Influence of SiO2 on the thermal behavior of high-energy activated natural phosphoritesPetkova, Vilma; Kostova, Bilyana; Kadiyski, Milen; Kaljuvee, Tiit12th Conference on Calorimetry and Thermal Analysis of Polish Society of Calorimetry and Thermal Analysis and 5th Joint Czech-Hungarian-Polish-Slovakian Thermoanalytical Conference : Book of Abstracts2015 / 218-220