Rheological behaviour modelling of phosphoric acid produced from Moroccan phosphate rocks

Rheological behaviour of the industrial phosphoric acid is considered as one if not the most important factor that affects the performance and profitability of phosphoric acid production in wet process facilities. This work is focused on studying and modelling the rheological behaviour of phosphoric acid produced from the Moroccan sedimentary phosphate rocks. The phosphoric acid is produced at different P2O5 concentrations, ranging from 18% P2O5 up to 54% P2O5. The rheograms experimentally elaborated under a range of temperature from 22 degrees C to 80 degrees C, allowed us to determine the rheological behaviours and the appropriate models for these acids. The recorded results indicate that the Herschel-Bulkley model fits all the acids perfectly under the different conditions, with regression coefficient R-2 greater than 99.3% and mean absolute error of less than 0.142. Furthermore, we managed to develop a mathematical model that describes the apparent viscosity of this acid in terms of P2O5 concentration and temperature. The model obtained presents a regression coefficient of 79.26% and a mean absolute error of 4.111.