JPS5916795Y2 - Electrode structure of electric furnace for silicon carbide production - Google Patents

Description

[Detailed Description of the Invention] This invention relates to an electrode part structure of an electric furnace for producing silicon carbide.

Electric furnaces for producing silicon carbide are usually long furnaces, with graphite electrodes installed through the fixed walls at both ends, the side walls above the floor level are made of open bricks, and the bottom of the furnace is made of highly refractory refractory bricks. There is.

Figures 1 and 2 show the fixed wall part of a conventional electric furnace for producing silicon carbide. The electrode part has a refractory material (refractory brick) 3a on the outside, silicon carbide casters (SiC aggregate cemented) 3b are provided inside, and graphite electrodes 3C are placed horizontally on these members. It is configured by inserting it.

4 in the figure indicates a water-cooled clamp.

Since this clamp and the graphite electrode are connected by screwing, they are water-cooled in terms of thermal expansion and heat generation.

In the structure of the electrode section described above, due to the difference in thermal expansion between the refractory and silicon carbide casters and the accuracy of construction, gaps may occur between the contact surfaces of each member, or cracks may occur in the electrode holding member, from which the external The intrusion of air causes oxidative wear and tear on the electrodes and refractories, and as the wear progresses, gas in the furnace leaks, shortening the service life of the electrodes.

This invention was devised with the intention of improving the drawbacks of the conventional structure of the electrode section.

The purpose of this invention is to provide an electrode part structure for an electric furnace for producing silicon carbide that can extend the service life of the electrode part, change the material of the electrode holding member, facilitate workability, and reduce costs. It's about doing.

Hereinafter, the configuration and effects of this invention will be explained with reference to the accompanying drawings.

Note that the symbols corresponding to those in FIG. 1 and FIG.

In FIG. 3, the electrode part 3 has an outer part made of refractory bricks 3a, an inner part integrally joined with a graphite electrode 3C by a carbon paste fired body 3b', and the electrode is inserted through the outer brick. ing.

Firebrick 3a and carbon paste fired body 3b' on the outside
A gap is provided in a part of the contact surface between the two members, and this gap is filled with heat-resistant powder (for example, silica powder) 5 to prevent the gas inside the furnace from leaking to the outside and to moderate the thermal expansion of both members. I'm letting you do it.

For the carbon paste fired body serving as the inner electrode holding member, a graphite electrode is inserted in advance through the side wall of a steel plate box of a size that can be fitted into the outer refractory brickwork.
Carbon paste is loaded into the box, then fitted into the outer brickwork section, and brickwork is then carried out covering the electrodes located in the outer brickwork section.

The loaded carbon paste is self-burned by the furnace heat generated by energization during silicon carbide production, and becomes a fired body integral with the electrode.

In this way, by integrating the electrode with the carbon paste fired body, it is possible to prevent gaps or cracks from forming in the electrode portion, thereby extending the service life.

According to test results in a 5,000 KVA furnace, the conventional electrode structure described above has a service life of about 2 years, while the one with the electrode structure of this invention has a service life of only 3 years. The reactor continues to operate smoothly without any trouble.

Further, by using an inexpensive carbon paste as silicon carbide for the caster, there is an advantage that cost I can be reduced and construction can be carried out simply and accurately.

The structure of the electrode part of this invention has the advantage of extending the service life of the electrode part, being easy to construct, and reducing costs overall.

[Brief explanation of the drawing]

FIG. 1 is a front view showing a fixed wall of a conventional electric furnace for producing silicon carbide, FIG. 2 is a side view thereof, and FIG. FIG. Explanation of symbols, 2... Concrete part, 3... Electrode part, 3a... Refractory, 3b... Silicon carbide caster, 3b'... Carbon paste)・Sintered body, 3C...
Graphite electrode, 5... heat-resistant powder.

Claims (1)

[Scope of utility model registration request] Graphite electrodes are installed through fixed walls installed at both ends of the furnace.
In an electric furnace for producing silicon carbide, the area above the floor surface of the side walls is made of empty bricks, etc., and the bottom of the furnace is made of refractory bricks, etc.
An electrode part structure of an electric furnace for producing silicon carbide, in which electrode parts on fixed walls at both ends of the electric furnace are integrally constituted by a graphite electrode and a carbon paste fired body.