机械-水热联合法制备高活性硅酸二钙

Preparation of Highly Reactive Dicalcium Silicate by Mechano Hydrothermal Processing

以稻壳灰和Ca(OH)_(2)为原料,B2O3为稳定剂,通过机械-水热联合法制备了高活性硅酸二钙(C_(2)S),研究了预处理工艺对稻壳灰活性以及烧成制度对硅酸二钙活性的影响.结果表明:稻壳灰经1%稀硫酸溶液预处理2.5 h后煅烧,可使稻壳灰活性增高,有利于提高水热合成的效率;分段煅烧和掺入0.5%的B_(2)O_(3)促进了β-C_(2)S的形成,并提升了其早期水化活性,有利于强度发展;按钙硅比为2配制的物料经球磨2.0 h、水热4.0 h后,先在500℃下预烧1.0 h,再升温至600℃煅烧1.0 h,可得到高活性硅酸二钙,其水化7、28 d后的抗压强度分别为33.0、41.1 MPa.

Highly reactive dicalcium silicate was prepared by mechano‑hydrothermal processing using rice husk ash and Ca(OH)_(2)as raw materials,and B_(2)O_(3)as stabilizer.The effects of pretreatment process on the activity of rice husk ash and calcination system were studied.The results show that the rice husk ash is highly activated by pretreating with 1%dilute sulfuric acid solution for 2.5 h and calcining,which favors to the efficiency improvement of hydrothermal synthesis.Both annealing and addition of 0.5%B_(2)O_(3)contribute to the formation ofβ‑C_(2)S and enhance its early hydration activity,which is beneficial to the strength development.The optimum procedure is ball‑milling for 2.0 h,then hydrothermal condition for 4.0 h,followed by preheating at 500℃for 1.0 h,and finally calcining at 600℃for 1.0 h.The compressive strength of highly reactive dicalcium silicate reaches 33.0 MPa and 41.1 MPa after 7 d and 28 d of curing,respectively.