Ispitivanje uticaja mehanicke aktivacije smeše MgO-Ti[O.sup.2] na sintezu magnezijum- titanata/Investigation of the impact of mechanical activation on synthesis of the MgO-Ti[O.sup.2] system

• Published in: Hemijska industrija 2021-07, Vol.75 (4), p.213
• Main Authors: Dordevic, Natasa G, Vlahovic, Milica M, Ma, Mihajlovic, Slavica R, Vusovic, Nenad M, Sokic, Miroslav D
• Format: Article
• Language: English
• Subjects: Analysis; Magnesium; Magnesium compounds; Steel, Stainless; Steel-works; Titanium dioxide
• ISSN: 0367-598X
• DOI: 10.2298/HEMIND210402022D

U ovom istraživanju izvršena je mehanicka aktivacija smeše magnezijum oksida i titanijum dioksida u cilju ispitivanja mogucnosti mehanohemijske sinteze magnezijum titanata. Mehanicka aktivacija (MA) je vršena tokom 1000 min u visokoenergetskom vibro mlinu sa torzionim oprugama i prstenastim radnim elementima. Nakon ovog vremena, analiza strukture difrakcijom X-zraka je ukazala na potpunu amortizaciju smeše polaznih komponenti. U skladu sa uputstvom za upotrebu vibro mlina u smislu vremenskog ogranicenja kontinualnog rada, eksperiment je prekinut nakon 1000 minuta aktivnog mlevenja. Nemogucnost sinteze magnezijum titanata objašnjava se suviše niskom negativnom vrednošcu Gibsove energije od -25,8 kJ [mol.sub.-1] (i pored teorijske mogucnosti da se reakcija odigra), kao i kolicinom energije unete u sistem tokom mehanicke aktivacije koja se pokazala nedovoljnom za dobijanje željenog proizvoda. Iako sinteza magnezijum titanata nije ostvarena, dobijeni su znacajni rezultati koji identifikuju metode za dalje ispitivanje mogucnosti odvijanja mehanohemijskih reakcija zemnoalkalnih metala i titanijum dioksida. Kljucne reci: visokoenergetski vibro mlin; magnezijum titanat; amorfizacija; analiza difrakcijom X-zraka. In this study, a mixture of magnesium oxide and titanium dioxide was mechanically activated in order to investigate the possibility of mechanochemical synthesis of magnesium titanate. Mechanical activation was performed for 1000 min in a high-energy vibro mill (type MH954/3, KHD Humboldt Wedag AG, Germany). The mill is equipped with housing having a horizontally placed shutter. The cylindrical stainless steel working vessel, with inner dimensions of 40 mm in height and 170 mm in diameter, has working elements consisting of two free concentric stainless steel rings with a total weight of 3 kg. The engine power is 0.8 kW. Respecting the optimal amount of powder to be activated of 50-150 g and the stoichiometric ratio of the reactants in the equation presenting the chemical reaction of magnesium titanate synthesis, the starting amounts were 20.2 g (0.5 mol) of MgO and 39.9 g (0.5 mol) Ti[O.sup.2]. During the experiments, X-ray diffraction analysis of the samples taken from the reaction system after 60, 180, 330, and 1000 min of mechanical activation was performed. Atomic absorption spectrophotometry was used for chemical composition analysis of samples taken at different activation times. Based on the X-ray diffraction analysis results, it can be concluded th