In recent years, arsenic (As) content in copper concentrates has increased along with environmental restrictions for their transport and processing. Under this scenery is being developed the Complex Concentrate Leaching Project (PLCC), which allows the treatment of copper concentrates with high As content (>0.5%) through a high pressure (2873 kPa) and temperature (220°C) leaching process within an autoclave. The addition of high purity oxygen and cooling water to control the temperature in the different autoclave compartments is possible to dissolve over 99% of copper and As compounds. Dissolved As is then precipitated as an arsenical residue. The PLS is sent to a solvent extraction plant to produce copper cathodes, where it is previously mixed with heap/dump PLS solutions. On the other hand, the arsenical residue is stored on a deposit or sent to a silver recovery process. The gases from the autoclave, slurry depressurization and slurry cooling are sent to a gas cleaning system, where water and entrainments are recovered before emitting the gas to the atmosphere. A process simulator was developed in order to assist the review of the feasibility study and analyze different process configurations. The purpose of this work is to describe the process simulator developed for the PLCC project and present some simulation results for different process configuration analyzed during the feasibility of the PLCC project, which permitted to improve the process and reduce the CAPEX and OPEX.