Effect of borax on sintering kinetics, microstructure and mechanical properties of porous glass-ceramics from coal fly ash by direct overfiring

The direct sintering process of coal fly ash for the preparation of glass-ceramics is the liquid-phase sintering process from non-densification to densification. When the temperature exceeds the densification temperature point, the porosity of glass-ceramics on the contrary increases and the pore diameter increases. This provides a basis for direct overfiring of porous glass-ceramics. Adding borax to coal fly ash can reduce the temperature of liquid phase formation, reducing the preparing temperature of porous glass-ceramics by overfiring, achieving the purpose of energy saving. The effects of borax on the structure, properties and sintering kinetics of porous glass-ceramics prepared from coal fly ash by overfiring were investigated. It is found that the introduction of B-O bond can change the network structure of non-crystalline vitreous in coal fly ash, reduce its melting temperature, promote the formation of liquid phase, and thus increase the porosity of porous glass-ceramics. When ...以粉煤灰为原料制备微晶玻璃的直接烧结工艺，属于从不致密化到致密化的液相烧结过程。当温度超过致密化温度阈值后，微晶玻璃的孔隙率反而升高，孔径也随之增大，这为多孔微晶玻璃的直接过烧工艺提供了理论依据。在粉煤灰中添加硼砂，可降低液相形成温度，从而通过过烧工艺降低多孔微晶玻璃的制备温度，达到节能目的。本研究探究了硼砂对过烧法制备粉煤灰基多孔微晶玻璃的结构、性能及烧结动力学的影响。研究发现，B-O键的引入可改变粉煤灰中非晶态玻璃相的网络结构，降低其熔融温度，促进液相形成，进而提升多孔微晶玻璃的孔隙率。当……时