Synthesis of cement based CaO–Al2O3–SiO2–H2O (CASH) hydroceramics at 200 and 250 °C: Ex-situ and in-situ diffraction
Synthesis of cement based CaO–Al2O3–SiO2–H2O (CASH) hydroceramics at 200 and 250 °C: Ex-situ and in-situ diffraction
复制标题
200 和 250 °C 水泥基 CaO-Al2O3-SiO2-H2O (CASH) 水陶瓷的合成：异位和原位衍射
DOI：
10.1016/j.cemconres.2007.03.006
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发表时间：
2007
影响因子：
11.4
通讯作者：
G. Giriat
中科院分区：
文献类型：
--
作者：
N. Meller;C. Hall;K. Kyritsis;G. Giriat
CaO-Al 2 O 3-SiO2-H2 O（CASH）系统中的水陶瓷组合物具有作为地热井密封剂以及高压灭菌建筑材料的潜力。我们报告了在200 °C和250 °C下单独使用商业API G级油井水泥以及在200 °C下添加二氧化硅粉和氧化铝（Al 2 O3）的水热合成中的相组成和反应速率的新数据。固化时间在1-240小时的范围内。我们使用非原位实验室X射线衍射和原位同步辐射能量色散X射线衍射来跟踪反应速率。当仅水泥水化时，生成水镁石、α-C_2SH和氢氧钙石。当加入硅石粉时，在结晶硅酸钙水合物相硬硅钙石和硅硅钙石之前形成结晶凝胶。XRD和EDD数据均表明，硅粉的加入延缓了水泥早期（<24 h）的水化。在含氧化铝系统中，熟料相的消耗速率与仅水泥系统中的相同。jafeite和α-C2 SH作为中间产物出现，但主要的最终产物是硅质katoite型水石榴石。定量相分析使用Rietveld细化的非原位衍射数据给出的结果，这是大多数在这里研究的所有三个系统的化学计量的限制是一致的。
Hydroceramic compositions in the CaO–Al2O3–SiO2–H2O (CASH) system have potential as geothermal well sealants as well as autoclaved construction materials. We report new data on phase compositions and reaction rates in hydrothermal syntheses at 200 °C and 250 °C using a commercial API Class G oilwell cement alone, and at 200 °C with additions of silica flour and of corundum (alumina). Curing times were in the range 1–240 h. We use both ex-situ laboratory X-ray diffraction and in-situ synchrotron energy-dispersive X-ray diffraction to track rates of reaction. When cement only is hydrated, jaffeite, α-C2SH and portlandite are formed. When silica flour is added a precursory gel forms prior to the crystalline calcium silicate hydrate phases xonotlite and gyrolite. Both XRD and EDD data suggest that the addition of silica flour retards the hydration of the cement at early times (<24 h). In alumina-containing systems the rate of consumption of clinker phases is the same as in cement only systems. Jaffeite and α-C2SH occur as intermediates but the major end product is a siliceous katoite-type hydrogarnet. Quantitative phase analysis using Rietveld refinement of ex-situ diffraction data gives results which are mostly consistent with stoichiometric constraints in all three systems examined here.