Study On Minerals Transformation Mechanism Of On-line Reconstruction Of Steel Slag With High Cementitious Activity

In order to solve problems such as the fluctuation of chemical composition,low cementitious activity and poor stability,which limit the utilization of steel slag seriously,in this study,the on-line reconstruction was performed,by adjusting appropriate components into the molten steel slag.So that the cementitious activity and stability were improved,and the mechanism of minerals transformation was explored.The results provide a technological basis for the utilization of steel slag and its heat.By taking KH as the tempering parameter,it's found that the highest cementing activity index is 98.07% when KH is 0.97.The free MgO content of the reconstructed steel slag is lower than that of the original steel slag,and the stability is good.It is found from X-ray diffraction that when KH is low,the RO phase decomposes to produce more MgFe₂O₄.With the increase of KH,the cementing minerals contents such as C2 S,C₃S,and C4 AF gradually increase,the production of MgFe₂O₄ decreases and MgO dissociates.The optimum cooling temperature is 1100?1150?,and it is not suitable to keep heat preservation in the process of cooling.The on-line reconstruction was simulated by high temperature lifting furnace.It's found that when the reconstruction temperature is 1400?,the tempering component is preheated to 600?,the heat preservation is 30 min,without mineralizer,and the mixing method is adding the tempering component into the molten steel slag,the cementing minerals contents and the crystallization degree are higher.Pure oxides?CaO,SiO₂,Al₂O₃?were added to RO phase,and the mechanism of RO phase transformation was explored.It's found that MgFe₂O₄ is generated after RO phase decomposition.When only Ca O added,CF and C2 F are generated,and MgFe₂O₄ content decreases.When SiO₂ added,C2 S,C₃S and MgFe₂O₄ are generated.When Al₂O₃ added,C4 AF is generated,and the production of C2 S,C₃S and MgFe₂O₄ is reduced compared with that of Ca O and SiO₂,but the production of MgFe₂O₄ is still higher than that of Ca O alone.Figure 58;Table 16;Reference 61...