Application of effective drying methods and storage characteristics of iron ore briquettes

Abstract

In the iron ore agglomeration industry, extensive research has been conducted on various drying techniques. Drying iron ore briquettes is essential to provide the initial strength needed for freshly prepared briquettes. Briquettes with the composition of iron ore fines (16.5%), (Linz-Donawitz) sludge (47.2%), flue dust (28.3%), bentonite (2%), and cement (6%) were dried using hot air oven drying, microwave drying and infra-red drying under controlled heating conditions. After drying the briquette samples were stored under ambient atmospheric conditions for 7 days. The open air drying of the briquettes is the cheapest method available for the curing of briquettes, but it mainly depends on sunlight. It adversely affects the continuous supply of iron ore briquettes for the steel industry in the winter and rainy seasons. This work aims to determine the most efficient drying technique with low carbon emission as compared to high temperature drying using conventional drying techniques. The briquettes should have some initial strength so they do not break while being transported from one place to another for steel production. These briquettes should be strong enough so that they do not disintegrate before the start of the reduction process in the blast furnace. Infra-red drying at 120°C produced the highest strength of 4.195 N/mm² (MPa), surpassing the strength (3.680 N/mm²) achieved by hot air drying. This method of low temperature drying not only facilitates the production of high-quality dried products but also contributes to the creation of eco-friendly briquettes with reduced carbon emission. Here this study employs low temperature drying as a sustainable drying practice.