Impurity Content Characterization of Brazilian Quartz Lascas

Abstract

Lattice impurities (Al, Li, Fe) free from the influence of cations in inclusion liquid were evaluated by atomic absorption spectrophotometry (AAS) in quartz lascas taken from 10 deposits with known localities in three states, Minas Gerais, Tocantins and Bahia. Levels of Al content and associated Li content depend on the localities of deposits. Quartz deposit regions with high Al content are composed of granite, gneiss, and pegmatite as surrounding rocks. It was concluded that the charge compensation for Al-Si substitution in quartz lascas was realized substantially by the formation of Al-Li and Al-OH centers which were confirmed from the linear relation of Al-Li plots by AAS data and IR spectra due to Al-OH center. The variety in Al-Li and Al-OH correlations was attributed to the fluctuation of growing conditions of quartz in nature.

Quartz resources in the Serra de Santa Helena formation, Brazil: A geochemical and technological study

“…Therefore those elements are found in trace amounts when quartz samples are analyzed (G€ otze, 2009;Miyoshi et al, 2005). Usually, the Al/Li ratio is particular from each quartz deposit and can indicate the conditions of crystallization (Iwasaki et al, 1991). G€ otze et al (2004) reported that the Al/Li for pegmatitic quartz is usually <10.…”

“…In addition, most of mines historically engaged in exportation frequently delivered the ore with irregular quality, i.e., with impurities and fluid inclusions exceeding the requirements of silica glass industry (Iwasaki et al, 1991;Santos et al, 2013). Furthermore, production was carried on using manual techniques, making it small and costly.…”

Estudo da suscetibilidade ao escurecimento por radiação gama de quartzo róseo-leitoso da província pegmatítica da Borborema

“…Não foi detectada a presença de P, Mg, Ca e Sr. A grande concentração de Cr, Fe e Ni medida apenas na variedade rósea pode ser explicada pela presença de inclusões sólidas microscópicas, de morfologia arredondada, observadas no resíduo da digestão ácida. Por sua vez, o Na, em concentração significativa na amostra de quartzo leitoso, pode ser proveniente de inclusões fluidas e, eventualmente, ocorrer como compensador de carga dos centros de Al (Iwasaki et al 1991).…”

Quartz sand resources in the Santa Maria Eterna formation, Bahia, Brazil: A geochemical and morphological study

“…The Al content, however, presents an abnormally low value. Most quartz resources, either hydrothermal, pegmatitic or diagenetic, usually contain more than 20 mg g À1 in Al (Santos et al, 2014;Müller et al, 2012;Suzuki et al, 2012;Li et al, 2010;Müller et al, 2007;Iwasaki et al, 1991). The content of Ge is also relatively low.…”