| 1. |
- Grandell, Leena, et al.
(författare)
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Assessing Rare Metal Availability Challenges for Solar Energy Technologies
- 2015
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Ingår i: Sustainability. - MDPI AG : MDPI AG. - 2071-1050. ; 7:9, s. 11818-11837
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Tidskriftsartikel (refereegranskat)abstract
- Solar energy is commonly seen as a future energy source with significant potential. Ruthenium, gallium, indium and several other rare elements are common and vital components of many solar energy technologies, including dye-sensitized solar cells, CIGS cells and various artificial photosynthesis approaches. This study surveys solar energy technologies and their reliance on rare metals such as indium, gallium, and ruthenium. Several of these rare materials do not occur as primary ores, and are found as byproducts associated with primary base metal ores. This will have an impact on future production trends and the availability for various applications. In addition, the geological reserves of many vital metals are scarce and severely limit the potential of certain solar energy technologies. It is the conclusion of this study that certain solar energy concepts are unrealistic in terms of achieving TW scales.
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| 2. |
- Morozovska, Kateryna, et al.
(författare)
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Trade-offs of wind power production: A study on the environmental implications of raw materials mining in the life cycle of wind turbines
- 2024
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Ingår i: Journal of Cleaner Production. - : Elsevier BV. - 0959-6526 .- 1879-1786. ; 460
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Tidskriftsartikel (refereegranskat)abstract
- The energy demand in Sweden is increasing due to the growing electrification, and to meet this need, the generation must be expanded. Wind power generation is a very attractive renewable power production alternative for Sweden because of the favorable weather conditions. Research looks at how much wind energy may be deemed sustainable. Increased energy demand puts pressure on the government and industry to build more wind farms and, as a result, produce more wind turbines. Raw materials are necessary for wind turbines to provide a secure transition to green energy technologies. To meet these demands, the materials from various countries should efficiently contribute towards the Sustainable Development Goals (SDGs). This paper gathers information about raw resources from diverse nations worldwide. All materials are mapped to the country where they are produced using social science criteria. A few nations are chosen based on a sample approach for further analysis, and the implications of mining operations are investigated. Finally, the direct and indirect effects of the SDGs are considered. Based on the data gathered, recommendations and considerations are given to avoid or mitigate the repercussions of raw materials mining and make wind power generation more socially and environmentally sustainable.
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| 3. |
- Vikström, Hanna, 1985-, et al.
(författare)
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Lithium availability and future production outlooks
- 2013
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Ingår i: Applied Energy. - : Elsevier BV. - 0306-2619 .- 1872-9118. ; 110:10, s. 252-266
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Tidskriftsartikel (refereegranskat)abstract
- Lithium is a highly interesting metal, in part due to the increasing interest in lithium-ion batteries. Several recent studies have used different methods to estimate whether the lithium production can meet an increasing demand, especially from the transport sector, where lithium-ion batteries are the most likely technology for electric cars. The reserve and resource estimates of lithium vary greatly between different studies and the question whether the annual production rates of lithium can meet a growing demand is seldom adequately explained. This study presents a review and compilation of recent estimates of quantities of lithium available for exploitation and discusses the uncertainty and differences between these estimates. Also, mathematical curve fitting models are used to estimate possible future annual production rates. This estimation of possible production rates are compared to a potential increased demand of lithium if the International Energy Agency’s Blue Map Scenarios are fulfilled regarding electrification of the car fleet. We find that the availability of lithium could in fact be a problem for fulfilling this scenario if lithium-ion batteries are to be used. This indicates that other battery technologies might have to be implemented for enabling an electrification of road transports.
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| 4. |
- Wagner, Michelle, et al.
