Selective flotation and adsorption of ilmenite from titanaugite by a novel method: Ultrasonic treatment

A Review of Ultrasonic Treatment in Mineral Flotation: Mechanism and Recent Development

Ultrasonic treatment has been widely used in the mineral flotation process due to its advantages in terms of operational simplicity, no secondary pollutant formation, and safety. Currently, many studies have reported the effect of ultrasonic treatment on mineral flotation and shown excellent flotation performance. In this review, the ultrasonic mechanisms are classified into three types: the transient cavitation effect, stable cavitation effect, and acoustic radiation force effect. The effect of the main ultrasonic parameters, including ultrasonic power and ultrasonic frequency, on mineral flotation are discussed. This review highlights the uses of the application of ultrasonic treatment in minerals (such as the cleaning effect, ultrasonic corrosion, and desulfuration), flotation agents (such as dispersion and emulsification and change in properties and microstructure of pharmaceutical solution), and slurry (such formation of microbubbles and coalescence). Additionally, this review discusses the challenges and prospects of using ultrasonic approaches for mineral flotation. The findings demonstrate that the application of the ultrasonic effect yields diverse impacts on flotation, thereby enabling the regulation of flotation behavior through various treatment methods to enhance flotation indices and achieve the desired objectives.

Separation of Ilmenite from Vanadium Titanomagnetite by Combining Magnetic Separation and Flotation Processes

Vanadium titanomagnetite (VTM) is an important mineral for developing titanium resources, but the comprehensive recovery of ilmenite separation is extremely poor, resulting in the low-efficiency utilization of titanium resources. Here, the separation of ilmenite from VTM ore is studied by combining magnetic separation and flotation technologies. In particular, the floatability of mixed MOH/PG-1 collectors is thoroughly investigated. The results show that a concentrate with a TiO2 grade of 9.90% can be separated via weak magnetic separation and coarse particle tailing dumping. The concentrate grade is then increased to 14.32% via strong magnetic separation and floating separation of sulfur minerals. Finally, a TiO2 grade of 46.34% is obtained through closed-circuit flotation using mixed MOH/PG-1 collectors. The mixed collectors are very efficient and can enhance the chemical adsorption of the Ti4+, Fe3+, and Fe2+ ions in the ilmenite concentrate compared with the MOH collector, thereby increasing the TiO2 grade and recovery by 3.31% and 1.20%, respectively. This is beneficial for improving the comprehensive utilization of titanium resources in VTM ores.

Experimental study of temporal dynamics of cavitation bubbles selectively attached to the solid surfaces of different hydrophobicity under the action of ultrasound

In this work, we experimentally investigated the dynamics of vapor-gas bubbles arising in distilled water under the action of ultrasound (US), near and on the surface of solid plates with various surface properties. In the experiments, we used the plates made of Teflon, acrylic glass, and amorphous quartz, with various hydrophobic properties (contact angle). The experiments showed a significant effect of surface properties on the dynamics of bubbles oscillating near and on a solid surface under the influence of ultrasound. In the case of a hydrophobic surface (Teflon), steady attachment of bubbles is observed, the surface area covered by the bubbles grows according to a law close to linear, and then it reaches a plateau. For less hydrophobic surfaces, the drift and rising of bubbles along the plates are observed, as a result of which, the area covered by the bubbles grows less rapidly over time. When the ultrasound is switched off some bubbles located near and on the surface of the acrylic plate float and drag other bubbles with them, differ from the surface of Teflon. This behavior of the bubbles limits both their maximum possible diameter and the maximum solid surface area covered by the bubble. In addition, experiments showed a significant effect of the concentration of gas dissolved in a liquid on the process of bubble formation: a decrease in gas concentration led to a qualitative change in the time dependence of the surface area covered by the bubbles; in the case of long-term degassing of water using ultrasound, the formation of extended bubble clusters on all solid surfaces becomes impossible.

In Situ Adsorption of Mixed Anionic/Cationic Collectors in a Spodumene-Feldspar Flotation System: Implications for Collector Design

Herein, we investigated the effects of mixed collectors with varying alkyl chain lengths and ligand types on the hydrophobicity of the spodumene-feldspar flotation system. Various collector-mineral interactions were compared using in situ attenuated total reflectance Fourier transform infrared (ATR-FTIR) spectroscopy with two-dimensional correlation spectroscopy (2D-COS), in situ microcalorimetry, and X-ray photoelectron spectroscopy (XPS). The highest flotation separation performance can be achieved at a molar ratio of 6:1 and pH 8-9. The in situ microcalorimetry results revealed that the difference in the adsorption reaction heat of the mixed collector is larger than that of the single anionic collector. Moreover, the inconformity between the magnitude of adsorption reaction heat and the results observed for flotation recovery indicates that the heat of the reaction presumably involves the adsorption configurations of the collectors and the amounts adsorbed. In in situ ATR-FTIR with 2D-COS, it can be observed that octanohydroxamic acid/dodecylamine (OHA/DDA) is adsorbed much more intensely onto feldspar than onto spodumene due to the availability of more space on feldspar for the subsequent sorption of DDA after the prior bidentate chemisorption of OHA under alkaline conditions, whereas the sodium oleate (NaOL)/DDA adsorption sequence at pH 4-5 was the reverse of that at pH 8-9. Lastly, XPS was employed to provide further supplemental evidence for the bonding between these two minerals and single anionic/mixed collectors at the optimal pH of 8-9. In this study, the powerful in situ detection technologies can establish a new platform for exploring the underlying mechanism of new reagents at the solid-liquid interface. Moreover, the in-depth understanding related to the adsorption behavior of the mixed collector is beneficial for facilitating the selection and design of efficient and environmentally friendly flotation collectors with improved selectivity.