NATURAL OLEOPHILICITY HYDROPHOBICITY OF SULFIDE MINERALS .1. GALENA

Oleophilicity/hydrophobicity of galena has been investigated by using two-liquid flotation and contact angle measurements under conditions of controlled electrochemical potential techniques. Unoxidised galena was oleophilic in a mineral/oil/water system, but hydrophilic in a mineral/gas/water system, though the oleophilicity is pH- and Eh-dependent. In alkaline and neutral pH conditions, it decreased with oxidation due to the formation of Pb(OH)2 or metal-sulphoxy compounds. However, in acidic conditions the oleophilicity increased with oxidation due to the formation of S0 on the surface. A critical evaluation of surface forces, present at the sulphide/water interface shows that sulphide minerals would not be wetted strongly by water. © 1990.