Flotation de-silicating from diasporic-bauxite with cetyl trimethylammonium bromide

Abstract

Using cetyl trimethylammonium bromide (CTAB) as collector, the flotation de-silicating from diasporicbauxite was investigated. And the Zeta potentials and contact-angles of silicate minerals and diaspore were also studied. The results show that in the presence of 2×10⁻⁴ mol·L⁻¹CTAB, the surface charges of pyrophyllite, kaolinite and illite become more positive, and the contact angles of these three silicates also increase evidently in the pH range of 2–8, but the Zeta potentials and contact angles of diaspore change little. So, the floatability of the four minerals is in the following order: pyrophyllite>kaolinite∼illite>diaspore. The open-circuit flotation results also show that a bauxite concentrate with m(Al₂O₃)/m(SiO₂) over 9.3 and Al₂O₃ recovery over 76% can be obtained from diasporic-bauxite ore. The result of XRD of the bauxite concentrate shows that pyrophyllite is easier to be removed from diasporic-bauxite than illite and kaolinite due to its better floatability.

Keywords

aluminum-silicate / bauxite / reverse flotation / cetyl trimethylammonium bromide