Influence of Preheating on the Grindability of Mono/Poli Mineral Ores

Abstract

In grinding practice, heterogeneous poli-mineral systems are more common than homogeneous mono-mineral system. The heterogeneity of raw materials in mineral beneficiation grinding circuit results by virtue of the varying properties of mineral constituents in an ore. In this investigation the effect of particle size and preheating conditions on the grindability of quartz as a mono-mineral ore, and nepheline syenite as a poli-mineral one was studied. 2n Factorial method was applied to arrange the studied parameters affecting the preheating of each of the two studied ores according to the importance of their relative effect on its grindability. The results revealed that incremented percentage of -200 µm in the preheated ground poli-mineral ore was less than that of monomineral one by about 32.9%. This behavior was interpreted by containing nepheline syenite on more than one mineral, consequently, phase change and anisotropic thermal expansion or contraction of the grain boundaries have a markedly effect on the grindability of preheated rocks, especially those contain more than one mineral.