渔塘坝富硒碳质岩石中硒淋滤实验的初步研究

PRELIMINARY LEACHING EXPERIMENTS ON SELENIUM RELEASE FROM Se-RICH CARBONACEOUS ROCKS AT YUTANGBA

渔塘坝是中国较为典型的高硒地区之一。从该区选取了4个典型的富硒碳质岩样品,并在常温条件下进行了淋滤实验研究(pH=2.0,4.0和6.5)。初步结果表明:随着液固比的增大和淋滤时间的延长,淋滤液中硒含量变化的总体呈降低趋势。不同岩类间硒的淋失量有所差别,但岩石总量硒并不是影响硒淋失的主要因素。淋滤原液的不同pH值对岩石硒的淋失有显著影响,其淋失量的排列顺序是pH=2.0>pH=6.5>pH=4.0。岩石中碳酸盐与黄铁矿含量之比同淋滤液pH的变化有关,并且极可能是影响岩石风化初始阶段硒淋失的重要因素之一。

Yutangba is a high-so area in China and is also the only site in the world where a sudden occurrence of Se poisoning took place, The leaching experiments were conducted at ambient temperature and different pH values （2.0, 4.0 and 6.5） on four So-rich carbonaceous rock samples collected from Yutangba. The results showed that the selenium concentrations of leachate tend to decrease with increasing ratio of leachate volume to solid mass and longer leaching time. The release of selenium during the experimental process is different for different rock types, but the total selenium in these rocks is not the key factor affecting selenium release, The release of selenium in rocks is significandy affected by different pH of leaching solutions and decreases in the following order： pH = 2.0 〉 pH = 6.5 〉 pH = 4.0. The ratio of carbonate to pyrite in the rocks generally corresponds to the variation of leachate pH, and is probably the main factor affecting the release of selenium at the beginning of weathering of So-rich rocks. So, to the local government, it is important to protect So-rich carbonaceous rocks in Enshi prefecture and make them free from mining again, and thoroughly manage the abandoned stone coal spoils produced from the mining of So-rich carbonaceous rocks.