JPS6362443B2 - - Google Patents

Description

[Detailed description of the invention]

The present invention relates to a method for producing a powder for carbonaceous compacts, and more specifically, the present invention relates to a method for producing a powder for carbonaceous compacts, and more specifically, a carbonaceous powder is obtained using rice husks as a raw material, a binder and additives are mixed into the carbonaceous powder, kneaded, granulated, and finely divided. The present invention relates to a method for producing powder for carbonaceous molded bodies, which comprises pulverizing it into powder. Conventional carbonaceous molded bodies are usually produced by molding carbon fibers as a raw material, adding synthetic resin, tar, pitch, etc. as a binder, and further adding graphite or mica. A carbonaceous molded article is required to have a certain mechanical strength and abrasion resistance, and the carbon fiber is essential for increasing the strength, and is usually blended in an amount of about 30% by weight. However, when carbon fiber is used as a raw material, various manufacturing processes such as drying, pulverization,
The molding and curing operations were complicated, and it was difficult to control the working conditions. For example, if the material is overdried during drying, it may adversely affect the strength after molding, so it is necessary to maintain an appropriate amount of moisture before proceeding to the next step. Therefore, sufficient consideration is required for drying time, temperature, etc., and other processing conditions are also required to be highly accurate, resulting in an increase in cost and a rise in product prices. In addition, from a performance standpoint, dimensional changes over time after molding and hardening are large, so
It has been particularly difficult to manufacture high-precision products using this material. The present invention aims to eliminate the drawbacks of the conventional carbonaceous compacts as described above, and provides a method for producing powder for carbonaceous compacts, in which rice husks are used as a raw material and the rice husks are placed in a reducing atmosphere. A step of generating a carbonaceous powder by heat carbonization, and mixing an arbitrary binder selected from synthetic resin, tar, or pitch into the carbonaceous powder, and an arbitrary additive selected from graphite, mica, or coke. The method is characterized by comprising a step of mixing, a step of kneading and granulating the above mixture, and a step of further pulverizing into a fine powder. The rice husk used as a raw material in the present invention is a waste product after rice grains are taken out in the rice husk production process, and can be obtained at low cost. Its main components are shown in Table 1.

[Table] An example of the manufacturing method according to the present invention will be described below. Rice husks are placed in a suitable container and heated in an atmosphere of a suitable reducing gas such as hydrogen gas within a temperature range of 900°C to 1200°C, preferably 1050°C to 1150°C.
Heat within range for about 30 minutes to obtain carbonaceous powder. Next, 35% by weight of this carbonaceous powder is blended with a blending ratio of 48% by weight of synthetic resin, 10% by weight of graphite, and 7% by weight of mica, and then kneaded in a kneader at room temperature for about 40 minutes. . Furthermore, the kneaded product is granulated using an extruder and air-dried for about 1 hour. And in the dryer 50
After drying for about 20 hours while maintaining the temperature at °C, it is roughly crushed using a crusher, and then crushed again to make a fine powder. The powder obtained through the above steps is put into a cylindrical mold with an outer diameter of 30 mm and an inner diameter of 20 mm heated to about 110°C, and molded by holding at a molding pressure of 200 kg/cm ² for about 10 minutes. Next, in an electric furnace maintained in an atmospheric atmosphere, the molded body is heat-treated at 150°C for about 5 hours, and then heated to 180°C for about 5 hours.
Further, the temperature is raised to 200°C and heat treated for about 15 hours to completely cure, completing the production of the carbonaceous molded body. On the other hand, in order to compare the carbonaceous molded body obtained by the above manufacturing method with the conventional example, 40% by weight of carbon fiber was used as the raw material, 43% by weight of synthetic resin was added as a binder, and as an additive. A material with 17% by weight of graphite added was created using the same manufacturing method. However, to avoid overdrying due to the above reasons,
The conditions for drying the kneaded product in a drying material at 50°C for 20 hours were changed to drying at 50°C for 5 hours (Comparative Example 1). In order to obtain Comparative Example 2, it was manufactured using the same compounding ratio as Comparative Example 1 and under exactly the same manufacturing conditions as the above manufacturing method according to the present invention, but as described above, it became over-dried. There was no bonding force during molding, and it became impossible to mold. Table 2 shows the results of measuring the dimensional changes after molding and hardening of the carbonaceous molded body according to the present invention obtained with the above raw material blending ratio and Comparative Example 1 (number of samples n=5).

[Table] As is clear from Table 2 above, the molded product according to the present invention has a dimensional change after being molded into a ring shape using a mold and then subjected to thermosetting treatment compared to Comparative Example 1, which is a conventional product. As a result, it has become possible to manufacture products with higher precision than conventional products using this material. Furthermore, a compressive strength test and a wear resistance test were conducted under other test conditions, and the molded article according to the present invention showed good results in both cases. Next, a second comparison between the molded article according to the present invention and the conventional product is performed.
As a comparison experiment, length 24 ~ 25 mm, width 24 mm, height 10
The 4% carbon fiber-containing molded body (Comparative Example 3) having the same shape as the molded body of the present invention formed into a rectangular body of mm was prepared, and continuously kept in air at 200°C.
The dimensions and weight of both were measured at predetermined intervals. The measured values were converted into rates of change and are shown in FIGS. 1 to 3. That is, FIG. 1 shows the rate of change in the vertical dimension of the molded article according to the present invention (A) and Comparative Example 3 (B),
FIG. 2 shows the rate of change in the same height dimension, and FIG. 3 shows the rate of change in the same weight. In each measurement, the molded body was taken out from the thermostatic oven and the temperature of the molded body was returned to room temperature. All the results showed the excellent properties of the molded article according to the present invention. As explained above, the present invention uses rice husks as a raw material instead of conventional carbon fibers, heat-treats the raw rice grains in a reducing atmosphere to obtain carbonaceous powder, and adds binders and additives to the powder. In addition, after kneading and granulating, it is ground into fine powder, and even if it is molded using a mold and then heat-cured, there is almost no dimensional change after curing, so it is suitable for products with high dimensional accuracy. It has the great advantage of being applicable and exhibiting good properties in terms of compressive strength and abrasion resistance. Moreover, rice husks, which are the raw material, are always generated during the production process of rice husks, and at present, farmers are at a loss as to how to dispose of them. This is extremely effective when combined with the high quality of the molded product.

[Brief explanation of drawings]

1, 2, and 3 are graphs showing changes in dimensions (vertical dimension, height dimension) or weight of the molded article according to the present invention and Comparative Example 3 during the test time.

Claims (1)

[Claims] 1 A step of heating raw rice husks in a reducing atmosphere to produce carbonaceous powder, mixing an arbitrary binder selected from synthetic resin, tar, or pitch into the carbonaceous powder, and adding graphite, mica, or coke to the carbonaceous powder. A method for producing a carbonaceous molded body powder, which comprises the steps of: mixing an arbitrary additive selected from the above, kneading and granulating the above mixture, and pulverizing the granules resulting from the step into fine powder.