Date of Award

Spring 2019

Degree Type


Degree Name

Doctor of Philosophy (PhD)


Materials Science

Committee Chair

Courtney Young

First Advisor

Avimanyu Das

Second Advisor

Paul Gannon

Third Advisor

Katie Hailer

Fourth Advisor

Rob Walker


The chalcopyrite-molybdenite (Cu-Mo) flotation industry is increasingly turning to organic depressants as suitable replacements for inorganic reagents such as NaHS due to environmental and safety concerns as well as high consumption rates of the inorganic reagents. An opportunity arises for improving, designing and synthesizing new alternative reagents. Disodium Carboxymethyl Trithiocarbonate (Orfom® D8) depressant is an organic depressant with a carboxylate group on one end and a trithiocarbonate group at the other end. Fundamental results are shown regarding the interaction of the Orfom® D8 depressant in the bulk flotation of a Cu-Mo concentrate from an operating North American mine. Cyclic Voltammetry on pure copper and Fourier Transform Infrared (FT-IR) Spectroscopy and X-ray Photoelectron Spectroscopy (XPS) measurements on pure chalcopyrite with Orfom® D8 depressant treatment are also reported. Carbon Disulfide (CS2) and Thioglycolic Acid (TGA) were determined as the decomposition products of Orfom® D8 depressant using Laser Raman Spectroscopy. Through such characterization techniques, a potential adsorption mechanism of Orfom® D8 on the mineral surface was identified, and its depressant characteristics in the Cu-Mo flotation system explained.


A dissertation submitted in partial fulfillment of the requirements for the degree of Doctor of Philosophy: Materials Science