JPS6211796A - Production of mesocarbon microbead - Google Patents

Abstract

PURPOSE:To obtain easily mesocarbon microbeads of smooth, spherical particles almost free from deposit on the surface and cracks, by dispersing pitch containing mesophase spherules into a specific solvent and settling and separating only the mesophase spherules. CONSTITUTION:Pitch containing mesophase spherules is dissolved in matrix pitch, the solution and a solvent not to dissolve the spherules are fed to a washing tank consisting of a filter medium having an opening capable of passing the spherules and the spherules are washed. Then, the mesophase spherules are fed to a settling tank in the downstream of the washing tank and settled. The concentrated dispersion of the spherules is continuously or intermittently taken out from the bottom of the settling tank. The mesophase spherules are separated from the dispersion and recovered as mesocarbon microbeads.

Description

DETAILED DESCRIPTION OF THE INVENTION Various known pitches containing mesophase spherules can be used in the present invention. Specifically, the light oil content of coal tar is removed (by filtration, etc.), coal tar pitch from which insoluble solids are removed, coal-based pitch such as coal liquefied material, or distillation residue oil obtained from petroleum refining is heat treated. Examples include petroleum-based pitches such as oil pitch.

In the present invention, optically anisotropic mesophase/J
Pitch containing S spheres (raw material pitch) is used, but the content of mesophase small particles is 2θwt% or more, preferably &O
It is desirable to use a pitch with as high a content as possible, such as wt% or more, and a pitch in which the degree of spherulite (determined from a polarized light microscope photograph) and the quinolinated content are equal.

The solvent to be used may be one that dissolves the matrix pitch but not the mesophase spherules; specifically, aromatic oils such as quinoline, pyridine, creosote oil, anthracene oil, and mixed oils thereof can be used. Preferably quinoline is used. If other solvents are used, 20-is of quinoline.

It is preferable to adjust the temperature so as to have a pitch-dissolving power corresponding to 0.degree. C., preferably 0.degree.

By the way, the dissolving power of quinoline for the mesophase small sphere-organized pitch used in the example is 70% at SO℃, and the equivalent dissolving power of other solvents is about 3/3 that of creosote oil.
0°C, mixed oil of anthracene and creonate oil.

is about to'C.

The amount of solvent used is J-1 for the supplied raw material pitch.
00 weight times more preferably i.

to 20 times by weight depending on the case.Cracks will occur on the surface of the carbon microbeads, and if the temperature is too low, the dissolution rate will decrease and the processing capacity will decrease, so the temperature conditions are room temperature to tg.

℃, preferably from room temperature to ioo℃, while considering the above factors.

In the present invention, it is possible to introduce the raw material pitch in a molten state when bringing it into contact with the raw material pitch in a solvent in the washing tank, but it is possible to introduce the raw material pitch in a molten state. =! If the mesocarbon microbeads are introduced as small solid particles of about mm in size and placed on the F material at the bottom of the cleaning tank, the mesocarbon microbeads in the raw material pitch will be exposed as the matrix pitch dissolves, and will then become free and be used as the door material. Since the mesocarbon microbeads sediment and descend from the opening, it is most preferable that the contact between the mesocarbon microbeads and the solvent for an appropriate short period of time is ensured in the same field.

Therefore, if the above F material has an opening and structure that allows the raw material pitch particles to be placed but mesocarbon microbead particles to freely come down, it is most convenient to use all kinds of materials for GC. /I′i opening 0. ! r -, a wire mesh of about 7 mm is sufficient.In addition, in case the raw material pitch, which has been successively melted and turned into microparticles, falls from this P material and sufficient dissolution is not achieved, It is preferable to install at least one other door material or screen with a smaller opening on the underside of the door.

This second door material is Q, / -0,! A wire mesh with an opening of about r mi can be suitably used.

In the present invention, it is of course possible to configure the washing tank and settling tank as separate devices or zones.

The most preferred embodiment B of the present invention is that the cleaning tank and settling tank are in contact with the door material, and the settling tank can contain a solvent solution in which a considerable amount of matrix pitch has already been dissolved and precipitated mesocarbon microbeads. The first P material with a smaller opening is installed below the F material at a small distance, and the small solid raw material pitch and solvent are continuously or continuously stored in the cleaning tank. The raw material pitch is fed intermittently, and the raw material pitch is placed on the furnace material. The mesocarbon microbeads were placed under flow conditions and settled from the bottom of the sedimentation tank.As a method for forming the above-mentioned liquid flow conditions near the F material at the bottom of the cleaning tank, it is possible to adopt the known cage method. For example, slow and/or intermittent external mechanical stirring, gas injection stirring, ultrasonic irradiation or a combination of two or more thereof.

It is also possible to use localized heating methods in conjunction with further flow techniques.

It is difficult to strictly define the degree of flow conditions, but the pinch concentration in the solution in the cleaning tank and the settling tank should be about the same, and the intensity approaching that of even stirring should not be This should be avoided, and at least a mode is selected in which standing conditions are maintained such that there is a difference in solution concentration in both tanks, and preferably, the concentration increases from the top to the bottom in the sedimentation tank.

