Optimum Water Content Estimation for Wet Granulation of Iron Ore Powders with Quicklime Binder

Abstract

Wet granulation plays an important role in the processing of fine ore powder. Water content is a critical process parameter that determines the granule properties during wet granulation. However, in the ironmaking industry, various types of iron ore powder imported from different regions are blended, quicklime powder is added as a binder, and used as raw materials. Therefore, the physicochemical properties of the raw powders are not always consistent, which makes it difficult to determine the optimum water content. In this study, we present a method to determine the optimum water content using the agitation torque of wet ore powder blended with quicklime. First, we investigated the agitation torque for blending of various types and ratios of ore powders and quicklime. Two types of torque profiles were observed: a unimodal torque profile (Type I) and a torque profile with a plateau region (Type II). From the agitation torque profile, the characteristic water content (Wtorque) for estimating the optimum water content (Woptexp) was individually defined for the types I and II. The Wtorque was well correlated with the Woptexp, regardless of the type and blending ratio of the original ore powders and quicklime. Finally, the optimum water content was estimated using the Wtorque. The estimated water content was confirmed to be in good agreement with the experimental results, demonstrating that the optimum water content for the wet granulation of fine ore powder with quicklime can be determined using agitation torque.