Autor(es): Lisboa, Jose ; Pereira, L. F. ; Osório, A. ; Rodrigues, José Feliciano ; Fernández, J. ; Oliveira, Álvaro ; Manuel, José
Data: 2024
Identificador Persistente: http://hdl.handle.net/10400.9/4457
Origem: Repositório do LNEG
Assunto(s): Metallurgy; Quartz; Gravel; Chemical composition; Benguela (Angola)
ABSTRACT: Vast occurrences of quartz in veins and extensive gravel beds in the coastal area of Equimina, approximately 100 km south of Benguela, constitute the object of this study, aiming for its industrial use. These occurrences are related to Paleoproterozoic gneisses and migmatites on which they outcrop. The veins are quite dismantled on the surface, and show a pronounced strike scattering, but the NE-SW orientation prevails. Some veins are pegmatitic (feldspar, quartz, and mica), others, if not the majority to the East in the study area, have a strong predominance of milky quartz with low content of other minerals. Except for a superficial and removable patina of iron oxides that often coats the quartz, it is free of visible impurities. Chemical analysis confirms high purity (SiO2 > 99.5%) and very low content of penalizing oxides. Although the composition of quartz is suitable for use in the ceramic and glass industry, due to the ways it occurs, the main potential of this abundant resource in the studied area is for the refractory and metallurgy industry. Besides the chemical composition, the size of the gravel mostly meets the dimensional requirements for silicon metal production, needing minimal beneficiation.
