The Experimental Research For Recycling Of Al And Fe In Wastewater Of Copper Mine

Copper is the important raw material in the national economic production.However, the formation of wastewater in the process of the development andutilization of the copper mine is inevitable. Now the wastewater can commonly betreated by precipitation and adsorption, the supernatant back to mine or used forafforestation and the sediment into the tailings. That can achieve the goal ofwastewater treatment, but it may increase economic investment in industrialproduction and lots of flocculants need to be added, and the metal ion in waste watercannot be recycled. The copper wastewater used in this paper contains a lot of Alelement and Fe element and has the recovery value. The neutralization precipitationand acid polymer was used for copper mine waste water in this topic. The PAFC wasprepared with the aluminum and iron in the wastewater. Using PAFC as flocculantsto precipitate the wastewater, which can achieve that obtaining raw material locallyand recycling useful resources and using waste to treat waste and making theeconomic benefits and environmental benefits achieved win-win.In the acid and alkali waste water mixing experiment, we determine the acid-base wastewater with mixing ratio of1:0.6, and then aluminum, iron were stepwiserecycled by neutralization precipitation. When dosage of Na2O2was20mg·L-1, at thepH of5.2, reaction time15min, the recovery effect is ideal, aluminum, ironrecovery rate more than99%, while the wastewater carries on the preliminarytreatmentFor acid soluble experiment of the precipitate adding35g the recovered solidprecipitate,5g aluminum hydroxide powder, hydrochloric acid concentration23%,hydrochloric acid in excess coefficient of1.4, reaction temperature105℃, reactiontime1.8h, the aluminum dissolved rate reaches73.2%, the iron leaching ratereaches91.5%, after reaction, the molar ratio of aluminum, iron in the acid solutionis7.37.Under the conditions of25g calcium aluminat, reaction temperature at95℃,polymerization time for3.5h and the PAFC that was prepared from sediment wasused as flocculants, the flocculation sedimentation experiments were done for the mixed wastewater after recycling Al and Fe. The results show that, at the pH of8.0,8mL·L-1of flocculants, at stirring speed of325r·min-1for5min, at stirring speed of80r·min-1for3min, flocculation effect is best. Heavy metal ion content in the treatedwater samples meets the secondary national wastewater discharge standard, CODcontent is198mg·L-1. By comparing the flocculation of the homemade PAFC withPAC、PFC and anionic PAM, show that homemade flocculant flocculation effect isideal. The value of turbidity, COD for effluent is lower than the other three kinds offlocculant.In order to further reducing the COD content in the waste water, the method ofpowder activated carbon adsorption was adopted to remove excess COD in wastewater. When the adsorption time for3.5h,0.4g·L-1of activated carbon, the CODcontent is dropped to87.2mg·L-1, removal rate56.06%. In the end, all the indexes ofwastewater meet the national secondary industrial wastewater discharge standards.