Study on Repairing Mechanism of Wind Quenching Slag Powder in Heavy Metal Contaminated Soil by XRD and SEM
ZHANG Hao1，YU Xian-kun2，XU Xiu-ping2*，YANG Gang3
1. School of Civil Engineering and Architecture, Anhui University of Technology, Ma’anshan 243032, China
2. Sinosteel Ma’anshan General Institute of Mining Research Co., Ltd., Ma’anshan 243000, China
3. MCC Baosteel Technology Services Co., Ltd., Shanghai 201999, China
Abstract：Steel slag tailings are the main solid waste in metallurgical industry, with the production of 15%~20% of crude steel. The utilization ratio is quite low and only reaches 10% of steel slag tailings production due to limited technology. Meanwhile, steel slag tailings are disposed of in direct stacking and landfill in general since the management system is not perfect, which pollutes land source, underground water source and air quality. In the face of the above problems, the development of an inexpensive curing agent is used for repairing of heavy metal contaminated soil has become not only one of the main methods to the sustainable development of metallurgical solid waste, but also one of the main methods to achieve the greatly reduce the production cost of heavy metal contaminated soil remediation. Wind quenching slag powder was used as curing agent to repair the heavy metal contaminated soil including Cd, Cu, Pb, Ni and Zn in this paper. This study investigates the wind quenching slag grinding time, wind quenching slag powder content and curing time on the repairing effect of heavy metal contaminated soil. The particle size distribution of wind quenching slag powder was characterized by LPSA, the pore structure of wind quenching slag powder was characterized by BET, the microstructure of mixture of wind quenching slag powder-heavy metal contaminated soil was characterized by SEM, mineral composition of wind quenching slag powder was characterized by XRD in order to the mechanism of wind quenching slag powder repairing heavy metal contaminated soil was analyzed. The results indicate that the properties of wind quenching slag are safe and there is no pollution to the ecological environment, which can be used as a curing technology for remediation of heavy metal contaminated soil. The solidification effect of wind quenching slag powder (the wind quenching slag grinding time, wind quenching slag powder content and curing time are 100 min, 20% and 14 d, respectively) on Cd, Cu, Pb, Ni and Zn of heavy metal contaminated soil was more than 91%. With the extension of wind quenching slag grinding time, the particle size of wind quenching slag powder is decreased and its particle size distribution tends to be uniform. The damage of porous structure and the increase of the specific surface area of wind quenching slag are beneficial to improve the effect of wind quenching slag powder on heavy metal contaminated soil restoration. With the increase of wind quenching slag powder content, the amount of hydrated gel (C—S—H) formed by wind quenching slag powder is increased, which is beneficial to improve the effect of wind quenching slag powder covering heavy metal contaminated soil, so as to achieve the purpose of curing Cd, Cu, Pb, Ni and Zn in heavy metal contaminated soil. Wind quenching slag powder can selectively be curing Cu, Cd, Ni, Zn and Pb in heavy metal contaminated soil. Under different curing times, heavy metals exist in the form of Cd2SiO4, Cu(OH)2·2H2O, PbCO3, 3Ni(OH)2·2H2O, Ni2SiO4, Zn(OH)2 and Zn2SiO4, respectively.
Key words：Wind quenching slag powder; Heavy metal contaminated soil; Repairing effect; Curing agent; Mechanism
张 浩，于先坤，徐修平，杨 刚. 基于XRD与SEM研究风淬渣微粉用于重金属污染土壤的修复机理[J]. 光谱学与光谱分析, 2021, 41(01): 278-284.
ZHANG Hao，YU Xian-kun，XU Xiu-ping，YANG Gang. Study on Repairing Mechanism of Wind Quenching Slag Powder in Heavy Metal Contaminated Soil by XRD and SEM. SPECTROSCOPY AND SPECTRAL ANALYSIS, 2021, 41(01): 278-284.
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