为考察疏浚污染底泥与垃圾焚烧灰混合烧制陶粒的可行性,根据陶粒的桶压强度和吸水率等性能确定了原料配比,考察了焙烧温度对陶粒微观形貌、重金属残留率、浸出比例及浓度的影响。结果表明:随着原料中焚烧飞灰比例增加,陶粒的筒压强度降低、吸水率升高,污染底泥与焚烧飞灰的合适配比为4:1,焙烧温度在1 100~1 150℃时陶粒内部微孔聚集,在1 200℃时陶粒出现大量玻璃相,陶粒焙烧温度宜控制在1 150℃左右;在最佳条件下烧制陶粒的筒压强度为4.56 MPa、吸水率为15.3%,堆积密度为735 kg/m3;陶粒中重金属残留率除了Zn外均随焙烧温度升高而下降,重金属浸出比例随着烧结温度的增加而降低,同时渗沥浓度都有一定程度降低,浸出浓度均达到相关标准。烧制的陶粒有作为铺路、堤坝建材骨料使用的潜力。
The sintering experiments of pollution sediment and incinerator fly ash were performed in order to investigate the feasibility of their sintering ceramsite. Effects of raw materials proportion and roasting temperature on the product properties including the cylinder compressive strength and water absorption ratio, microstructure, residual fraction of heavy metals, the leaching ratio and concentration of heavy metals were investigated. Experimental results showed that cylinder compressive strength reduced and water absorption rate increased with the proportion increase of the incineration fly ash in the raw materials. The appropriate proportioning of pollution sediment and incinerator fly ash was at 4 : 1. Minuteness pore aggregation formed in the ceramsite at 1 100-1 150℃ of the roasting temperature and large glass phase occurred at 1 200℃. Roasting temperature should be controlled at 1 150℃. At the optimum heat treatment condition, the ceramics had the compressive strength of 4.56 MPa, water absorption of 15.3% and the bulk density of 735 kg/m^3. The residual fraction of heavy metals reduced except Zn with the increase of the roasting temperature. The leaching rate of heavy metal decreased with the increase of sintering temperature, at the same time the leaching concentration decreased to a certain degree. The leaching concentration of heavy metals in the ceramics is below environmentally regulatory thresholds, which make the lightweight aggregates non-hazardous for construction use as paving, dam building.