成灰温度对污泥灰矿物质演变及熔融特性的影响研究

采用STA、SEM、XRD等谱学表征技术对不同成灰温度下的污泥灰样进行理化特性分析。研究表明,低温灰样仍含有残余未燃尽物而呈黑棕色,矿物质成分变以方解石、石英以及焦磷酸盐为主,随着成灰温度升高,灰样中的未燃尽物逐渐燃烧分解而逐渐变为铁红色,并形成较多晶枝结构,直至熔融,同时矿物质成分变化显著,主要以中长石类、硬石膏、赤铁矿以及磷酸正盐为主。同步热分析实验表明,随着受热温度升高,不同成灰温度下的灰样均出现了吸附水、结晶水析出,污泥灰残余有机物燃烧分解,白云石、方解石和白云母分解,以及随后的硬石膏分解等失重阶段,而且成灰温度越低,终止失重质量越大。由于低温灰样保留了较多的污泥原有特征,因此吸热量大于高温灰样。

Effect of ashing temperature on the mineralogical composition evolution and thermogravimetric characteristics of sewage sludge ash

Physical and chemical properties of sludge ash samples at different ashing temperatures are studied by spectroscopy characterization technologies such as STA, SEM and XRD. The results show that ash samples at low temperature are black-brown due to remaining unburned materials, and the main mineral compositions are calcite, quartz and pyrophosphate. As the ashing temperatures increases, the unburned materials are combusted and decomposed, and then turned to iron-red with more dendritic structures. The mineralogical compositions change significantly with feldspar, anhydrite, hematite and orthophosphate as the main components. STA experiments imply that as heating temperature increases, ash samples at different ashing temperatures undergo the loss of absorption water and crystal water, combustion of residual organic materials, decomposition of dolomite, calcium and muscovite, and further decomposition of anhydrite. The lower ashing temperatures of the ash samples are, the more weights lose. The ash samples with lower ash temperature remains more original properties of sewage sludge, thus the heat absorption is greater than that of high temperature samples.