.55Å and the average height of the graphite crystal was 17.58Å, which was about 20 times lower. This means that there are almost no graphite crystals on the surface of coke.

Experimental Example 2 (nickel plating)

The smaller the ID/IG value in the Raman spectrum, the more highly crystalline coke is produced. As an example shown in FIG. 11, in the case of H16-Ni-D5-S10 (heat treatment at 1600°C, nickel plating solution, immersion time in plating solution 5 minutes, ultrasonic input time 10 minutes during plating), the ID/IG value was 0.13. . On the other hand, it can be seen that when the coke is heat-treated at 1600°C without nickel plating, the ID/IG value is increased by 10 times to 1.37. This means that there are almost no graphite crystals on the surface of coke.

Experimental Example 3 (nickel-cobalt alloy plating)

As an example shown in FIG. 12, in the case of H16-NiCo-D20-S20 (heat treatment at 1600°C, nickel-cobalt plating solution, immersion time in nickel-cobalt plating solution 20 minutes, ultrasonic input time 20 minutes during plating), graphite crystals are formed. It can be seen that the formed layer distance is 3.36Å and the average height of the graphite crystal is 269.73Å.

Experimental Example 4 (nickel-cobalt alloy plating)

As an example shown in FIG. 13, in the case of H16-NiCo-D20-S20 (heat treatment at 1600°C, nickel-cobalt plating solution, immersion time in nickel-cobalt plating solution 20 minutes, ultrasonic input time 20 minutes during plating), ID/IG The value was found to be 0.25. On the other hand, in the case of only heat treatment at 1600°C without nickel-cobalt plating, it can be seen that the ID/IG value is 1.09, which is about 4 times larger. This means that amorphous or unaligned grains of coke are rearranged.

Claims (5)

A first step of pre-treating coke;
A second step of plating a transition metal on the surface of the pre-treated coke; And
It characterized in that it comprises a third step of heating the coke plated with the transition metal to a set temperature, and aligning the carbon component on the surface of the coke while repeating penetration and separation of the transition metal, and making graphite crystals on the surface of the coke. High crystalline coke manufacturing method. The method of claim 1, wherein in the first step,
A method for producing highly crystalline coke, characterized in that the catalyst is impregnated after the coke is subjected to acid treatment, wherein the degree of impregnation of the catalyst is controlled by the supporting time of the coke in the catalyst solution. The method of claim 2, wherein in the second step,
The transition metal is a method for producing highly crystalline coke, characterized in that some of nickel or a nickel-cobalt alloy and a transition metal. The method of claim 3, wherein in the second step,
The transition metal is a high crystalline coke manufacturing method, characterized in that the electroless plating on the surface of the coke impregnated with the catalyst. The method of claim 4, wherein in the second step,
While the transition metal is electrolessly plated on the surface of the acid-treated coke, an ultrasonic wave is applied.

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