Effects of Fluorapatite in Limestone on Burnability and Compressive Strength of Cement Clinker

Effects of fluorapatite in limestone from Africa on burnability,mineral composition,mineral morphology and compressive strength of the clinker are analyzed.It is found that with the increase of the P2O5 in clinker,the effect of fluorapatite on improving burnability of raw meals is positive and significant at 1300℃ and 1350℃,and not obvious at 1400℃ and 1450℃.The content of C3S,C3A and C4AF in clinkers decrease with the increasing of the P2O5 content.When the content of P2O5 in clinker is between 0.05% and 1.50%,the significant amount of well-developed alite is formed.When the content of P2O5 in clinker is between 2.00% and 5.00%,alite is mainly irregular and inhomogeneous.The strengths of cement pastes at 3d and 28d would have a gradual decline with the increasing of the P2O5 content.When the content of P2O5 in clinker is not more than 1.50%,cements produced may meet the strength requirements of 42.5 Portland cement national standards.It is analyzed that the amount of P2O5 in clinker should not be more than 1.50% combined with burnability of raw meals,microstructure of the clinker and strength of the cement.