关于MSWI飞灰凝固沉积物的半动态水和微观结构特征的研究
Xinmiao Shi1, Haoqing Xu1, Nan Zhang1
1Jiangsu Province Engineering Research Center of Geoenvironmental Disaster Prevention and Remediation of School of Architecture and Civil Engineering, Jiangsu University of Science and Technology, Zhenjiang, 212100, China.
Journal of environmental management
|November 4, 2023
概括
城市固体废物焚烧的飞灰和沉积物被固化,以创建垃圾填埋场的覆盖材料. 这种材料表现出良好的强度和降低重金属漏,特别是在酸性条件下,使其成为一个可行的资源利用选项.
科学领域:
- 地质技术工程 地质技术工程
- 环境科学 环境科学
- 材料科学 材料科学 材料科学
背景情况:
- 城市固体废物焚烧 (MSWI) 飞灰提出了一个处置挑战.
- 对MSWI飞灰和沉积物的资源利用对于可持续的废物管理至关重要.
- 固化/稳定 (S/S) 是处理废物的一种常见方法.
研究的目的:
- 为了研究MSWI飞灰固化沉积物的强度和浸出特性.
- 为了评估材料的适用性作为填埋场中间覆盖.
- 评估不同pH值的盐酸攻击对固化材料的影响.
主要方法:
- 不受限制的压力强度 (UCS) 测试.
- 半动态浸出试验. 半动态浸出试验. 半动态浸出试验.
- 进行X射线衍射 (XRD),里埃变换红外光谱 (FTIR) 和热重力测量分析 (TGA).
主要成果:
- 随着固化年龄和水泥含量增加,UCS在7天内超过50kPa,而75-80%的飞灰被替换.
- 强度主要来自酸水合物 (C-S-H) 和碳酸盐.
- 在强酸性 (pH2) 条件下,重金属 (Zn,Cu) 出明显高于在弱酸性 (pH4) 或中性 (pH7) 条件下.
- 凝固材料表现出优异的抗酸缓冲能力.
- 观察到的扩散系数 (D^obs) 是<10^-9 m2/s,表明移动性较低.
结论:
- MSWI飞灰固化沉积物显示出有前途的强度发展.
- 该材料有效地固定重金属,特别是在酸性条件下.
- 凝固的材料适合用作填埋场中间覆盖,促进资源利用.
相关概念视频
01:21Pozzolans
120
Pozzolans are siliceous or aluminous materials blended with Portland cement. They interact with the calcium hydroxide produced during the hydration of Portland cement and contribute to improved strength and durability of concrete. The pozzolanic activity, a measure of a pozzolan's effectiveness, is typically assessed using the strength activity index, as defined in ASTM C 618-93, which calculates the ratio of the compressive strength of cement mixtures with and without pozzolan.
Fly ash is...
Fly ash is...
120
01:15Fineness of Cement
133
The fineness of cement directly influences the rate of hydration, as the hydration begins at the surface of the cement particles. In addition to hydration, the fineness of cement is vital for various properties of concrete including workability, gypsum requirement, and long-term behavior. The fineness of cement is represented in terms of the specific surface of cement which is typically measured in square meters per kilogram, with several methods available for this determination.
Direct...
Direct...
133
01:25Deleterious Substances in Aggregate
172
Deleterious substances in aggregates can be detrimental to the quality and durability of concrete. These substances include organic impurities like loam, which interfere with cement hydration and are usually present in the sand. These prevent a good bond between aggregate and cement paste. Organic impurities can be detected using the colorimetric test, where the darkness of a solution after agitation indicates the level of organic content.
Another type of impurity is clay and fine material that...
Another type of impurity is clay and fine material that...
172
01:16Segregation in Fresh Concrete
142
Segregation in fresh concrete is a phenomenon where the components of the concrete mix separate, leading to uneven distribution and compromised structural integrity. This separation typically occurs when concrete is subjected to excessive horizontal movement within forms, or when it is dropped from considerable heights or forced through narrow, winding paths. As a result, heavier coarse aggregate particles settle at the bottom, while lighter, finer materials such as cement and water rise to the...
142
01:08Sample Preparation for Analysis: Advanced Techniques
365
Accurate analysis of complex samples often requires advanced preparation techniques to achieve reliable and reproducible results. Samples containing inorganic or organic materials can be challenging to dissolve or decompose effectively. Standard sample preparation methods include acid digestion, fusion, dry ashing, and wet digestion.
Acid digestion with strong acids is commonly used to dissolve inorganic materials that are insoluble (do not dissolve) in water. This method can be useful for...
Acid digestion with strong acids is commonly used to dissolve inorganic materials that are insoluble (do not dissolve) in water. This method can be useful for...
365