Characteristics of Nickel Laterite Crushed Ore Agglomerates

Crushed ore agglomeration has been used and is considered as a pretreatment step to improve heap leaching performance of complex copper and gold ores. It is well known that proper agglomeration can prevent solution channeling and ponding, improve percolation within the heap and increase metal recovery rates. However, not much is published regarding nickel laterite agglomeration behavior. Agglomerate size distribution and bed permeability are important parameters to evaluate the quality of agglomerates. With proper considerations, electrical conductivity can be used to control the agglomeration conditions. In this study, a nickel laterite ore from Piaui, Brazil was agglomerated and subjected to different tests to evaluate agglomeration conditions. The study included determination of agglomerate size distribution, saturated hydraulic permeability and electrical conductivity response. It has been found that moisture content and acid concentration have opposite effects on the agglomerate size. Also, retention time and drum rotation speed have small effect on agglomerate size. As expected the permeability of the agglomerate bed is strongly correlated to agglomerate size. Electrical conductivity of the agglomerate bed is affected by agglomeration size, moisture content, acid concentration, and external compaction