The production of a standard material for liberation analysis /

In mineral processing, the liberation distribution of the mineral phases in an ore is an important factor. Unfortunately, liberation distribution is very difficult to measure accurately. One problem is the stereological effect associated with a microscopic liberation analysis.Many methods have been proposed to correct for the stereological effect, but they remain essentially untested, in part due to the lack of a standard or reference material. In this work, a method was established to create an artificial standard material.Silica grains were placed in an epoxy resin to create a block of material that was crushed to yield liberated and locked particles. The composition, and thus liberation, of these particles was determined with a series of heavy liquid separations.By changing the grain size to particle size ratio, the type and amount of locking was affected. The best compromise between the amount of locked material produced and the production of simple locked particles (which pose the greatest stereological challenge) was found; it occurred at the point where the grain and particle sizes were the same.Liberation analyses were performed on this material and compared with a model prediction based on the sectioning of spheres with single planar interfaces. There were some discrepancies between the analysis and model results