卢锐,李磊,孔尧辉,等. 脱硫废水替代工艺水制备蒸压加气混凝土实验研究[J]. 煤炭学报,2024,49(S1):1−11. doi: 10.13225/j.cnki.jccs.2023.0268
引用本文: 卢锐,李磊,孔尧辉,等. 脱硫废水替代工艺水制备蒸压加气混凝土实验研究[J]. 煤炭学报,2024,49(S1):1−11. doi: 10.13225/j.cnki.jccs.2023.0268
LU Rui,LI Lei,KONG Yaohui,et al. Experimental study on preparation of autoclaved aerated concrete by replacing process water with desulphurization wastewater[J]. Journal of China Coal Society,2024,49(S1):1−11. doi: 10.13225/j.cnki.jccs.2023.0268
Citation: LU Rui,LI Lei,KONG Yaohui,et al. Experimental study on preparation of autoclaved aerated concrete by replacing process water with desulphurization wastewater[J]. Journal of China Coal Society,2024,49(S1):1−11. doi: 10.13225/j.cnki.jccs.2023.0268

脱硫废水替代工艺水制备蒸压加气混凝土实验研究

Experimental study on preparation of autoclaved aerated concrete by replacing process water with desulphurization wastewater

  • 摘要: “水污染防治行动计划”的施行,标志着国家对水环境保护提出了更高的要求,实现脱硫废水零排放已成为电力环保的大趋势。脱硫废水水质特征复杂,易受工况和煤种的影响,处理难度较大。而传统的蒸发和结晶工艺存在成本高、二次污染严重的问题。基于脱硫废水水质分析,提出将脱硫废水应用于蒸压加气混凝土砌块的制备,以此来实现脱硫废水的资源化替代和盐分的固定。制备的加气混凝土砌块可作为高价值建筑材料外售,为电厂带来环境效益的同时创造经济效益。实验以蒸压加气混凝土砌块的抗压强度和干密度作为评价指标,探究脱硫废水掺量、钙硅比、水泥石灰比以及脱硫石膏掺量等因素对混凝土建材性能的影响规律。结果表明,随着脱硫废水、脱硫石膏掺量增加,制品抗压强度降低;最佳钙硅比和水泥石灰比分别为27∶70和16∶11。通过4因素3水平的正交实验,得出优选的水料比为0.75,最佳配方为粉煤灰∶水泥∶石灰∶废水∶中水=73∶16∶11∶30∶45,极差分析显示各影响因素对固化体比强度影响排序为:水料比>脱硫废水掺量>钙硅比>水泥石灰比。通过SEM、XRD和FTIR对水化产物进行分析,结果表明蒸压反应前主要产物为钙矾石与Ca(OH)2,蒸压反应后的产物为托贝莫来石、水石榴子石和碳酸钙。对砌块成品进行重金属浸出实验,5种脱硫废水中超标的重金属离子均符合规定。利用脱硫废水可制备强度等级为A5.0级、干密度等级为B06级且对环境无危害的脱硫废水蒸压加气混凝土,为脱硫废水的资源化利用提供了新路径。

     

    Abstract: The implementation of the "Water Pollution Prevention Action Plan 10" marks a higher demand for water environmental protection in China, and achieving a zero discharge of desulfurization wastewater has become a major trend in power plant environmental protection. Desulfurization wastewater has complex characteristics and is easily affected by operating conditions and coal types, making its treatment more difficult. Traditional evaporation and crystallization processes have high costs and serious problems with secondary pollution. Based on the analysis of desulfurization wastewater quality, this study proposes that the desulfurization wastewater is used to prepare autoclaved aerated concrete blocks, thus achieving the resource utilization of desulfurization wastewater and fixed salt. The prepared aerated concrete blocks can be sold as high-value building materials, bringing environmental benefits to power plants while creating economic benefits. The compressive strength and dry density of the aerated concrete blocks are used as evaluation indicators to explore the impact of factors such as desulfurization wastewater content, calcium-silicate ratio, cement-lime ratio, and desulfurized gypsum content on the performance of the concrete building materials. The results show that with the increase of desulfurization wastewater and desulfurized gypsum content, the product compressive strength decreases. The optimal calcium-silicate ratio and cement-lime ratio are 27:70 and 16:11, respectively. Through a four-factor three-level orthogonal test, the optimized water ratio is 0.75, and the optimal formula is fly ash: cement: lime: wastewater: midstream water = 73:16:11:30:45. The difference analysis shows that the influence order of each factor on solidified specific strength is: water ratio > wastewater content > calcium-silicate ratio > cement-lime ratio. Through the SEM, XRD, and FTIR analysis of hydrated products, it is found that the main products before steam compression are calcareous albite and Ca(OH)2, and the products after steam compression are tobermorite, hydrogarnet, and calcium carbonate. The heavy metal leaching tests on block products show that all exceedances of heavy metals in five types of desulfurization wastewater meet the regulations. It is possible to prepare the autoclaved aerated concrete blocks with strength grade A5.0 and dry density grade B06 without harm to the environment from desulfurization wastewater, which provides a new path for the resource utilization of desulfurization wastewater.

     

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