Cobre las Cruces.

Leaching Process Modelling and Control

Project Description

The main aim of this project was to produce a leaching process model so as to allow further development of control strategies for First Quantum Minerals Ltd. (a Canadian metals company focused on copper, nickel, gold, zinc and platinum group metals) copper mining complex Cobre Las Cruces, S.A. (CLC). Cobre Las Cruces, which is is placed in Spain, operates an open pit mine and hydrometallurgical process plant, its facilities occupying 946 hectares including both the mine pit and the process plant with an expected annual production averages 72,000 tonnes of copper, equivalent to 25% of Spanish internal demand. The total for the entire 15-year operating period is estimated at 1 million tonnes of copper and, although good leaching yields were obtained, the process designed nominal operation was not reached. This frame set the basis for this private research project involving CLC, AICIA and IDENER.

In order to meet CLC expectations about leaching process performance, research was conducted to gain extensive knowledge from the process. Such information was used for the production of a process mathematical model which was then validated with experimental data and latter used for designing control strategies. More specifically, this project was accomplished in two phases: 1) current control system analysis and evaluation, dynamic non-linear models development and control strategies assessment; and 2) multivariable controllers evaluation, process simulation under several controllers and final assessment for control deployment. As impact for this industry, the deployment of the control strategies developed allows increasing leaching process yield, thus making high the copper extraction from ore rates and therefore increasing overall copper production and lowering operational costs, i.e. achieving a process more cost-effective.

Involved technologies

CLC’s leaching process is a very innovative technology, far away from traditional copper extraction practices and based in hydrometallurgical principles. Hydrometallurgy is a method for obtaining metals from their ores involving the use of aqueous chemistry, being typically divided into three general areas: Leaching, Solution concentration and purification and Metal recovery.

Specifically, CLC leaching process is based in atmospheric sultafe leaching. In this process, mineral ores (mostly chalcosite and covellite) with high copper content are leached in a sulfate environment. The aforementioned process requires ferric ions to dissolve the copper from the ore and ferric ion is continuously regenerated by reaction with oxygen and sulfuric acid in the solution. Atmospheric leaching takes place at 90°C (reaction heat is effectively utilized in the process, which reduces operation costs and environmental impact) and can lead into high operational costs due to the reagent consumption when it is not optimally carried out. Thus, fine process tuning considering raw material composition, impurities and valuable metals available is required in order to achieve a high copper extraction yield.

Project Details

  • Date 29 September, 2013
  • Tags Environment, Industrial technologies, Modeling and Simulation, Private
  • Partners AICIA; IDENER
  • Start date May, 2012
  • End date December, 2012
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