| 2. |
- Larsson Ivanov, Oskar, et al.
(författare)
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Prolca—treatment of uncertainty in infrastructure LCA
- 2019
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Ingår i: Life-Cycle Analysis and Assessment in Civil Engineering. - : CRC Press/Balkema. - 9781138626331 - 9781351857574 ; , s. 2923-2930
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Konferensbidrag (refereegranskat)abstract
- The construction, operation and maintenance of transportation infrastructure require energy and materials which impact the environment. Large infrastructure projects thus use resources intensively and leave a significant environmental footprint. To demonstrate and support the sustainability of such large-scale projects, life cycle assessment (LCA) has become a common tool to evaluate environmental impacts in all stages of infrastructure life cycle, from raw material production through end-of-life management. However, the various phases of the assessment are all associated with uncertainties. If decisions are made without consideration of these uncertainties, they might be misleading and suboptimal. In this paper, results are presentedwhere variations associated with different parameters and tools for life cycle assessment have been considered using probabilistic methods. A categorization of common uncertainties in LCA is also included. The most influential parameters can be identified with sensitivity analysis methods, since for LCA with a large number of parameters it may be unreasonable to incorporate all in a probabilistic simulation. For a limited amount of influential variables, Monte Carlo simulation has been used to assess the effects of uncertainties on the results.A bridge has been used as a case study to find important aspects in infrastructure LCA. The results indicate that if the most influential parameters are considered as random variables, it is possible to estimate the uncertainty and increase the validity of the life cycle assessment.
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| 3. |
- Ye, Guozhu, et al.
(författare)
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Elimination of zinc ferrite for hydrometallurgical recovery of zinc from EAF dust
- 2006
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Ingår i: 2006 TMS Fall Extraction and Processing Division: Sohn International Symposium. - 0873396332 - 9780873396332 ; , s. 397-411
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Konferensbidrag (refereegranskat)abstract
- Hydrometallurgical zinc recovery from EAF dust has several advantages compared to pyrometallurgical alternatives in terms of low temperature operation, lower energy consumption and higher flexibility. Many hydrometallurgical processes have been suggested and tested over the years without success. The main reasons are: - Low leaching yield of zinc due to the fact that a high fraction of ZnO in the EAF dust exists in the zinc ferrite structure which makes selective leaching of ZnO not possible - Many of the proposals could not handle the halide in the EAF dust To eliminate these two disadvantages, two zinc ferrite elimination concepts have been tested and developed in the REZIN project of the EU 5 th Framework Programme. The two concepts for zinc ferrite elimination could be shortly described by the following chemical reactions: A. ZnOFe 2O 3 + 2CaO = Ca 2Fe 2O 5 + ZnO free B. ZnOFe 2O 3 + C = Fe met + CO/CO 2 + ZnO free These two concepts were investigated in details in combination with a subsequent leaching step using the novel EZINC process for recovery of zinc from EAF dust. Leaching of pretreated samples has shown great increases of a zinc recovery yield. A zinc recovery of over 90 % could be reached, as compared to about 50 % for no-pretreated samples. This paper will describe the two concepts in details.
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