Surface Properties and Flotation Characteristics of Boron Minerals

Flotation of soluble salt minerals such as potash, trona and borax exhibits similarities because all are conducted in their brine solutions. The most commercially important boron minerals in the world are borax (Na2B4O7.10H2O), colemanite (Ca2B6O11.5H2O), ulexite (NaCaB5O9.8H2O), and kernite (Na2B4O7.4H2O). Most of them contain low grades when mined and must be upgraded by mineral processing techniques to commercially acceptable quality for the production of basic chemicals, such as boric acid. Boron minerals exhibit a spectrum of solubilities depending upon the cations in the lattice structure. Accordingly, a classification of semi-soluble (colemanite and ulexite) and soluble (borax and kernite) boron minerals may be appropriate as each class of minerals behaves differently in flotation. While borax has to be concentrated from its saturated brine, colemanite and ulexite can be recovered by flotation as is the case for other semi-soluble salt minerals. A common problem encountered in both classes of boron minerals is the presence of significant amounts of clay type minerals which adversely affect flotation recoveries in the form of slime coating. Despite the successful application of flotation technology in the potash industry, flotation has not yet been well developed for boron recovery. This may be attributed to inherent difficulties such as high ionic strengths, high viscosity brines, interaction of cations at the solid/liquid interface, and particularly the presence of clay minerals acting as persistent slimes. In this paper, we have reviewed the flotation chemistry studies on the interaction of boron minerals with anionic (sodium dodecylsulfate) and cationic (dodecylamine hydrochloride) surfactants along with the electrokinetics properties of boron