The Synthesis And Properties Of Super Low Density Xonotlite

As the deeper and wider study on the hydration of silica acid calcium light-duty heat preservation material, improving the existence material's use performance, developing more excellent capability new silica acid calcium is always the focus of people's attention. Tobermorite(5CaO·6SiO₂·5H₂O) and xonotlite(6CaO·6SiO₂·H₂O) are the most widely used and best capability heat preservation material, between them, xonotlite is not only has lower water contain, but also can sustain 1000℃(tobermorite is 650℃), so it has bright future.Calcium material was obtained by calcining, the calcining temperature is very important, when the temperature is too low, the limestone will sustain too much in the mixture; when the temperature is too high, the sinter phenomenon will appear, and it will make for low active. This paper chose the best temperature is 1000℃by testing different calcining temperature's product's active and comparing with the calces's content.Silica material has great impact on the xonotlite's production. This paper chose the non-crystal silica material white silica and crystal silica material quartz, the xonotlite was synthesized by dynamic hydrothermal method, and the reaction condition such as C/S, synthesis temperature, synthesis time, water-solid radio was discussed, XRD, SEM was used to obtain the production's composing and micro image. As the experimentation, in the non-additive condition, using the non-crystal material can make well crystalloid xonotlite under lower heat preservation temperature and shorter heat preservation time, its secondary particle looks like nest, and it is built by fibers interlace each other, the surface is not flat, when dehydrate and desiccation it is easily form compact structure, result in high bulk density. Crystal silica material is not active, the technics is higher than using non-crystal silica material. But its secondary particle's surface is smooth, and it is easily to deposit, after dehydrate and desiccation the produce has lower density.On this basis, the ZrOCl₂·H₂O was used as addictive to synthesis by dynamic hydrothermal method, the best proportion of accession was studied.The xonotlite's micro fiber and secondary particle's growth mechanism were discussed, and the condition of the formation of secondary particle was studied.