MODELING OF AGGLOMERATE SIZE DISTRIBUTION FOR HEAP LEACHING

Agglomeration has become a common pre-treatment step to improve heap leach percolation and, thereby, recovery; however, the fundamental understanding of the agglomeration process for crushed ores is still lacking. This study investigates the agglomeration required for ores with excessive amounts of clay or fines generated during mining and crushing. Numerous experiments were conducted using different ores in laboratory scale batch drums, revealing that experimental agglomerate size distributions exhibit self-preserving spectra. These distributions are independent of operating conditions and are uniquely determined by the size enlargement mechanism. An empirical model based on the absolute difference between the moisture applied and optimum moisture was developed, utilizing self-preserving spectra in the form of a Rosin-Rammler distribution function to predict size distribution under various operating conditions. The model proved easier to work with in plant-scale agglomeration drums. Additionally, a dip test was developed, which enhances fundamental understanding of agglomerate formation and growth mechanisms, providing progeny size distributions for each agglomerate size. The progeny size distribution was analyzed using a model that categorizes particles into host and guest types, with the partition coefficient indicating particle behavior in agglomeration. This concept aids in predicting the type of agglomerate resulting from specific feed size distributions.