DEVELOPMENT OF AUTOMATED ATR-FTIR SYSTEM FOR WORSLEY BAYER PROCESS LIQUOR ANALYSIS

Worsley is no longer restricted from developing an optimised FTIR method for analysis of Bayer process liquors since patent AU2006225251(a patent for a method and system for the measurement of chemical species in caustic aluminate solutions by FTIR) was WITHDRAWN on June 12, 2014. In late 2015, an attenuated total reflectance (ATR) module was attached to Worsley iS50 Nicolet FTIR spectrometer to develop an in-house ATR-FTIR method to determine refinery liquor properties. Spectral data collected on a manual ATR-FTIR module were used to create multivariate calibration models. Probationary validation of calibration models showed applicability to refinery process liquors. Paired t-tests (95% confidence) on FTIR predicted and reference values for samples in test set (not included in calibration) suggest that the values from FTIR and primary test/reference method were not significantly different.
Quantitative FTIR offers a method that is easy and cheap to run, no sample preparation, non-destructive, and fast analysis. In 2017, Worsley approached Thermo Fisher Scientific to provide an ATR-FTIR unit with automated sampling system and tested their iS5-Simplex system. This system was optimized to have a high throughput for Bayer liquor analysis for A, C, S, TOC, Na2C2O4, Na2SO4, NaCl, and density. Later, the automated system paved the way for an online system for process liquors.
The automated FTIR system allows more frequent analysis delivering complete liquor composition with fast turnaround. To obtain information about the process or material properties in a time shorter than the time it takes for such properties or process behaviours to change allows better process analysis, improved feedback loop, better quality, and process control as well as process optimization.
The FTIR-ATR automated system opens up opportunities to develop methods for other process liquors from other South32 assets.