Particle size distribution of iron ore sludge determined by using different methods and iron content by size class

Abstract

This paper presents the results of the study of the particle size distribution of the limonite sludge that occurs as a hydro-cyclone overflow in the Omarska iron mine. The primary role of the precise characterization of grains of mineral raw material is in obtaining quantitative data about their particle size and analysis of the distribution of mineral grains by volume, which is a necessary step in controlling the processes of the iron ore beneficiation. Since the overflow of the hydro-cyclone size class is -25 μm, in this paper the following methods of sub-sieve analysis are used: sedimentation method-Beaker decantation; pipetting method by Andreasen-Borner; and Warman cyclosizer. Different methods were used in order to analyze the compliance of the results, as well as comparison of them, because expensive and rapid instrumental methods are often unavailable in practice. Also, the content of iron in the sludge varies, so the correlation of iron content with granulometric particle distribution was analyzed. These analyzes were carried out on two samples of sludge with different average iron content (29.43% and 41.19%). On both samples the iron content was determined per size class. The results showed a largest iron content in the smallest classes (-9+6 microns). These results indicate the necessity of applying some of the methods for selectively separating fine particles (such as selective flocculation, for example) in a further process of preparation.