Fe2O3对污泥与底泥制备轻质陶粒性能的影响

Effect of Fe2O3 on the characteristics of lightweight aggregate made from sewage sludge and river sediment

摘要:

为研究在以污水污泥和河道底泥为主要原料制取轻质陶粒过程中,Fe₂O₃质量分数对陶粒性能的影响,对陶粒的物理性能、表面形态、抗压强度和晶体构成进行研究,结果表明,Fe₂O₃质量分数在3.5％～7％时,可取得松散容重和表观密度较高、吸水率比较小、抗压强度较高的陶粒．扫描电子显微镜(SEM)分析表明,随着Fe₂O₃质量分数的增加,陶粒表面玻璃化效果明显．在Fe₂O₃质量分数为5％时,可得到致密性较好、表面微孔分布均匀的陶粒．Fe₂O₃质量分数在3.5％～7％时,陶粒的抗压性能良好(14 MPa以上)．X射线衍射分析(XRD)表明,陶粒中主要晶体为石英、钠钙长石、蓝晶石和赤铁矿,内部以稳定的硅酸盐晶体为主．随着Fe₂O₃质量分数的增加,更多的Fe₂O₃可以在高温条件下转换为晶体结构的赤铁矿．在利用污水污泥与河道底泥制取轻质陶粒的过程中,控制Fe₂O₃质量分数在3.5％～7％较合适．

Abstract:

The aim of this article is to investigate the effect of Fe₂O₃ contents on the characteristics of lightweight aggregate that is made from sewage sludge and river sediment. The physical characteristics, compressive strength, morphological structures and crystalline phases of lightweight aggregate were studied, and the results showed that the lightweight aggregate with higher bulk density, higher apparent density, and lower water absorption could be obtained at Fe₂O₃ contents between 3.5％-7％. The SEM analysis points out that the surface of lightweight aggregate exhibits more vitrification phenomenon as the Fe₂O₃ contents increase, the dense surface of lightweight aggregate with evenly distributed micro porous can be found at Fe₂O₃ contents=5％. The lightweight aggregate with stronger compressive strength (more than 14 MPa) can be obtained when Fe₂O₃ contents are between 3.5％-7％. The XRD analysis implies that the main crystal phase in the lightweight aggregate are quartz, albite-anorthite, kyanite and hematite, and the silicate crystals with stable structure are the main crystal in the internal of lightweight aggregate. As the Fe₂O₃ contents increase, more Fe₂O₃ will transform to hematite with crystal structure. The results indicate that the Fe₂O₃ contents between 3.5％-7％ are appropriate in the process of making lightweight aggregate from sewage sludge and river sediment.