Evaluation of the baryte and fluorite ore containing rare earth elements

This study was contucted to evaluate barite and fluorite ore containing rare earths elements, which is located in the boundaries of Sivrihisar district of Eskişehir and has a great deal of importance in view economy of our country.In the first stage of the study, the ore samples were ground at a certain particle size (-100 mesh). These ground samples were sieved to make them homogeneous. Then, component analysis of the ores were performed and so the rare earth elements (Th, Ce and La), barite and fluorite found in the ore were determined.In the second stage, it was aimed to separate the rare earth elements from the ore and enrich them. So far, liberation extent of the compound containing the rare earth elements found in the ore studied has not been raised to the satisfactory level, which is due to mineralogic structure of the ore. The most important aspect of this study has been to obtain liberation extent at a certain size by crystal structure of the ore before flotation and then to separate the rare earth elements of the sample from the main mineral by flotation in high yield. The process carried out for providing liberation extent at a certain size by altering crystal structure of the ore is sulphidization. In these experiment effect of temperature, time and amount H2S on sulphidization and that of pH, amount of the collector, pulp density and some refreshing and suppressing reactive on the flotation yield were studied and optimum conditions were established. In this conditions, flotation yields of Th(IV), Ce(IV) and La(III) in the ore were 95%, 96% and 95%, respectively. As for Th(IV), Ce(IV) and La(III) contents of the concentrates were 0.37%, 10.3% and 11.0%, respectively.In the third stage, the experiments were performed to take Th(IV), Ce(IV) and La(III), whisch had been separated and concenrated from the ore by flotation, in to the solution by roasting. Thus, the concentrated samples were roasted at high temperatures and several parameters such as roasting temperature and time were studied. It was determined that 99% of Th(IV), 100%, of Ce(IV) and 98 of La(III) were taken into the solution in optimum conditions.In the fourth stage, extraction conditions of Th(IV), Ce(IV)and La(III) in the solution with Aza-18-Crown-6 ligand and aqueous leaching were studied; Th was separeted selectively depending on pH. In addition, each element was complexed with the ligand and a spectrophotometric determination method was developed.In the fifth stage of the study, in order to separate the fluorite remained in the residual (floated) sample from the structure and to get its high grade concentrate, a second flotation was carried out. In these experiments it was tried to float the fluorite, while the barite and the other compounds were tried to remain in the residue. Effects of pH, amount of the collector and the depressant on the separation of the fluorite were studied and 94% of the fluorite was floated in the optimum conditions. A concentrate of 99% by the fluorite was obtained after this process.In the sixth and the last stage of the study, a third flotation process was executed to separate the barite, grade of which had been increased to 40% levels due to the preprocesses carried out before, from the other compounds and to obtain its higher grade concentrate. In these experiments the barite was separated from the other components by flotation. Effects of several parameters such as pH, amount of the collector, stimulant and depressant on the flotation were investigated and in this optimum conditions all of the barite was floated. A concentrate of 91% by the barite was obtained after this flotation.