Improvement of alkali resistance of glass fiber from basalt and lignite bottom ash mixture by addition of ZrO2 content

Abstract

In this work, silica-rich basalt from Chai Badan, Lopburi province was melted with lignite bottom ash from Mae Moh power plant as fluxing agent. To improving the alkali resistance, the series of glass batch samples were varied amount of ZrO2 content by 0 wt% to 10 wt%. The batches were melted at 1500℃ and drawn into a fiber. The results found that the alkali resistance of basalt fiber sample increase with increasing of ZrO2 content up to 7.5 wt% ZrO2. The sample with 7.5 wt% ZrO2 performed the highest alkali resistance, while the sample with 5 wt% ZrO2 obtained the highest tensile strength. The alkali resistance of these basalt fibers was given by a formation of stable hydrated zirconium-rich layer retarding the preinitiation of OH- inside the surface. The corrosion of shell thickness of higher ZrO2 content fiber increased at a slower rate according to its higher alkali resistance. The excess addition of ZrO2 content up to 10 wt% in glass composition resulted in an increase of brittleness and weakness of the fiber caused by a defect from undissolved ZrO2 crystal in a fiber and its solubility limit.