Effect of barium oxide on the formation and coexistence of tricalcium silicate and calcium sulphoaluminate

Formation and coexistence of tricalcium silicate (C₃S) and calcium sulphoaluminate (C₄A₃ ) minerals in Portland cement clinker containing calcium sulphoaluminate were investigated. The f-CaO content, mineral composite and formation of mineral in the clinker were analyzed respectively by chemical analysis, differential scanning calorimetry(DSC) and X-ray diffraction. The results show that, adding a suitable amount of BaO can improve the burnability of raw meal and promote the f-CaO absorption. Tricalcium silicate and calcium sulphoaluminate minerals can form and coexist in clinkers at 1 234–1 317 °C by the addition of BaO to the raw meal. A suitable amount of BaO expanded the coexistence temperature of two minerals by 58 °. Funded by the National Basic Research Program of China (No. 2009CB623100), National Eleven Five-Year Scientific and Technical Support Plans (No. 2006BAF02A24), the Natural Science Fund for Colleges and Universities in Jiangsu Province(No. 08KJB430006), the Open Fund for the Key Laboratory of Inorganical and Composite Materials in Jiangsu Province(No. wjjqfhxc1200801) and the Innovation Fund of Doctoral Dissertation of Nanjing University of Technology (No. BSCX200705)