Evaluation And Analysis On Upgrading The Arsenic-containing Heavy Metals Wastewater From The Gold Ore Processing And Smelting Plants

During the production process of the gold ore dressing and smelting, a largeamount of wastewater which contain refractory heavy metal ions, such as lead,cadmium, arsenic, mercury, copper etc. is produced. At present, most of theenterprises’s wastewater treatment technology level and clean production level are nothigh. So they seriously pollute the surrounding environment.According to the current environmental states, Sanmenxia city in Henan provinceputs stricter emission targets for the local mining, mineral processing and smeltingenterprises. The concentration of Cu in effluent after treatment should meet therequirement of Water Pollutant Discharge Limits in Particular specified in PollutantDischarge Standard for Copper nickel and cobalt Industry(GB25467-2010); The otherindexes meet the quality of Ⅲ category surface water of the standard (GB3838-2002).A company in this city uses taillings pond as the dressing wastwater treatment process,and uses neutralization+extraction+neutralization+filtration+precipitation as thesmelting wastwater treatment process. In tailling pond drainage, the concentrations oftotal lead, total cadmium and total arsenic were187,239and0.48times respectively ashigh as emission targets; And for total zinc, total lead, total mercury, total arsenic andtotal cadmium in the treated smelting wastwater, the exceed levels were0.43,4.2,399,5.4and16times respectively. Both of them can not reach the standard.By studying the existing dressing and smelting wastwater treatment process andaccording to the comparison of various heavy metal wastewater treatment methods, we choose the sulfide precipitation+oxidation precipitation+fiber beam filtration+ceramic membrane filtration as the dressing wastwater treatment process, and sulfideprecipitation+oxidation precipitation+dynasand continuous sand-filterying+ceramic membrane filtration+reverse osmosis membrane as the smelting wastwatertreatment process. According to the paraments of the two processes, the equipmentsand the dimensions were determined. After the implementation of the project, theremoval efficiency of total cadmium and total lead in the dressing wastewater couldreach97%, and the removal efficiency of total arsenic in the dressing wastewater couldreach73%.150m~3/h deionized water is generated during the process of smeltingwastwater treatment which can be used as Circulating Cooling Water. In the process,1188000m~3fresh water can be saved every year and wich gain the enterprise directprofit of$433.6million. The removal efficiency of total arsenic, total mercury, total zincand total lead could reach95%, the removal efficiency of total cadmium in the dressingwastewater could reach53%. The quality of the effluent can meet the area’s newstandards. The project can alleviate the situation of the heavy metal contamination inthis area. Also, this technology has remarkable economic benefit,environmental benefitand social benefit.