The average residence time of mesocarbon microbeads in the sedimentation tank varies depending on the concentration of the solution, but in general! ~l-
○ minutes, y) Preferably, it may be selected from the range of about 30 to 60 minutes.

The mesocarbon microbeads taken out from the sedimentation tank with the solution in this way are separated by F using a precision P material that does not allow the mesocarbon to pass through, such as a micropore filter.
Preferably, it is washed with an organic solvent such as toluene or acetone.

It is obtained dry.

Naturally, the present invention is applicable to both batch processing and continuous processing.

(e) Jl' effect I (Thus, according to the method of the present invention, extremely smooth spherical mesocarbon microbeads with almost no deposits or cracks on the surface can be produced using extremely simple equipment and operations. It is expected that such mesocarbons will greatly expand the application in fields that require as material surface properties as possible.Also, the opening of the bottom PI can be changed as appropriate. By selection, it is possible to very easily obtain mesocarbon microbeads having a desired spherical diameter below a certain y value.

The present invention will be explained in more detail with reference to Examples below.
The present invention is not limited to the following examples unless it exceeds the gist thereof.

Example: A wire mesh with an opening of 1- is installed horizontally as the F material at the intermediate position of the longitudinal tank, and the upper part is configured as a cleaning tank and the lower part as a sedimentation tank. At approximately V3 position, KAP material was closed and a wire mesh with openings of small to micron was installed.

The nine-spherulite concentration was 43% by weight as measured from the polarized light micrograph.
A mesophase small spherical proprietary pitch having a quinoline solubility of 3-wt% was roughly crushed to approximately 100 to 1000 ml and placed on a wire gauze made of ThF material, and 100 parts by weight of quinoline was supplied to the pitch. The liquid was filled so that the pitch was completely immersed and there was some liquid space, and the matrix pitch was dissolved in the pitch at a predetermined temperature and in a predetermined method as shown in Table 1. Then, at predetermined intervals, the mixture of matrix pitch solvent solution and mesophase spherules that have settled through the first door material is extracted from the lower outlet of the settling tank, and Okaya's amount of quinoline is added to the washing tank. death.

The extracted mixture is filtered through a 10μ Millipore filter, thoroughly washed with toluene and acetone, and then dried. Repeat this operation several times for each.

The yield (% by weight) of the pitch containing the mesophase microspheres and mesophase microspheres obtained was investigated, and the results are shown in Table 7.

When the surface condition of the particles was observed (using scanning electron micrographs), it was found that the surfaces of the particles were perfectly spherical with an extremely smooth surface, and almost no cracks were observed.

In addition, the fluidization of the liquid near the F material in the cleaning tank shown in Table 1 is achieved by blowing i1 elementary gas, vibrating the F material with a vibrator, and applying slow mechanical stirring ultrasonic vibration using a stirring blade. Do it using method q.

Care was taken to keep the sedimentation tank as static as possible. For reference, the results were obtained in the case of vibrator vibration. A microscopic photograph of mesocarbon microbeads with a magnification of 30x is attached as a reference photograph 11 with a magnification of 100x as a reference photograph 1, but the situation was the same in other fluidization methods.

Comparative Example The same mesophase spherule-containing pitch as in the example was placed in a container of the apparatus used in the example, with the upper and lower wire meshes removed, and the flow conditions of the species used in the example were applied to the entire contents. t℃
, JD minutes to dissolve whlix pitch. Then, the contents were completely extracted, and filtered, washed, and dried in the same manner as in the example. The yield of the obtained men carbon micropeas was not much different from that in the examples, but the particle condition was such that a large amount of pitch residue was attached to the surface, and large racks were observed. Ta. For reference, a microscopic photograph taken with vibrator vibration is attached as reference photograph XJ.

Claims (5)

[Claims] (1) Mesophase spherules with bottom surfaces pass through a raw material pitch consisting of mesophase spherules and matrix pitch obtained by heat treating heavy oil, and a solvent that dissolves the matrix pitch but not the mesophase spherules. Introducing it into a cleaning tank consisting of a filter medium with possible openings,
The mesophase spherules are washed, and then at least some of the mesophase spherules in the washing tank are led out through the filter medium to a sedimentation tank provided downstream of the washing tank and allowed to settle, and the mesophase spherules are concentrated from the lower part of the sedimentation tank. 1. A method for producing mesocarbon microbeads, which comprises continuously or intermittently deriving a dispersion liquid, and separating mesophase spherules from the dispersion liquid and recovering them as mesocarbon microbeads. (2) The method for producing mesocarbon microbeads according to claim (1), wherein the raw material pitch is introduced into the cleaning tank as a solid with a particle size of 1 to 10 mm. (3) The temperature of the cleaning tank is maintained at 20 to 150°C, and the temperature of the settling tank is maintained at 20 to 100°C, respectively. The method for producing mesocarbon microbeads as described. (4) The method for producing mesocarbon microbeads according to any one of claims (1) to (3), characterized in that an inert gas is blown into the cleaning tank. (5) The method for producing mesocarbon microbeads according to any one of claims 1 to 3, characterized in that mechanical vibration or ultrasonic vibration is applied to the contents of the cleaning tank. .