2025 Svantesson H DRI EAF Melting Time

The melting time of hydrogen direct reduced iron pellets (H-DRI) significantly impacts productivity in electric arc furnace steelmaking aimed at fossil-free steel production. This study aimed to evaluate the effect of material and process parameters on the melting time of H-DRI under laminar conditions using computational fluid dynamics. Results indicated that the primary determining factor for melting time is the characteristics of the slag bath and its movement, with the properties of H-DRI being secondary. The shortest observed melting time of 4.56 seconds occurred under optimal conditions of high temperature (greater than 1950 K), high viscosity foam (greater than 0.1 Pa s), and high thermal conductivity (greater than 0.9 W m/C0 1 K/C0 1) of the slag. It was found that reducing H-DRI porosity from 65 to 50 percent increased melting time by 4 percent, while raising the initial temperature from 300 K to 1100 K led to a 20 percent decrease in melting time. Furthermore, increasing the slag bath temperature from 1850 K to 1950 K resulted in an approximate 55 percent reduction in melting time due to enhanced superheat. The study also determined that forced convection could significantly decrease melting time for H-DRI.