Impala Platinum’s Base Metals Refinery (BMR) in Springs, South Africa, receives its raw material from the company’s mining, concentrating, smelting, and converting facilities in nearby Rustenburg. The BMR then removes as much of the base metals as possible and sends the PGM (Platinum Group Metals) concentrate to the Precious Metals Refinery (PMR) plant for further processing. The base metals are refined and sold separately to maximize the conversion of raw material into revenue.
Poor pH control, complex, multi-variable environment
The processing of platinum is a complex and costly affair. The quality of the upstream process (BMR) can have serious financial consequences on the profitability of the downstream PMR process.
Impala Platinum identified difficulties in controlling the pH in the first stage autoclaves, and poor pH control has a serious and negative impact on the PMR processes. Up to this point, the pH had been controlled through a cumbersome process of manual sampling and operator intervention. Responses to changes were delayed and future values could not be predicted automatically.
Advanced pH controller provides real-time optimization
Impala Platinum turned to GE to help address its challenges. Over a period of six weeks, GE installed Proficy CSense, providing Impala BMR with control and optimization of its nickel-leaching process. The software relieved operators of many decisions that were previously difficult given the complex, variable, and real-time nature of the processes in their charge.
An advanced controller based on a hybrid of fuzzy logic technology and fundamental principles was implemented to provide stabilization of the pH to improve the leaching efficiency of iron and nickel. It also provided online and real-time pH sampling to help optimize the process.
With Mine Performance, I know I have got a dedicated solution that is running real time with no disruptions. It has freed up time for me and my staff, and time is important in terms of production.
Sello Semosa - BMR Manager, Impala
Since the Proficy CSense has been implemented, it has greatly reduced the level of impurities in the product from the BMR, thus increasing the concentration of PGMs. This ultimately leads to more platinum being extracted in the PMR downstream—boosting productivity and significantly increasing pH stability for Impala Platinum.
Other benefits included:
- Reduction in pH peaks in the autoclave, which can lead to certain elements becoming very difficult to leach
- Stable process control in spite of variations
- Indirectly limits environmental emissions