Numerical and Experimental Investigation of Arsenic Removal Process from Phosphoric Acid by Vertical Zone Melting Technique

A combined numerical and experimental approach was undertaken to investigate the arsenic removal process from phosphoric acid by vertical zone melting technique. The numerical model, which predicts the arsenic re-distribution at any point of the single zone pass, multiple molten zone passes, or ultimate distribution, is described for providing simulations. Experimental work on arsenic removal by vertical zone melting process was carried out with prepared phosphoric acid samples as the starting material. The experimentally obtained axial concentration profiles were compared with the theoretical predictions, which proved the efficiency of the proposed model in removing the arsenic concentration significantly. Following the model and as evidenced from the theoretical predictions, the arsenic concentration reduced to <50 ng.g(-1) and a 99.8% removal rate were obtained under the conditions of molten zone length of 0.1L, molten zone velocity of 3 mm.h(-1), and nine molten zone passes. Also, the experimental and simulated results were undertaken to find out the influence of the crucial zone melting parameters including the number of passes, the molten zone length, and the molten zone velocity on the efficiency of arsenic removal from phosphoric acid by vertical zone melting technique.