Bankowski P, Zou L, Hodges R
School of Engineering and Technology, Deakin University, Geelong, Victoria 3217, Australia.
J Hazard Mater. 2004 Oct 18;114(1-3):59-67. doi: 10.1016/j.jhazmat.2004.06.034.
Current regulations classify fly ash as a prescribed waste and prohibit its disposal in regular landfill. Treatment of the fly ash can reduce the leach rate of metals, and allow it to be disposed in less prescribed landfill. A geopolymer matrix was investigated as a potential stabilisation method for brown coal fly ash. Precipitator fly ash was obtained from electrostatic precipitators and leached fly ash was collected from ash disposal ponds, and leaching tests were conducted on both types of geopolymer stabilised fly ashes. The ratio of fly ash to geopolymer was varied to determine the effects of different compositions on leaching rates. Fourteen metals and heavy metals were targeted during the leaching tests and the results indicate that a geopolymer is effective at reducing the leach rates of many metals from the fly ash, such as calcium, arsenic, selenium, strontium and barium. The major element leachate concentrations obtained from leached fly ash were in general lower than that of precipitator fly ash. Conversely, heavy metal leachate concentrations were lower in precipitator fly ash than leached pond fly ash. The maximum addition of fly ash to this geopolymer was found to be 60wt% for fly ash obtained from the electrostatic precipitators and 70wt% for fly ash obtained from ash disposal ponds. The formation of geopolymer in the presence of fly ash was studied using 29Si MAS-NMR and showed that a geopolymer matrix was formed. X-ray diffraction (XRD) analysis and scanning electron microscopy (SEM) imaging showed the interaction of the fly ash with the geopolymer, which was related to the leachate data and also the maximum percentage fly ash addition.
当前法规将粉煤灰归类为指定废物，并禁止将其处置在常规垃圾填埋场。对粉煤灰进行处理可以降低金属的浸出率，并使其能够在规定较宽松的垃圾填埋场进行处置。研究了用地质聚合物基质作为褐煤粉煤灰的一种潜在稳定化方法。从静电除尘器中获取沉淀粉煤灰，从灰渣处置池中收集浸出粉煤灰，并对这两种类型的地质聚合物稳定化粉煤灰进行浸出试验。改变粉煤灰与地质聚合物的比例，以确定不同组成对浸出率的影响。浸出试验针对14种金属和重金属，结果表明地质聚合物能有效降低粉煤灰中多种金属的浸出率，如钙、砷、硒、锶和钡。浸出粉煤灰获得的主要元素浸出液浓度总体低于沉淀粉煤灰。相反，沉淀粉煤灰中的重金属浸出液浓度低于浸出池粉煤灰。对于从静电除尘器获得的粉煤灰，发现这种地质聚合物中粉煤灰的最大添加量为60wt%，对于从灰渣处置池获得的粉煤灰，最大添加量为70wt%。利用29Si MAS-NMR研究了在粉煤灰存在下地质聚合物的形成，结果表明形成了地质聚合物基质。X射线衍射（XRD）分析和扫描电子显微镜（SEM）成像显示了粉煤灰与地质聚合物的相互作用，这与浸出液数据以及粉煤灰的最大添加百分比有关。
