关键词: 铅锌尾矿库, 重金属污染, 岩溶区, 环境风险, 资源化利用, 无害化治理

Abstract: A lead-zinc mine tailings pond in Guangxi has left a large number of high-sulfur tailings due to historical mining activities，and has been stacked in the open air for a long time.Under the dual in⁃ fluence of subtropical rain and karst development，the risk of heavy metal pollution is prominent.In order to explore the environmental status of the tailings pond and seek sustainable treatment approaches，the tail⁃ ings and surrounding water samples were systematically collected.The physical and chemical properties of the tailings，the occurrence characteristics of heavy metals and the law of water pollution were analyzed， the environmental risks were evaluated，and the feasibility of resource utilization was discussed based on the concept of "treating waste with waste".The results show that the tailings are mainly composed of quartz （65 .40%），rich in sulfides，such as pyrite，and the sulfur content is as high as 47.56 ~60.78 times of the background value，and the acid production potential is strong.The contents of Pb，Zn，Cd and As signifi⁃ cantly exceeded the standard，among which Cd exceeded the standard by up to 135 times，and Pb and Zn were mainly enriched in fine particles（-0 .045 mm distribution rate >71%）.The concentrations of Zn and Cd in the surrounding water were 4.24 times and 2 times higher than the groundwater Class III standard， respectively，due to the influence of tailings leachate.The karst medium had a certain interception effect on heavy metals，but extreme Hg pollution (up to 71 870 μg/L)occurred in the groundwater outlet and res⁃ervoir of the downstream cave，suggesting that there was an independent mercury source.Aiming at the characteristics of high proportion of fine-grained tailings and complex sulfide dissemination，a technical route with flotation recovery of lead-zinc mixed concentrate and sulfur concentrate as the core is proposed. Preliminary economic analysis shows that the output value of resource products can cover the treatment cost.According to the research，the treatment of the tailings pond should follow the phased strategy of pol ⁃ lution control first，resource recovery leading，terminal harmless disposal，ecological restoration，and es⁃ tablish a long-term monitoring network，which can provide reference for the collaborative treatment of his ⁃ torical tailings ponds in similar karst areas.

Key words: lead-zinc tailings pond, heavy metal pollution, karst area, environmental risk, resource utilization, harmless treatment