Influencing mechanism of Al₂O₃ on sintered liquid phase of iron ore fines based on thermal and kinetic analysis

ABSTRACT

The sintering behaviour of ore fines under different Al₂O₃ content and different alkalinity was studied by DSC–TG method. The reaction kinetics of the sintering process was calculated. Simultaneously, the experimental products were analysed by microscopic analysis. The effects of different content of Al₂O₃ and alkalinity on the sintered liquid phase were investigated. The results show that the increase of Al₂O₃’s content promoted the formation of calcium ferrite and the increase of liquid phase's formation in a certain range. When the content of Al₂O₃ is 2.5%, that is, A/S = 0.42, the heat flux is the largest, correspondingly, the maximum amount of liquid phase is formed under this condition. The liquid phase's formation during the reaction under high alkalinity conditions is greater than that under low alkalinity conditions. The influencing mechanism of Al₂O₃ and alkalinity on the liquid phase of sintering is verified by the kinetic analysis.

KEYWORDS:

• High-alumina iron ore
• sintering
• calcium ferrite
• liquid phase's formation
• kinetics

Disclosure statement

No potential conflict of interest was reported by the authors.

List of symbols

${\omega }_0$	=	Sample mass before reaction;
${\omega }_t$	=	Sample mass at time t;
${\omega }_{\mathrm{\infty }}$	=	Residual mass after reaction;
${\displaystyle \frac{d\alpha }{dt}}$	=	Reaction rate;
$k$	=	Constant of reaction rate;
$n$	=	Reaction order;
$A$	=	Pre-exponential factor;
E	=	Reaction activation energy;
$R$	=	Ideal gas constant, 8.314 J/(mol·K);
$\beta$	=	Heating rate, $\beta ={\displaystyle \frac{dT}{dt}}$;
$f\left(\alpha \right)$	=	Weightlessness function;
$T_0$	=	Initial reaction temperature.

Additional information

Funding

This work was supported by the National Basic Research Program of China [grant number 2012CB720401].