The collected tungsten carbide/cobalt scrapped waste typically contains approximately 90% tungsten carbide and 10% cobalt.A nitric method is used to extract tungsten and cobalt from tungsten-containing waste.The waste...The collected tungsten carbide/cobalt scrapped waste typically contains approximately 90% tungsten carbide and 10% cobalt.A nitric method is used to extract tungsten and cobalt from tungsten-containing waste.The waste is first dissolved in nitric acid,which then makes cobalt soluble and becomes cobalt nitrate solution.The waste also oxidizes tungsten carbide to insoluble tungstenic acid precipitate.If tungsten carbide scraps are obtained from leftover of LCD glass cutting,after applying the same process as above,the remaining glass also needs to be separated from the tungstenic acid.XRF analysis shows that 93.8% of cobalt and 97.72% of tungsten can be obtained separately by this wet chemical method.By ICP analysis,no more tungsten ion remains after 2 h reaction in the cobalt recovery when 12 N of nitric acid is used for oxidation.The recovery materials obtained for tungsten are tungsten oxide and for cobalt a mixture of Co3O4 and CoO.展开更多
Scrapped tires from vehicles are produced in large quantities. Despite numerous existing uses of scrapped tires, alarge quantity ends up at the landfill sites, which contributes to environmental degradation. The devel...Scrapped tires from vehicles are produced in large quantities. Despite numerous existing uses of scrapped tires, alarge quantity ends up at the landfill sites, which contributes to environmental degradation. The development ofmore applications of scrapped tire usage can reduce the disposal of tires at landfill sites. This research proposes anovel use of scrapped tires by using the strips taken from scrapped tires in replacement of steel bars as reinforcement. Manhole covers were produced using scrapped tires by completely replacing the steel with scrapped tires.Four different samples of manhole covers were prepared and tested. The highest bearing capacity of 25.5 kN wasrecorded with a sample of 100 mm thickness made with cementitious composite, which is 2.25 times higher thanthe bearing capacity of a conventional reinforced-concrete manhole cover. The use of manhole covers made withscrapped tires can effectively address the theft issue of manhole covers. The lifecycle cost analysis shows that themanhole cover made with scrapped tires is 3.4 times more cost-effective in comparison with the conventionalmanhole cover. This research shows a new avenue of the potential use of scrapped tires as reinforcement in structures, which can improve sustainable construction practices.展开更多
基金Supported by the project of National Science Council in Taiwan(No.:NSC-95-2622-E-159)
文摘The collected tungsten carbide/cobalt scrapped waste typically contains approximately 90% tungsten carbide and 10% cobalt.A nitric method is used to extract tungsten and cobalt from tungsten-containing waste.The waste is first dissolved in nitric acid,which then makes cobalt soluble and becomes cobalt nitrate solution.The waste also oxidizes tungsten carbide to insoluble tungstenic acid precipitate.If tungsten carbide scraps are obtained from leftover of LCD glass cutting,after applying the same process as above,the remaining glass also needs to be separated from the tungstenic acid.XRF analysis shows that 93.8% of cobalt and 97.72% of tungsten can be obtained separately by this wet chemical method.By ICP analysis,no more tungsten ion remains after 2 h reaction in the cobalt recovery when 12 N of nitric acid is used for oxidation.The recovery materials obtained for tungsten are tungsten oxide and for cobalt a mixture of Co3O4 and CoO.
文摘Scrapped tires from vehicles are produced in large quantities. Despite numerous existing uses of scrapped tires, alarge quantity ends up at the landfill sites, which contributes to environmental degradation. The development ofmore applications of scrapped tire usage can reduce the disposal of tires at landfill sites. This research proposes anovel use of scrapped tires by using the strips taken from scrapped tires in replacement of steel bars as reinforcement. Manhole covers were produced using scrapped tires by completely replacing the steel with scrapped tires.Four different samples of manhole covers were prepared and tested. The highest bearing capacity of 25.5 kN wasrecorded with a sample of 100 mm thickness made with cementitious composite, which is 2.25 times higher thanthe bearing capacity of a conventional reinforced-concrete manhole cover. The use of manhole covers made withscrapped tires can effectively address the theft issue of manhole covers. The lifecycle cost analysis shows that themanhole cover made with scrapped tires is 3.4 times more cost-effective in comparison with the conventionalmanhole cover. This research shows a new avenue of the potential use of scrapped tires as reinforcement in structures, which can improve sustainable construction practices.
