IMPERIAL BLUE QUARTZITE CHARACTERIZATION PURPOSING THE REMOVAL OF STAINS IN NATURA

• DOI: 10.22533/at.ed.8732021099

• Palavras-chave: Ornamental stones; Technological characterization; Quartzite; Removal; Stains.

• Keywords: Ornamental stones; Technological characterization; Quartzite; Removal; Stains.

• Abstract:

  The blue quartzite of the Serra do Espinhaço, Northern of Bahia is marketed under different commercial names, such as: "Azul Imperial", "Azul Boquira" and "Azul Macaúbas". The bluish color, which generates the exotic features to the rock, comes from the minerals rich in boron, mainly the dumortierite. This ornamental stone has high market value and, currently, has a great demand for this type of rock, mainly for export. However, in some portions of this stone pit, there are stain spots of yellowish to reddish tons that cause the final price of the benefited rock (slabs) to lose up to 40% of its market value. Thus, the purpose of this work aims to characterize this material in order to identify the minerals that cause the stains and provide a chemical treatment capable of returning the market value to the rock. For this purpose, characterization tests were used, such as: petrographic description of rock samples, X-ray fluorescence (FRX) and X-ray diffraction (XRD). Analyzes showed a presence of minerals containing Iron (Fe), Aluminum (Al) and Titanium (Ti), possible causes of such changes in rock coloration.

• Número de páginas: 8