利用废弃加气混凝土制备硅酸钙绝热材料

发布时间：2018-03-02 13:27

  本文选题：废弃加气混凝土　切入点：锆渣　出处：《南京理工大学》2015年硕士论文　论文类型：学位论文

【摘要】：废弃的加气混凝土数量庞大,并占用大量土地,加气混凝土行业的健康发展受到了极大的限制。同时,硅酸钙绝热材料因其密度小,强度高,易加工,保温效果好,可回收利用等特点,在讲究节能减排,可持续发展的当今社会中受到了极大的重视。利用废弃砂加气混凝土作为主要硅质原料,硅藻土和锆渣作为次要硅质原料,通过调整废弃砂加气混凝土占硅质原料总量的比例制备托贝莫来石型硅酸钙绝热材料,并掺加泥粉,聚醋酸乙烯乳胶等添加剂提高材料力学性能。借助力学试验测试仪,XRD,氮吸附等近现代化测试技术分析不同原料配比制得的托贝莫来石型硅酸钙绝热材料的抗折强度,高温线收缩率,物相组成,结构形貌等。废弃加气混凝土掺量为70%时制得的硅酸钙材料主要物相是结晶良好的托贝莫来石型水化硅酸钙,容重为285 kg/m3,导热系数为0.069 W/(m.K),抗折强度达到0.26 MPa。废弃加气混凝土掺量为100%,泥粉掺量为50%,聚醋酸乙烯乳胶掺量为7%时制得的硅酸钙材料抗折强度达到0.51 MPa。并利用高温煅烧活化后的砂加气混凝土制备硅酸钙绝热材料,研究其物理力学性能,分析废弃加气混凝土高温活化在制备托贝莫来石型硅酸钙绝热材料过程中的作用机制。利用微米尺度、无定形二氧化硅与氧化钙制备层间距为11.3A托贝莫来石,研究了托贝莫来石725℃高温煅烧过程中微结构变化。托贝莫来石经过725℃煅烧2h转变为脱羟基托贝莫来石(无定形态),这种无定型非晶态结构的形貌和托贝莫来石的晶体形貌相似,都是针状、片状的晶体以及大量颗粒状结构,这些颗粒状结构由针状、片状结构互相交错堆积形成；在725℃煅烧温度下,部分纳米尺度的托贝莫来石转变为单斜链状的硅灰石结构(结晶态)。将11.3A托贝莫来石725 ℃煅烧2h后制备高温脱水相。研究再水化试样的盐酸不溶物、有效钙以及结合水含量变化,分析再水化反应历程变化,发现反应历程满足对数变化：F(t)=k1ek2t+k3;利用XRD,SEM,TEM和氮吸附等近现代检测分析技术研究11.3A托贝莫来石高温脱水相再水化过程中的物相结构变化。从研究结果看,11.3A托贝莫来石的再水化过程产物包括新生成的11.3A托贝莫来石、CSH凝胶。在再水化过程中,层片状的脱羟基托贝莫来石结构会溶解反应生成CSH凝胶,并随着再水化反应的进行,CSH凝胶会转变为11.3A托贝莫来石。
[Abstract]:The healthy development of aerated concrete industry is greatly restricted by the large quantity of waste aerated concrete, which occupies a large amount of land. At the same time, because of its small density, high strength, easy processing and good insulation effect, calcium silicate insulation material is easy to be processed. The characteristics of recycling have been paid great attention in the society of energy saving and emission reduction and sustainable development. Waste sand aerated concrete is used as the main siliceous raw material, diatomite and zirconium slag are used as secondary siliceous raw materials. The Tobamolite-type calcium silicate insulation material was prepared by adjusting the proportion of waste sand aerated concrete to the total amount of siliceous raw materials and mixed with mud powder. The mechanical properties of the materials were improved by additives such as polyvinyl acetate latex. The flexural strength of the Tobiamurite type calcium silicate adiabatic material was analyzed by means of mechanical test instrument XRD, nitrogen adsorption and other modern testing techniques. High temperature linear shrinkage, phase composition, structure morphology, etc. The main phase of calcium silicate material made of 70% waste aerated concrete is the well-crystallized Tobamolite calcium silicate, The bulk density is 285 kg / m ~ (3), the thermal conductivity is 0.069 W / m ~ (-1), the flexural strength is 0.26 MPA, the volume of waste aerated concrete is 100, the amount of mud powder is 50 and the content of polyvinyl acetate emulsion is 7. The flexural strength of calcium silicate material is 0.51 MPA. Calcined activated Sand aerated concrete to prepare calcium silicate Thermal Insulation material, The physical and mechanical properties were studied, and the mechanism of high temperature activation of waste aerated concrete in the preparation of Tobamolite-type calcium silicate insulation material was analyzed. The spacing between amorphous silica and calcium oxide preparation layer is 11.3A tob mullite, The changes of microstructure of tobermorite during high temperature calcination at 725 鈩，

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