Development of a model for serpentine quantification in nickel laterite minerals by infrared spectroscopy

An investigation into the possibility of using infrared techniques to quantify serpentine in nickel laterite ores was carried out. Results obtained from this preliminary study confirmed that high confidence in serpentine content prediction is possible obtaining RMSEP and R2 values of 1.76 and 0.97 respectively.One hundred and forty mineral mixtures simulating limonite, transition and saprolite horizons of a Western Australian nickel laterite deposit were prepared. Diffuse reflectance infrared Fourier transform spectroscopy spectra obtained from these mixtures were used as a training set to prepare a quantitative model for serpentine content using Partial least squares multivariate analysis.The model in turn was validated by predicting the serpentine content of 20 synthetic mixtures with confidence. The model was applied to 10 natural ores from various deposits, diversity between the synthetic and natural ore assemblages meant the analysis was qualitative. Model development using real ore samples would be required to enable incorporation of the intrinsic properties of the natural serpentine and the ore mineralogy in general.