Influence of CuO on formation and coexistence of tricalcium silicate and calcium sulphoaluminate

The influence of CuO on the formation and coexistence of tricalcium silicate (C₃S) and calcium sulphoaluminate (C₄A₃S̄) in Portland cement containing calcium sulphoaluminate was investigated. The calcium sulphoaluminate content and tricalcium silicate content in clinkers were determined by chemical analysis and the X-ray diffraction internal standard method. The composition of clinkers was analyzed by an X-ray diffraction apparatus. The influence of CuO on the formation of clinkers was investigated by differential thermal analysis, and the structure of C₃S crystal was determined by transmission electron microscopy. The results show that a reasonable addition of CuO(0.1% in mass) in raw meal can lower the burn temperature of the clinker, promote the coexistence of C₃S and C₄A₃S̄, and increase the strength of clinkers. Excessive CuO in the raw material will lower the decomposition temperature of C₄A₃S̄.