硅酸钙结合蛭石轻质材料制备及孔隙结构研究

Preparation of Calcium Silicate-Vermiculite Composite Light Materials and Study on Their Pore Structures

为了探寻电力防火领域对轻质新型防火材料的需求,采用氢氧化钙和粉石英为钙、硅原料,膨胀蛭石为骨料,配合增强纤维,经静态水热蒸压反应,制备了体积密度介于538~859 kg/m3的硅酸钙结合蛭石轻质材料。探讨了蛭石加入量20%~40%、成型压力1.0~4.0 MPa对材料体积密度与强度的影响。结果表明,托贝莫来石和硬硅钙石组成的结合相中微细孔隙结构与蛭石片层间的孔隙使得材料孔隙率高达60%以上。同时,结合相与蛭石的穿插结合结构使材料具有较高强度。蛭石加入量30%、压力2.0 MPa下成型的样品,抗拉拔强度接近40 MPa,热面温度1000℃时其导热系数只有0.209 W/(m·K)。这种材料在高温下的低收缩和低导热系数特性使得其在电力防火领域具有潜在用途。

In order to fit for the demand for lightweight new fireproof material in the electric power fire protection,calcium silicate bonded vermiculite lightweight material with bulk density of 538-859 kg/m3 was prepared by static hydrothermal autoclave reaction using calcium hydroxide and powder quartz as calcium and silicon raw materials,expanded vermiculite as aggregate and adding reinforced fiber.The effects of 20%-40%vermiculite addition and 1.0-4.0 MPa molding pressure on the bulk density and strength of the material were discussed.The results showed that the fine pore structure was developed in the binding phase mainly composed of tobermorite and xonotlite,and the pores between it and vermiculite lamellae created up to more than 60%porosity of the material.At the same time,the interspersed binding structure of the binding phase and the vermiculite made the material have higher strength.The tensile strength of sample with 30%vermiculite and molding pressure at 2.0 MPa was close to 40 MPa,and its thermal conductivity was only 0.209 W/(m·K)at the hot surface temperature of 1000℃.The material had low shrinkage and low thermal conductivity at high temperature,which had potential applications in the field of electric fire prevention.