Sintering characteristics and kinetics of acidic haematite ore pellets with and without mill scale addition

Abstract

Haematite ore pellets require very high induration temperature (>1573 K) while, magnetite ore pellets require much lower temperature due to the oxidation of magnetite during induration. Mixing of some magnetite in haematite ore can improve the sintering property of pellets during induration. Mill scale is a waste material of steel plant which contains mainly FeO and Fe 3 O 4. It can also be blended in haematite ore pellet mix which can enhance diffusion bonding and recrystallisation bonding and facilitate sintering at the lower temperature like magnetite ore. The extent of improvement in sintering property, sintering mechanism and its kinetics in the presence of mill scale is very imperative to study. In current study, the sintering characteristics of acidic iron ore pellet with 15% mill scale and without mill scale has been studied separately through microstructure observation, apparent porosity measurement and volume change. The volume changes due to heating at varying temperature and time has been measured by mercury displacement method and the data has been exploited for sintering kinetics study, wherein, extent of sintering α has a power relation with time. Several kinetics parameters such as time exponent (n), rate constant (k) and activation energies have been estimated for above two pellets and compared. While acidic pellet without mill scale requires 385 k cal mol −1 , acidic pellet with 15% mill scale requires only 310 k cal mol −1 activation energy.

Experimental Investigation of Different Fineness and Firing Temperatures on Pellets Properties of Different Iron Ore fines from Indian Mines

“…As compared to Iron Ore No.2 has a 53% of 44-micron excessive fineness makes the grains react more and, instead of transforming solid solution, liquid melt deteriorates the structure. As it can be noted from particle size analysis, more fineness in either iron ore always does not support the strength an optimal value makes the pellets strong [26,27]. The chemical composition of iron ore fines behaves differently as per the thermal treatment process of pelletization.…”

Review of pellets and blast furnace slag research progress: the effects of MgO on metallurgical properties

“…Reducibility of iron-bearing burden is dominant in the blast furnace. The large-scale utilization of high basicity sinter is based on its high reducibility and good softening performance [53]. Generally speaking, the reducibility of acid pellets is poor [54,55], while the reducibility of MgO-bearing pellets has been improved to a considerable extent [56][57][58].…”

Reinforcement of Pellet Consolidation Strength Based on Iron Filings: Microstructural Evolution and Mechanism

“…However, the efficient utilization of iron-based solid wastes is not fully realized because of the high consumption of sintering materials and the low usage of them as secondary resources. Y. Rajshekar et al [21][22][23] found that the iron oxide scale can be used as an additive to hematite pellets to improve its metallurgical properties such as reduction index.…”