Effect of Pb(II) on the flotation behavior of scheelite using sodium oleate as collector

In this study, the effect of Pb(NO3)(2) on the flotation behavior of scheelite using sodium oleate (NaOL) as a collector in the presence and absence of Ca2+ ions was investigated through the micro-flotation tests, solution chemistry calculation, zeta potential measurements, and FT-IR analysis. The micro-flotation results indicated that the addition of Pb(NO3)(2) or Pb-OL complex obviously improved the scheelite recovery, and eliminated the adverse effect of Ca2+ ions on the scheelite flotation. The mechanism studies indicated that the addition of Pb (NO3)(2) improved the amount of adsorbed NaOL onto the scheelite surface, or react with NaOL in the solution to form the complexes of Pb(II) and NaOL, thus improved the scheelite recovery. The chemical reaction between Pb (NO3)(2) and NaOL was stronger than those of calcium ions and NaOL at pH 6-9.3, therefore, the addition of Pb (NO3)(2) could eliminate the adverse effect of calcium ions on the scheelite flotation. However, at pH > 9.8, Pb (OH)(2) and Pb(OH)(3)(-) were the main lead species. The chemical reaction between Pb(OH)(2) or Pb(OH)(3)(-) and NaOL was weaker than those of calcium ions and NaOL, hence cannot eliminate the adverse effect of calcium ions on the scheelite flotation.