Characterization of Bauxite Residue from a Press Filter System: Comparative Study and Challenges for Scandium Extraction

Autor(es)

Botelho Junior, Amilton Barbosa ; Espinosa, Denise Crocce Romano ; Tenorio, Jorge Alberto Soares

• Tipo de documento: Artigo Científico
• Fonte: MINING METALLURGY & EXPLORATION; v. 38, n. 1, p. 16-pg., 2020-10-19.

Resumo

A new step in the Bayer process has been used to recover NaOH and to reduce its content in red mud. After digestion, the residue is separated from the Bayer liquor and goes through press filters, which enables the recovery of NaOH and decreases the moisture content. It is well known that red mud is one of the most important sources of scandium. For this reason, the goal of this work was to characterize a Brazilian red mud (BRM) for scandium recovery. The sample was collected after the press filter system process. Analysis of energy-dispersive X-ray fluorescence (EDXRF), scanning electron microscopy/energy-dispersive X-ray spectroscopy (SEM/EDS), and X-ray diffraction (XRD) was performed. Microwave digestion using an acid mixture was carried out to determine the concentration of the main elements. Fe2O3 represented 40% of the BRM, and the Sc concentration was 43 mg/kg. The SiO2 content was 24%, which is the highest value found in the literature, whereas the sodium concentration was the lowest. A literature review was carried out to compare results with BRM, as well as the current studies for recovery of scandium by the leaching/ion-exchange process. Scandium recovery using a leaching/ion exchange process may be possible with efficiency higher than 90%. The greatest challenge is the occurrence of silica gel formation during leaching. (AU)

• Processo FAPESP: 18/11417-3 - Obtenção de escândio a partir de resíduo de bauxita lama vermelha utilizando processo de lixiviação em meio ácido
• Beneficiário: Jorge Alberto Soares Tenório
• Modalidade de apoio: Auxílio à Pesquisa - Regular
• Processo FAPESP: 18/03483-6 - Estudo cinético e termodinâmico da recuperação de escândio da lama vermelha brasileira utilizando técnicas hidrometalúrgicas
• Beneficiário: Amilton Barbosa Botelho Junior
• Modalidade de apoio: Bolsas no Brasil - Doutorado