Research Article
Hydrochloric Acid Leaching Study of Rare Earth Elements from Moroccan Phosphate
Figure 6
Response surface three-dimensional plots of the interaction of every two variables: (a) percentage of HCl (X1) and temperature (X2); (b) percentage of HCl (X1) and stirring speed (X3); (c) percentage of HCl (X1) and S/L ratio (X4); (d) percentage of HCl (X1) and time (X5); (e) temperature (X2) and stirring speed (X3); (f) temperature (X2) and S/L ratio (X4); (g) temperature (X2) and time (X5); (h) stirring speed (X3) and S/L ratio (X4); (i) stirring speed (X3) and time (X5); (j) S/L ratio (X4) and time (X5).
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