硫化镍矿废石和尾矿中重金属排放特征与防治对策

硫化镍矿由于镍品位低、提取工艺复杂,形成大量的废石和尾矿。废石目前普遍在废石场堆存,尾矿粒度较细,一般排入尾矿库。废石和尾矿中含有的重金属元素,在堆放过程中由于淋滤作用,不仅可能污染地表水,而且可以通过水力联系发生污染转移。选取我国典型硫化镍矿采选企业有代表性的废石和尾矿样品进行重金属组分分析和浸出毒性实验分析,目标重金属包括五种毒性较高的重金属镉、铬、铅、砷、汞及矿石主金属镍、钴、铜,确定每种重金属的污染负荷率,分析得出废石和尾矿中重点防控的重金属为砷、镉、铬,主金属镍和铜也应重点防控。针对现有企业废石和尾矿处置过程中存在的问题,提出有针对性的防治措施,可为镍采选企业废石和尾矿的重金属污染监管提供依据。

Heavy metals discharge characteristics and prevention measures of nickel sulphide ore waste rock and tailings

The acquisition process of nickel sulphide ore is complex, and the taste of nickel in nickel sulphide ore is low, thus generates lots of waste rock and tailings. Waste rock are stored in waste dump field. Particle size of tailings is fine, and are discharged to the tailing ponds. Waste rock and tailings contain a lot of heavy mental elements, which can pollute ground water and transfer through the hydraulic connection. This paper selected representative samples of waste rock and tailings from typical nickel sulfide ores acquisition corporate to analyze the heavy mental component and complete the leaching toxicity test. The most concerned highly toxic heavy metals, including five kinds of heavy metals Cd, Cr, Pb, As, Hg and the main metal ore Ni, Co and Cu. The pollution load rate of each type of heavy metal was analyzed. Results revealed that the focus on prevention and control of waste rock and tailings is Cd and Cr, Ni and Cu are also the important metal. For the problems in disposal process of waste rock and tailings, targeted prevention measures were proposed. The results can provide basis for heavy metal pollution supervision.