EFFECT OF THE GEOLOGICAL TEXTURE AT MESO AND MICRO-SCALE ON GRINDING PERFORMANCE

摘要

Comminution indices are used to represent the grindability of combination of minerals treated by specific processes. If two rock samples with similar values for an index are treated in the same comminution process linked to that index, they should have an analogous behavior. However, indices are obtained assuming the breakage of homogeneous and continuous materials without considering minor scale mineral and geological properties, so eventual differences in the process may not be explained by comminution indices. In the present study, two different copper ores samples with similar Bond Work index were used to evaluate the influence of mineralogy and geological texture at meso and micro-scale in a ball grinding process at laboratory scale. The effect on grinding was assessed through controlled grinding kinetics performed in a Magotteaux Mill?, while samples were characterized through geological texture analysis at microscale following an appropriate protocol of mineralogical characterization using hyperspectral characterization, X-ray diffraction and X-ray fluorescence. Results show that the BWi allows to describe the transition between initial and final states at long grinding times, but it cannot reproduce the entire grinding kinetic, while textural properties such as grain size and matrix-grain mineralogical composition may be linked to Pgo variation over time and the variation of cumulative particle size distributions at different grinding times. Results suggest that geological texture may be considered as a complement of traditional grindability indices to evaluate the grinding performance.