Measured and predicted consistency values for C massecuite

Wilmar considered replacing the non-functioning crystalliser and reheater station at Kalamia Mill with a single BMA Oscillating Vertical Crystalliser (OVC) as part of the 2023 capital program. This OVC would be the first one in Australia. Modelling, consistency measurements and predictions of exhaustion performance were carried out in the 2022 crushing season to determine the relevant functional specifications to aid with the design of a new station. The rheology of C massecuites has a strong influence on the practical exhaustion that can be achieved and on the mechanical design requirements for the equipment and pipework. It was intended to utilise correlations from literature for determining the expected consistencies of the OVC feed and discharge. To verify the suitability of using these correlations, the consistencies of pan drop massecuites and fugal feed massecuites were measured and compared to the predicted values obtained from the correlations. The assessments were compared against two correlations. One correlation provided a reasonable match, with an average agreement to the measured values of -12%. The other correlation provided larger and more variable differences between the measured and predicted consistencies. Further work to upgrade the correlations for low grade massecuite consistency would be beneficial for all investigations related to C massecuite processing.