In recent years, the output of stainless steel in China has increased by leaps and bounds. This rapid development benefited from the rise of nickel iron smelting from laterite nickel ore and the rapid formation of industrial scale, which made stainless steel enterprises break through the monopoly containment of foreign nickel metals. At present, the output of electric furnace ferronickel with 11% – 16% nickel in China has exceeded 3million tons, which is dominant in China.
Ferronickel production cannot be separated from special sealed paste
The electric energy of ferronickel production in submerged arc furnace mainly comes from the conversion of self baking electrode. The self baking electrode is self sintering and coking in the production process by relying on the Joule heat generated when the current passes through and the heat conduction in the furnace. The electrode can work by using and sintering at the same time. The quality of electrode paste is closely related to the material formula and process.
Self baking electrode and electrode paste.
2.1 requirements for the use of electrodes in thermoelectric furnaces
Taking electric energy as the main heat source, mining reduction electric furnace (submerged arc furnace), reducing ore with carbon as reductant, and producing deoxidizer and alloying agent required by iron and steel industry is the process of ferroalloy production in submerged arc furnace. The high temperature and heat energy required for the production of ferroalloys are usually converted after the electric energy is sent into the furnace through the self baking electrode. Self baking electrode is the basic condition and premise of smelting ferroalloy in submerged arc furnace.
In view of the continuous operation of high-temperature production, the submerged arc furnace usually operates continuously for several years. Therefore, the self baking electrode of the electric furnace is required to be able to transmit power continuously. The quality, performance, roasting technology and conditions of electrode paste should meet the technical requirements of production.
2.2 preparation process of self baking electrode
The self baking electrode is made of anthracite, coke, asphalt and coke as raw materials, mixed according to a certain proportion of particle size, stirred and kneaded at an appropriate temperature, pressed into shape and cooled into paste. When in use, small pieces of electrode paste are loaded into the electrode shell of the submerged arc furnace. In the production process, it is self sintered and coking by relying on the Joule heat generated when the current passes through and the heat conduction in the furnace. The electrode can be continuously shaped while being used, connected and sintered, and different diameters are configured according to the capacity of the electric furnace. Self baking electrode is widely used in ferroalloy production because of its simple process and low cost.