:: Outokumpu’s Laser-Based Particle Analysis Advances Process Efficiencies

A new slurry particle size analyser that uses advanced laser diffraction technology to improve mineral processing operations has been introduced by Outokumpu Technology Pty Ltd.

The Outokumpu PSI 500^TM is designed to enhance monitoring and control of mineral particle size. Through this monitoring and control, throughput and particle recoveries are maximised, essential steps in ensuring successful plant design and performance, says Outokumpu’s Automation Manager, Brandt Henriksson. The PSI 500^TM also further enhances the return on investment (ROI) because it both minimises reagent and dewatering costs and optimises quality.

One of the applications of this technology is in grinding circuit control. Mr Henriksson says the PSI 500TM provides real time and accurate particle size distribution measurements between 1-600 micron, which are critical variables for grinding circuit control. Since the instrument is not sensitive to entrained air in the sample, the PSI 500TM can be used in regrind circuits. Additionally, the PSI 500TM improves downstream activities, making processes such as thickening and filtration more effective.

The robust and reliable use of diffraction technology in the PSI 500^TM allows precise management and control of the grinding circuit, while guaranteeing high and stable quality of the end product, as well as effective tailings disposal. The PSI 500^TM is also applicable over a wide particle size range and is rapid (results in just over one minute), non-destructive and exhibits high resolution with up to 20 size fractions, along with specific surface areas.

Major applications of the new technology include:

• Grinding circuit products with bimodal distributions
• Control of large thickeners
• Mine backfill monitoring
• Quality control of industrial minerals products

A significant advantage of the laser diffraction technology built into the PSI 500^TM ensures a consistent result without any external calibration. This means the instrument’s repeatability and precision - the most important features in automation process control applications - are excellent over a wide particle size.

"Also the speed, non-contact nature and robustness of the method to ambient conditions make laser diffraction very suitable for on-line mineral slurry applications," says Mr Henriksson. The PSI 500TM’s optical measuring head - designed and manufactured by Malvern Instruments in co-operation with Outokumpu technology - is based on industry-standard laser diffraction technology used in most laboratories for particle size analysis.

Diffraction technology, or low angle light scattering, is based on the intensity distribution measurement of coherent light scattered by particles. When the laser beam interacts with particles, their size distribution can be calculated from the scattered light distribution.