1. Professor, Dept. of Silicate Technology, Chemical Technology Faculty, Kaunas Univ. of Technology, Kaunas 50254, Lithuania (corresponding author).
2. Associate Professor, Dept. of Silicate Technology, Chemical Technology Faculty, Kaunas Univ. of Technology, Kaunas 50254, Lithuania.
3. Dept. of Silicate Technology, Chemical Technology Faculty, Kaunas Univ. of Technology, Kaunas 50254, Lithuania.