[1] Univ Fed Santa Maria, Dept Chem Engn, BR-88040900 Santa Maria, RS, Brazil
[2] CETMIC CIC CONICET, Ctr Technol Mineral Resources & Ceram, Buenos Aires, DF, Argentina
[3] Univ Fed Santa Catarina, Dept Chem & Food Engn, BR-88040900 Florianopolis, SC, Brazil