Effect of various ligands on the selective precipitation of critical and rare earth elements from acid mine drainage.

Acid mine drainage (AMD) has been of environmental concern for decades but recently found to be a viable source of critical elements including rare earth elements (REEs). Recovery of these elements while treating AMD for environmental compliance improves the sustainability of the treatment process. The precipitation behavior of the REEs and other cations during the AMD neutralization process depends strongly on the solution chemistry, available ligands, and concentration of elements.

Recovery of rare earth elements from coal fly ash by integrated physical separation and acid leaching.

Coal fly ash (CFA) is one of the most promising secondary sources of rare earth elements and yttrium (REY). This research first studied the modes of occurrence of REY in CFA collected from a China's power generation plant which utilizes a coal feedstock with an elevated REY content. The fact that rare earth minerals remain in CFA and REY associate with metal oxides was proved by emission-scanning electron microscope with an energy-dispersive X-ray spectrometer.

Attachment, Coalescence, and Spreading of Carbon Dioxide Nanobubbles at Pyrite Surfaces.

Recently, it was reported that using CO as a flotation gas increases the flotation of auriferous pyrite from high carbonate gold ores of the Carlin Trend. In this regard, the influence of CO on bubble attachment at fresh pyrite surfaces was measured in the absence of collector using an induction timer, and it was found that nitrogen bubble attachment time was significantly reduced from 30 ms to less than 10 ms in CO saturated solutions. Details of CO bubble attachment at a fresh pyrite surface have been examined by atomic force microscopy (AFM) measurements and molecular dynamics (MD) simulations, and the results used to describe the subsequent attachment of a N bubble.

The surface state of hematite and its wetting characteristics.

Apart from being a resource for iron/steel production, the iron oxide minerals, goethite and hematite, are used in the paint, cosmetics, and other industries as pigments. Surface characteristics of these minerals have been studied extensively both in resource recovery by flotation and in the preparation of colloidal dispersions. In this current research, the wetting characteristics of goethite (FeOOH) and hematite (Fe2O3) have been analyzed by means of contact angle, bubble attachment time, and Atomic Force Microscopy (AFM) measurements as well as by Molecular Dynamics Simulation (MDS).