Chen How-Ji, Chen Pen-Chou, Peng Ching-Fang, Huang Chien-Wei
Department of Civil Engineering, National Chung-Hsing University, No. 250, Kuo Kuang Road, Taichung 402, Taiwan.
Materials (Basel). 2022 Jun 9;15(12):4097. doi: 10.3390/ma15124097.
Industrial sludge continues to increase in quantity with the development of industry. Therefore, how to effectively treat industrial sludge continues to be an environmental focus around the world. Due to the high calorie content of industrial sludge in Taiwan, most of the sludge is incinerated for simplicity and convenience. However, this incineration causes environmental pollution and cannot effectively reuse the industrial sludge. In this study, we investigated the feasibility of lightweight aggregates produced from water treatment sludge (WTS) mixed with industrial sludge. The industrial sludge was obtained from three industrial zones in Taiwan. The lightweight aggregate materials were prepared by mixing WTS with 7.5%, 15.0%, or 22.5% of industrial sludge as a secondary ingredient. The chemical composition analyses revealed that the ternary phase diagrams of the chemical components were within the range recommended by C.M. Moreover, Riley indicated that the ingredients could expand. The sintering experiments were conducted in two stages. Stage I served to determine the optimal sintering temperature, while Stage II produced lightweight aggregates at the optimal sintering temperatures after 5, 10, or 15 min of preheating. The results indicated that an increase in preheating time increased the particle density of the lightweight aggregates but decreased the water absorption ratio, because increasing preheating time causes more gases to escape, resulting in aggregates that could not produce sufficient gas to support expansion during the sintering stage. The sintering results of the lightweight aggregates showed that their particle density was between 0.5 and 1.4 g/cm, which met the requirements of the specification. Their water absorption rate was below 21%, which was roughly in line with the recommendations of the specification. When the amount of industrial sludge added was less than 22.5%, the lightweight aggregate was sintered successfully, which is suitable for engineering applications. The industrial sludge experienced a loss of between 50% and 70% on ignition, resulting in pores and cracks that were observed on the surfaces of the lightweight aggregate. Based on the energy required to sinter lightweight aggregates, a greater loss on ignition indicates the conversion of more materials into heat energy. Therefore, the use of industrial sludge in lightweight aggregates not only provides ways to reuse industrial sewage waste but also reduces the consumption requirements for sintering lightweight aggregates, thereby achieving energy-saving and carbon-reduction goals.
随着工业的发展，工业污泥的数量持续增加。因此，如何有效处理工业污泥仍然是全球环境关注的焦点。由于台湾工业污泥的热值较高，为简便起见，大部分污泥都被焚烧处理。然而，这种焚烧方式会造成环境污染，且无法有效再利用工业污泥。在本研究中，我们探讨了将水处理污泥（WTS）与工业污泥混合制备轻质骨料的可行性。工业污泥取自台湾的三个工业区。轻质骨料材料是通过将WTS与7.5%、15.0%或22.5%的工业污泥作为次要成分混合制备而成。化学成分分析表明，化学成分的三元相图在C.M.推荐的范围内。此外，莱利指出这些成分可以膨胀。烧结实验分两个阶段进行。第一阶段用于确定最佳烧结温度，而第二阶段在预热5、10或15分钟后，在最佳烧结温度下生产轻质骨料。结果表明，预热时间的增加会提高轻质骨料的颗粒密度，但会降低吸水率，因为预热时间增加会使更多气体逸出，导致骨料在烧结阶段无法产生足够的气体来支持膨胀。轻质骨料的烧结结果表明，其颗粒密度在0.5至1.4 g/cm之间，符合规范要求。其吸水率低于21%，大致符合规范建议。当工业污泥添加量小于22.5%时，轻质骨料烧结成功，适用于工程应用。工业污泥的烧失量在50%至70%之间，导致轻质骨料表面出现孔隙和裂纹。基于烧结轻质骨料所需的能量，较大的烧失量表明更多的材料转化为热能。因此，在轻质骨料中使用工业污泥不仅提供了再利用工业污水废物的途径，还降低了烧结轻质骨料的能耗需求，从而实现节能和碳减排目标。
