Hydrochloric Acid Leaching Study of Rare Earth Elements from Moroccan Phosphate

Table 4

Experimental domain for the Doehlert experimental design.

	Factor (XI)	HCl (%)	Temperature (°C)	Stirring (rpm)	S/L ratio (%)	Time (min)
Level 1	−1	13	25	100	20	30
Level 2	0	18	45	200	35	45
Level 3	+1	23	65	300	50	60