Date of Award


Document Type

Open Access Master's Thesis

Degree Name

Master of Science in Chemical Engineering (MS)

Administrative Home Department

Department of Chemical Engineering

Advisor 1

S. Komar Kawatra

Committee Member 1

Rebecca G. Ong

Committee Member 2

Tony N. Rogers


Specifically adsorbed ions, such as calcium and magnesium in iron ore flotation, are ions that can chemically bind with the mineral surfaces and alter the surface properties. Calcium and magnesium are unavoidable in process water and their concentrations are increasing due to water recirculation and reagent additions. These ions are detrimental to the flotation process. Calcium has always been the main focus in research, yet we found that magnesium is more detrimental in flotation due to its smaller atomic size. Starch adsorption in iron ore flotation is key for the effective depression of hematite. It has been determined by flotation, zeta potential, and settling tests, that increasing calcium concentrations promote starch adsorption and reduce entrainment of hematite, whereas increasing magnesium concentrations greatly reduce the selectivity overall by promoting the adsorption of starch to everything in the slurry and resulting in lower selectivity.