关键词: 粉煤灰, 发泡陶瓷, 氟锆酸钾, 抗压强度, 显微结构

Abstract: In order to achieve the widespread application of high additions of fly ash in low-cost and high-performance foamed ceramics,foamed ceramics were prepared by high temperature calcination,using fly ash,talcum,feldspar and silicon carbide as raw materials,and adding different additions (0,2%,5%,and 7%,by mass) of potassium fluorozirconate (K₂ZrF₆).The effect of the K₂ZrF₆ addition on the phase composition,microstructure and properties of the foamed ceramics was studied.The results show that:with the addition of K₂ZrF₆ increasing from 2% to 7%,the characteristic peaks of zircon and spinel gradually increase,while those of mullite gradually weaken.Meantime,the bulk density and compressive strength decrease,the thermal conductivity shows a trend of first decreasing and then increasing.At the same time,the addition of K₂ZrF₆ improves the pore size,uniformity and roundness.However,when the addition of K₂ZrF₆ reaches 7%,the pore size further increases,the roundness decreases and the pore structure deteriorates.In general,compared with the sample without K₂ZrF₆,the compressive strength of the samples containing K₂ZrF₆ significantly increases,and the bulk density as well as thermal conductivity obviously reduces.When the addition of K₂ZrF₆ is 5%,the sample has the best comprehensive performance.

Key words: fly ash, foamed ceramics, potassium hexafluorozirconate, compressive strength, microstructure