The particle size at the output of the ball mill circuit influences the nickel and copper recovery at Vale’s VBN concentrator. The particle size is measured using a physical instrument which is frequently offline for maintenance and calibration. This means operators are unable to track an important process parameter, recoveries drop, and revenue is lost.
NTWIST developed a virtual instrument to predict P80 of the ball mill cyclone overflow. The solution analyzes the circuit’s existing instrumentation and predicts P80 in real time. P80 predictions are available in Vale’s HMI as well as NTWIST’s GUI. This provides a backup and check for the physical instrument.
When the physical instrument is online, operators compare any suspicious readings to the virtual instrument as a check. When the physical instrument is offline, operators monitor the P80 virtual instrument for deviations from the engineering limits or abnormal trends. If needed, operators can correct the P80 by varying the water additions in the ball mill circuit.
Once the instrument is in use Vale will have near 100% availability of P80 measurements. A process engineer at Vale (Connor) believes this will conservatively generate $170k in additional revenue through improved recoveries.