2.2. Reagents Sodium oleate (CH3(CH2)7CH=CH(CH2)7COONa) was used as the anionic collector for the microflotation tests. H2SO4 or NaOH were used for the pH adjustment of aqueous suspensions in the experiments. All of the chemicals were of analytical grade, and the water used in all of the experiments was ultrapure water (18.25 MX cm).