Abstract: The physicochemical characteristics of corn cob ash obtained at different ashing temperatures(600℃ and 815℃) were studied with X-ray fluorescence spectrometry， X-ray diffraction， scanning electronic microscopy and grading analysis. Muffle furnace burning experiment was adopted to study the influence of ashing temperature and holding time on ash content. The ash composition and morphology of the fly ash samples collected from biomass gasification station were analyzed by using scanning electron microscopy(SEM) and energy disperse X-ray microanalysis(EDX). The results indicated that ashing temperature has a remarkable effect on the ash granularity， content， composition， morphology and phase composition， but has no obvious effects on the fouling and slagging characteristics. The main component elements of ash are potassium and chlorine， which means that the major existent form of potassium is potassium chloride in the pyrolysis and gasification process of corn cob. The morphology of ash surface is in different shapes.Flocculent large particles were formed at the ashing temperature of 600℃， while the ash surface happens to soften and fuse， and the flocculent particles decreases at 815℃. Above research results can provide guidance not only for the purification of gas obtained from the thermal chemical conversion of biomass fuel， but also for the comprehensive utilization of biomass ash.

Key words: corn cob, biomass ash, ashing temperature, pyrolysis and gasification, ash characteristics