Comparison of Manual Versus Metrohm Auto-Titration in the Estimation of Short-Soda in Bayer Process Clarification Liquors

Abstract

Comparison of manual titration with an automated method developed using the Metrohm auto- titrator to analyse plant clarification liquors from an alumina refinery for short soda is the subject of this investigation. Our study revealed a Metrohm repeatability of ~ 99.80% whereas the repeatability of the manual titration could vary considerably depending on liquor strength and operator dexterity (≥93% in this study). Comparative data generated by manual titration and the automated Metrohm method indicated an acceptable level of correlation (R2 = 0.9957) with greater agreement being obtained with stronger liquors. With weaker liquors discrepancies arose mainly from variability due to the subjective nature of the color determined end point. The end point of the titration using the Metrohm was set at pH 4.20. From this study the measured end point pH for the manual titration ranged from 3.66-5.7. Automation of the short soda analysis would not significantly change the analytical results but would increase repeatability and relative accuracy of these analyses. Key Words: Short Soda, Bayer Process, Clarification, Liquors RUNNING TITLE: Bayer Process Short Soda Analysis

Keywords

References