Study the effects of P2O5 mineralization additives on cement clinker quality at low calcination temperature 1300oC and 1400oC

In this study, the cement clinker was mixed with P2O5 mineralization additives with the rate of 1.0% and 2.0% (compared to the content of cement clinker without P2O5 mineralization additives which was called the control sample) and then this mixture was calcined at temperatures of 1300oC and 1400oC by gas furnace. The mechanical properties of the prepared cement samples were determined: density and free lime content of clinker; normal consistency and setting time of cement paste; soundness and compressive strength of hardened cement paste. The results showed that, the cement samples mixed with P2O5 mineralization additives had free lime content (1.36-1.91%) which was lower than the control sample (1.39-2.34%). The setting time significantly reduced compared with that of the control sample. The soundness of cement samples mixed with P2O5 reache 0.55-1.2 mm in accordance with TCVN 4031:1985 and it was smaller than that of the control sample. The compressive strength of hardened cement paste sample which mixed with P2O5 of 1.0% (at the age of 28 days) reached 25.23 N/mm2 at 1300oC (the control sample reached 24.32 N/mm2) and reached 28.6 N/mm2 at 1400oC (the control sample reached 27.00 N/mm2). The study showed that, The using of P2O5 mineralization additives with appropriate content will bring to the improved quality of the cement clinker.