Comprehensive mineralogical and technological characterisation of the Araxá (SE Brazil) complex REE (Nb-P) ore, and the fate of its processing

Neumann, Reiner; Medeiros, Edmar B.

doi:10.1016/j.minpro.2015.08.009

Cited by 34 publications

(28 citation statements)

References 14 publications

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“…The carbonatite deposit of Araxá is located near the city of Araxá, Minas Gerais State in south-eastern Brazil. The total REE oxide content of the ore is 3.0% [2] with a high Fe content (>30%) [3].…”

Section: Introductionmentioning

confidence: 99%

Modeling of REE and Fe Extraction from a Concentrate from Araxá (Brazil)

et al. 2019

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The study aimed to employ a comprehensive methodology for the acid processing of a rare earth element (REE) concentrate obtained from the ore from Araxá (MG-Brazil). The most important process variables have been identified and their levels determined to maximize REE extraction (%RE) and minimize Fe extraction (%Fe). The thermodynamic analysis showed that the roasting temperature (TF) is crucial for the control of Fe solubilization in the aqueous leaching step of the acid processing. A statistic design of laboratory experiments and a process optimization method were applied to address the interaction among the process variables. Experimental results showed that a TF of about 700 °C can significantly reduce the Fe concentration in the aqueous leaching liquor. Mathematical models were proposed to predict the effect of process variable on REE and Fe extraction of the concentrate. A multi-objective technique was employed for optimization of chemical processing and the best conditions were reached for roasting temperature (TF) = 700 °C, acid to sample mass ratio (ACs) = 0.8 and leaching time (tL) = 20 min, which led to %RE = 96.91% and %Fe = 21.69%.

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Section: Introductionmentioning

confidence: 99%

Modeling of REE and Fe Extraction from a Concentrate from Araxá (Brazil)

et al. 2019

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“…Estudos realizados em alguns depósitos associados a complexos alcalinocarbonatíticos demonstram que os minerais de terras raras ocorrem, usualmente, na forma de agregados de cristais de granulação micrométrica, com tendência natural de concentração junto às frações finas e ultrafinas, o que dificulta significativamente as possíveis etapas de concentração física (VIERA;LINS, 1997;KAHN et al, 2012;NEUMANN;MEDEIROS, 2015).…”

Section: 11unclassified

“…Estudos de caracterização tecnológica em amostras contendo terras raras vêm sendo desenvolvidos no Brasil e no mundo há muitos anos. A monazita é o principal mineral portador de terras raras nos depósitos alcalino-carbonatíticos brasileiros e ocorre geralmente na forma de agregados de cristais micrométricos, em associações bastante complexas com a ganga, restringindo sobremaneira a aplicação de processos de concentração física (MARIANO, 1989;VIERA;LINS, 1997;KAHN et al, 2012;NEUMANN;MEDEIROS, 2015).…”

Section: Inovação Tecnológica E Justificativasunclassified

“…Dependendo da composição mineralógica do material, algumas substâncias (reagentes) podem ser introduzidas ao sistema para adsorver à superfície de determinadas espécies e torná-las hidrofóbicas ou hidrófilicas (afinidade pela fase líquida), atuando como reagentes seletivos (coletores ou depressores) e viabilizando sua separação (LUZ et al, 2010). As principais características mineralógicas levantadas nesses estudos estão sumariadas a seguir (WEDOW JUNIOR, 1967;MARIANO, 1989;LAPIDO-LOUREIRO, 1994;MORTEANI;PREINFALK, 1996;VIERA;LINS, 1997;NEUMANN, 1999;TASSINARI et al, 2001;MORAIS et al, 2001;NEUMANN;VALARELLI, 2001;TASSINARI, 2001;TOLEDO et al, 2004;KAHN et al, 2012;ANTONIASSI et al, 2015;NEUMANN;MEDEIROS, 2015;TESTA et al, 2017 Tabela 3 -Descrição das amostras estudadas.…”

Section:  Flotaçãounclassified

“…Os procedimentos físicos e analíticos aplicados ao trabalho permitiram a geração de uma quantidade significativa de informações de detalhe sobre os minerais de terras raras. Estes procedimentos vêm sendo aplicados rotineiramente em estudos de caracterização tecnológica de minérios, mas poucos trabalhos abordam a aplicação específica de técnicas de mineralogia avançadas e automatizadas para o estudo de depósitos alcalinos e alcalino-carbonatíticos de terras raras (KAHN et al, 2012;GRAMMATIKOPOULOS et al, 2013;SMYTHE et al, 2013;NEUMANN;MEDEIROS, 2015 +0,60 9,5 9,5 1,10 0,25 0,39 0,33 0,13 0,28 2,76 64,9 5,41 0,92 1,36 0,85 <0,10 6,32 4,71 3,68 0,47 <0,10 6,13 -0,60+0,30 7,8 17,3 1,35 0,32 0,49 0,40 0,14 0,34 4,11 59,7 6,51 0,92 1,35 0,67 <0,10 6,75 5,55 4,10 0,54 <0,10 6,88 -0,30+0,15 12,0 29,3 1,43 0,35 0,53 0,40 0,14 0,42 5,95 52,0 7,53 1,18 1,27 0,52 <0,10 8,41 6,70 4,73 0,67 <0,10 7,91 -0,15+0,074 10,8 40,1 1,65 0,43 0,65 0,42 0,15 0,51 6,23 46,8 7,42 1,31 1,28 0,46 <0,10 11,7 7,20 5,32 0,71 <0,10 8,21 -0,074+0,037 10,9 50,9 2,26 0,56 0,95 0,57 0,18 0,55 5,73 42,8 8,64 1,29 1,42 0,42 <0,10 12,0 7,98 5,79 0,77 <0,10 9,65 -0,037+0,020 9,3 60,2 2,72 0,69 1,15 0,68 0,20 0,62 5,03 39,7 9,40 1,27 1,52 0,38 <0,10 11,0 8,79 6,22 0,78 <0,10 10,6…”

