The difference between self-baked electrodes, carbon electrodes and graphite electrodes in submerged arc furnaces

The function of the electrode is to conduct electricity and convert electrical energy into heat energy. Electrodes are divided into three types according to their use and manufacturing process: carbon electrodes, graphite electrodes and self-baking electrodes. In submerged arc furnaces, self-baking electrodes are mainly used because they are low in cost, but when producing ferroalloy products with low carbon content, such as industrial silicon, graphite electrodes are required. The differences between self-baking electrodes and carbon electrodes and graphite electrodes are as follows:

1. Carbon electrodes are made of low-ash anthracite, metallurgical coke, asphalt coke and petroleum coke as raw materials, in a certain proportion and particle size. Binders asphalt and tar are added during mixing, and then pressed into shape after stirring evenly at an appropriate temperature, and then slowly baked in a baking furnace.

2. Graphite electrodes are made of petroleum coke and asphalt coke as raw materials. Carbon electrodes are then placed in a graphitization resistance furnace at a temperature of 2000~2500 degree and graphitized to obtain graphite electrodes.

3. Self-baking electrodes use anthracite, coke, asphalt and tar as raw materials, and make electrode paste at a certain temperature. Then the electrode paste is loaded into the electrode shell installed on the electric furnace. During the production process of the electric furnace, it relies on the Joule heat generated by the current passing through and the heat transfer in the furnace to sinter and coke by itself. This kind of electrode can be used continuously, and it can be sintered and formed while being used, and it can be burned into a large-diameter self-baking electrode.

The production process of self-baking electrodes is simple and the cost is low. It is widely used in ferroalloy production. It is usually used to produce ferrosilicon, silicon-chromium alloy, silicon-manganese alloy, high-carbon ferromanganese, medium-low carbon ferromanganese, high-carbon ferrochrome, medium-low carbon ferrochrome, silicon-calcium alloy, tungsten iron, etc. Self-baking electrodes can easily increase the carbon content of alloys, and the iron sheet of the electrode shell can also easily bring iron into the alloy. Therefore, carbon electrodes or graphite electrodes are used to produce ferroalloys and pure metals with very low carbon content, such as micro-carbon ferrochrome, industrial silicon, silicon-aluminum alloy, and metallic manganese.