Investigation of electric potential difference during the top oxygen blowing in converter

Abstract

Purpose: of this paper is to investigate the method of monitoring the course of the main oxidation-reduction processes and dust depression during the top oxygen blowing, based on the registration of natural electric potential difference on the lance-metal melt site during the blowing. Design/methodology/approach: Exchange processes in the converter bath take place with exchange of electrons and ions between metal and slag melts and gas phase. Since the processes are far from equilibrium, if to complete the circuit it will be possible to register the potential difference. Investigation was conducted in industrial converters of 60-t capacity at medium-carbon steel smelting. During the blowing the potential difference in the lancemetal bath site, the position of the lance and the dust level after gas cleaning were recorded. Findings: It was revealed that the level and sign of variation of the potential difference in the lance-metal bath site reflects the course of the main oxidation-reduction processes in the sub lance area during melting periods: oxidation of silicon, carbon and iron. The probable course of gaseous oxygen interaction with the metal fusion was discussed. Practical implications: In order to reduce the dust level without slowing down the carbon oxidation process, it was recommended to place the lance at a level corresponded to the potential difference during the active carbon oxidation period 30 % lower than 200-210 mV. The results of heats, conducted with the proposed mode of lance position, showed that the level of dust emission was 16% lower than on the comparative melting. Originality/value: The level and sign of the potential difference is possible to use to select the lance position during the blowing for longer slag foamed state without overflow that ensures a lower level of dust emission.