(författare)
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ORAMA Project - D6-6 Technical Final Report and Recommendations
- 2019
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Rapport (övrigt vetenskapligt/konstnärligt)abstract
- Securing the sustainable access to and supply of raw materials, and particularly of Critical Raw Materials (CRM), is of high importance for the European economy. Complex primary and secondary resources contain many different raw materials. The inability to easily produce reliable statistics about reserves, resources, stocks, and flows of raw materials limits the understanding of global trends in resource availability and hampers formulation of mineral and waste policies. This ultimately affects supply chain security and strategic decisions by industry. Hence, it is an issue of great concern for the European Commission (EC) and many other stakeholders. The ORAMA project (Optimising quality of information in RAw MAterial data collection across Europe) seeks to contribute to better supply of raw materials by improving the quality of harmonised raw materials data collection and information sharing among the different levels within the European Union (EU). Data collection practices for primary and secondary raw materials (PRM and SRM) face specific challenges in EU Member States (MS). For PRM data, the main concerns are related to data availability, geographical coverage, accessibility, harmonisation, interoperability, quality, and thematic coverage. The reporting of primary mineral resources and reserves statistics is currently carried out by a wide variety of systems, standards or codes which are not directly comparable. Hence, it is currently impossible to produce reliable pan-European figures for resources for any mineral commodity. ORAMA addresses these issues by recommending a single standard for reporting of resource data, the United Nations Framework Classification (UNFC), a framework for reporting mineral resource data developed by the UN. To enable and encourage data providers to adopt this standard for European PRM data, the ORAMA project has developed resources in the form of a range of training materials and good practice examples. The ORAMA project demonstrates that the analysis of various classifications and reporting systems that sit within the INSPIRE (Infrastructure for Spatial Information in the European Community) concept and data services, are not opposing but rather integral elements of the proper European level data collection and production of information for PRM and SRM. The use of UNFC/UNRMS (United Nations Resource Management System) in the framework of the INSPIRE compliant data service can significantly contribute to sustainable resource management taking into account not only geological knowledge and raw materials potential but also environmental and social issues, based on using the national/regional legislative elements for exploration and exploitation as well. In the case of SRM, the challenges are somewhat different. Regarding mining waste (MIN), the lack of information on deposit characteristics (composition, volumes, and suitable processing technology) is a huge barrier in the identification of recovery potential of the valuable materials that remain in the waste. Furthermore, the lack of a single reporting standard commonly accepted at EU level has created a dispersion of existing information in various systems and project deliverables. In the case of electrical and electronic equipment (EEE) and batteries, beyond the lack of harmonisation, substantial data gaps exist for the market inputs, materials consumption and stocks, and for waste electrical and electronic equipment (WEEE) for unaccounted flows ending up being scavenged, metal scrap and export channels. For vehicles, huge amounts of data, both on stocks and flows and on composition, are systematically collected by authorities and the manufacturing industry, but are only publicly available in a somewhat too aggregated form (placed on market (POM), stock, waste flows) or not at all (composition data). Even when collected, the reporting of the composition of these flows on a product, component and materials level are currently poorly described across all MS, and when actually ending up in recycling processes, the recovery efficiency for all elements and CRMs, in particular, is disappointing. In order to improve the data collection and reporting practices for SRM a structured review and inventory were made followed by a data gap analysis which resulted in the developments of recommendations and subsequently the selection of 6 case studies. The SRM case studies tackle the main data gaps encountered in the analysis and developed tools that will enable the improvement and harmonisation of collection and reporting practices in MS, treatment facilities, data providers, academia among others. The ORAMA project recommends to establish more structured and continuous funding for realising and maintaining a European data infrastructure for tracking both PRM and SRM. The current project-by-project based financing is insufficient and not sustainable to properly track and understand Europe’s strengths and weaknesses in the early resource intensive stages of global supply chains.
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| 5. |
- Kosaraju, Sravya, 1983
(författare)
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A review of the importance of recycling lithium-ion batteries for lithium, in view of impending electric vehicle industry
- 2012
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Rapport (övrigt vetenskapligt/konstnärligt)abstract
- Automobile electrification is one the technological developments, that will commence an earth friendly transport system, by mitigating emissions and hopefully lead to a less fossil fuel dependent society. With commercial success attained by models like Nissan’s leaf and Chevy’s Volt, the consumer market looks promising to assimilate vehicle electrification. At present these technologies include HEVs (hybrid electric vehicles), PHEVs (plug-in hybrid electric vehicles), EVs (complete electric vehicles).A closer look at these technologies will lead us to one of the crucial components of electric vehicles, the “batteries”. This component decides one of the key performance factors which is the energy storage and usage, which means it is the basis for public acceptability.The lithium-ion battery chemistries are chosen to fulfill this requirement. Although lithium constitutes of a small fraction of the complete battery weight, still its contin-ued availability in future is debated among many resource analysts.
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| 6. |
- Acuña, José, 1982-
(författare)
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Distributed thermal response tests : New insights on U-pipe and Coaxial heat exchangers in groundwater-filled boreholes
- 2013
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Konstnärligt arbete (övrigt vetenskapligt/konstnärligt)abstract
