金矿尾矿胶结充填试验及环境效应研究

为探究某金矿尾矿胶结充填后充填体的抗压强度和环境效应，采用金矿全尾砂进行充填配比、重金属浸出和固化试验。充填配比试验中共制备灰砂比分别为1∶6，1∶8，1∶12，1∶20，质量浓度分别为77％，75％，73％的12组试块，分别测试12组试块固化7，12，28 d后的抗压强度。在重金属浸出试验中探究了尾矿充填后的环境效应以及潜在的污染元素，在明确潜在的污染元素后进行了相应的重金属固化试验。结果表明：金矿全尾砂最佳充填配比参数为灰砂比1∶8，质量浓度为75％；金矿尾矿在与胶凝材料混合凝固形成充填体后能够有效控制尾矿中有害元素的浸出，减少对环境的破坏；充填体浸出的As元素对地下水环境有潜在的污染风险，添加3％浓度的FeCl₃后能够有效避免污染发生。

Study on Cementation Filling Test and Environmental Effect of Gold Mine Tailings

The total amount of gold produced in China is among the highest in the world，and the massive mining of gold has led to a large accumulation of gold mine tailings.There are a lot of toxic and harmful heavy metals in gold mine tailings.How to deal with gold mine tailings in a safe and environmentally friendly way is a very intractable problem at present.Recycling gold mine tailings as cemented paste backfill（CPB） filling into the mine as support is currently a popular method to solve the problem.In order to explore the compressive strength and environmental effects of gold mine tailings after being recycled as CPB，the cementing ratio test，heavy metal leaching and solidification test of gold tailings was carried out.In the cementing ratio test，12 groups of samples were prepared，the cement-tailings ratio was 1∶6，1∶8，1∶12，1∶20，and the mass concentration was 77%，75%，73%.After a period of maintenance，the uniaxial compressive strength for 7 days，12 days and 28 days of 12 sets of test pieces were tested respectively.Finally，the optimum cementing ratio parameters were determined on the premise of considering the strength requirements of mining technology support and the economic cost of filling comprehensively.Heavy metal leaching test was carried out in two groups：48 hours leaching test of filling slurry and dynamic leaching test of CPB.The two sets of experiments were used to simulate the short-term leaching of the filled slurry and the long-term leaching of the CPB，and the purpose was to explore the environmental effects and potential pollution elements of the gold mine tailings after being recycled as CPB.After the heavy metal elements with potential contamination risks are identified by the leaching test，the corresponding curing agent was selected to carry out the curing test of heavy metals.The leaching of potentially polluting elements was tested again by adding different concentration of solidifying agent，and the concentration of solidifying agent which could eliminate the pollution risk of heavy metals leaching from CPB to groundwater was finally determined.Based on the above experiments，a safe and environmentally friendly method for recovering gold tailings is finally determined.The results show that The optimum cementation ratio of the gold tailings is 1∶8 for the cement-tailings ratio and 75% for the mass concentration.The leaching of harmful elements in the tailings can be effectively controlled after the gold tailings are recovered as CPB，which reduces the pollution to the environment.The As leached from CPB has potential pollution risk to groundwater，adding 3% FeCl₃ to CPB can effectively avoid the pollution.