The Study About The Technologies Of Extracting The Gold From Electronic Wastes And Analysis Their Performance

In past several decades, with the rapid development of technique of electronics information, the catalogues and quantities of electronic product increase fleetly, and they are updated frequently. If no proper methods are taken to deal the wasted electronic products, the waste and damage are obviously. The electronic wastes usually include various kinds of components and precious metals, such as the gold, copper and silver, in addition to some pollutants, such as mercury, selenium, chrome. If electronic wastes is directly disposed as garbage, there will be dramatic wastes adding to the endangering of environment. The best way to solve this problem is to recycle the electronic wastes.The text is about the study of the extraction of gold from electronic wastes and its benefit. It summed up the characteristics of electronic wastes and the existing condition of the technology extracting gold fromit. Take the case of discarded printed circuit board, the author had done feasible researches concerning the pretreatment methods and the methods extracting gold.In the craft scheme of electronic wastes pretreatment, extraction method adopts the device absorbing nitric oxides by lye and the mixed acid system composed of nitric acid and sulfuric acid to dissolve non noble metals of electronic wastes and as a result makes their solution percentage over 93 percent. Making use of the principle of catalytic oxidation, catalytic oxidation method adopts three-phase fluidized bed reactor and the system made up of nitric acid, sulfuric acid, water and oxygen to dissolve non noble metals of electronic wastes and as a result makes their solution percentage over 92.87 percent.In the craft scheme of the extraction of gold from electronic wastes, extraction method adopts diethyl malonate to extract gold of electronic waste and makes the total recovery ratio of gold over 97.5 per. Catalytic oxidation method adopts the system composed of aluminum powder and sodium dodecyl sulfate to permute gold dissolved the acidic thiourea liquid and makes the total recovery ratio of gold over 94 per.On the grounds of the trial, the author manages the theories of the techno-economic analysis and environmental economics to analyze and compare economic benefit and environmental benefit of the technology extracting gold adopting respectively extraction method and catalyticoxidation method. The result shows that economic benefit and environmental benefit of catalytic oxidation method have an advantage over which of extraction method. Considering social benefits, economic benefit and environmental benefit and according to the schemes introduction of extraction method and catalytic oxidation method and their benefit analysis, the author puts forward a new scheme. Namely adopt the pretreatment project of catalytic oxidation method to dissolve non noble metals of electronic wastes and diethyl malonate to extract gold.