- U-pipe Borehole Heat Exchangers (BHE) are widely used today in ground source heating and cooling systems in spite of their less than optimal performance. This thesis provides a better understanding on the function of U-pipe BHEs and Investigates alternative methods to reduce the temperature difference between the circulating fluid and the borehole wall, including one thermosyphon and three different types of coaxial BHEs.Field tests are performed using distributed temperature measurements along U-pipe and coaxial heat exchangers installed in groundwater filled boreholes. The measurements are carried out during heat injection thermal response tests and during short heat extraction periods using heat pumps. Temperatures are measured inside the secondary fluid path, in the groundwater, and at the borehole wall. These type of temperature measurements were until now missing.A new method for testing borehole heat exchangers, Distributed Thermal Response Test (DTRT), has been proposed and demonstrated in U-pipe, pipe-in-pipe, and multi-pipe BHE designs. The method allows the quantification of the BHE performance at a local level.The operation of a U-pipe thermosyphon BHE consisting of an insulated down-comer and a larger riser pipe using CO2 as a secondary fluid has been demonstrated in a groundwater filled borehole, 70 m deep. It was found that the CO2 may be sub-cooled at the bottom and that it flows upwards through the riser in liquid state until about 30 m depth, where it starts to evaporate.Various power levels and different volumetric flow rates have been imposed to the tested BHEs and used to calculate local ground thermal conductivities and thermal resistances. The local ground thermal conductivities, preferably evaluated at thermal recovery conditions during DTRTs, were found to vary with depth. Local and effective borehole thermal resistances in most heat exchangers have been calculated, and their differences have been discussed in an effort to suggest better methods for interpretation of data from field tests.Large thermal shunt flow between down- and up-going flow channels was identified in all heat exchanger types, particularly at low volumetric flow rates, except in a multi-pipe BHE having an insulated central pipe where the thermal contact between down- and up-coming fluid was almost eliminated.At relatively high volumetric flow rates, U-pipe BHEs show a nearly even distribution of the heat transfer between the ground and the secondary fluid along the depth. The same applies to all coaxial BHEs as long as the flow travels downwards through the central pipe. In the opposite flow direction, an uneven power distribution was measured in multi-chamber and multi-pipe BHEs.Pipe-in-pipe and multi-pipe coaxial heat exchangers show significantly lower local borehole resistances than U-pipes, ranging in average between 0.015 and 0.040 Km/W. These heat exchangers can significantly decrease the temperature difference between the secondary fluid and the ground and may allow the use of plain water as secondary fluid, an alternative to typical antifreeze aqueous solutions. The latter was demonstrated in a pipe-in-pipe BHE having an effective resistance of about 0.030 Km/W.Forced convection in the groundwater achieved by injecting nitrogen bubbles was found to reduce the local thermal resistance in U-pipe BHEs by about 30% during heat injection conditions. The temperatures inside the groundwater are homogenized while injecting the N2, and no radial temperature gradients are then identified. The fluid to groundwater thermal resistance during forced convection was measured to be 0.036 Km/W. This resistance varied between this value and 0.072 Km/W during natural convection conditions in the groundwater, being highest during heat pump operation at temperatures close to the water density maximum.
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| 7. |
- Ahrné, Karin, et al.
(författare)
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Tillstånd och trender för arter och deras livsmiljöer – rödlistade arter i Sverige 2015
- 2015
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Rapport (övrigt vetenskapligt/konstnärligt)abstract
- 2015 års upplaga av den svenska rödlistan är den fjärde i ordningen. Den är baserad på IUCN:s rödlistningskriterier och revideras vart femte år. I rödlistan bedöms risken som enskilda arter av djur, växter och svampar löper att försvinna från Sverige. Bedömningen utförs av ArtDatabankens medarbetare i samverkan med över 100 externa experter, indelade i 14 expertkommittéer för olika organismgrupper. Under arbetet med 2015 års rödlista har tillstånd och trender bedömts för 21 600 arter och 1 318 lägre taxa (apomiktiska arter, underarter och varieteter), sammanlagt ca 22 900 taxa. Av de bedömda arterna klassificerades 2 029 som hotade (kategorierna CR, EN och VU) och 4 273 som rödlistade (inkluderar även kategorierna NT, RE och DD). Förhållandet mellan antalet rödlistade och antalet bedömda arter ar 19,8 %, vilket är ungefär samma värde som 2010 och 2005. I denna rapport jämförs antalet och andelen rödlistade arter mellan olika organismgrupper, biotoper, substrat och påverkansfaktorer. Texten ar indelad i en allmän del och åtta kapitel inriktade på olika landskapstyper. Landskapstyperna utgör en grov indelning av landets miljöer enligt följande kategorier: Skog, Jordbrukslandskap, Urbana miljöer, Fjäll, Våtmarker, Sötvatten, Havsstränder och Havsmiljöer. Skogen och jordbrukslandskapet är de artrikaste landskapstyperna med 1 800 respektive 1 400 arter som har en stark anknytning dit, och ytterligare flera hundra arter som förekommer där mer sporadiskt. De faktorer som påverkar flest rödlistade arter i Sverige är skogsavverkning och igenväxning, som båda utgör ett hot mot vardera ca 30 % av de rödlistade arterna. Avverkning minskar arealen av skog där naturliga strukturer och naturlig dynamik upprätthålls, och den orsakar därmed förlust av livsmiljöer. Igenväxning orsakas av ett antal faktorer, bland annat upphörande hävd (bete och slåtter), gödsling, trädplantering och brist på naturliga störningsregimer som t.ex. regelbundna översvämningar kring vattendrag och sjöar. Andra viktiga påverkansfaktorer är fiske, torrläggning av våtmarker, tillbakagång hos värdarter (främst alm och ask som drabbats av invasiva svampsjukdomar), klimatförändringar och konkurrens från invasiva arter. IUCN:s rödlisteindex beräknas för ett urval av de bedömda organismgrupperna. Rödlisteindex visar att skillnaderna mellan rödlistorna från 2000, 2005, 2010 och 2015 är små. Ett par undantag finns dock. Groddjur och stora däggdjur har fått en något förbättrad situation sedan 2000. Totalt förefaller det ändå som att trycket mot Sveriges artstock har förblivit relativt konstant under de senaste 15 åren.
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| 8. |
- Evertsson, Magnus, 1967, et al.
(författare)
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Control systems for improvement of cone crusher yield and operation
- 2014
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Ingår i: Proceedings of Comminution '14.
