Properties and mechanism of red mud in preparation of ultra-lightweight sludge-red mud ceramics

New ultra-lightweight sludge-red mud ceramics (ULS-RMC) were prepared by red mud (RM), clay and dried sewage sludge (DSS). The properties and mechanism of RM in the preparation of ULS-RMC were discussed. The chemical components, thermal properties and mineral phases of RM were determined by energy dispersive X-ray (EDX), differential scanning calorimetry/thermal gravimetric analysis (DSC/TGA) and X-ray diffraction (XRD), respectively. Constant dosage of DSS to clay and different amounts of RM were utilized in the preparation of ULS-RMC. Physical properties test (bulk density, grain density, water absorption and expansion ratio), XRD and scanning electron microscopy (SEM) were employed to characterize the ULS-RMC. The results show that RM exhibits high hydroscopic property and good water-retention property, and bloating property and fluxing property of RM are caused by abound of gaseous components and flux, respectively. The two chemical properties are utilized to discuss the mineral phases and microstructures differences between ULSC and ULS-RMC.     

用于水处理填料的超轻污泥-粉煤灰陶粒的研制

以光大水务(济南)有限公司脱水污泥、粘土为原料,以粉煤灰为添加剂烧制超轻污泥陶粒。通过配比试验和单因素实验,确定了原料添加量和工艺流程;由L18(37)正交试验,得到应用于水处理填料的超轻污泥陶粒的最佳配料比例和最佳烧制流程;最后将所得超轻污泥陶粒进行ICP-AES分析并与商品陶粒进行SEM比较。结果表明,应用于污水处理填料的超轻陶粒吸水率49.46%,堆积密度365.50kg/m3,颗粒密度1047.78kg/m3。经有毒金属浸出测试证明,生产的超轻污泥陶粒有毒重金属浓度在国标要求范围内不会造成二次污染。     

粘土中铁含量对烧制轻质/超轻污泥陶粒的影响

以济南粘土,淄博某砖厂粘土和光大水务(济南)有限公司脱水污泥为原料,不添加任何膨胀剂烧制污泥陶粒。首先对两种粘土进行化学成分分析(EDX),矿物成分分析(XRD)和热重量分析(TGA);之后将粘土和污泥分别进行配比烧制试验,得到不同原料和配比所生产污泥陶粒的物理性质;最后对两种污泥陶粒进行矿物成分分析(XRD)和微观结构分析(SEM)。实验结果表明,济南粘土适合于烧制轻质污泥陶粒;淄博粘土更适合于烧制超轻污泥陶粒。两种粘土化学成分除含铁量外其它成分基本相似但矿物组成有所不同,并且污泥陶粒物理性质的变化随着污泥添加量的增大表现出明显不同的趋势。由于两种粘土中所含铁量的不同,生产的两种陶粒在矿物组成和微观结构上也有所差异。     

轻质/超轻粉煤灰陶粒的研制及陶粒膨胀机理的探讨和应用

以煤灰和粘土为原料制备轻质/超轻粉煤灰陶粒;从原料化学成分的角度推理膨胀过程并推导出可以用于指导实际生产的成分比例.首先对两种原料进行化学成分分析(EDX)和热分析(DSC/TGA);之后对原料进行配比烧制试验,得到不同原料和配比所生产粉煤灰陶粒的物理性质;最后对产品进行微观结构分析(SEM)和矿物组成分析(XRD).实验结果表明,粉煤灰中含有的成气成分和粘土中含有的助熔成分是引起粉煤灰陶粒高温膨胀的主要原因.产生膨胀现象的骨架成分:成气成分:助熔成分≈78.5:4.0:16.5.