# Reduction Behavior and Melting Characteristics of Blast Furnace Iron Ore Mixed with Carbon-Rich Iron Particles

## TL;DR

This study examines how adding carbon-rich iron particles affects the melting and reduction behavior of blast furnace iron ores.

## Contribution

The study identifies the optimal carbon content in iron particles to enhance blast furnace performance.

## Key findings

- Iron particles with over 1.6 wt.% carbon achieved reduction rates similar to typical blast furnace charges.
- Iron particles with 3.6 wt.% carbon maximized carbon availability for reduction and raised slag melting temperature to 1398 °C.
- The iron–slag dripping temperature range narrowed to 132 °C, optimizing blast furnace operations.

## Abstract

The currently available hot briquetted iron (HBI) typically contains approximately 1 wt.% carbon. In the CO–CO2 atmosphere of a blast furnace, carbon loss from iron is significant, accompanied by overoxidation. Based on the high metallicity of HBI, this study designed iron particles with varying carbon contents. These pellets were mixed with three typical blast furnace iron ores–sinter, pellet, and lump– and subjected to thermogravimetric analysis reduction experiments. The investigation explored the effects of substituting 15 wt.% sinter with HBI containing different carbon contents and assessed the resulting impact on the temperature difference between iron and slag melting, ultimately determining the optimal carbon content for blast furnace operations. The findings showed that the addition of iron particles with carbon contents exceeding 1.6 wt.% achieved reduction rates and iron–slag melting characteristics similar to those of typical blast furnace charges. When iron particles containing 3.6 wt.% carbon were added, the iron oxides of various valence states in the charge and pellets exhibited the highest availability of carbon for both direct and indirect reduction. Consequently, the slag melting temperature rose to 1398 °C. Due to the presence of unreacted carbon, the molten iron melted at approximately 1530 °C, while the iron–slag dripping temperature range narrowed to 132 °C, achieving the optimal temperature range for blast furnace application.