| According to the statistics [9] the produces of Hunan lead-zinc ore is about thirty thousand tons each day produces. The average water of lead-zinc ore is5m3per ton, it will produces nearly one hundred and fifty thousand tons of dressing wastewater daily, nearly forty-five million tons of dressing wastewater yearly. It have various substances in the dressing wastwater including a certain amount of heavy mental ions, residue mineral processing reagents, high content of SS and etc. Not only have the single pollution such as heavy metal pollution and organic pollution but also have the combined pollution. Hence, devastating influences must generate to the surrounding ecological environment, if discharged dressing wastewater without any management and controlling. Accordingly, it is very important to take measures in controlling and reusing the dressing wastewater whether to consider in protecting the mining surrounding ecological environment,or realizing water resources reclying and sustainable development of the mining.Hunan Baoshan lead-zinc plant is a domestic typical polymetallic sulifide ore and associated with high grade of silver and gold. The produces is about five hundred tons per day, the annual production time is about three hundred day,it will produces nearly one hundred and fifty thousand tons of green ore yearly and nearly eighty hundred and one thousand wastewater yearly. The wastewater treatment methods of multi-metal ore is more difficulty than the single ore.If the heavy metals and the mineral processing reagents can not reach the degree of purification,it will make a serious affect in heavy metal separation and recovery.In this dissertation, the dressing wastewater is from Baoshan lead-zinc plant.Basing on the industry production procedures, the text mainly carried out the following works:The analysis and the check of the wastewater; Wastewater natural degradation test; The influence of heavy metal ions and residue mineral processing reagents to lead-zinc flotation; Wastewater treatment test; Wastewater reuse test. Finally, the dressing wastewater successfully reused and realized the zero discharge.The results of the analysis and the check of the wastewater show that:The dressing wastewater pH>12, high suspended solids and difficult to settlement,CODcr reach210mg/1, Pb2+content reaches6.21mg/1. The results of wastewater natural degradation test show that:Through24hours of natural degradation, wastewater pH value almost unchanged,The removal rate of SS, CODcr, Pb2+achieved50%,25.6%,43.6%respectively. Water quality can not reach the emissions standards. The results of the influence of heavy metal ions and residue mineral processing reagents to lead-zinc flotation show that:It have a great influence to the lead-zinc flotation.the concentrate and the recovery of lead, the concentrate and the recovery of zinc declined dramatically.The wastewater treatment test included the following jobs:Coagulation,Activated Charcoal adsorption,Oxidation.The coagulation test identified DA-1was the best coagulant, best dosage was60mg/l.After the coagulation,the Pb2+content dropped from6.21mg/l to1.15mg/l.The CODcr dropped from210mg/l to105mg/l,SS and sulfide reached the emissions standards. The adsorption test identified the dosage of activated charcoal was150mg/l, the best adsorption time was30min. After adsorption,the Pb2+content dropped from1.15mg/l to0.95mg/l, the CODcr dropped from106mg/l to77mg/l,The oxidation test identified the ClO2,was the best oxidant and the dosage was40mg/l. after the oxidation the CODcr mg/l less than50mg/l.The results of wastewater reuse test show that:Adopted the following process to dispose the dressing wastewater’regulation pH-coagulation-Absorption-ClO2oxidation-Clarification-Reuse" the flotation index is nearly the same with that of fresh water.The indexes of the treatment-water were followed as:Lead content in lead concentrate is55.78%, zinc content in lead concentrate is2.17%, the lead recovery is95.22%. Zinc content in zinc concentrate is55.26%, lead content in zinc concentrate is0.68%,the zinc recovery is95.44%.The indexes of the fresh water were followed as:Lead content in lead concentrate is56.75%, zinc content in lead concentrate is1.89%, the lead recovery is95.71%. Zinc content in zinc concentrate is55.08%, lead content in zinc concentrate is0.64%, the zinc recovery is96.00%.Test will provide the technical reference for realizing the nonferrous metal mining waste-water zero emissions and water resources comprehensive utilization. |
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