关于矿产资源循环利用及其建议与对策

本文阐述了矿产资源的特点及其对我国经济和社会发展的意义，同时提出了矿产资源持续供应面临的问题，提出了循环经济的概念，并对矿产资源领域如何发展循环利用提出了相应的对策、建议，并总结了今后应该研究的方向。     

PEM water electrolysis: Innovative approaches towards catalyst separation,recovery and recycling

We report the development of a facile recycling process for catalyst coated membranes (CCMs) used in polymer electrolyte membrane (PEM) water electrolyzers. After performance evaluation in an assembled electrolysis cell, ultrasonication is used to provide high-yield recovery of not only the noble-metal catalyst materials, but also of the fluoropolymer membrane itself, without the release of hazardous gases. Transmission electron microscopy (TEM) and electrochemical characterization are used to confirm the retention of catalyst particle size, and of the performance of the recycled CCMs. Furthermore, our projections indicate that, if this approach is widely employed, existing resources of noble metals will prove sufficient for the gigawatt-scale implementation of PEM water electrolyzers. This has profound implications for the achievement of current targets for reducing the consumption of precious metals for applications in electrolyzers, fuel cells and other energy storage devices.     

Effects of grain size on the wear of recycled AZ91 Mg

Magnesium alloy AZ91 chips have been recycled using mechanical milling to yield samples with fine grain sizes. Together with cast samples of the same alloy, the wear behavior of these materials was studied through pin-on-disc sliding, with speeds varying from 1 to , under a normal load of 10 N. Despite the differences in grain size (0.6–) and mechanical properties, the various specimens did not differ significantly in their wear performance. Scanning electron microscopy observed abrasive wear to be dominant under low-speed sliding, and a transition to the formation of a protective mechanically mixed layer (MML) as sliding speed increased.     

Properties of high volume glass powder concrete

Mechanical and durability properties of concrete with cement replaced by finely grounded glass powder in high volume up to 60% were investigated. XRD and TGA analyses indicated that the fine glass powder reacted with calcium hydroxide to form calcium-silicate-hydrates. As such, the microstructures of concrete were more compact and homogeneous, especially at the interfacial transition zone. Concrete with cement replaced by 15% and 30% glass powder exhibited the highest strength increase and correspondingly the lowest porosity. Beyond a replacement of 30%, calcium hydroxide became insufficient for the pozzolanic reaction of glass powder. However, the high volume glass powder concrete retained distinct resistance against water and chloride ingress, due to the reduction in pore size and connectively. Reductions of 77%, 83%, 96%, 91% and 92% were observed respectively for water penetration depth, sorptivity, conductivity, chloride diffusion and migration coefficients in concrete with cement replaced by glass powder by 60%.     

可回收的塑料包装解决方案顶层设计——同材质化

废旧塑料回收已经成为世界性难题,因为废旧塑料材质的多样性,其回收与再生也面临巨大困难。本文拟提出塑料包装应用设计方案同材质化,为废塑料回收便捷及利用可行性提供新方法。     

Recycling GTL catalysts—A new challenge

The Fischer Tropsch synthesis of motor fuel from natural gas on a large scale may become significant in the near future for economic and environmental reasons. This process requires solid-phase catalysts containing large amounts of cobalt (catalyst) and traces of platinum group metals or rhenium (promoter). The economic data presented in this paper shows why recycling of those metals will be mandatory. Several recycling processes will be presented along with their technical challenges, most of which can be handled by Umicore using its know how and experience in the recycling of cobalt and the precious metals.     

Effects of adhesive type and polystyrene concentration on the shear strength of bonded polystyrene/high-density polyethylene blends

The lap-shear strengths of adhesively bonded polystyrene (PS), high-density polyethylene (HDPE), and their blends, were studied as a function of adhesive type and blend composition. The performance of virgin and recycled polymer systems was examined. The lap-shear strength depended strongly on the amount of PS in the blend and the type of adhesive, and the acrylic adhesives demonstrated the best performance for all compositions. Bonded strengths of HDPE increased by approximately 50% when HDPE was blended with 34% PS, the co-continuous composition. The results indicate that structural elements made from PS/HDPE immiscible blends may be effectively bonded with adhesives without expensive surface treatments.     

Evaluations of existing waste recycling methods: A Hong Kong study

Environmental problems have been considered as a serious situation in Hong Kong construction. Waste management is pressing harder with the alarming signal warning the industry. Reuse, recycling and reducing the wastes are considered as the only methods to recover the wastes generated; however, the implementations still have much room for improvement. In order to ameliorate the existing situations, evaluations of the existing waste recycling methods are studied in this research. A telephone interviewing to the recyclers, site visits to the construction and demolition sites (including the Lower Ngau Tau Kok Estate Phase 1) and the centralized recycling plant in Tuen Mun Area 38 are under investigation. Difficulties encountered for various recycling parties are investigated. Rather than the poor quality found from the recyclable materials, they found the high investment cost, lengthy demolition period and limited space caused the major barriers for them. Therefore, some recommendations are suggested: (i) proposing a higher landfill charging scheme; (ii) setting up a centralized centre for recycling the materials; (iii) examining the Hong Kong government should be supported in the provision of land for recycling plants; (iv) implementing innovative demolition methods; (v) allowing some locations in town for residents’ easy access to drop-off recyclable materials; (vi) allowing flexible demolition periods; (vii) setting up recycling plant in town or in the form of mobile installations; (viii) reusing the reusable components as donations to the charity organization; (ix) providing higher flexibility in receiving concrete waste in Tuen Mun Area 38 recycling plant; and (x) balancing the supply and demand of recycled materials through legislations or incentive schemes.