Department of College of Safety and Environmental Engineering, Shandong University of Science and Technology, 579 Qianwangang Road, Huangdao District, Qingdao, 266590, Shandong Province, China.
Environ Sci Pollut Res Int. 2023 Apr;30(19):56774-56785. doi: 10.1007/s11356-023-26444-0. Epub 2023 Mar 16.
In order to achieve sustainable development and control environmental pollution, this paper proposes sewage sludge (SS) as an auxiliary cementitious material, which is mixed with ordinary Portland cement (OPC), fly ash (FA), and gangue to produce sewage sludge cemented paste backfill (SS-CPB) material. The fluidity and mechanical properties of backfill materials with different SS contents and the heavy metal leaching mechanism of SS-CPB are investigated. The results reveal that (1) with the increase of SS content from 10 to 30%, the slump of fresh SS-CPB mortar decreased from 21.7 to 18.2 cm, the initial setting time decreased from 2.83 to 0.58 h, and the final setting time decreased from 4.92 to 0.83 h. (2) Compared with the control group, the 3-day unconfined compressive strength (UCS) of the SS-CPB mixed with 10% SS increased by 49.5%, and the UCS decreased slightly in the later stage, but it also met the actual needs of coal mines. (3) Scanning electron microscopy (SEM), X-ray diffraction (XRD), and Fourier transform infrared (FTIR) spectroscopy were used to study the SS-CPB samples. It was found that the free Al in SS promoted the formation of ettringite (AFt), provided part of the early UCS, and accelerated the setting time. (4) The leaching rule of heavy metal ions was analyzed in combination with leaching kinetics, and the change of heavy metal ion mass concentration in the rising stage was in line with the contraction core model controlled by diffusion.
为了实现可持续发展和控制环境污染，本文提出将污水污泥（SS）作为辅助胶凝材料，与普通波特兰水泥（OPC）、粉煤灰（FA）和矸石混合，制成污水污泥胶结膏体回填材料（SS-CPB）。研究了不同 SS 含量的回填材料的流动性和力学性能以及 SS-CPB 的重金属浸出机理。结果表明：（1）随着 SS 含量从 10%增加到 30%，新鲜 SS-CPB 砂浆的坍落度从 21.7cm 降低到 18.2cm，初凝时间从 2.83h 降低到 0.58h，终凝时间从 4.92h 降低到 0.83h。（2）与对照组相比，掺 10%SS 的 SS-CPB 的 3 天无侧限抗压强度（UCS）提高了 49.5%，后期略有降低，但仍能满足煤矿的实际需要。（3）通过扫描电子显微镜（SEM）、X 射线衍射（XRD）和傅里叶变换红外（FTIR）光谱对 SS-CPB 样品进行了研究。结果表明，SS 中的自由 Al 促进了钙矾石（AFt）的形成，提供了部分早期 UCS，并加速了凝结时间。（4）结合浸出动力学分析了重金属离子的浸出规律，重金属离子质量浓度在上升阶段的变化符合扩散控制的收缩核模型。
