JP2651529B2 - Method for producing spherical carbon - Google Patents

Description

Description: TECHNICAL FIELD The present invention relates to a method for producing spherical carbon.

Conventional technology and its problems Crude mesocarbon microbeads obtained by heat-treating coal-based heavy oil such as coal tar and coal tar pitch are refined by washing, dried, carbonized, and various composite materials. It is used as a filler. The washed and dried mesocarbon microbeads contain agglomerates consisting of residual pitch components derived from the raw materials, so that the particle size of the powder is non-uniform. It decreases significantly. Further, when carbonizing the dried mesocarbon microbeads in a state where the particle size is non-uniform including the aggregates, the particle size distribution becomes non-uniform. Japanese Patent Application Laid-Open No. 56-5310 proposes that dry mesocarbon microbeads are mechanically pulverized to make the particle size uniform and to be finely divided. The sphere of beads is destroyed, and the characteristic of the material of the sphere cannot be utilized.

Means for Resolving the Problems The present inventor has conducted various studies in view of the problems of the prior art as described above. By performing the processing and classification processing in a specific order, not only can manufacturing troubles be solved,
It has been found that spherical carbon having excellent physical properties can be produced with good yield.

That is, the present invention provides the following method for producing spherical carbon: Coal-based heavy oil is heat-treated, the resulting crude mesocarbon microbeads are separated, washed and purified, dried and obtained. When carbonizing the purified mesocarbon microbeads in an inert atmosphere, the mesocarbon microbeads immediately after drying are primarily dispersed with a force that does not cause destruction, and
A method for producing granular carbon, which comprises carbonizing at a temperature of 0 to 1500 ° C., secondary dispersing with a force that does not cause destruction again, and then classifying.

The steps before the primary dispersion step in the present invention may be performed according to a known method. That is, the crude mesocarbon microbeads can be obtained by heat-treating coal-based heavy oil according to a conventional method. Next, the obtained crude mesocarbon microbeads are separated from the clarified liquid as solids by, for example, centrifugation, and then washed with an appropriate solvent. An example of a method for producing, separating and washing such mesocarbon microbeads is disclosed in
No. 51612 discloses this. However, the process from production of the crude mesocarbon microbeads to separation and washing is not particularly limited, and can be performed by any method.

The washed mesocarbon microbeads are dried. The drying step is not particularly limited, but is usually performed by drying the mesocarbon microbeads in an atmosphere in which the oxygen concentration is controlled to a certain value or less. If the oxygen concentration in the drying atmosphere is too high, the mesocarbon microbeads may ignite spontaneously, while if the oxygen concentration is too low, drying takes a long time. The oxygen concentration varies depending on the drying temperature, drying time, and the like, and is not particularly limited. For drying, use a rotary evaporator, paddle dryer,
It is preferable to use a disk dryer or the like while stirring.

The dried mesocarbon microbeads are then subjected to a primary dispersion step. The primary dispersion step is performed by mechanically dispersing the microbeads with a mild force that does not destroy the dried mesocarbon microbeads. Examples of the mechanical dispersion means include an atomizer mill and a pulverizer.

The mesocarbon microbeads after the primary dispersion are heat-treated and carbonized in a non-oxidizing atmosphere. On this occasion,
Although it varies depending on the particle size and physical properties of the mesocarbon microbeads, in order to prevent troubles due to generation of a relatively large amount of gas, the heating rate is set to about 5 to 300 ° C / hr, and 200 to 150 ° C.
It is preferable to keep the temperature at about 0 ° C. for about 0.5 to 10 hours.

After the heat treatment, the carbon is subjected to a secondary dispersion treatment.
The secondary dispersion step is performed by mechanically dispersing carbon with a mild force that does not destroy carbon. As the mechanical dispersing means, for example, an atomizer mill, a pulverizer and the like can be used. The force applied in the secondary dispersion processing may be greater than that in the primary dispersion processing because the strength of the object to be processed is increased as compared with the case of the primary dispersion processing.

The carbon having undergone the secondary dispersion treatment is then classified to obtain a desired spherical carbon. In this classification, agglomerates mainly composed of components derived from the remaining pitch and coarse particles containing a large amount of ash are removed.

