新型脱汞技术下粉煤灰中的含汞量及其堆存时汞的浸出特征研究

Mercury concentration and its leaching characteristics of coal fly ash from a generator with different mercury removal techniques

添加溴化钙、喷射活性炭或溴化活性炭等脱汞技术会将更多的汞转移到粉煤灰中，增加了粉煤灰在堆存过程中的环境风险。主要讨论了添加溴化钙、喷射活性炭或溴化活性炭等不同新型脱汞技术产生的粉煤灰（分别简称为BCFA、CFA、BFA）的理化特性，并模拟了极端酸性降雨条件下粉煤灰在堆存过程中汞的释放规律。结果表明，BCFA、CFA、BFA与常规协同控制脱汞下产生的粉煤灰（简称RFA，作为对照）的矿物组成与颗粒粒径无显著差异。添加不同量的溴化钙后BCFA中含汞量变化不明显，与RFA中含汞量差异也不明显；BFA和CFA中含汞量随喷射速率提高而逐渐增加，且明显高于RFA中含汞量。RFA、BCFA、CFA、BFA的浸出液含汞量在13．7～42．6ng／L，均低于《地表水环境质量标准》（GB3838--2002）中I类标准，因此不同新型脱汞技术产生的粉煤灰在堆存初期，即使在极端酸性降雨的条件下，也不会对周围水环境造成汞污染。

New specific mercury removal techniques such as adding calcium bromide,injecting activated carbon or brominated activated carbon could capture more mercury into the fly ash, consequently increase the environment risk during the fly ash stockpiling process. The fly ash produced in different mercury removal techniques of adding calcium bromide,injecting activated carbon and brominated activated carbon, respectively named BCFA, CFA, BFA for short,were collected to investigate their physicochemical property. The mercury leaching character of different fly ash was investigated under the simulated extreme acid rain. The study found that the mineral composition and particle size had no significant differences among coal fly ash of regular mercury control technique （RFA） ,BCFA,CFA and BFA. The calcium bromide dosage had no significant effect on the mercury concentration in BCFA. With increasing the acti- vated carbon or brominated activated carbon injection quantity, the mercury concentration in CFA, BFA were gradually increased,they were much higher than that of RFA, while the difference between BCFA and RFA was not obvious. The mercury concentrations in leaching liquid of RFA, BCFA,CFA and BFA ranged from 13.7-42.6 ng/L, which were lower than the first classic surface water quality standard （GB 3838-2002）. Overall,the mercury in fly ash would not pollute the environment during initial stockpile and landfill, even under the extreme acid rain condition.