Predicting the Liberation of Sulfide Minerals Using the Breakage Distribution Function

Abstract

The study validates how the original grain size of the ore influences the propensity of a mineral to be liberated. An Australian zinc ore was investigated for the variation in composition with respect to grain size using QEMSCAN. The breakage patterns of the ore showed that the liberated phases were influenced by the association of various phases in the original ore affecting the size distribution of different species. The combined breakage and the QEMSCAN data were used to predict the effect of grinding which affects the grain size and hence the distribution of grain phases in different size fractions, and relates the latter to the proportions of binary and ternary composite grains in the original ore sample. The study provides a direct correlation between the grain size distribution resulting from grinding to the liberated free minerals, binary and ternary composites. The liberation model parameters determined in the present study are used to predict the liberation of different mineral compositions directly from the size distribution analysis as well as from the t₁₀ parameter. The study has implications for optimizing grinding practice for improved beneficiation, and liberation as over-grinding produces undesirable fines difficult to process as well as incur additional energy input.

Keywords:

• binary and ternary mineral phases
• breakage pattern
• liberation
• QEMSCAN

Acknowledgment

The author expresses sincere thanks to Prof. T. J. Napier-Munn for his comments.