摘要
通过＂硫酸-硝酸法＂浸出实验,以砷的浸出浓度为控制指标,选用Fe Cl2为稳定药剂,对矿区砷渣进行药剂稳定化研究。考察Fe/As摩尔比、p H值、粒度、温度及稳定时间对砷浸出浓度的影响,通过研究稳定化前后砷形态的变化,探讨重金属迁移转化规律。结果表明：砷浸出浓度随Fe Cl2投加量增加而降低,当Fe/As摩尔比为1,p H=6.5～7.5时,常温下稳定化1 h后,砷浸出浓度低于2.5 mg/L且基本达到稳定,达到《危险废物填埋污染控制标准》（GB 18598-2001）的入场要求;随反应温度升高,砷浸出浓度略有升高;矿渣稳定化处理后,砷从生物有效性高和毒性大的形态逐渐转化为毒性小、稳定性强的形态,但矿物组成和化学组成不同,砷形态的迁移转化也略有不同。
The stabilization of arsenic waste residue by ferrous chloride（ Fe Cl_2） was studied using the sulfuric acid and nitric acid leaching test with an arsenic leaching concentration as the evaluation index. Effects of parameters such as the molar ratio of iron（ Fe） to arsenic（ As）,the p H value,granularity,temperature,and leaching time on arsenic leaching were investigated. The migration and transformation of heavy metals were discussed by comparing the change in the arsenic form before and after stabilizing. The results showed that the arsenic leaching concentration decreased with the increase in Fe（ II）. When the Fe / As molar ratio was 1 and the p H value was 6. 5 to 7. 5,the arsenic leaching concentration was lower than 2. 5 mg / L and remained stable after leaching for 1 hour at room temperature,meeting the admission requirements of the Standard for Pollution Control on the Security Landfill Site for Hazardous Wastes（ GB 18598-2001）. With the increase in reaction temperature,the arsenic leaching concentration could also slightly increase. After stabilizing the arsenic waste residue,the chemical forms of arsenic were transformed from high biological effectiveness and toxicity to high stability and low toxicity. The migration and transformation of arsenic also differed slightly in varied mineral and chemical compositions.
出处
《环境工程学报》
CAS
CSCD
北大核心
2016年第5期2587-2594,共8页
Chinese Journal of Environmental Engineering
基金
国家自然科学基金资助项目(KKGL201222003)
国家发改委重金属治理项目(2014-GH-03)
关键词
砷
氯化亚铁
稳定化
浸出浓度
重金属形态
arsenic
ferrous chloride
stabilization
leaching concentration
chemical speciation of heavy metals
