底泥陶粒的制备及其性能研究

为实现河道底泥的无害化和资源化利用，以河道底泥为主要原料，膨润土、淀粉、石灰石为辅料，采用高温烧结法制备底泥陶粒。通过单因素试验探讨膨润土、淀粉、石灰石用量对陶粒性能的影响，采用正交试验优化陶粒的原料配比和焙烧工艺，并通过XRD、SEM分析陶粒的物相组成、微观结构。结果表明，适宜的原料配比为：底泥、膨润土、淀粉及石灰石的质量比70∶30∶10∶13，最佳的工艺条件为预热温度400 ℃、预热时间10 min、焙烧温度1 000 ℃、焙烧时间15 min。在该条件下制得的陶粒堆积密度为725.52 kg/m³、表观密度为1 326 kg/m³、吸水率为25.00%、抗压强度为3.32 MPa、除磷率为98.69%。底泥陶粒表面粗糙，孔隙结构丰富，吸水渗透性好，除磷率较高，是一种可以应用于水处理的陶粒滤料。

Preparation of Sediment Ceramsite and Its Properties Research

In order to realize the harmless and resource utilization of river sediment,the sediment ceramsite was prepared by high temperature sintering using river sediment as the main raw material and bentonite,starch and limestone as auxiliary materials.Through single factor experiment,the influence of bentonite,starch and limestone dosage on the properties of ceramsite was discussed,and the raw material ratio and roasting process of ceramsite were optimized by orthogonal test.At the same time,the phase composition and microstructure of the ceramsite were studied by XRD and SEM analysis.The results showed that the optimal ratio of raw materials was the mass ratio of sediment,bentonite,starch and limestone of 70∶30∶10∶13,and the process conditions were preheating temperature of 400 ℃,preheating time of 10 min,roasting temperature of 1 000 ℃,roasting time of 15 min.Under the conditions,the bulk density of ceramsite was 725.52 kg/m³,the apparent density was 1 326 kg/m³,the water absorption rate was 25.00%,the compressive strength was 3.32 MPa,and the phosphorus removal rate was 98.69%.Sediment ceramsite has rough surface,rich pore structure,good water absorption and permeability,and high phosphorus removal rate,which could be used as ceramsite filter material in water treatment.