Environmental impacts of phosphoric acid production using di-hemihydrate process: a Belgian case study

This paper undertakes an environmental evaluation of phosphoric acid production, using industrial data from Prayon SA in Belgium. Phosphoric acid is produced using the wet di-hemihydrate process also called Central Prayon process. Both grades of phosphoric acid are evaluated: fertilizer and purified grades. Specificities of this plant are highlighted and improvements of the process in terms of energy and facilities integration through years are quantified as environmental benefits. The implementation on site of two sulphuric acid production facilities and their energetic integration allow a reduction of climate change impact of 80%. Results also show the importance of phosphogypsum valorisation which is sold for the main part in this case study. Concerning the purified grade, this specific process has been compared to the thermal process, using Best Available Techniques (BAT) values for the modelling. It shows a reduced environmental impact for the wet process in the majority of categories studies.