Flotation tests Flotation tests were carried out with a XFG5-35 flotation machine with 40 mL effective cell volume and the impeller speed fixed at 1650 r/min. 2.0 g pure mineral was put into a 100.0 mL breaker with 40.0 mL distilled water to clean the surface for 10 min to wipe off the attached oxide by using ultra-sonic cleaner. The treated mineral was washed with distilled water for three times and then transferred into the flotationcell. The pulp pH was adjusted with HCl or NaOH aqueoussolution and then agitated for 2 min. After adding the desiredamount of reagents, the suspension was agitated for 2 min,and the frother was last added before flotation. The flotationprocess was conducted for 5 min. The products and tails wereweighed separately after filtration and dried and the recoverywas calculated.The specific flotation process was shown in Fig. 1 and therecovery was calculated according to the following equation:
R
= m1
m1 +
m2
×
100%
where R represents the pure minerals’ recovery; m1and m2arethe weight of froth products and prod