Abstract
A transient mathematical model was developed for the description of fluid flow, heat transfer and electromagnetic phenomena involved in the production of ferronickel in electric arc furnaces. The key operating variables considered were the thermal and electrical conductivity of the slag and the shape, immersion depth and applied electric potential of the electrodes. It was established that the principal stimuli of the velocities in the slag bath were the electric potential and immersion depth of the electrodes and the thermal and electrical conductivities of the slag. Additionally, it was determined that, under the set of operating conditions examined, the maximum slag temperature ranged between 1756 and 1825 K, which is in accordance with industrial measurements. Moreover, it was affirmed that contributions to slag stirring due to Lorentz forces and momentum forces due to the release of carbon monoxide bubbles from the electrode surface were negligible.
Highlights
Nickel is of particular economic consequence in the production of stainless steels, superalloys and fuel cells [1,2]
We will first discuss the results of our sensitivity analysis with regard to the effect of Lorentz forces, CO bubbles, slag and ferronickel properties as well as parameters related to the electrodes geometries; this analysis was aimed at the determination of the basic flow and heat-transfer mechanisms which are likely to occur during melting
A number of consistent conclusions can be drawn: (1) The electric conductivity of slag and ferronickel has a substantial effect on the Joule heat produced in the furnace and the maximum temperature of the bath
Summary
Nickel is of particular economic consequence in the production of stainless steels, superalloys and fuel cells [1,2]. The principal nickel production route comprises the reductive smelting of calcine in electric submerged arc furnaces (EAFs); calcine is the yield of reductive roasting of nickelferrous lateritic ores in rotary kiln furnaces [3,4,5]. Owing to the poor electric conductivity of the calcine, the electric energy leads to the formation of a molten slag layer due to the effect of Joule heating and, to a lesser extent, because of the development of multiple small-scale electric arcs formed in the vicinity of the electrodes [6]. Transport properties affect the maximum temperatures achieved, the temporal distribution of liquid fraction and the formation of stirring velocity gradients in the slag melt. In view of the physical complexity involved in reductive smelting, analytically descriptive efforts tend to separate fluid flow from electromagnetic phenomena [6,12,14,15,16,17]; here we attempt the coupling of fluid flow, electromagnetic phenomena, melting and discrete phase phenomena (e.g. the interaction of CO bubbles with the bath), as a rational progression step towards a pragmatic description of the EAF continuum
Sign-in/Register to view highlights & summary Sign-in/Register to access full text options 
Talk to us
Join us for a 30 min session where you can share your feedback and ask us any queries you have
Schedule a callDisclaimer: All third-party content on this website/platform is and will remain the property of their respective owners and is provided on "as is" basis without any warranties, express or implied. Use of third-party content does not indicate any affiliation, sponsorship with or endorsement by them. Any references to third-party content is to identify the corresponding services and shall be considered fair use under The CopyrightLaw.
