Spodumene Flotation Mechanism

Fine and coarse fractions of spodumene were obtained from a pegmatite ore and their flotation was investigated under different conditions. In particular, the optimum pH and collector dosage were studied. It was found that the best flotation performance occurs at pH 10 using 250 mg/L of sodium oleate. It was also observed that upon the addition of CaCl2, spodumene flotation recovery increases to about 90%. In addition, poor floatability was found for spodumene when Na2CO3 was used as a pH regulator (compared to NaOH).The zeta potential data confirmed the adsorption of oleate on the spodumene surface. It was found that activation of spodumene by calcium ions makes the surface charge less negative due to the adsorption of Ca2+ on the surface. The crystallographic properties of spodumene were analyzed. The adsorption of sodium oleate was attributed to the chemisorption of oleate to the exposed Al and Si sites generated after breakage of the Al–O and Si–O bonds on the mineral surface. It was observed that the {110} planes are the most favorable for the adsorption of oleate. The {110} plane is the weakest plane, and spodumene has the highest tendency to cleave along this plane. The XRD data revealed that fine spodumene particles have more {110} planes than the coarser fraction, which may explain why the former has better floatability.