Mill Scale - Biomass Pellet as a Charged Material for EAF Steelmaking

With an aim to utilize the local-based waste materials, this research investigated the production of mill scale - biomass pellet (MBP) as an alternative charged material for EAF steelmaking. Rubber tree bark (RTB) is one of the major biomasses in Thailand, consisting of carbon and hydrogen as the main compositions. The carbon derived from RTB was mixed with coal into five different ratios. Pure coal and RTB were employed for comparison. Seven carbonaceous samples were blended with mill scale at a C/O molar ratio of 1:1 to produce MBP, namely Coal, blend#1 – blend#5 and RTB. The reduction of MBP was investigated in a horizontal tube furnace under argon atmosphere at 1550°C for 15 and 30 minutes. The obtained products were iron droplets and residual black powder of unreacted oxides. Quantities of reduced iron from the MBP of blend#1 – blend#5 was about 58 – 61 wt% after 30 minutes, while it was 62 wt% and 57 wt% for coal and RTB, respectively. Degree of metallization (DOM) for blend#1 – blend#5 was between 78.1 – 81.7%, while it was 82.7% and 83.3% for coal and RTB. This research offers the possible method to utilize mill scale and RTB biomass toward circular economy.