The FLSmidth~R Rapid Oxidative Leach (ROL) process: a mechano-chemical approach and industrial applications for rapid metal sulphide dissolution

摘要

The leaching of primary copper concentrates using acidic ferric sulphate lixiviants is known to suffer from slow kinetics and poor copper recoveries. A number of processes have been developed over the years to improve the leach kinetics and copper recoveries, and while many are effective, they have high CAPEX and/or OPEX. FLSmidth is developing a mechano-chemical approach that confers significant process efficiencies by taking advantage of the enhanced reactivity of transitory, surface-defect structures generated during particle fracture. The patent-pending FLSmidth~R Rapid Oxidative Leach (ROL) process uses a stirred media reactor (SMRt) to achieve copper recoveries of more than 97% in less than 6 hours under atmospheric conditions. The mechano-chemical approach overcomes many of the surface passivation problems that have hindered other atmospheric leach processes. Results of batch leach tests and new insights to leach mechanisms are presented.During the life-cycle of many orebodies, the mineralogy transitions from oxides to secondary and primary sulphides, ore grades decrease, and the ore become more difficult to process. Cost-efficient leach processes will be required to maintain copper production at existing mines or take advantage of new orebodies, particularly those containing arsenic-rich minerals like enargite. To date, the majority of the FLSmidth work has been on primary chalcopyrite concentrates, with a minor amount of work done on enargite and arsenopyrite concentrates. Brownfleld and greenfield industry applications are reviewed for potential use of the FLSmidth? ROL process, primarily looking at copper recovery from chalcopyrite and enargite. We also include a discussion on applications to other metals, like refractory gold, nickel, and zinc.