Effective reverse flotation separation of siderite from hornblende using pentaethoxylated tallow amine as a selective collector

To effectively separate siderite from hornblende, pentaethoxylated tallow amine (PTA) was introduced as a hornblende collector for the first time and its selective collection mechanism was revealed. The flotation results indicated that PTA strongly collected hornblende but not siderite, which enlarged the differences in flotation performance. The measurements of contact angle and adsorption amount suggested that hornblende adsorbed much more PTA than siderite, which greatly enhanced the surface hydrophobicity of hornblende. The analysis of zeta potential and Fourier transform infrared (FTIR) proved that the strong adsorption of PTA on hornblende was attributed to hydrogen bonding and electrostatic attraction. Extended Derjaguin–Landau–Verwey–Overbeek (EDLVO) theoretical calculations confirmed that PTA enhanced attractive hydrophobic interaction and electrostatic attraction interaction between hornblende and bubbles, and promoted the adhesion of hornblende to the bubble surface, resulting in a high recovery of hornblende. However, the repulsive interaction between siderite and bubbles prevented siderite from adhering to the bubbles, resulting in poor flotation performance. Consequently, effective separation of hornblende from siderite was achieved by PTA, in which 90.46% of siderite was effectively recovered and 94.26% of hornblende was effectively removed. Thus, PTA can be used as an effective collector to separate siderite from hornblende.