PLANT TRIAL OF A NEW PRECIPITATION LINE-UP BASED ON PREDICTION FROM THE ALCAN PRECIPITATION SIMULATION

Audet, D.R. and Larocque, J.E.

Alcan's precipitation simulation, HYPROD, was developed based on an extensive laboratory program to determine the governing laws for the population balance, growth rate, alumina solubility and nucleation rate, etc.. The calibration of the simulation done at an ALCAN alumina plant was aimed at adjusting the various parameters that are plant/liquor dependent: organic effects on solubility and growth, agglomeration and efficiency and the classifier characteristics.

With this calibrated version, it was then possible to predict the change in product quality that would be gained by modifying the line-up. The most promising of the evaluated proposals, the parallel line-up, was tried in that plant for one month. The results show that an exceptionally good quality could be obtained with that line-up and confirmed the prediction of the models in every point.