The effect of breakage method on the shape properties of an iron-oxide hosted copper–gold ore

Using a mineral liberation analyser (MLA), the shape properties of an iron-oxide hosted copper–gold ore following comminution in either a hammer mill or a piston–die compression unit were examined. It was found that particle angularity distributions were able to be fitted to the beta distribution, providing a convenient way to quantify changes in particle shape properties as a function of the breakage method employed. Particles discharged from the hammer mill were less angular than particles discharged from the piston–die compression unit. This was attributed to attrition breakage mechanisms, whereby topographical features are chipped off parent particle surfaces. The results suggest that the quantification of shape properties is a convenient method for obtaining insight into the nature of breakage events that take place inside comminution devices.

MLA images of comparatively angular and round particles produced following breakage in a piston–die compression unit (top) and a hammer mill (bottom) respectively.Figure optionsDownload as PowerPoint slideHighlights
► Particles discharged from a hammer mill are comparatively round.
► Particles discharged from a piston–die compression unit are comparatively angular.
► Angularity properties can be quantified using the beta distribution.
► Shape properties provide insight into the nature of different comminution processes.