摘要
选取内蒙古某矿区在采煤层2种煤样，研究矿区砷的污染迁移规律。采用砷钼蓝分光光度法测定煤样中砷质量比；对试样在不同温度下进行灼烧试验，并在不同pH值下对燃烧后产物（粉煤灰和灰渣）进行淋溶试验，同时对砷进行形态分析。结果表明：该矿区两煤样在450-1 000℃灼烧过程中，砷的释放率分别从39.52%和21.88%升高到73.77%和65.89%；随温度升高，砷的释放率有增大的趋势；粉煤灰与灰渣中砷质量比平均值分别为8.76 mg/kg和6.87 mg/kg，且多以碳酸盐结合态存在；粉煤灰中砷赋存形态及其质量比由大到小为碳酸盐结合态、水溶态、残渣态、可交换态、有机结合态，灰渣中砷的赋存形态及其质量比由大到小为碳酸盐结合态、可交换态、残渣态、有机结合态、水溶态。淋溶试验表明pH值越小，粉煤灰中砷的淋出速度越快；淋溶量350 mL， pH=5与pH=7时粉煤灰中砷的淋出砷量分别占总淋出量的78.14%和76.65%，说明粉煤灰中砷更易析出。
The paper is aimed at a study of the arsenic pollutant migration regularity in the mining area by choosing two kinds of coal samples at different coal layers in some Inner Mongolia coal mine area. In this paper, we have measured the mass ratio of arsenic in the coal samples by using a arsenic molybdenum blue spectrophotometric method. And, then, the coal samples were treated via ignition experiments under different temperatures, and analyzed its arsenic content and forms in combustion products（ash and ash residue）. Moreover, we have also tested the leaching experiments of the coal ash samples under different pH value. The results of our experiments and tests have shown that two coal samples in the calcinations process at temperatures of 450-1 000℃, the arsenic release rate tend to go on from^39.52% and 21.88% to 73.77% and 65.89%, respectively. However, with the increase of temperature, its release rates have been found increased obviously, too. The experiments also show that the average arsenic content in the coal ash and ash residue turn to be about 8.76 mg/kg and 6.87 mg/kg respectively in a carbonate combination pattern. What is more, the arsenic content in the coal ash has been found easy to leach. In addition, the mass ratio of arsenic combined with carbonate in the fly ash proves to be the main speciation content, which is soluble in water, with its residue exchangeable into organic combination state in turn. The trend of the speciation and distribution of arsenic residue in the ash can be stated as follows： The arsenic combined with the carbonate in the residue serves the main speciation, with the exchangeable, residual state, organic combination state and soluble remaining in water. Further leaching experiment indicates that the lower the pH, the faster the arsenic tends to leach. The release rates of the arsenic content （leaching of arsenic content to the total leaching amount） prove to be different under different pH values. When pH=5 and pH=7, the release rates of arsenic can increase to 78.14% and 76.65%, respectively, with the arsenic content easily released out from the coal ashes.
出处
《安全与环境学报》
CAS
CSCD
北大核心
2014年第3期255-258,共4页
Journal of Safety and Environment
基金
国家自然科学基金项目(51174266)
关键词
采矿环境工程
砷
粉煤灰
燃烧试验
淋溶试验
迁移规律
mining environmental engineering
As
fly coal ashes
buming experiment
leaching experiment
migration regularity
