Ferric chloride leaching of a mechanically activated pentlandite-chalcopyrite concentrate

Mechanical activation accelerates the leaching of non-ferrous metals from s ulfide ores by increasing the surface area and reactivity of the concentrat e, and through lattice distortions resulting from deformation due to millin g. In this study we examine the feasibility of applying the process to a co mplex ore concentrate containing both pentlandite and chalcopyrite through the use of a horizontal ball mill for the mechanical activation of chalcopy rite, using a concentrated (similar to 5 M Cl-) ferric chloride solution fo r the leaching. The kinetics of dissolution are correlated with specific ar ea and with line broadening as determined by X-ray diffraction. Mechanical activation improves the kinetics both of copper extraction from the chalcop yrite, and of nickel extraction from the pentlandite. As both leached readi ly using the ferric chloride solution, selective leaching using this lixivi ant does not seem feasible. (C) 1999 Elsevier Science B.V. All rights reser ved.