基于低品位天然凹凸棒石黏土的低成本蜂窝陶瓷

Low cost honeycomb ceramic from natural low grade attapulgite clay

低品位凹凸棒石黏土由于凹凸棒石含量低,被大量弃用,造成资源浪费,迫切需要开发基于低品位凹凸棒石黏土的功能材料,以提高其利用效率和价值.以低品位凹凸棒石黏土为主要原料,采用挤出成型法制备了表面光滑无缺陷的凹凸棒石蜂窝陶瓷坯体,经焙烧后获得凹凸棒石黏土-氧化铝蜂窝陶瓷成品.考察了水、黏结剂和增塑剂的加入量以及焙烧制度等对蜂窝陶瓷性能的影响.研究表明,当水含量在17.5%~20.0%、黏结剂含量为8.0%~10.0%、增塑剂含量为3%~4%时,经真空练泥及陈腐后,获得的泥料具有优异的塑性,挤出成型能力最好,在挤出成型过程中蜂窝陶瓷生坯结构完整、无缺陷.经合适的焙烧温度和保温时间焙烧后,所得蜂窝陶瓷壁厚约0.34 mm、孔密度为169孔/in^(2)、孔隙率为43.43%±0.12%、吸水率为25.98%±0.1%、体积密度为(0.9±0.12)g/cm^(3)、机械强度为(16.34±1.23)MPa.

Honeycomb ceramics with regular,parallel channels have high mechanical strength,good thermal shock resistance,high specific surface area and good permeability.The performance of the honeycomb ceramics largely depends on the material and formation process.Low-grade attapulgite clay(LATP)is a natural,non-metallic mineral preferred for its abundance,low cost,inert property and low sintering temperature.In this study,honeycomb ceramics were prepared by extrusion molding and sintering of LATP and alumina.Carbon powder was used for making pores,methyl cellulose for binding,boric acid for sintering,while glycerol and liquid paraffin for plasticizing and lubrication,respectively.Plasticity of the mud was best when the content of water,binder and plasticizer were 17.5%~20.0%,8.0%~10.0%and 3.0%~4.0%,respectively.This produced excellent extrusion and subsequently,honeycomb ceramic green with no defects.After sintering at 700℃for 3 h,the thickness of the walls and pore density were about 0.34 mm and 169 holes/in^(2),respectively.Open porosity,water absorption,volume density and mechanical strength was 43.43%±0.12%,25.98%±0.1%,(0.9±0.12)g/cm^(3),(16.34±1.23)MPa,respectively.Honeycomb ceramics provided a new way for the application of low-grade attapulgite clay.