Constraining the Economic Potential of By-Product Recovery by Using a Geometallurgical Approach: The Example of Rare Earth Element Recovery at Catalão I, Brazil

Abstract

Geometallurgy aims to develop and deploy predictive spatial models based on tangible and quantitative resource characteristics that are used to optimize the efficiency of minerals beneficiation and extractive metallurgy operations. While most current applications of geometallurgy are focused on the major commodity to be recovered from a mineral deposit, this contribution delineates the opportunity to use a geometallurgical approach to provide an early assessment of the economic potential of by-product recovery from an ongoing mining operation. As a case study for this methodology, possible rare earth element (REE) recovery as a by-product of Nb production at the Chapadão mine in the Catalão I carbonatite complex is used. Catalão I is part of the Alto Paranaíba igneous province in the Goias Province of Brazil. Currently, niobium is produced in the complex as a by-product of the Chapadão phosphates mine. This production is performed in the Tailings plant, the focus of this study. REEs, albeit present in significant concentrations, are currently not recovered as by-products. Nine samples from different stages of the Nb beneficiation process in the Tailings plant were taken and characterized by mineral liberation analyzer, X-ray powder diffraction, and bulk-rock chemistry. The recovery of REEs in each of the tailing streams was quantified by mass balance. The quantitative mineralogical and microstructural data are used to identify the most suitable approach to recover REEs as a by-product—without placing limitations on niobium production. Monazite, the most common rare earth mineral identified in the feed, occurs as Ce-rich and La-rich varieties that can be easily distinguished by scanning electron microscopy (SEM)-based image analysis. Quartz, Fe-Ti oxides, and several phosphate minerals are the main gangue minerals. The highest rare earth oxide content concentrations (1.75 wt % total rare earth oxides) 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 Browns Range deposit in Australia is drawn. Its technical flow sheet was used to estimate the cost for a hypothetical REE production at Chapadão. 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 Chapadão if the process recovers at least 53% of the particles with no less than 60% of monazite on their surface. Applying capital expenditure and operational expenditure values similar to those of Browns Range suggests that such an operation would be profitable at current REE prices.

A study of metallogenic potential index of ores from the Bayan Obo Nb-Fe-REE deposit and its indication of geometallurgy and remote sensing exploration

“…Geometallurgy is the combination of geologic and metallurgical information applied to establish geometallurgical matrix and database [14], which aims to reduce the associated risk of capital investment and improve the comprehensive utilization of ores [15]. Bayan Obo mine has been mainly used as an iron ore since it has been exploited.…”

A Special Issue Dedicated to Geometallurgy: Preface

“…They discuss key levers for value creation in industrial mineral operations and the differences to those used in the mining of metallic ores along with the extent to which geometallurgy has been adopted. Pereira et al (2019) use the Catalão I Nb deposit at the Chapadão phosphate mine, Brasil to examine the feasibility of recovering rare earth elements as a by-product. They characterised the mineralogy and chemistry of tailings plant streams and identified the stream with the greatest potential for recovery of REE without compromising the current Nb beneficiation process.…”

Process Mineralogy of the Tailings from Llallagua: Towards a Sustainable Activity

“…The extreme dependence on China, which is the main provider of these elements, makes them critical for many countries [18,19]. Thus, it is necessary to extract them from different sources, such as tailings [20], where they can be found in relative abundance and recovered as a by-product from certain mining processes [21].…”