S. Zadavičiūtė “Synthesis of oxide and silicate materials denoted by specific properties” doctoral thesis defence

Author, Institution: Skirmantė Zadavičiūtė, Kaunas University of Technology,

Science area, field of science: Technological Sciences, Chemical Engineering – 05T

Summary of doctoral thesis: Summary

Scientific supervisor:  Prof. Dr. Kęstutis Baltakys (Kaunas University of Technology, Technological Sciences, Chemical Engineering 05T)

Dissertation Defence Board of Chemical Engineering Science Field:
Prof. Dr. Raimundas Šiaučiūnas (Kaunas University of Technology, Technological Sciences, Chemical Engineering, 05T) – chairman;
Prof. Dr. Rimvydas Kaminskas (Kaunas University of Technology, Technological Sciences, Chemical Engineering, 05T);
Prof. Dr. Habil. Aivaras Kareiva (Vilnius University, Physical Sciences, Chemistry, 03P);
Prof. Dr. Saulius Kitrys (Kaunas University of Technology, Technological Sciences, Chemical Engineering, 05T);
Assoc. Prof. Dr. Jolanta Rousseau (Artois University, Technological Sciences, Chemical Engineering, 05T).

The doctoral dissertation is available on the internet and at the library of Kaunas University of Technology (K. Donelaičio str. 20, Kaunas).

Annotation:

The most common method used for the synthesis of metal mixed oxides is a multistep process. Thus the involved production technologies are complex, expensive and time-consuming; they also suffer from other drawbacks, which can be eliminated by conducting the proposed hydrothermal/microwave synthesis. Therefore, it is important to examine an environmentally friendly periodic operation technology of oxide and silicate materials which would include hydrothermal and microwave synthesis of the initial compounds featuring specific properties. It was determined that the formation of compounds denoted by specific properties in the MgCO3-Al2O3-H2O stirred suspension is induced by hydrothermal treatment. By changing the conditions of the activation methods (i.e., mechanochemical and thermal ones), the mineralogical composition and the morphological properties of the researched compounds can be controlled. Also, the recommended optimal duration of one cycle for microwave treatment of 3 h was not suitable for the formation of calcium silicate hydrate – gyrolite. Meanwhile, after performing hydrothermal treatment (200 C, 48 h), the main synthesis product – gyrolite was formed, and no other compounds were observed in the system. According to the obtained results, conclusions, recommendations and the rational application areas of the above mentioned synthetic materials were proposed.