This paper describes the low temperature synthesis of belite (β-C2S) from silica fume. Mixtures of lime, BaCl2, and silica fume with the ratio of (Ca + Ba)/Si = 2 were hydrothermally treated in stainless steel capsule at 110–150°C for 2–5 hours, calcined at 600–700°C for 3 hours, and analyzed by FTIR, XRD, TGA/DTA, and SEM techniques. Dicalcium silicate hydrate (hillebrandite) was prepared by hydrothermal treatment of lime/silica fume mixtures with (Ca + Ba)/Si = 2 at 110°C for 5 hours. Hillebrandite partially dehydrates in two steps at 422 and 508°C and transforms to γ-C2S at 734°C which in turn transforms to α′-C2S at 955°C which in turn transforms to β-C2S when cooled. In presence of Ba2+ ions, β-C2S could be stabilized with minor transformation to γ-C2S. Mixture of silica fume, lime, and BaCl2 with the ratio of (Ca + Ba)/Si = 2 was successfully utilized for synthesis of β-C2S by hydrothermal treatment at 110°C for 5 hours followed by calcination of the product at 700°C for 3 hours.
展开▼
机译：本文描述了从硅粉中低温合成珍珠岩（β-C2S）的方法。 （Ca + Ba）/ Si = 2的石灰，BaCl2和硅粉的混合物在不锈钢容器中于110–150°C进行水热处理2–5小时，然后在600–700°C煅烧3小时，然后通过FTIR，XRD，TGA / DTA和SEM技术进行分析。通过用（Ca + Ba）/ Si = 2的石灰/硅粉混合物在110°C下水热处理5小时来制备水合硅酸二钙（钙钛矿）。辉石在422和508°C下分两步进行部分脱水，然后在734°C转化为γ-C2S，然后在955°C转化为α'-C2S，冷却后又转化为β-C2S。在Ba 2 + 离子存在下，β-C2S可以稳定地转化为γ-C2S。 （Ca + Ba）/ Si = 2的硅粉，石灰和BaCl2的混合物通过在110°C水热处理5小时，然后在700°C煅烧产物成功地用于合成β-C2S C持续3小时。
展开▼