Section: Contribuições Tecnológicas Aos Estudos De Caracterizaçãounclassified

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Caracterização tecnológica de recursos minerais de terras raras em complexos alcalinos e alcalino-carbonatíticos do Brasil.

Antoniassi¹

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This work focused on the acquisition of chemical and mineralogical detailed information in samples from Brazilian alkaline and alkaline-carbonatitic deposits containing rare earths, in order to provide subsidies for process development. These deposits present high volumes of resources, low contents of rare earth elements (essentially light rare earths) and high mineralogical complexity. The studied samples are lateritic materials, with a total content of rare earth oxides between 1.27 and 6.45%, being monazite the main rare earth bearing mineral, except in one of the samples, where bastnaesite is predominant; cerianite, xenotime and a scandium-phosphate occur as trace. Rare earth minerals tend to enrich toward the finest sieve fractions with an medium grain size of 15 μm in the fractions greater than 0.008 mm and decreasing below 0.1 μm in finer fractions. These minerals occur preferentially in intimate associations with the gangue; liberation greater than 60% (in area) are observed under 0.020 mm fractions. The concentration potential of these minerals was evaluated through physical separation and hydrometallurgical extraction. Physical separations (heavy liquid and magnetic) did not succeed in obtaining products enriched in rare earths. The most promising result were the possibility of removing magnetic phases above 0.020 mm (responsible for 30%, on average, of the total Fe2O3 contained in the samples) without significant losses of rare earths. The rare earths acid leaching protocols and conditions were established by statistical experimental design. For samples comminuted below 0.30 mm, the best rare earths solubilization (77%) and with minimum gangue leaching was obtained in concentrate sulfuric acid, low solids concentration, environmental temperature and four hours of reaction. Higher levels of rare earths solubilization can be achieved, however accompanied by higher gangue solubilization.

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High-Grade REE accumulation in regolith: Insights from supergene alteration of an apatite-rich vein at the Kapunda Cu mine, South Australia

Bamforth,

Xia,

Tiddy

et al. 2024

Miner Deposita

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The stratiform and vein-hosted Kapunda Cu deposit in South Australia contains a saprolitized hydrothermal vein with 12.37 wt.% total rare earth oxide (TREO). The vein was analyzed by X-ray diffraction, scanning electron microscopy, synchrotron-based X-ray fluorescence microscopy and electron backscatter diffraction to understand the controls that govern high-grade REE accumulation during periods of intense weathering. Petrological assessments indicate the transformation of an apatite-calcite-aluminosilicate-bearing protolith to a supergene assemblage of Fe-oxides, kaolinite and REE-phosphate minerals that include rhabdophane-(Ce), monazite-(Ce) and florencite-(Ce). This transformation was facilitated by progressive acidification of the weathering fluid, which is indicated by: 1) the increasing crystallinity of authigenic Fe-oxides and kaolinite, which led to REE desorption; 2) the textural evolution and increase in grain size of authigenic REE-phosphates from nanoscopic crystallites, to acicular needles, to micro-scale hexagonal prisms; 3) the late dissolution of REE-phosphates; and 4) the replacement of goethite by jarosite, whose sulfate component originated from the oxidation and weathering of proximal sulfide minerals. Alongside the depletion of pH-buffering carbonate minerals that are indicated by the preservation of calcite menisci, this sulfide dissolution also facilitated acid generation. Results illustrate how highly acidic weathering fluids might facilitate either REE mobilization or REE accumulation in regolith. High-grade REE accumulation under acidic supergene conditions is prioritized when the host-rock contains a significant source of depositional ligands (i.e., phosphate in the form of apatite) that can be readily leached during intense weathering. Exploration companies should therefore assay routinely for REEs in any heavily weathered phosphatic rock, due to the observed efficiency of phosphate minerals as geochemical traps for REE accumulation.

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Comprehensive mineralogical and technological characterisation of the Araxá (SE Brazil) complex REE (Nb-P) ore, and the fate of its processing

Cited by 34 publications

References 14 publications

Modeling of REE and Fe Extraction from a Concentrate from Araxá (Brazil)

Modeling of REE and Fe Extraction from a Concentrate from Araxá (Brazil)

Caracterização tecnológica de recursos minerais de terras raras em complexos alcalinos e alcalino-carbonatíticos do Brasil.

High-Grade REE accumulation in regolith: Insights from supergene alteration of an apatite-rich vein at the Kapunda Cu mine, South Australia

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