Effects Of Mineral Component On Sintering Process And Performance Of Eco-cement

The main composition is limestone, quartz and hardened cement paste which has the same chemical composition as cement clinker. Based on the previous work, it is feasible to produce clinker from all components of waste concrete as a renewable resource. Compared with conventional materials, crystalline silica and hydrated cement paste of which the proportion is30%in the concrete can be introduced into the raw meals in the same time while concrete is used in cement production. The exist of unhydrated cement particles and the high activity of dehydration phase can improve the burnability. But on the contrary, crystalline silica is difficult to react with CaO. Therefore, the selection of parameters is different between eco-cement and ordinary cement. Focused on these problems, reflection macroscope, X-Eay diffraction, and scanning electron microscope were used in this study, and Ea of C3S in eco-cement was calculated. And on this basis the realitions of mineral component were studied for searching the rule of effect in the clinker.First the influence of parameters was studied in this paper and the matching relationships of KH. SM and IM were discussed. The results show that the sintering temperature of eco-cement clinker was1400℃which was different from ordinary cement; the the free calcium content at1350℃was up to the standard.In this study, the range of KH, SM, and IM which was study in this paper was extended. The ranger of KH, SM, IM is0.82～0.98,1.8～3.0,0.8～2.0. Nine series with36groups experimental plans were designed. The resuls shows that the content of waste concrete in raw material has a significant impact on the appearance and the development of minerals. Some samples with the content of waste concrete below75%were powdering after moving from muffle furnace.The Ea of C3S of the samples with different parameters in eco-cement were calculated, the result shows that the Ea of C3S was lower at the point which KH is0.95than others; the Ea was increased with the SM. The clinker with the selection of low IM, high SM and KH was easy to sintered; the suitable range of SM is2.4～2.8. IM is1.2～1.4and the suitable KH is0.95.At last, the problems compared with industrial clinker in the study were discussed. The hydration strength of eco-cement is low, the main reason of this problem is the poor development and the low content of alite; the compaction of hydration products is poor; the content of waste concrete in raw material has a significant impact on the development of the minerals in the clinker. And appropriate proporition is the first work in the follow-on study. Some samples were powdering after moving from muffle furnace; and the mineral component of some samples were not well developed. The quality of concrete in raw material may be the main reason of these problems.