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Konferensbidrag (övrigt vetenskapligt/konstnärligt)abstract
- Gyratory and cone crushers are regaining interest and are becoming more frequently used in order to create more energy efficient comminution circuits. A typical example is found in coarse comminution circuits were HPGRs are used as a first milling stage. In this case the preparation of a suitable feed with a well-defined width of the particle size distribution and a controlled top size are of high importance. In turn, this emphasizes the importance of a stable and controlled operation of the preceding crushing stages. Control systems for cone and gyratory crushers were first introduced during the early 60ths. The common opinion is that if these systems are able to compensate for the wear of the crushing liners the production yield can be increased with 20-25%. Over the years these types of systems have been widely used but the theory behind the principles have not been thoroughly scientifically scrutinized and presented. Of special interest is the capability to protect the crushers from long term overloading commonly defined as fatigue.With developments in electronics and plant control the crusher control systems have become more refined over the years. Though, there are sometimes conflicting interests in the control strategies between process requirements and crusher protection. In the paper an overview of the challenges, opportunities and existing control systems for cone and gyratory crushers is presented. A requirement specification for a system that is possible to fully integrate into modern plant control systems is outlined.
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| 9. |
- Kalmykova, Yuliya, 1981, et al.
(författare)
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Phosphorus Recovery from Municipal Solid Waste Incineration Fly Ash
- 2013
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Ingår i: Waste Management. - : Elsevier BV. - 0956-053X .- 1879-2456. ; 33:6, s. 1403-1410
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Tidskriftsartikel (refereegranskat)abstract
- The potential of phosphorus (P) recycling from municipal solid waste incineration (MSWI) residue is investigated. Vast and ever increasing amounts of incineration residues are produced worldwide; these are an environmental burden, but also a resource, as they are a major sink for the material flows of society. Due to strict environmental regulations, in combination with decreasing landfilling space, the disposal of the MSWI residues is problematic. At the same time, resource scarcity is recognized as a global challenge for the modern world, and even more so for future generations. This paper reports on the methods and efficiency of P extraction from MSWI fly ash by acid and base leaching and precipitation procedures. Phosphorus extracted from the MSWI residues generated each year could meet 30 % of the annual demand for mineral phosphorus fertiliser in Sweden, given a recovery rate of 70 % achieved in this initial test. The phosphorus content of the obtained product is slightly higher than in sewage sludge, but due to the trace metal content it is not acceptable for application to agricultural land in Sweden, whereas application in the rest of the EU would be possible. However, it would be preferable to use the product as a raw material to replace rock phosphate in fertilizer production. Further development is currently underway in relation to procedure optimization, purification of the phosphorus product, and the simultaneous recovery of other resources.
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| 10. |
- Malovanyy, Myroslav, et al.
(författare)
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Disposal of pine wood waste by pelleting with sulphate soap binder
- 2024
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Ingår i: Pollack Periodica. - Poland. - 1788-1994 .- 1788-3911. ; 19:1, s. 47-52
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Tidskriftsartikel (refereegranskat)abstract
- Promising method for disposal the pine wood waste through extrusion pelleting using sulphate soap as a natural binder is considered in the article. Prior to pelleting, the wood waste requires drying to a water content of no more than 10%. Analysis of pine wood waste drying in filtration mode yielded optimal parameters: A 20 mm layer thickness, temperature of 135 °C, and drying time of 3,900 s. The optimal content of sulphate soap binder was determined to be about 20%, resulting in reduced coke residue, increased volatile components, higher calorific value, and enhanced static strength. This binder facilitates formation of pellets at lower pressures, increases calorific value, and acts as a lubricant, reducing friction and associated energy costs.
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| 11. |
- Johansson, Nils, 1981-, et al.
(författare)
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The institutional capacity for a resource transition : A critical review of Swedish governmental commissions on landfill mining
- 2017
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Ingår i: Environmental Science and Policy. - : Elsevier. - 1462-9011 .- 1873-6416. ; 70, s. 46-53
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Tidskriftsartikel (refereegranskat)abstract
- Recycling of minerals from waste deposits could potentially double the recycling flows while offering an opportunity to address the many problematic landfills. However, this type of activity, i.e., landfill mining, brings many advantages, risks and uncertainties and lacks economic feasibility. Therefore, we investigate the capacity of the Swedish authorities to navigate the environmental, resource, and economic conditions of landfill mining and their attitude to support such radical recycling alternatives towards a resource transition.By analyzing three governmental commissions on landfill mining, we show how the authorities seem unable to embrace the complexity of the concept. When landfill mining is framed as a remediation activity the authorities are positive in support, but when it is framed as a mining activity the authorities are negative. Landfill mining is evaluated based on how conventional practices work, with one and only one purpose: to extract resources or remediation. That traditional mining was a starting point in the evaluation becomes particularly obvious when the resource potential shall be evaluated. The resource potential of landfills is assessed based on metals with a high occurrence in the bedrock. If the potential instead had been based on metals with low incidence in the Swedish bedrock, the potential would have been found in the human built environment.Secondary resources in landfills seem to lack an institutional affiliation, since the institutional arrangements that are responsible for landfills primarily perceive them as pollution, while the institutions responsible for resources, on the other hand, assume them to be found in the bedrock. Finally, we suggest how the institutional capacity for a resource transition can increase by the introduction of a broader approach when evaluating emerging alternatives and a new institutional order.
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| 12. |
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| 13. |
- Quist, Johannes, 1985, et al.
