JPS609966B2 - graphitization furnace - Google Patents

Description

[Detailed description of the invention] The present invention relates to a graphitization furnace for producing artificial graphite.

Conventionally, crude borundum containing silicon carbide as a main component has been used for the lining layer of a graphitization furnace from the viewpoints of thermal and electrical properties, structural properties, and economical efficiency, and has usually been used 10 to 20 times. However, if the number of times of energization exceeds 5, a considerable amount of current will flow through the lining layer, and the power consumption rate will gradually increase, as well as damage to the furnace wall bricks, cracks in the lining layer, and poor oxidation. The lining layer is hard and the bond is strong, so replacement work is difficult and requires a lot of man-hours. Furthermore, carborundum is generated on the surface of the product.
There were drawbacks such as adhesion and poor purity of the product. In addition, raw or calcined coke and carbon black are used in the lining layer.

Through repeated use, coke becomes graphitized,
Thermal and electrical characteristics deteriorate, resulting in an increase in power consumption and a decrease in the maximum temperature of the furnace. Lining using raw or calcined coke has very good thermal and electrical properties.
Although this method is effective in reducing power consumption and the maximum temperature of the furnace, it has to be replaced with a new lining layer each time, which poses a problem in disposing of this used coke.

Furthermore, in the carbon black lining method, unless a special type of carbon black with a particle size of 500 mm or more and a bulk density of 0.6 or more is used, a blow-out phenomenon tends to occur, and the cooling rate after graphitization is slow. There were problems such as slowness.

The object of the present invention is to provide a graphitization furnace for producing artificial graphite that eliminates the above-mentioned drawbacks of conventional apparatuses, reduces the cost of graphitization treatment, and improves the quality of the product.

In order to achieve the above object, the gist of the present invention is that at least one kind selected from raw coke, calcined coke, and carbon black is added to the innermost part of the lining layer inside the furnace body. The graphitization furnace is characterized in that a new heat insulating layer containing carbon powder is provided each time.

The raw coke mentioned above contains 7 types of easily carbonizable raw materials.
False coke is obtained by heat-treating raw coke or coal to a temperature of 700 to 110,000, and these particles are used by cutting them into particles with a particle size of 1 cob or less. These coke grains are preferably those with low ash and sulfur impurities. The carbon black may be of any commercially available grade such as gas black, naphthalene black, acetylene black, etc., and is not particularly limited by particle size or bulk density, but carbon black with low impurities such as ash and sulfur is preferred. Next, the present invention will be specifically explained with reference to the embodiments shown in the drawings.

Figures 1 to 3 show a subordinate graphitization furnace. ``Furnace body 1 is box-shaped made of refractory bricks, terminal electrodes 2 are fixed at both ends,
The bottom and side walls of the furnace body are lined with a lining 3 of crude silicon carbide several tens of layers thick.

When stuffing into a furnace, filler powder 4 is spread to an appropriate thickness, carbon-fired products (products to be graphitized) 5 are arranged on top of it at regular intervals, and filler powder 4 is placed in the voids and above. The method is to fill the tank and then cover it with coke or a mixture 9 of coke and sand for heat insulation and prevention of combustion. In the method shown in FIG. 3, a lining layer 6 of raw or false coke is provided between the furnace body 1 and a packed coke powder 4 that has been graphitized and once used as a lining material for the graphitization furnace. The graphitization furnace according to the present invention has a heat insulating layer 7 provided at the innermost part of the lining layer 8, as shown in FIG.
A thickness of ~200 mm is appropriate, and the carbon powder used for this purpose is raw coke, false coke, carbon black, singly or in a mixture thereof. In the case of carbon black, it may be used by mixing 20% or more by volume in raw coke or calcined coke repeatedly used as a lining layer. For the lining layer 8, the material used for the heat insulating layer 7 is used repeatedly. The carbon powder used for the heat insulating layer 7 may be used as the lining layer 7r on the furnace bottom side (FIG. 5).

In the graphitization furnace according to the present invention, by providing a heat insulating layer at the innermost part of the lining layer close to the product to be graphitized, it is possible to provide heat insulation and prevent current from spreading. Furthermore, by providing this heat insulating layer, the lining layer around it can be used repeatedly, which greatly reduces the generation of old powder, which is a drawback of the conventional raw breeze lining method in which a lining layer 6 of raw or calcined coke is provided. could be reduced to Furthermore, the graphitization furnace according to the present invention reduces the electric power consumption by 10 to 20% or more compared to the conventional carborundum lining method, and the properties of the obtained artificial graphite products are significantly improved. In particular, since there is no carborundum mixed in the stuffed powder and uniform heat treatment is possible, the ash content of the conventional product was about 0.3%, but with the method of the present invention, it was 0.03% or less. Furthermore, since the graphitization furnace having the lining layer and heat insulating layer of the present invention is easy to construct and dismantle, "furnace packing and furnace unloading work is extremely easy, and the number of man-hours for large and medium production can be reduced.

[Brief explanation of the drawing]

Fig. 1 shows a side sectional view of a conventional graphitization furnace, Fig. 2 shows a top sectional view taken along line A-A in Fig. 1, and Fig. 3 shows a front sectional view of a graphitization furnace with conventional lining. FIG. 4 is a front sectional view of the graphitization furnace according to the invention of FIG. 4, and FIG. 5 shows another embodiment of the invention. Explanation of symbols, 1... Furnace body, 2... Terminal electrode,
3...Carbon random lining, 4...Powder filling 5
..., Carbon fired product, 6... Raw or calcined coke lining layer L 7... Heat insulation layer, 8... Lining layer. Thorns 1 Figure 2 Younger brother 3 Power V Figure Leopard 5

Claims (1)

[Claims] 1 Place the product to be graphitized and the heating graphite breeze that surrounds it in the center of the graphitization furnace, and surround it with carbon powder containing 20% or more of carbon black, raw coke, or calcined coke. A new heat insulating layer with a thickness of 20 to 200 mm is provided each time using one or more types of carbon powder and granules, and the area between the outer periphery of the heat insulating layer and the furnace wall is covered with raw coke or calcined coke and the heat insulating layer at least once. A graphitization furnace characterized by arranging a mixture of used carbon powder and granules as a lining material.