Effect of the Invention According to the present invention, high-purity spherical carbon having a uniform particle size and a small ash content can be obtained. The spherical carbon obtained by the present invention is used as a carbonaceous filler of various composite materials.

EXAMPLES Hereinafter, examples will be shown to further clarify features of the present invention.

Benzene wash mesocarbon microbeads obtained by the method described in Example 1 of JP Example 1 JP 60-51612 using a rotary evaporator while blowing with 0.91 / min N ₂ gas, 130 ° C. For 1 hour to obtain dried mesocarbon microbeads having a particle size of 235 mesh or more and a component content of 14% by weight.

Next, the dried mesocarbon microbeads were supplied to an atomizer mill (having 12 hammers) at a rate of 100 kg / hr, subjected to a primary dispersion treatment at a rotation speed of 6000 rpm, and a primary component of a coarse component having a particle size of 235 mesh or more 1.6% by weight. Dispersed mesocarbon microbeads were obtained.

The obtained primary dispersed mesocarbon microbeads were heated at a rate of 50 ° C./hr from room temperature to 1000 ° C.
Heat treatment was performed by holding for a time to obtain carbon having a particle size of 235 mesh or more and a coarse component content of 91% by weight.

Next, the carbon was atomized with a atomizer mill (hammer number 12).
100 kg / hr, and subjected to secondary dispersion at 8000 rpm to obtain a coarse component having a particle size of 235 mesh or more.
After obtaining the secondary dispersion carbon of weight%, it was classified with an air classifier to obtain spherical carbon having a particle size of less than 235 mesh and a central particle size of 5.0 μm.

The yield of spherical carbon based on secondary dispersed carbon was 95%.

Comparative Example 1 Dry mesocarbon microbeads prepared in the same manner as in Example 1 were treated in the following order.

I. Primary dispersion → II. Heating (carbonization) → IV. Classification The conditions in each step of this comparative example and Comparative Examples 2 to 4 were the same as those in Example 1.

Table 1 shows the content of coarse components having a particle size of 235 mesh or more (A: weight%) after the completion of each step of Examples 1 to 3 and Comparative Examples 1 to 4, and the central particle size of particles having a particle size of less than 235 mesh (B: μ).
m) and the yield (%) based on carbon are shown together.

Comparative Example 2 Dry mesocarbon microbeads prepared in the same manner as in Example 1 were treated in the following order.

I. Primary dispersion → II. Heating (carbon) → III. Secondary dispersion Comparative Example 3 Dry mesocarbon microbeads prepared in the same manner as in Example 1 were treated in the following order.

I. Primary dispersion → II. Heating (carbon) Comparative Example 4 Dry mesocarbon microbeads prepared in the same manner as in Example 1 were treated in the following order.

II. Heating (carbonization) → III. Secondary dispersion → IV. Classification Example 2 A spherical carbon of the present invention was obtained in the same manner as in Example 1 except that the heat treatment was performed at 300 ° C. for 1 hour.

Example 3 A spherical carbon of the present invention was obtained in the same manner as in Example 1, except that the heat treatment was performed at 1400 ° C. for 1 hour.

 ──────────────────────────────────────────────────続 き Continuing on the front page (72) Yoshiteru Nakagawa, 5-1-1 Hirano-cho, Higashi-ku, Osaka-shi, Osaka Osaka Gas Co., Ltd. (72) Toshimasa Kagajo 5-1-1, Hirano-cho, Higashi-ku, Osaka, Osaka (56) References JP-A-56-5310 (JP, A)

Claims (1)

(57) [Claims] Claims: 1. Coal-based heavy oil is heat-treated, and the generated crude mesocarbon microbeads are separated, washed and purified, and dried. When the obtained purified mesocarbon microbeads are carbonized in an inert atmosphere, The mesocarbon microbeads immediately after drying are primarily dispersed with a force that does not cause destruction, carbonized at a temperature of 200 to 1500 ° C., secondarily dispersed with a force that does not cause destruction again, and then classified. A method for producing spherical carbon, comprising: