Investigation of The Enrichment of Rare Earth Ore in Eskişehir-Beylikova Region By Flotation

Abstract

Rare earth minerals have great importance in advanced technology products and defense industry. Rare earth mineral deposits in the Eskişehir - Beylikova region, which is one of the most important deposits in Turkey, is known as a "Complex Ore" since it consists of a wide variety of minerals. Bastnaesite, fluorite, barite, and calcite minerals are reported to be found in the ore within a complex mineralization. Lanthanum (La), cerium (Ce) and neodymium (Nd) are primary rare earth elements found in the deposit. Many technological studies have been carried out in previous years for the separation and enrichment of both thorium and rare earth oxides from Beylikova complex REE ore. However, R&D studies up to now could not be able to present convincing data for a comprehensive process for economically enriching the ore components such as bastnaesite, fluorite and barite all along. The aim of the thesis is to investigate flotation behavior of the Eskişehir- Beylikova ore primarily focusing on the valuable gangue minerals of fluorite and barite, along with the rare earth oxides. Removing and separating fluorite and barite from this ore as separate sellable products are key to operate the field economically. Within this aim, zeta potential measurements of fluorite and barite within ore were conducted as a function of pH, under different collectors and under different depressants. Following, flotation behavior of related contents was investigated under varying collector dosages and different pH values. For this purpose, experimental studies were started with the characterization of the minerals to determine the mineralogy of the Beylikova deposit. Following, pure barite, and fluorite minerals were obtained. All the mineral samples were subjected to the measurement of the zeta potential by means of the electrophoresis technique under all the quoted variants. Within these measurements, the effects of the solution on the mineral surface of interest being evaluated under different conditions. In addition, IEP values are presented which could be useful as a database for future research. Following, a series of flotation tests under different conditions were performed for validation. During flotation tests, different collector types, depressants, collector mixtures and activators were used, and results were evaluated. The zeta potential results for pure barite with the instrumentation used (optical and laser) showed results so close that the IEP variation is ZN=5.25 and ZS=5.27. The addition of collecting agents had an effect on the zeta potential, especially in the case of positive electrical charges and the implementation of an upright absorption. In contrast, the zeta potential of fluorite with ZN and ZS showed a similar trend and the IEP variation was ZN=8.8 and ZS=8.1. The zeta potential was also significantly reduced by the addition of a collector. For the flotation process that was carried out sequentially, starting with the barite rougher and counting with the fluorite rougher. In the flotation of barite, the best results are shown with the mixture of A825 (300 g/t) and A845 (100 g/t) with 77.51% BaSO4 grade and 95.93% recovery. The rougher tail of the barite flotation was transferred to the fluorite rougher flotation. Where the recovery and grade were 35.68% and 79.80% respectively with A726, being the higher results obtained under the two different collectors used (A704 and A726).