| Abstract:Aluminum and aluminum alloy are widely used in national defense, construction, transportation, packaging and other areas of daily life because of its varieties of excellent performances. On one hand, the mineral resource required for primary aluminum production is decreasing, and on the other hand, the reserve of renewable resources required for secondary aluminum production is increasing. The production of secondary aluminum has the advantages of saving energy, reducing process and decreasing environmental pollution, which achieve the recycling of resource and meet the requirements of continuing economic development.Vacuum pyrolysis and hydrometallurgy process were used to de-lacquer used beverage cans (UBCs), which could avoid the produce of dioxin and furan generated in direct combustion of organic composition contained in paints. Meanwhile, condensed pyrolysis oil could be reused in other chemical aspects. Under the condition that pyrolysis temperature of650℃, system pressure lower than0.1kPa and holding time of20min, the de-coating rate can achieve nearly100%. The mainly composition of pyrolsis oil is phenol. After vacuum pyrolysis, the de-lacquered UBCs were leached in5vol.%H2SO4for60s. Cleaning aluminum foil could be obtained after filtration. Titanium dioxide was recycled by calcining the filter residues in muffle at450℃for15min.Salt fluxing method was adopted to melt de-lacquered UBCs and capacitor. The experiments showed that for the melting of UBCs, the recovery rate and effective coalescence rate can both reach over98%under the condition that melting temperature of700℃, melting time of15min, salt flux/scrap ratio1.0and1:1NaCl-KCl with addition of5wt.%NaF. For the melting of capacitor, the recovery rate and effective coalescence rate can both reach over99%under the condition that melting temperature of715℃, melting time of15min, salt flux/scrap ratio0.5and1:1NaCl-KCl without fluoride addition. |
PDF Full Text Request