Lower temperature pelletizing process of iron ore fines

Abstract

A method of processing iron ore fines from various possible sources, with particle size up to 0.15 mm (through 100 mesh sieve) with no or limited comminution, directly into the intense mixer, with a set of binders in specific proportions, aiming to optimize physical and metallurgical properties of the pellets with minimal binder addition, thus not compromising the quality of steel products. The binders are starch, sodium silicate and sodium hydroxide, among others. The mixture with adjusted moisture content goes through conventional balling discs or drums and size screening. The green pellets then undergo drying with forced air at around 150° C. for a short time. The pellets obtained have excellent metallurgical properties, and compression resistance around 70 kgf/pellets, without the high and undesirable economic and environmental costs of the conventional indurating process. An alternative embodiment (FIG. 3) considers indurating the pellets at temperatures below 1,200° C. to obtain similar mechanical resistance than pellets made by the conventional induration process, with temperatures above 1,300° C.

Dependencies are inferred from the claim text.