| The main pollutants of mineral processing wastewater are persistent heavy metal ions,flotation agent,oil and suspended solids,etc.If not being discharged,There will be destructive effects on farmland,soil,rivers and wetlands of the beneficiation plant surrounding and downstream areas,and ultimately endanger human health.Therefore,it is necessary to select a proper process to treat mineral processing wastewater without drawing in secondary pollution.Furthermore,the investment cost,operation cost,area and other factors should also be considered to remove COD and heavy metals in flotation wastewater by the greatest extent,which will improve the concentrator peripheral environment and ultimately provide process selection and theoretical reference to China's mineral processing wastewater treatment.Coagulation sedimentation is the most commonly used method for the treatment of mineral processing wastewater.The process can effectively remove heavy metals from the mineral processing wastewater,but it has little effect on the removal of COD from the wastewater.The research planed to use coagulation as the pretreatment of mineral processing wastewater.Then,physical adsorption or chemical oxidation method were used as the advanced treatment of mineral processing wastewater.Three-dimensional electrolysis were using to treat raw water of processing wastewater directly because it can remove COD and heavy metals in mineral processing waste water simultaneously.Under the condition of the comprehensive comparison of the treatment effect,operation cost and the stability of each process,the best technology and process parameters are selected to the mineral processing wastewater treatment.Research shows that when using coagulation pretreatment-physical adsorption method,COD concentration in wastewater was reduced to 96.26 mg·L-1 and Pb concentration was dropped to 0.38 mg·L-1 under the condition of the initial pH value of 10,FeCl3 dosage at 50 mg·L-1,the flocculant dosage of PAM at 30 mg·L-1,the coagulation reaction time of 15 min,activated carbon dosage at 3.0 g·L-1,stirring time of.2.0 h.However,it is still not up to the emission standard.When using coagulation pretreatment-chemical oxidation process,the concentration of COD in flotation wastewater was reduced to 68.16 mg·L-1 and Pb concentration was dropped to 0.38 mg·L-1 under the condition of coagulation and sedimentation in the same processing conditions,the aeration rate at 5 m3·h-1,the ozone concentration with 10 mg·L-1,oxidation time of 60 min.But it can not make ore dressing wastewater emissions reach the standard.The operation cost was up to 7.08 yuan t-1,which is far higher than the capacity of the enterprise.Further exploring of new process is needed.A new device of ‘?' shape three-dimensional electrolysis device was used When using the three-dimensional electrolysis method to treat mineral processing wastewater.The concentration of COD and Pb were reduced to 32.67 mg·L-1 and 0.18 mg·L-1 respectively under the condition of the voltage at 20 V,the current density of 40 mA·cm-2,the plate spacing of 4.0 cm,the initial pH value of 5,the concentration of Fe2+ at 0.18mmol·L-1,powdered activated carbon dosage of 20g·L-1,aeration at 0.4m3·h-1,electrolysis time at 45 min,which is superior to the emission standard.The operation cost is 5.7 yuan·t-1.Compared with the traditional three dimensional electrolysis method,the processing efficiency is increased by 25%,and the operation cost is only about 75% of the traditional three dimensional electrolysis treatment process. |
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