Physical and Low Temperature Reducing Properties of Lime-fluxed Pellets

Abstract

This paper describes experimental results of physical and reducing properties of pellets up to 1 100°C of reduction temperature as a function of basicity, SiO₂ contents and indurating temperature during the addition of limestone. These properties are closely correlated to the bonding structures of indurated pellets which are classified into 6 types.
Those are hematite (A), hematite+low-basicity silicate slag (B), hematite+calcium ferrite (C), hematite+high basicity silicate slag+di-calcium silicate (D), A+B, and C+D bonding structures.
A-type pellets have lower crushing strength and higher open porosity, swelling index and reduction degree, B-type ones have the highetst crushing strength and swelling index and the lowest open porosity and reduction degree, C-type ones have the highest open porosity and reduction degree and the lowest swelling index, and D-type ones have much higher crushing strength and reduction degree and much lower swelling index.
Therefore, physical and reducing properties of pellets change remarkably by adding limestone.
Pellets with (C+D)-bonding structures give the highest levels of crushing strength and reduction degree, and the lowest swelling index.