稀土尾矿库周边地下水中稀土元素含量及特征

REE Contents and Characteristics in Groundwater Surrounding the Rare Earth Tailings Reservoirs

对稀土尾矿库周边18个地下水样稀土元素的地球化学研究表明,尾矿库周边地下水中ΣREE含量是河套平原地区的4倍,大同盆地的10倍。对地下水中ΣREE浓度按照北美页岩平均组分（NASC）归一化处理后,发现所有18个水样轻稀土元素（LREEs）富集,重稀土（HREEs）贫化;尾矿库周边所有水样的稀土相对百分含量与白云鄂博稀土矿的稀土配分一致,这与尾矿库来源于白云鄂博矿相符。所采的地下水水样中大部分呈现Ce的负异常和Eu的正异常,异常的原因较为复杂,主要受到胶体、络合物和氧化还原条件的控制,一些微生物的吸附及催化氧化作用也有影响。

Study of geochemistry of the 18 groundwater samples surrounding rare earth tailings reservoirs shows that ΣREE content of groundwater surrounding the tailings is 4 times of that in the Hetao Plain and 10 times of in the Datong Basin.After normalization of ΣREE concentration in groundwater according to Northern American Shale Composite（ NASC）,it is found that in all the 18 water samples light rare earth elements（ LREEs） enriched and heavy rare earth（ HREEs） depleted; the REE relative percentage in all the water samples around the tailing reservoirs is consistent with the REE distribution in the Bayan Obo rare earth deposits,which is in accordance with the fact that the tailings reservoir derived from the Bayan Obo mine.Most of the mining groundwater samples presented negative anomalies of Ce and positive anomalies of Eu. The abnormal reasons are complex. It is mainly controlled by colloid,complex and redox conditions,and also affected by the adsorption and catalytic oxidation of some microbes.