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赣南离子型稀土浸矿开采过程中,因大量使用(NH_4)_2SO_4作浸矿剂造成土壤氮化物累积,引发矿区土壤及水体氮化物的持续严重污染。通过模拟土柱实验,测定原矿土壤(未开采的稀土矿土壤)和一般土壤(矿山周边的普通土壤)在模拟浸矿过程中氮化物的污染含量,研究氮化物在土柱实验中的迁移特征及规律。结果表明:浸矿过程中,原矿土壤和一般土壤中氮化物主要以铵态氮形式存在,说明铵态氮是导致稀土矿区土壤污染和水环境污染的主要原因;同时由于土壤的固氮作用、淋滤过程中铵态氮向下迁移及减少的共同作用,致使试验中原矿土壤和一般土壤铵态氮含量总体随天数表现为降低、升高、再降低趋势;并且与一般土壤相比,原矿土壤中稀土离子和NH~+_4会发生交换解析作用增加原矿土壤的固氮作用,同时稀土的存在会增加土壤本身对氮化物的吸附能力。研究结论为赣南离子型稀土矿浸矿过程中氮化物的迁移规律提供基础依据。
During the exploitation of ion-type rare earth leaching in southern Jiangxi, the accumulation of soil nitrides caused by extensive use of (NH 4) 2 SO 4 as a leaching agent led to continuous and serious pollution of nitrogen and nitrogen in the mining area. By simulating the soil column experiment, the pollution content of nitrides in the simulated leaching process was determined by the determination of the content of nitrogen in the ore mining soil (untreated rare earth mine soil) and the general soil (ordinary soil around the mine), and the migration characteristics of the nitride in the soil column experiment And the law. The results showed that during the leaching process, the nitrogen compounds in the ore and common soils mainly existed in the form of ammonium nitrogen, which indicated that ammonium nitrogen was the main reason of soil pollution and water environment pollution in the rare earth mining area. At the same time, due to the nitrogen fixation of the soil, During the process of filtration, the downward migration and reduction of NH 4 + -N together led to the decrease, increase and then decrease of ammonium nitrogen content in the ore and common soils as a whole, and compared with the general soil, In rare earth ions and NH ~ + _4 will exchange analytical role to increase the nitrogen fixation of the ore soil, while the presence of rare earth will increase the soil itself on the adsorption capacity of nitride. The conclusions of the study provide the basis for the migration of nitrides in the process of ore leaching of the southern Jiangxi province.