煤矸石中某些物淋溶释放特点的实验分析

为全面了解煤矸石中污染物的释放特点,定量预测煤矸石中污染物在大气降水作用下对土壤-地下水污染的强度,对新邱露天矿不同风化程度的煤矸石溶解释放污染物进行了动态淋溶实验研究.采用国家标准分析方法进行分析,并绘制了实验曲线.结果表明,煤矸石风化程度越高,溶解释放物的总硬度(CaCO3)、硫酸盐(SO42-)、钠(Na )、总溶解性固体(TDS)越多,并释放出一定量的氟化物(F-)、化学需氧量(CODMn)、总铁(Fe)等.淋滤液pH值在6.6～7.0间,有少量氯化物(C1-)、锰(Mn)、锌(Zn),微量其他重金属和砷(As).新鲜混合煤矸石溶解释放出较多的氟化物(F-)、化学需氧量(CODMn)和总铁(Fe).淋滤初期,污染物溶解释放速率较快,之后随降水量增加,污染物溶出速率也越来越慢,煤矸石中污染物的溶解释放主要受扩散控制.采用最小二乘法拟合得出各污染物浓度与降水量间呈指数衰减曲线关系,即Cv=Co Vn模型,该模型可定量预测煤矸石中污染物对土壤-地下水污染的强度.

Analysis of characteristics of leaching release of some substances in coal gangue

This article intends to report the authors' dynamic leaching experiment with the contaminant dissolving and releasing regularity of coal gangue at different efflorescence degrees of Xinqiu strip mine. In order to discover the release characteristics of the contaminant in gangue,we have studied and estimated the coal gangue effect of the groundwater soil contamination degree. Our experiment results prove that the efflorescence degree of coal gangue is higher with more dissolved releasing contaminants, such as the total hardness (CaCO_3), sulfate (SO 2-_4), natrium (Na\++), total soluble solid (TDS), fluoride (F-), chemical oxygen demand (COD_ Mn), total iron (Fe), etc. The coal gangue can also release minor amounts of chloride (Cl-), manganese (Mn) and zinc (Zn), as well as trace elements. In addition, it also gives out some elements of heavy elements, such as arsenic (As), with pH of leaching liquid being between 6.6 and 7.0, and fresh mix coal gangue release being the higher mass of fluoride (F-), chemical oxygen demand (COD_ Mn) and total iron (Fe). At the beginning of leaching, the dense of total hardness, SO 2-_4, Na+, TDS, F-, COD_ Mn, total Fe is higher and current rate of leaching is faster, especially when the dissolved releasing rate of Na+ is fastest, if the rainfall is bigger, pollutants of coal gangue can be washed away by the rain water gradually. And when each pollutant density of leaching liquid falls gradually, the contaminant dissolved release can be controlled by diffusion mainly. The SO 2-_4, Na+, TDS, F-, COD_ Mn and total Fe of leaching liquid as well as the rain water have all had a relation of index fading, i.e. \%C_V\%=C_0V\+n model, this model may predict that pollutants of coal gangue effect the degree of groundwater soil pollution.