Constraining the economic potential of by-product recovery by using a geometallurgical approach: the example of rare earth element recovery at Catalão I, Brazil


Constraining the economic potential of by-product recovery by using a geometallurgical approach: the example of rare earth element recovery at Catalão I, Brazil

Pereira, L.; Birtel, S.; Möckel, R.; Michaux, B.; Silva, A. C.; Gutzmer, J.

Located in Goiás state of Brazil, Catalão I is a carbonatite complex that is part of the Alto Paranaíba Igneous Province. A niobium deposit in the complex, named Boa Vista, has been exploited for more than 40 years and is currently the world’s second largest niobium producer. The deposit is owned and operated by Niobrás, part of China Molybdenum Co.. Phosphates are also produced in the Catalão I complex at the Chapadão mine, an operation that is owned and operated by Copebrás, also part of China Molybdenum Co.. The phosphate production tailings are reprocessed at Boa Vista for recovering niobium as a by-product. Rare earth elements, albeit present in significant concentrations, are not recovered as by-products. This study provides quantiative mineralogical and microfabric data on the occurrence of rare earth minerals – and provides constraints for concentration of rare earth elements during current niobium beneficiation routes at the Tailings plant. Nine samples from different stages of the process were taken and characterized by Mineral Liberation Analyzer, X-ray powder diffraction and bulk rock chemistry. The recovery of rare earth elements in each of the tailing streams was quantified by mass balance. The results are used to identify the most suitable approach to recover REE as a by-product – without placing limitations on niobium production.
Monazite, the most common rare earth mineral identified in the feed to the Tailings Plant, occurs as Ce-rich and La-rich varieties that can be easily distinguished by SEM-based image analysis. Quartz, FeTi-oxides and several phosphate minerals are the main gangue minerals. The highest rare earth element content concentrations (1.75 wt.% TREO) and the greatest potential for REE processing are reported for the final flotation tailings stream. To place tentative economic constraints on REE recovery from the tailings material, an analogy to the Brown's Range deposit in Australia is drawn. Its technical flow sheet was used to estimate the cost for a hypothetical REE-production at Boa Vista. Parameters derived from SEM-based image analysis were used to model possible monazite recovery and concentrate grades. This exercise illustrates that a marketable REE concentrate could be obtained at Boa Vista, if the process could recover all particles with at least 60% of monazite on their surface. Applying CAPEX and OPEX values similar to that of Brown’s Range showed that such an operation would be profitable at current REE prices.

Keywords: REE production; by product; geometallurgy; economic assement

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Publ.-Id: 26653