Modelling and optimization of carbon-in-pulp gole recovery processs

The paper presents a mixed-integer nonlinear programming (MINLP)approach to construction and operational optimization of carbon-in-pulp(CIP) processes related to hydrometallurgical gold recoveryplants. In this plant section, gold in the form of aurocyanidecomplex ions is adsorbed on the active sites of carbon particles.This takes place in a series of agitated tanks where carbonis countercurrently transferred with respect to the pulp. Threebasic process operating modes are reported and analysed: namelycarousel, continuous, and sequential. The mathematical modelof the CIP process is developed for each one of the operatingmodes examined. Economic evaluation is carried out proposingthe sum of annual gold loss to the tailings plus the total annualcost as a minimization object subject to constraints dictatedby the process model. The original problem is suitably decomposedinto a series of nonlinear programming problems and solved withsuccessive quadratic programming techniques. A characteristiccase study is presented to demonstrate the effectiveness ofthe proposed method.