Experience of using evaporative cooling of graphitized electrodes to reduce their consumption in ore smelting furnaces

Abstract

Consumable graphitized electrodes (GE) are widely used for supplying current to AC and DC EAF's, ore-smelting and indirectly heated electric arc furnaces. Due to large current, thermal and mechanical loads, their consumption in the structure of the cost of smelting in some cases, for example, in steel smelting reaches 30 %. Considering this, as well as the unstable global economic situation, when many enterprises use imported electrodes, solving the issue of reducing them is urgent. Foreign-made arc steel furnaces with a capacity of 100 tons and more successfully use evaporative cooling (EC) technology. Its use leads to a reduction in graphite consumption by an average of 10–15 %. However, for ore-thermal furnaces, no data on the experience of using EC GE has been found in the literature. The purpose of the work is to study the possibility of reducing the temperature and consumption of GE in arc ore-smelting furnaces when using EC technology. Experimental studies were carried out at the enterprise PC “AVISMA” (Berezniki), which includes three ore-smelting furnaces with a capacity of 100 tons. For the graphite electrodes used in these furnaces, modeling of their thermal state was performed with and without EC. Rational technological parameters of the cooling process were determined: water flow 1.5 m3/h and system turn-on time 5–15 minutes from the start of the current supply. An experimental design of the EC ring and a system for monitoring water and air flow have been developed. As a result of several heats, a decrease in the surface temperature of the GE was recorded when using EC with water on its side surface and a number of shortcomings were identified. Recommendations for improving technology and improving the design of the AI system are formulated