Teck Highland Valley Copper's Froth Velocity Improvements with Advance Process Control

摘要

The process control culture at Teck Highland Valley Copper Partnership (THVC) has changed in the last five years. As a part of this culture change, and with the objective of creating sustainable process control solutions, a fully instrumented flotation circuit was commissioned in 2014. The main process variable used to measure the performance of the rougher/scavenger circuit is froth velocity. Froth velocity is the speed at which froth overflows the concentrate lip of a flotation cell. The aim of this work is to present the advance process control (APC) platform and the froth velocity control improvements with a constrained model predictive control (MPC) strategy changes in the rougher/scavenger cells of the bulk copper flotation circuit at THVC. Froth velocity is controlled by manipulating the airflow rate and froth depth in each rougher/scavenger cell. Airflow rate and froth depth were chosen due to the interdependence of these manipulated variables and the capability of predictive controllers to handle variability and process constraints. Since the stability of the process impacts the metallurgical and economic performances of the circuit, an upgrade of the MPC strategy was implemented in 2017. Changes in the control application and froth depth set-point target utilisation were made. These changes have shown an improvement in process performance, increasing recovery average by more than 2 % with 24% lower standard deviation, increasing total froth velocity by 22 % with a 20 % lower standard deviation, and reducing operator interventions in the froth velocity controllers by 47 %. This work has demonstrated the importance of maintaining and expanding a process control culture, confirmed the efficiency of the MPC strategy, and prepared the process for metallurgical real-time optimisation.