Detachment Of Gold And Controlll Ing Potential Chlorination Leaching—Extraction—Reduction Recycling Gold From Waste Electronic Component

Electronic waste contains a lot of dilute?scattered and base metals,has become an important secondary resource,known as the“city mine”.Extraction of varous metals in electronic waste has become a hotspot,especially precious metal gold.At present,cyanide and aquatic process have the risk of environmental pollution in the extraction process of good,and thiourea?thiosulfate and halogenation method has not been applied to the actual.Therefore,it is urgent to develop efficient?environmentally friendly and meanwhile,has the potential of industiral applications technology and equipment for extraction of gold from electronic components.Hence,in this paper,the method of stripping gold and chloride leaching-extraction-reduction of recover gold-containing were studied,the chlorination leaching-extraction-reduction-waste liquid treatment technology and equipment were also set up.Meanwhile,the environmental friendly and economic feaibility analysis for the above process were conducted.Strpping gold from surface of the electronic component is the process for the base metals are dissolved by the strong oxidation of the oxidizing agent,and then the plating gold was peeled off.Based on the factor design and response suface design of the gold stripping process,the second-order nonliner model of the stripping process was established.The main factors and secondary effects of ammoniun persulfate concentration,hydrogen peroxide dosage and reaction temperature were obtained.The influence of the process on gold stripping process was also revealed.The parameters of gold stripping process were optimized.Under the optimized conditions,the concentration of?NH₄?₂S₂O₈ was 0.8 mol/L,the dosage of H₂O₂ was 14.45 mL,the reaction temperature was 80^oC,and reaction time was 30min,the gold recovery rate was 98.95%,the gold purity was 93.11%.The kinetic analysis of the stripping process reveals that the gold stripping process conforms to the layer diffusion model in the nucleation model,and it activation energy?E_a?is 10.57 kJ?mol^-1Through the theoretical research,proposing the control potential chloride leaching-extraction-reduction process to recover the gold content in the components.In this paper,the waste electronic components mainly contain copper and gold was selected as object,based on the method of factor experiment and response surface design,the theoretical model of leaching copper and gold were obtained respectively,the main factors and secondary effects of leaching copper and gold were obtained respectively.The result showed that the optimum extraction conditions of copper were as follows:reaction time was 8 h?reaction temperature was 75^oC?sulfuric acid concentration was 150 g/L,the leaching rate of copper was 99.75%,which is consistent with the theoretical budgent value?99.80%?.The result showed that the optimum extraction conditions of gold were as follows:reaction time was 80 min?reaction temperature was 50^oC?NaCl concentration was 17 g/L,the leaching rate of copper was 92.85%,which is consistent with the theoretical budgent value?92.95%?.The results of extraction showed that the acidity has no direct effect on the extraction rate of gold,when the radio was 0.3,the extraction rate of gold was 95%.At the conditions of 100^oC?1 h and radio was 1:1,after the reduction of oxalic acid,the purity of recovery gold was 99.75%.The recovery of gold in the waste electronic components mainly contains polymetalliic component was also carried out by using the controlled potential chlorination leaching-extraction-reduction process to verify the applicaboility of the process.Under the optimized conditions,the results showed that the leaching rate of gold was 93.16%,the extraction rate was 95.12%,the purity of the recovered gold was 98.54%.In addition,after crushing?magnetic separation and vortex separation process,the iron recovery efficiency was 98.75%,and the aluminun recovery efficiency was 91.16%On the basis of above research,control potential chlorination leaching-extraction-reduction process combined gold extraction process and self-developed gold device were established,through the operation and debugging,the results basically reached the laboratory experiments,the leaching rate and extraction rate of gold were 94.83%and95.38%,the purity of gold can reach 99.64%.The wastewater containing heavy metal ions produced by the process of chlorination leaching-extraction-reduction process was treated by NaOH-FeSO₄ ferrite method,and the toxic leaching analysis was carried out on the waste water treatment process.The results showed that the treated water quality lower than the national standards,and the sediment is not a hazardous waste.Environmental-friendly analysis of chlorination leaching-extraction-reduction gold out by Biewer-Henizle method was conducted.The results showed that the chloride leaching-extraction-reduction gold process had the advantage of less comtamination risk.The above research provides the theoretical basis and reference for the extraction of gold from electronic components.