(författare)
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Investigation of Roller Pressure and Shear Stress in the HPGR Using DEM
- 2016
-
Ingår i: XXVIII International Mineral Processing Congress Proceedings. - 9781926872292 ; 2016-September:Canadian Institute of Mining, Metallurgy and Petro
-
Konferensbidrag (refereegranskat)abstract
- HPGRs have since introduced in the 1980s (Kellerwessel, 1993; Schönert, 1988), now becomeintegral comminution units at several minerals processing plants around the world. Even though a lot of theinitial issues concerning performance, availability and wear have been addressed and solved there are stillphenomena and aspects which can be improved and understood further. Schönert and Sander (2002)presented experimental results and a mechanistic model including the internal force dynamics between therollers and the compacted bed. They derived expressions for the pressure distribution involving most of theinfluencing terms and effects. However, in order to solve the differential equations several of the termsvanish by assumptions. The Schönert and Sander model reflects the experimental data in many aspects butthe predicted shear force distinctly deviates from the experimental results at the angular position of thepeak pressure level. This finding suggests that the particle to particle interaction and breakage process inthe different zones seen in Figure 1 are complex and difficult to model using analytical models. Anumerical modelling approach using DEM does not require the same amount of assumptions andsimplifications of boundary conditions. Hence such modelling may provide further knowledge and vitalunderstanding. In this paper the breakage process is simulated in order to investigate the shear slipbehaviour and how it relates to different operating variables. A laboratory scale HPGR corresponding tothe experimental setup used by Schönert (2002) have been modelled in EDEM (DEM-Solutions). Thebonded particle model (BPM) is used for modelling quartz particles (Potyondy, 2004). The breakage modelstrength parameters are calibrated against interparticle breakage experiments in an Instron 400RDcompression device. The contact model parameters are calibrated using calibration methods developed byQuist (2015). The floating roller dynamics are modelled using a spring-damper system. Results presentinsights regarding the interparticle slip behaviour as well as the frictional tangential force distribution onthe rollers. The simulated roller pressure distribution shows good correspondence with previously reportedfindings in the literature.
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| 14. |
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| 15. |
- Eivazihollagh, Alireza, et al.
(författare)
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On chelating surfactants : Molecular perspectives and application prospects
- 2019
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Ingår i: Journal of Molecular Liquids. - : Elsevier BV. - 0167-7322 .- 1873-3166. ; 278, s. 688-705
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Tidskriftsartikel (refereegranskat)abstract
- Chelating agents, molecules that very strongly coordinates certain metal ions, are used industrially as well as in consumer products to minimize disturbances and increase performance of reactions and applications. The widely used sequestering agents, nitrilotriacetic acid (NTA), ethylenediaminetetraacetic acid (EDTA) and diethylenetriaminepentaacetic acid (DTPA) belong to this branch of readily water-soluble compounds. When these chemical structures also have hydrophobic parts, they are prone to adsorb at air-water interfaces and to self-assemble. Such bifunctional molecules can be called chelating surfactants and will have more extended utilization prospects than common chelating agents or ordinary ionic surfactants. The present review attempts to highlight the fundamental behavior of chelating surfactants in solution and at interfaces, and their very specific interactions with metal ions. Methods to recover chelating surfactants from metal chelates are also described. Moreover, utilization of chelating surfactants in applications for metal removal in environmental engineering and mineral processing, as well as for metal control in the fields of biology, chemistry and physics, is exemplified and discussed.
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| 16. |
- Grip, Carl-Erik, et al.
(författare)
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Application of Pinch Analysis in an Integrated Steel Plant in Northern Sweden
- 2013
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Ingår i: ISIJ International. - : Iron and Steel Institute of Japan. - 0915-1559 .- 1347-5460. ; 53:7, s. 1202-1210
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Tidskriftsartikel (refereegranskat)abstract
- The energy system in a modern integrated steel plant is a complicated network of units exchangingenergy and matter with each other. System studies using process integration tools are important to avoidsub-optimization. At the steel plant in Luleå such studies have been carried out using a MILP-based mathematicalprogramming tool (reMIND), mainly because of its inherent flexibility for handling combinedflows and reactions of both matter and chemical, thermal and mechanical energy. There are, however,areas where the energy system is dominated by creation, transport and exchange of thermal energy, andwhere pinch analysis can be expected to be a valuable tool. For this reason a pinch targeting study wascarried out for the plant site of the integrated steel plant in Luleå. The coke plant and the iron making/steelmaking plant were both studied with three ambition levels of possible improvements. The study confirmedthat pinch analysis is a powerful tool for targeting energy savings in areas where thermal energyflows dominate the local energy system, e.g., the gas cleaning area at the coke plant. The study also indicatedthat a connection between the energy systems in the coke plant and the iron making/steelmakingwould be valuable. This is not 100% feasible because of distance, but, a common steam net could add adegree of flexibility.
