2.2. Collector-less flotation
According to Kantar (2002), enargite displays natural floatability
under oxidizing conditions, and nonfloatability under reducing
conditions. In acidic solutions of pHb5.5, the hydrophobicity of
enargite increased with increasing solution potential due to the
formation of elemental sulfur on the mineral surface. However, in
alkaline solutions, the hydrophobicity decreased with increasing
solution potential due to the formation of CuO. Such observations
are in line with the findings of Arribas (1995) and Lattanzi et al.
(2008). However, it is noteworthy to point out that Castro and
Honores (2000) reported poor flotability of enargite in a wide pH
range and thus concluded the nonexistence of natural floatability of
enargite.