煤矸石中氟的赋存特性及生态风险评价

Occurrence Characteristics and Ecological Risk Assessment of Fluorine in Coal Gangue

为确定陕西韩城矿区和黄陵矿区煤矸石中氟的赋存特征及潜在生态风险,以韩城石炭-二叠纪煤矸石和黄陵侏罗纪煤矸石为研究对象,对两地煤矸石中6种形态的氟化物进行连续分级提取,使用分光光度计测定含量。结果表明:韩城矿区和黄陵矿区煤矸石中氟赋存形态以次生相(水溶态、离子交换态、无定形铁铝结合态、结晶铁铝结合态和有机结合态)为主,质量分数分别为92.19%(韩城)和87.76%(黄陵),各次生相形态氟中又以水溶态氟质量分数最高(分别为31.56%(韩城)和33.30%(黄陵));对煤矸石中各形态氟与煤矸石理化性质分别进行的相关性分析表明,pH值、交换性Ca和交换性Mg与水溶态氟在0.01水平下呈极显著正相关(r=0.837**,r=0.802**,r=0.727**),是影响煤矸石氟含量的主要因素;对韩城矿区和黄陵矿区煤矸石中氟污染进行潜在生态风险评价,考虑到不同赋存形态氟的生物有效性不同,对不同赋存形态氟含量实测值赋予不同的权重,计算出的生态风险指数表明,韩城矿区生态风险指数(ERb)呈东部高西部低,且S4(下峪口煤矿)点为高风险地区(ERb=2.4),黄陵矿区生态风险指数北部高南部低,Z1(黄陵二号矿,ERb=2.1)和Z6(集贤煤矿,ERb=2.26)为高风险区,整体风险等级低于韩城矿区。

In order to determine the occurrence characteristics and potential ecological risks of fluorine in coal gangue in Hancheng mining area and Huangling mining area in Shaanxi. This paper takes the Carboniferous-permian coal gangue from Hancheng and the Jurassic coal gangue from Huangling as the research objects. The six forms of fluoride in the coal gangue from the two places were continuously and fractionally extracted, and the content was measured by a spectrophotometer. The results show that the fluorine occurrence forms in coal gangue in Hancheng and Huangling mining areas are mainly secondary phases (water soluble, ion exchangeable, combination of amorphous iron and aluminum, combination of crystalline iron and aluminum, combination of organic matters), and the mass fraction is 92.19%(Hancheng) and 87.76%(Huangling), the mass fraction of the water soluble fluorine in each secondary phase form of fluorine is the highest, 31.56%(Hancheng) and 33.30%(Huangling)). The correlation analysis between various forms of fluorine in coal gangue and the physical and chemical properties of coal gangue show that pH value, exchangeable Ca, exchangeable Mg and water soluble fluorine are extremely significantly positively correlated ( r=0.837 ** , r=0.802 ** , r =0.727 ** ), is the main factor affecting the fluorine content of various forms. The potential ecological risk assessment of fluorine pollution in coal gangue in Hancheng and Huangling mining areas is carried out. Taking into account the different bioavailability of different forms of fluorine, the measured values of different forms of fluorine are assigned different weights to calculate the ecological risk index. The results show that the ecological risk index of the Hancheng mining area is higher in the east and lower in the west, and S4 (Xiayukou coal mine) is a high-risk area (ER b=2.4), and the ecological risk index of the Huangling mining area is higher in the north and lower in the south. Z1 (Huangling No. 2 Mine, ER b=2.1) and Z6 (Jixian Coal Mine, ER b=2.26) are high-risk areas, and the overall risk level is lower than that of Hancheng mining area.