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| 17. |
- Hildor, Fredrik, 1992
(författare)
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Steel converter slag as an oxygen carrier
- 2023
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Doktorsavhandling (övrigt vetenskapligt/konstnärligt)abstract
- Thermal conversion of fuels can be used to produce heat and power in addition to chemicals. In order to be aligned with climate targets, it is necessary that such systems do not emit carbon dioxide to the atmosphere. Carbon capture and storage (CCS) can be used together with fuel conversion systems to prevent CO2 from entering the atmosphere. If CCS is used together with biomass-based fuels, it is possible to achieve a net-flow of carbon dioxide out of the atmosphere, so called negative emissions. Chemical looping technologies for combustion (CLC) and gasification (CLG) are technologies which can be used for heat, power and chemical production with no or low penalties for carbon capture. In any chemical looping applications, a functional oxygen carrier is essential. The oxygen carrier is normally a metal oxide based material that can transport oxygen from one reactor to another. However, when fuel is introduced into the system, ash can react with the oxygen carrier and decrease its operational lifespan, especially reactive ash from biomass and low-grade fuels. Therefore, there is growing interest in low-cost oxygen carriers that can contribute to making the process economically feasible. Low-cost oxygen carriers can be obtained from ores or as byproducts of the steel industry. Of particular interest is steel converter slag, which is also known as Linz-Donawitz (LD) slag. LD slag is generated in significant amounts, contains sufficient amount of iron oxide (that can act as an oxygen carrier) and available at a low cost. This work presents a comprehensive overview of the chemistry and behavior of LD slag when it is implemented as an oxygen carrier in chemical-looping applications. The material has been investigated in laboratory reactors, in addition to pilot and semi-industrial units, and LD slags interactions with different fuel components, ash, alkali salts, sulfur and tars have been investigated. It is concluded from this work that LD slag can be viable as material for both CLC and CLG processes with biomass. In contrast to other bed materials, such as silica sand or the commonly investigated iron-based oxygen carrier ilmenite, the slag has limited reactivity with reactive alkali components. This results in more alkali being available in the gas phase, which is beneficial for tar cracking and for the gasification rate of the solid char. The high content of calcium in the LD slag is also favorable in terms of gasification and ash interactions. Calcium oxide catalyzes both the water-gas shift reaction and is catalytic towards tar cracking. A high level of calcium also increases the melting points of both the K-Ca-P and K-Ca-Si matrixes. However, the structural integrity of the material is lower compared to, for example, ilmenite, resulting in more fines being generated during the process. Overall, LD slag is a potential oxygen carrier that is suitable for chemical-looping processes that utilize low-grade fuels.
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| 18. |
- Jianliang, Wang, et al.
(författare)
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Chinese coal supply and future production outlooks
- 2013
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Ingår i: Energy. - : Elsevier BV. - 0360-5442 .- 1873-6785. ; 60, s. 204-214
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Tidskriftsartikel (refereegranskat)abstract
- China's energy supply is dominated by coal, making projections of future coal production in China important. Recent forecasts suggest that Chinese coal production may reach a peak in 2010–2039 but with widely differing peak production levels. The estimated URR (ultimately recoverable resources) influence these projections significantly, however, widely different URR-values were used due to poor understanding of the various Chinese coal classification schemes. To mitigate these shortcomings, a comprehensive investigation of this system and an analysis of the historical evaluation of resources and reporting issues are performed. A more plausible URR is derived, which indicates that many analysts underestimate volumes available for exploitation. Projections based on the updated URR using a modified curve-fitting model indicate that Chinese coal production could peak as early as 2024 at a maximum annual production of 4.1 Gt. By considering other potential constraints, it can be concluded that peak coal in China appears inevitable and immediate. This event can be expected to have significant impact on the Chinese economy, energy strategies and GHG (greenhouse gas) emissions reduction strategies.
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| 19. |
- Kahlert, Maria
(författare)
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Analys av kiselalger LKAB, Kiruna 2011
- 2012
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Rapport (övrigt vetenskapligt/konstnärligt)abstract
- Sammanfattningsvis så visar kiselalgsfloran i de undersökta vattendragen inte på någon störning. Både referenser skiljer sig ej mycket från lokalerna nedströms. Den ganska rika diversiteten, det medelstora taxaantalet, det låga andelen deformerade skal och den höga statusklassningen tyder alla på att kiselalgsfloran i de undersökta vattendragen mår bra. Det verkar inte heller finnas en övergödning- eller försurningsproblem och lokalerna är inte kalkade. Det nya utloppet från sjön öppnades den 11 juli 2011 och proverna togs den 25 augusti, vilket innebär att lokalerna exponerats under ca 1,5 månad. Vattenkemidata visar dock att inga förändringar i t.ex. metallhalten hade skett under denna tid, vilket gör det osannolikt att kiselalgerna exponerades för någon toxiskt påverkan. Undersökningen kan därför anses vara ett underlag vid bedömningen av kommande undersökningar.
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| 20. |
- Mohr, Steve, et al.
