Physical Sciences and Mathematics Commons^™

Oxygen Speciation In Potassium Silicate And Potassium Aluminosilicate Glasses: Insights From X-Ray Photoelectron Spectroscopy, Ryan Sawyer

Electronic Thesis and Dissertation Repository

In a geological context, glasses are useful analogues for silicate melts as they are more readily studied in the laboratory using a wide range of techniques that are impractical for molten liquids. Understanding the structure of binary silicate glasses can help us understand more about the magmatic processes that affect terrestrial planetary bodies.

Potassium silicate glasses ranging in composition from 10 mol% to 35 mol% K₂O were studied using X-ray Photoelectron Spectroscopy (XPS). From high resolution O 1s XPS spectra, Bridging Oxygen (BO) mole fractions were calculated and compared with those of previous ²⁹Si MAS NMR studies. …

Study On The Surface Features Of Preg-Robbing Carbonaceous Matter During Oxidation Treatment, Mana Pourdasht

Electronic Thesis and Dissertation Repository

Carbonaceous gold ores have the ability to adsorb gold (I) cyanide from leach solutions during processing. This phenomenon, known as preg-robbing, is responsible for poor recoveries as the carbonaceous materials of the ore compete with activated carbon used during the leaching and adsorption phase of processing. Chemical oxidation of carbonaceous materials by different reagents has been utilized to investigate and compare the mechanism of Au (CN)₂ adsorption onto carbonaceous materials prior to and following the treatment.

The procedure for characterization of the carbonaceous materials (plain and modified) in the sample combines the use of several analytical techniques and test …

A Surface Chemistry Study Of The Effects Of Zinc Sulphate On Sphalerite During Flotation Separation At The Laronde Mine, Dennis M. Laliberty

Electronic Thesis and Dissertation Repository

The LaRonde mine is a gold-rich VMS deposit in the Abitibi Greenstone Belt of Canada. Like many polymetallic ore deposits, loss of sphalerite occurs during the Cu circuit of flotation separation at the mill. Zinc sulphate was tested as a sphalerite depressant. XRD, TOF-SIMS and XPS were used to examine the mineralogy and surface chemistry of ore samples collected at select stages of the milling process in the mill and in the laboratory. Data analyses showed that ZnSO4 likely promotes sulphoxyl and hydroxide adsorption to the sphalerite surface inhibiting Cu activation. Addition of ZnSO4 in the LaRonde mill has reduced …