Flotation Behaviors of Perovskite, Titanaugite, and Magnesium Aluminate Spinel Using Octyl Hydroxamic Acid as the Collector

Abstract

Abstract:The flotation behaviors of perovskite, titanaugite, and magnesium aluminate spinel (MA-spinel), using octyl hydroxamic acid (OHA) as the collector, were investigated using microflotation experiments, zeta-potential measurements, Fourier transform infrared (FT-IR) analyses, X-ray photoelectron spectroscopy (XPS) analyses, and flotation experiments on artificially mixed minerals. The microflotation experiments show that the floatability of perovskite is clearly better than titanaugite and MA-spinel at around pH 5.5, while titanaugite possesses certain floatability at pH 6.0-6.5, and MA-spinel displays good floatability at pH > 8.0. The results of the FT-IR and XPS analyses show that OHA mainly interacts with Ti, resulting in perovskite flotation, and that the Al on titanaugite, as well as the Mg and Al on the MA-spinel surface, chemically react with OHA under acidic conditions. However, OHA mainly reacts with the Ti and Ca on the perovskite surface, Ca and Mg on the titanaugite surface, and Mg and Al on the MA-spinel surface under alkaline conditions. The results of the artificially mixed mineral flotation experiment show that the concentrate of TiO 2 grade increased from 19.73% to 30.18% at pH 5.4, which indicates that a weakly acidic solution is the appropriate condition for the flotation separation of perovskite from titanaugite and MA-spinel. The results of the modified slag flotation experiments show that the TiO 2 grade of concentrate increased from 18.13% to 23.88% at pH 5.4, through the open circuit test of "one roughing and one cleaning". OHA displays selectivity toward perovskite in the modified slag flotation, but the consumption of H 2 SO 4 is very high. The CaSO 4 precipitate covered on the mineral surfaces results in poor TiO 2 grade and recovery.

Activation Mechanism of Lead Ions in Perovskite Flotation with Octyl Hydroxamic Acid Collector

“…Because perovskite has a fine grain size (<10 µm) and a complex association with gangue minerals in blast furnace slag, it is difficult to separate pure minerals by physical methods [17]. Thus, equivalent amounts of CaO and TiO 2 were mixed and heated at 1350 • C for 10 h to obtain perovskite [36].…”

“…Thus, equivalent amounts of CaO and TiO 2 were mixed and heated at 1350 • C for 10 h to obtain perovskite [36]. After being ground and screened, 38-75 µm of powdered samples were used in the flotation experiments [17]. The samples used for the zeta-potential measurements and FT-IR analysis were further ground to about 2 µm.…”

“…Previous studies have shown that in a weakly acidic environment, calcium ions on the perovskite surface are largely dissolved into the slurry, and titanium on the perovskite surface becomes the main site for hydroxamic acid [17]. Compared with calcium ions, titanium ions and hydroxamic acid have a stronger effect [37][38][39].…”

“…According to the ionization constant pK α of OHA ∼ = 9 [17,40], the concentration logarithmic of each component in different pH solutions of OHA can be calculated. The logarithmic diagram of OHA hydrolysis components as functions of pH when the OHA concentration is 0.2 mM are presented in Figure 4.…”

“…In industry, various methods are used to recycle qualified perovskite product, such as gravity separation, magnetic separation, smelting reduction, and hydrometallurgy [11,15,16]. However, because perovskite is disseminated in gangue minerals in fine grains (<10 µm), flotation separation is the most common method for the effective separation of perovskites from gangue minerals [17]. Previous studies on perovskite have indicated that, compared with ilmenite and rutile, perovskite exhibits poor flotability under typical flotation conditions [1,17].…”