Hematite ore selective flocculation-dispersion process water is a complex system of ions and reagents working together to produce a concentrated iron oxide product. The purpose of this study was to determine the process water concentrations of the important ionic species in a selective flocculation-dispersion hematite ore concentrating plant while process conditions were stable. This information was used to provide a detailed water chemistry analysis and to further understand how water quality affects the process. An analysis of the water chemistry of an operating selective flocculation-dispersion iron ore concentration plant has never before been published. The pH of the process water was the most important factor in the selective flocculation and dispersion process because, according to prior studies, it has a direct relationship with the surface chemistry of the particles (Carlson, 2010). The pH also had a direct relationship with the solubilities of both calcium and magnesium in the process. Water hardness was significantly increased with the addition of calcite/dolomite flux which may cause issues in pelletization and in the reuse water. Soluble iron was removed in the flotation circuit suggesting that it may have been oxidized during flotation or it may have been absorbed by the collector. (C) 2011 Elsevier B.V. All rights reserved.