Phase transition mechanism of high-silica fluxed pellets during consolidation

ABSTRACT

An in-depth study of the consolidation behaviour of high-silica fluxed pellets will help promote the development of a high-proportion pellet smelting process suitable for China’s resource structure. Lime, slaked lime, and limestone were used as calcium-containing additives to prepare high-silica fluxed pellets, and the suitable calcium-containing additives were lime and limestone. Compared with acid pellets, the suitable preheating temperature of high-silica fluxed pellets is higher (1100°C). The phase transformation during preheating consists mainly of the thermal decomposition of CaCO₃ and Ca (OH)₂ and the reaction between the solid phases.The roasting temperature of high-silica fluxed pellets should be controlled within a small range (1250°C–1280°C). The phase transition during the roasting of mainly lies in the generation and migration of the liquid phase. The Fe₂O₃ consolidation, the pore distribution law, and the liquid phase formation jointly determine the consolidation properties of the pellet.

KEYWORDS:

• Ironmaking
• phase transition
• high-silica magnetite
• calcium-containing additives
• fluxed pellets
• consolidation
• liquid phase
• pore distribution

Disclosure statement

No potential conflict of interest was reported by the author(s).

Additional information

Funding

The authors acknowledge the financial support of the National Natural Science Foundation of China [52174291].