(1. 中南大學 冶金與環(huán)境學院，長沙 410083； 2. 中南大學 國家重金屬污染防治工程技術研究中心，長沙 410083)
摘 要: 以模擬含砷廢渣為研究對象，考察機械活化鐵錳穩(wěn)定劑對砷穩(wěn)定效果的影響，確定了最優(yōu)參數(shù)：穩(wěn)定劑種類為Fe-MnO2、穩(wěn)定劑鐵錳摩爾比為0.4:0.6、穩(wěn)定劑用量為8%、球磨時間為1 h。在此最佳條件下，可將砷酸鐵渣中As的浸出毒性由51.45 mg/L降至2.36 mg/L，優(yōu)于國家危險廢物鑒別標準浸出毒性鑒別(GB 5085—2007)。借助X射線衍射、粒度和比表面分析、掃描電鏡等，從球磨過程中鐵錳反應機制、鐵錳復合穩(wěn)定劑腐蝕過程特征以及砷吸附后的鐵錳復合穩(wěn)定劑形貌結構變化等方面，研究鐵錳復合穩(wěn)定劑穩(wěn)定含砷廢渣的機理。在機械力化學和MnO2復合作用下，促進零價鐵粉表面的腐蝕過程，生成了大量高效吸附砷的水鐵礦類物質，實現(xiàn)砷的高效穩(wěn)定。
關鍵字: 含砷廢渣；機械力；穩(wěn)定化；浸出毒性
（1. School of Metallurgy and Environment, Central South University, Changsha 410083, China; 2. Chinese National Engineering Research Center for Control and Treatment of Heavy Metal Pollution, Central South University, Changsha 410083, China）
Abstract:The simulated arsenic bearing solid waste was prepared, and the parameters of stabilizer, mole ratio of Fe and Mn, dosage of stabilizer and ball-milling time for the stabilization effect were optimized. The results show that the extraction toxicity of arsenic decreases from 51.45 mg/L to 2.36 mg/L under the optimized conditions of stabilizer of Fe-MnO2, mole ratio of Fe and Mn of 0.4:0.6, stabilizer dosage of 8% and ball-milling of 1 h, which is lower than that of identification standards for hazardous wastes-identification for extraction toxicity (GB 5085—2007), and the stabilization of arsenic is accomplished. Stabilization mechanism of arsenic bearing solid waste with Fe-MnO2 activated by mechanochemical process was investigated with XRD, SEM-EDS, particle size and specific surface analysis. Because of the synergistic action of mechanochemical process and MnO2, the surface corrosion process of zero-valent iron powder is accelerated and large amount of ferrihydrite material absorbing arsenic effectively forms. Therefore, highly effective stabilization of arsenic is achieved.
Key words: arsenic bearing solid waste; stabilization; mechanochemical process; extraction toxicity
