The use of biotechnology to explore low-grade ore deposits and mining tailings is one of the most promising alternatives to reduce environmental impacts and costs of copper extraction. However, such technology still depends on improvements to be fully applied in Brazil under industrial scale. In this way, the bioleaching, by Acidithiobacillus ferrooxidans, in columns and stirred reactors were evaluated regarding to copper extraction of a mineral sulfide and a weathered ore from the Brazilian Amazon region. Samples (granulometry of 2.0/4.75 mm) were characterized by X-ray diffraction (XRD), energy dispersive X-ray fluorescence (EDXRF) spectrometry and scanning electrons microscopy (SEM). The pH and Oxidation-reduction potential (Eh) were daily monitored and leachate samples were collected for copper extraction determination by EDXRF. After 47 days, the columns bioleaching efficiency was 1% (1298 mg Cu·L−1) and 0.95% (985 mg Cu·L−1) for 2.00/4.75 mm sulfide ore, respectively, whereas the stirred reactors bioleaching resulted in 4% (348 mg Cu·L−1) for the mineral sulfide and 47% (295.5 mg Cu·L−1) for the weathered ore.
Resumo A biolixiviação consiste na solubilização de componentes metálicos insolúveis presente nos minérios, em formas solúveis em água, por atividade direta ou indireta de micro-organismos, como o Acidithiobacillusferrooxidans. O objetivo deste trabalho foi avaliar a eficiência da biolixiviação em colunas, por A. ferrooxidans, de um sulfeto mineral proveniente de Carajás (PA), com granulometrias de 2,00 e 4,75 mm. Caracterizações mineralógica e química foram realizadas por DRX e FRX. O pH, potencial redox (Eh),extração do cobre, densidade e viabilidade bacteriana na solução lixiviadora foram medidos. A colonização bacteriana nas partículas foi determinada por MEV.Os minerais calcopirita, quartzo, magnetita e magnesiohornblenda ferrosaforam identificados, com o predomínio dos elementos S, Fe, Cu e Si na amostra mineral. Após 54 dias, foram extraídos 1,07% e 0,95% de cobre para as granulometrias de 2,00 e 4,75 mm, respectivamente. As bactérias permaneceram viáveis na forma planctônica e formaram biofilmes nas partículas. Os resultados indicam que a menor granulometria do minério favoreceu a extração, apesar da refração da calcopirita à biolixiviação. Mesmo pequena em escala laboratorial, esta diferença pode ser significativa em pilhas de processos industriais. Palavras-chave:Biolixiviação; Biomineração; Calcopirita;Copper. COLUMN BIOLEACHING FOR COPPER EXTRACTION FROM AN ORE OF THE AMAZON REGION Abstract The bioleaching consists in the solubilization of insoluble metals present in the ores to a water-soluble form, by the direct or indirect microorganism's action, like Acidithiobacillusferrooxidans. The goal of this work was to evaluate the column bioleaching, using A. ferrooxidans, of a sulfide mineral from Carajás (PA), with particle sizes of 2.00 and 4.75 mm. Mineralogical and chemical samplecharacterization were performed by XRD and EDXRF, respectively. The pH, redox potential (Eh), copper extraction, bacterial density and viability were monitored in the leaching solution. Bacterial colonization over the ore surface was checked by SEM.The minerals chalcopyrite, quartz, magnetite and iron-magnesium hornblende were identified, and the elements S, Fe, Cu e Si were the most abundant in the ore sample. After 54 days, were extracted 1.07% and 0.95% of copper for the 2.00 and 4.75 mm particles, respectively. Viable bacteria was observed in planktonic form and forming biofilms over the particles. The results indicated that lower granulometry favored the copper extraction, despite the chalcopyrite recalcitrance to bioleaching. Despite the small differences, it may be very significant considering a bioleaching heap scale.
scite is a Brooklyn-based organization that helps researchers better discover and understand research articles through Smart Citations–citations that display the context of the citation and describe whether the article provides supporting or contrasting evidence. scite is used by students and researchers from around the world and is funded in part by the National Science Foundation and the National Institute on Drug Abuse of the National Institutes of Health.
hi@scite.ai
10624 S. Eastern Ave., Ste. A-614
Henderson, NV 89052, USA
Copyright © 2024 scite LLC. All rights reserved.
Made with 💙 for researchers
Part of the Research Solutions Family.