(författare)
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Projection of long-term paths for Australian coal production : comparisons of four models
- 2011
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Ingår i: International Journal of Coal Geology. - : Elsevier BV. - 0166-5162 .- 1872-7840. ; 86:4, s. 329-341
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Tidskriftsartikel (refereegranskat)abstract
- Coal exports are an important source of revenue for Australia and for this reason Australian coal production and resources have been examined in detail and two recoverable resource estimates determined namely Standard and High. The Standard case calculated the likely recoverable coal resources in Australia to be 317 Gt, whereas the High scenario determined the maximal amount of recoverable coal resources at 367 Gt. Different modelling approaches (Logistic, Gompertz, Static and Dynamic supply and demand models) were used to project fossil fuel production and the projections of the relative approaches were compared. Good agreement was found between the Logistic, Static and Dynamic supply and demand models with production peaking in 2119 +/- 6 at between 1.9 and 3.3 Gt/y. Contrasting these projections the Gompertz curves peak in 2084 +/- 5 at 1-1.1 Gt/y. It was argued that the Logistic, Static and Dynamic models are more likely to produce accurate projections than the Gompertz curve. The production forecast is based on existing technology and constraints and a qualitative discussion is presented on possible influences on future production, namely: export capacity, climate change, overburden management, environmental and social impacts and export market issues.
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| 21. |
- Moldenhauer, Patrick, 1983, et al.
(författare)
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Avoiding CO2 capture effort and cost for negative CO2 emissions using industrial waste in chemical-looping combustion/gasification of biomass
- 2020
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Ingår i: Mitigation and Adaptation Strategies for Global Change. - : Springer Science and Business Media LLC. - 1381-2386 .- 1573-1596. ; 25:1, s. 1-24
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Tidskriftsartikel (refereegranskat)abstract
- Chemical-looping combustion (CLC) is a combustion process with inherent separation of carbon dioxide (CO2), which is achieved by oxidizing the fuel with a solid oxygen carrier rather than with air. As fuel and combustion air are never mixed, no gas separation is necessary and, consequently, there is no direct cost or energy penalty for the separation of gases. The most common form of design of chemical-looping combustion systems uses circulating fluidized beds, which is an established and widely spread technology. Experiments were conducted in two different laboratory-scale CLC reactors with continuous fuel feeding and nominal fuel inputs of 300 Wth and 10 kWth, respectively. As an oxygen carrier material, ground steel converter slag from the Linz–Donawitz process was used. This material is the second largest flow in an integrated steel mill and it is available in huge quantities, for which there is currently limited demand. Steel converter slag consists mainly of oxides of calcium (Ca), magnesium (Mg), iron (Fe), silicon (Si), and manganese (Mn). In the 300 W unit, chemical-looping combustion experiments were conducted with model fuels syngas (50 vol% hydrogen (H2) in carbon monoxide (CO)) and methane (CH4) at varied reactor temperature, fuel input, and oxygen-carrier circulation. Further, the ability of the oxygen-carrier material to release oxygen to the gas phase was investigated. In the 10 kW unit, the fuels used for combustion tests were steam-exploded pellets and wood char. The purpose of these experiments was to study more realistic biomass fuels and to assess the lifetime of the slag when employed as oxygen carrier. In addition, chemical-looping gasification was investigated in the 10 kW unit using both steam-exploded pellets and regular wood pellets as fuels. In the 300 W unit, up to 99.9% of syngas conversion was achieved at 280 kg/MWth and 900 °C, while the highest conversion achieved with methane was 60% at 280 kg/MWth and 950 °C. The material’s ability to release oxygen to the gas phase, i.e., CLOU property, was developed during the initial hours with fuel operation and the activated material released 1–2 vol% of O2 into a flow of argon between 850 and 950 °C. The material’s initial low density decreased somewhat during CLC operation. In the 10 kW, CO2 yields of 75–82% were achieved with all three fuels tested in CLC conditions, while carbon leakage was very low in most cases, i.e., below 1%. With wood char as fuel, at a fuel input of 1.8 kWth, a CO2 yield of 92% could be achieved. The carbon fraction of C2-species was usually below 2.5% and no C3-species were detected. During chemical-looping gasification investigation a raw gas was produced that contained mostly H2. The oxygen carrier lifetime was estimated to be about 110–170 h. However, due to its high availability and potentially low cost, this type of slag could be suitable for large-scale operation. The study also includes a discussion on the potential advantages of this technology over other technologies available for Bio-Energy Carbon Capture and Storage, BECCS. Furthermore, the paper calls for the use of adequate policy instruments to foster the development of this kind of technologies, with great potential for cost reduction but presently without commercial application because of lack of incentives.
