اثر اعمال كار مكانيكي در اتمسفر آرگون بر احياي مخلوط هماتيت سينتر شده و گرافيت

The effect of ball milling under Ar atmosphere on the reduction behavior of sintered hematite and graphite mixture. Was studied. Hematite which was sintered at 1050°C for 24 hour, was mixed with 19.84 wt% graphite (C:O ratio was 1.1:1) and subjected to ball milling under Ar atmosphere. The milling time varied between 6 to 200 hours. In order to study the effect of milling time on reduction process under Ar atmosphere a TG-DTA technique was adopted. The samples were heated at a constant heating rate of 10°C/min from room temperature up to 1100°C and maintained for 30 min at this temperature, According to TGL curves, the onset temperature of reduction was decreased with milling time. The rate of reaction (RTG) was calculated using differentiation of weight loss curve. It was found that the RTG curve consisted of two reaction peaks. The first peak corresponded to hematite-magnetite (HM) reduction and the second one could be attribute to the overlapping curves of magnatie-wustite (MW) and wustite-iron (WF) reductions. The two peaks were overlapped and broadened as milling time proceeded. The temperature of reactions decreased and the time of reactions increased significantly with milling time.