天然矿物低成本制备多孔陶瓷支撑体

Low-cost Preparation of Porous Ceramic Supports Using Natural Minerals

陶瓷支撑体是多孔陶瓷膜应用的基础。对于传统陶瓷支撑体(如氧化铝),昂贵的原料价格及较高的烧结成本限制了其进一步应用。因此,选用合适的天然矿物原料来实现陶瓷支撑体的低成本制备成为当前研究重点。本工作以高岭土、滑石、碳酸钙为原料,制备出系列多孔陶瓷支撑体。采用热膨胀仪、X射线衍射仪、扫描电子显微镜、压汞仪、万能试验机对坯体的烧结特性以及多孔陶瓷支撑体的物相组成、显微结构、孔径尺寸分布、抗弯强度和耐酸碱腐蚀性进行了研究。结果表明:坯体具有优良的低温烧结特性,通过化学反应烧结机制实现了多孔陶瓷支撑体的制备。烧结温度在1000~1200℃间较为适宜,所得支撑体的显微结构均匀,孔径呈单峰分布,开口气孔率、平均孔径尺寸、抗弯强度、0.1 MPa气体压力差下氮气通量分别为49.8%~49.4%、1.09~1.83μm、40.57~28.85 MPa、119~340 m^(3)·m^(-2)·h^(-1),同时具有良好的耐碱腐蚀性能。

The base application of porous ceramic membrane is ceramic support.For conventional ceramic supports(such as alumina),the expensive raw materials and high sintering cost both restrict their applications.Therefore,the low-cost preparation of ceramic support with natural minerals has attracted more attention.In this paper,a series of porous ceramic supports were fabricated with kaolin clay,talc and calcium carbonate as raw materials.The sintering characteristic of the green body was analyzed by thermal expansion instrument.The phase composition,micro-structure,pore size distribution and bending strength were characterized by X-ray diffractometer,scanning electron microscope,mercury porosimeter and universal testing machine.The acid and alkali corrosion resistances of the supports were also investigated.The results indicate that the obtained green body exhibits a superior low-temperature sintering characteristic.The porous supports were prepared via chemical reaction sintering.The suitable sintering temperatures of the supports are in the range of 1000-1200℃.The obtained supports have a homogeneous micro-structure and a unimodal pore size distribution.The porous supports prepared at 1000-1200℃have the open porosities of 49.8%-49.4%,the average pore sizes of 1.09-1.83μm,the bending strengths of 40.57-28.85 MPa,the nitrogen gas flux of 119-340 m^(3)·m^(-2)·h^(-1) under a trans-membrane pressure of 0.1 MPa and a superior alkali resistance as well.