氟与多种重金属离子共掺对C_(3)S形成及水化进程的协同影响

The synergistic effect of co-doping of fluorine and various heavy metal ions on the formation and hydration process of C_(3)S

水泥窑协同处置技术有望实现含氟污泥的高值化利用,但含氟污泥中含有的CaF_(2)和多种杂质重金属离子都具有一定的矿化作用,容易导致所制备水泥熟料的性能波动且难以稳定控制。鉴于此,探究了含氟污泥中CaF_(2)与多种重金属离子共掺对水泥熟料主要矿物硅酸三钙(C_(3)S)形成及水化特性的协同影响。研究表明:相较于CaF_(2)单掺或多种重金属离子复掺,两者共掺能显著减少C_(3)S中的f-CaO含量,促使C_(3)S由低对称性向高对称性的多晶转变,使颗粒尺寸细化,表观缺陷数量明显增多。CaF_(2)与多种重金属离子共掺可提升C_(3)S的初始水化速率,增大C_(3)S的3 d水化放热总量,但会使诱导期结束时间延长约8.1 h。

The co-processing technology of cement kiln is expected to realize the high-value utilization of fluorine-containing sludge.However,CaF_(2)and a variety of impurity heavy metal ions containeal in the fluorine-containing sludge has a certain mineralization effect,which is easy to cause the performance of the prepared cement clinker to fluctuate and difficult to control stably.In view of this,this paper systematically explored the synergistic effect of CaF_(2)and various heavy metal ions in fluorine-containing sludge on the formation and hydration characteristics of tricalcium silicate(C_(3)S),the main mineral of cement clinker.The results show that compared with CaF_(2)single doping or multiple heavy metal ions co-doping,the co-doping can significantly reduce the content of f-CaO in C_(3)S,promote the transformation of C_(3)S from low symmetry to high symmetry,refine the particle size,and increase the number of apparent defects.The co-doping of CaF_(2)and various heavy metal ions can increase the initial hydration rate of C_(3)S and increase the total amount of 3 d hydration heat release of C_(3)S,but it will prolong the end time of the induction period(prolonged about 8.1 h).