Mechanism of oleate interaction on salt-type minerals part I. Adsorption and electrokinetic studies of calcite in the presence of sodium oleate and sodium metasilicate

Electrokinetic properties of hydroxyapatite under flotation conditions

“…Several models have been described to explain the nature of the adsorption of the long-chain surfactants at the solid/liquid interface depending on the experimental conditions [29,35,[84][85][86][87]. Thus, the treatment by Cases et al [85] assumes that the association of adsorbed ions forms two-dimensional aggregates (hemimicelles) due to strong lateral bonds.…”

“…However, electrokinetic and flotation studies of apatite and calcite by Mishra [29] suggested the chemical bondage of oleate with surface calcium species. Also, the results of Rao and co-workers [35,86,89] showed that oleate condenses two dimensionally on calcium sites (oleate adsorption density of 5 lmol m À2 for 33 Â 10 À2 nm 2 /ion oleate in a liquid crystal state, or 8 lmol m À2 for 20.5 Â 10 À2 nm 2 /ion oleate in a hydrated crystal state [35,42]), followed by the second layer formation with a tail-tail bond. They concluded that the surface calcium oleate might be the product of ionic exchange and/or adsorption of the oleate ion (RCOO À ) according to the reaction [35,90] ÀCaO nÀ Na þ þ RCOO À ¢ À CaONaOOCR; ð14Þ…”

An Overview of Calcite Recovery by Flotation

“…Calcite, scheelite, and apatite are sparingly soluble minerals and due to its solubility, it is difficult to measure the zeta potential below pH 7. Almost all the researchers indicated that after increasing sodium oleate concentration, there is an increase in negative values of zeta potential for calcite (Somasundaran 1969;Mishra 1979;Somasundaran et al 1985;Rao et al 1989;Zimmels and Lin 1974;Smith and Shonnard 1986); a few peculiarities are explained below.…”

Surfactant-induced wetting transitions: Role of surface hydrophobicity and effect on oil permeability of ultrafiltration membranes

“…In flotation a surfactant that adsorbs preferentially onto one of the minerals to be separated is added which makes the surface of this mineral more hydrophobic. Air bubbles will preferentially adhere to the more hydrophobic mineral grains, and a separation can be achieved [4][5][6]. In detergency (washing) adsorption of surfactants with their hydrophobic part onto a fibrous substrate will increase the wettability for water.…”