Laser particle sampling at Paraburdoo iron ore

The installation of an Outotec PSI 500 particle size analyser at Rio Tinto Iron Ore at Paraburdoo, in the Pilbara, is the first in Australia.

The installation — which is also one of the first PSI 500 iron ore installations in the world — is designed to save time, labour and money while increasing product quality and value in highly competitive markets.

The on-stream Outotec PSI 500, which uses laser diffraction technology, provides real time particle size analysis, essential to maximising throughput and recoveries, says Outotec’s Application Engineer – Automation in Australia, Brian McPherson.

“The PSI 500 system, selected by Paraburdoo to reliably and continuously monitor feeds from the cyclones to the thickener, gives infinitely better process control than typical intermittent manual sampling methods. This user-friendly automation technology increases production value by enhancing output quality and reducing downtime,” he explains.

One of the main reasons why the PSI 500 technology was selected for Paraburdoo is its highly reliable monitoring. With 80 cyclones per stream, the cyclone overflow reporting directly to the thickener and tailings pumped 7 km, it was critical to ensure correct cyclone operation at Paraburdoo. Dependable monitoring is vital for mass recovery and optimised thickener and tailings operation.

“The analyser is also one of the few in the market which can actually cover particle size measurement in the 1-500 µm range. It monitors particle size distribution and therefore cyclone performance. Also, laser diffraction is a well-established, proven technology, delivering greater precision for particle size analysis.

“Particle size monitoring and control increases average throughput and reduces particle size variability in grinding circuit products, leading to easier thickening as there is a more consistent feed.”

Paraburdoo’s two-stream PSI 500 installation uses a pair of two-stage samplers to monitor thickener feed from four modules of cyclones. The installation was designed and commissioned by Outotec with Rio Tinto Iron Ore Plant Projects Co-ordinator Brady Stump.

Outotec PSI 500 technology was also selected because of its ability to accommodate varying specific gravity of solids at Paraburdoo, while still not affecting accuracy in measurement, and the fact that it is a robust and compact technology requiring a very small footprint.

Normally the sampling system is controlled by a distributed control system, so the PSI 500 installation cost is lower due to no configuring and cabling costs. The unit is also simple to use and capable of measuring random manual samples, and calibration is not required.

Outotec also provided additional services to facilitate the brownfields installation at Paraburdoo, which was challenging in terms of existing structure and plant layout. Outotec supplied the equipment platform, consulted with site management on the ideal location and provided localised training to optimise system performance.