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| 22. |
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| 23. |
- Pondja, Estevao
(författare)
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Environmental aspects of coal mine drainage: a regional study of Moatize in Mozambique
- 2017
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Doktorsavhandling (övrigt vetenskapligt/konstnärligt)abstract
- Mozambique is one of the largest coal producers in Africa. Extraction of the coal is carried out in the Moatize district of the Tete province in the center of the country. A surface mining technique is used to extract the coal below ground level. During mining activities, sulfide minerals, which are commonly associated with coal, are exposed to oxygen and water, leading to the generation of acid mine drainage (AMD). AMD is high in acidity and has a high content of metals, metalloids and sulfate that can cause severe damage to the environment. Moatize is inside the lower Zambezi River basin, the pollution that occurs there due to mining activities constituting a risk both for public health and for the water resources. The standard guidelines in Mozambique for wastewater from coal mining are very weak, allowing the coal mining companies to pollute considerably. The prevention, containment and remediation of polluted mine water are measures that should be carried out to avoid the spread of pollution. Prevention is the least expensive strategy, but it cannot always prevent the generation of polluted mine water. Thus containment and treatment need to be put into practice. Both active and passive treatment are used to treat polluted mine water. Since Moatize is a largely unstudied area, both static and leaching tests were carried out to investigate the possibility of AMD being generated. The geochemical processes that could impact on the quality of mine drainage stemming from the waste rock there were assessed. Use of cost-effective methods for the treatment of mine water by use of bioremediation coupled with adsorption, using cassava peels that are readily available in the country as a carbon source and as an adsorbent is proposed. Since climate changes and climate variability can exacerbate the negative impact of surface mining, the possibility of this was assessed. It was found that the production of AMD was likely in at least one of the coal mines in Moatize. The mine water from coal mines in Moatize was found to have a high content of sulfate, calcium, magnesium and manganese. A set of guidelines for coal mine effluents that was developed, based on different guidelines obtained from around the world, was proposed for Mozambique. Sulfate reducing bacteria coupled with adsorption appeared to be appropriate for removing these pollutants. Cassava peels used as adsorbents appeared to be effective in removing calcium, magnesium and manganese. Based on climate data, the period from November on through February was found to be the period in which the pollution load in Moatize was greatest. Since the flow rate in the Revúbué River, which is close to the coal mines, is highly dependent upon the precipitation that occurs during the rainy season, the discharge of polluted mine water should be avoided. To achieve sustainable mining in Moatize, the coal mining companies, the regulators and the stakeholders from water sector there need to work together. A framework for integrating efforts to satisfy the needs of the different stakeholders involved in the water sector in Moatize was proposed.
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| 24. |
- Qureshi, Asif, 1986-, et al.
(författare)
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Effects of the co-disposal of lignite fly ash and coal mine waste rocks on AMD and leachate quality
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Annan publikation (övrigt vetenskapligt/konstnärligt)abstract
- Lignite fly ash (FA) and waste rocks (WRs) were mixed in three different ratios (1:1, 1:3 and 1:5) and studied to compare the effects of adding FA on AMD generation from coal mining WRs, leachability of elements and the potential occurrence of secondary minerals. FA mixed with WRs showed significant differences in pH levels compared to previous research. The 1:1 mixture performed best of all the three mixtures in terms of pH and leachability of elements, mainly due to the higher proportion of FA in the mixture. The pH in the 1:1 mixtures varied between 3.3 – 5.1 compared to other mixtures (2.3 – 3.5). Iron and SO42- leached considerably less from the 1:1 mixture compared to the others, indicating that the oxidation of sulphides was weaker in this mixture. Aluminium leached to a high degree from all mixtures, with concentrations varying from mg L-1–g L-1. The reason behind this increase is probably the addition of FA which, due to acidic conditions and the composition of the FA, increases the availability of Al. For the same reason, high concentrations of Mn and Zn were also measured. Geochemical modelling indicates that the 1:1 mixture performs better in terms of precipitation of Al3+ minerals, whereas Fe3+ minerals precipitated more in mixtures containing less FA. These results suggest that, with time, the pores could possibly be filled with these secondary minerals and sulphate salts (followed by a decrease in sulphide oxidation), improving the pore water pH and decreasing the leachability of elements. Since grain size plays a crucial role in the reactivity of sulphides, there is a risk that the results from the leaching tests may have been influenced by crushing and milling of the WR samples.
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| 25. |
- Qureshi, Asif, 1986-, et al.
(författare)
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Effects of the co-disposal of lignite fly ash and coal mine waste rocks on AMD and leachate quality
- 2019
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Ingår i: Environmental Science and Pollution Research. - : Springer. - 0944-1344 .- 1614-7499. ; 26:4, s. 4104-4115
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Tidskriftsartikel (refereegranskat)abstract
- Lignite fly ash (FA) and waste rocks (WRs) were mixed in three different ratios (1:1, 1:3 and 1:5) and studied to compare the effects of adding FA on acid mine drainage generation from coal mining WRs, leachability of elements and the potential occurrence of the secondary minerals. FA mixed with WRs showed significant differences in pH levels compared to previous research. The 1:1 mixture performed best of all the three mixtures in terms of pH and leachability of elements, mainly due to the higher proportion of FA in the mixture. The pH in the 1:1 mixtures varied between 3.3 and 5.1 compared to other mixtures (2.3–3.5). Iron and SO42− leached considerably less from the 1:1 mixture compared to the others, indicating that the oxidation of sulphides was weaker in this mixture. Aluminium leached to a high degree from all mixtures, with concentrations varying from mg L−1 to g L−1. The reason behind this increase is probably the addition of FA which, due to acidic conditions and the composition of the FA, increases the availability of Al. For the same reason, high concentrations of Mn and Zn were also measured. Geochemical modelling indicates that the 1:1 mixture performs better in terms of precipitation of Al3+ minerals, whereas Fe3+ minerals precipitated more in mixtures containing less FA. These results suggest that, with time, the pores could possibly be filled with these secondary minerals and sulphate salts (followed by a decrease in sulphide oxidation), improving the pore water pH and decreasing the leachability of elements. Since grain size plays a crucial role in the reactivity of sulphides, there is a risk that the results from the leaching tests may have been influenced by crushing and milling of the WR samples.
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