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