Wastewater Treatment Technology Research And Engineering Design Of A Mine

Due to the expansion of production scale,the existing sewage treatment system of the mining company in Anhui Province is unable to work properly and there is continuous discharge of wastewater from the dump and tailings ponds.Its p H is 2 to 4,and there is a large amount of copper ions leaching,which affects the surrounding ecological environment.In view of the fact thatthe existing sewage treatment system of the mining can operate hardly and it is difficult to meet the environmental protection requirements,thus,it is proposed to rebuild the sewage treatment facilities.The existing process has the problems of low processing efficiency,large dosage demand,high operating cost,and no copper ions recovery.The paper aims to solve the pollution problems of mine wastewater,and how to recover the copper in the wastewater.The experimental study mainly focus on the amount of iron shavings,reaction time,stirring speed,reaction temperature,reaction p H,and p H change of wastewater after reaction,etc.The main results obtained in this study are as follows:(1)The optimum process parameters for the replacement of copper by waste iron shaving replacement precipitation method was obtained through waste copper scrap recovery experiment.The optimum dosage of the waste iron shavings in the displacement pool,reaction p H and time were 80 mg/L,2 to 4 and 20 min respectively,and the temperature had a negligible effect on the replacement rate.The copper exchange rate could reach 95% with the stirring rate at 120 r/min.The p H value had slightly increase after the reaction,while it is useful for the subsequent wastewater neutralization treatment.(2)Based on the actual production condition of the company and the existing sewage treatment system,the design plans to improve the existing sewage treatment system and meanwhile waste iron shavings and high-density slurry process were added as a supplement.The process design of the structures and the selection of major equipment had been completed,which is based on the above-mentioned experiment,some references and design specifications.The plans and elevations were arranged according to the layout principles and requirements of the sewage treatment system,and the drawings of each structure were finished as well.(3)Through the cost-benefit analysis of the reconstruction project,it is estimated that the new investment would be about 20 million yuan,and the process operation cost after reconstruction would be 0.881 yuan/t.The annual recovery amount of copper would reach 648.459 tons with 0.469 yuan/t water revenue.The annual revenue would be up to 6.7613 million yuan.Thus,it satisfied the wastewater discharging standards and achieved economic benefits of recycling of copper metal by waste treatment.This case study and design provides ideas for a similar mine acidic wastewater treatment project and a good demonstration and guidance for similar wastewater treatment process design and engineering benefit analysis.