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Diener, Silvia
Publications (10 of 13) Show all publications
Brännvall, E., Andreas, L., Sjöblom, R., Diener, S. & Lagerkvist, A. (2014). Factors influencing chemical and mineralogical changes in RDF fly ashes during aging (ed.). Journal of environmental engineering, 140(3), Article ID 4013014.
Open this publication in new window or tab >>Factors influencing chemical and mineralogical changes in RDF fly ashes during aging
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2014 (English)In: Journal of environmental engineering, ISSN 0733-9372, E-ISSN 1943-7870, Vol. 140, no 3, article id 4013014Article in journal (Refereed) Published
Abstract [en]

The effects of aging should be considered for reliable long-term assessments of the environmental risks of the use of refuse-derived-fuel (RDF) fly ash as landfill top cover liner material. Mineral transformations that occur in RDF fly ash, and the effects of selected factors on these transformations, were studied on compacted fly ash specimens in an accelerated aging experiment using a reduced factorial design. Carbon dioxide concentration, temperature, relative air humidity, time, and the quality of added water were varied in six factor combinations. Acid neutralization capacity and leaching behavior were analyzed after four different periods of time. The results were evaluated with multivariate data analysis. A significant change in the acid neutralization capacity, a decrease in leaching of Ba, Ca, Cl − , Cr, Cu, Pb, K, and Na, and an increase in solubility of Mg, Si, Zn, and SO 2− 4 could be attributed to different aging conditions

National Category
Other Environmental Engineering
Research subject
Waste Science and Technology
Identifiers
urn:nbn:se:ltu:diva-9814 (URN)10.1061/(ASCE)EE.1943-7870.0000802 (DOI)000332659800009 ()2-s2.0-84894352857 (Scopus ID)87fa6fee-92b6-4121-bb20-1f4cc6fca0fa (Local ID)87fa6fee-92b6-4121-bb20-1f4cc6fca0fa (Archive number)87fa6fee-92b6-4121-bb20-1f4cc6fca0fa (OAI)
Note

Validerad; 2014; 20130923 (evebra)

Available from: 2016-09-29 Created: 2016-09-29 Last updated: 2018-07-10Bibliographically approved
Andreas, L., Diener, S. & Lagerkvist, A. (2014). Hydraulic performance of a land-fill top cover based on steel slag (ed.). In: (Ed.), Raffaello Cusso (Ed.), Sardinia 2013: 14th International Waste Management and Landfill Symposium, Forte Village, S. Margherita di Pula (CA), Italy, 30 September - 4 October 2013 ; CD-ROM: Symposium proceedings. Paper presented at International Waste Management and Landfill Symposium : 30/09/2013 - 04/10/2013. Cagliari: CISA, Environmental Sanitary Engineering Centre
Open this publication in new window or tab >>Hydraulic performance of a land-fill top cover based on steel slag
2014 (English)In: Sardinia 2013: 14th International Waste Management and Landfill Symposium, Forte Village, S. Margherita di Pula (CA), Italy, 30 September - 4 October 2013 ; CD-ROM: Symposium proceedings / [ed] Raffaello Cusso, Cagliari: CISA, Environmental Sanitary Engineering Centre , 2014Conference paper, Published paper (Other academic)
Abstract [en]

HYDRAULIC PERFORMANCE OF A LAND¬FILL TOP COVER BASED ON STEEL SLAGThe steel industry is expanding and following the amount of produced steel, more and more by-products and residuals are generated. About 17.6 million tonnes of steel slags arise in Europe every year. In Sweden about 18 % of the iron- and steelmaking slags are landfilled (Jernkontoret, 2012). One application for steel slags are landfill covers where large amounts of virgin materials are needed. The legal requirement in Sweden is directed towards the maxi¬mum amount of lea¬chate generated at the bottom of the landfill: < 5 and < 50 l (m2*a)-1 for landfill class 1 and 2, respec¬ti¬vely. To secure these demands, a layer of low permeability is needed to reduce water infiltration. The hydraulic load of this layer ought to be controlled by a protective water balance layer and an effective drainage layer.Previous investigations indicate that steel slags can be used as construction material for both liner and drainage layer (Herrmann et al., 2010). In order to verify this in full scale, five tests areas (A1-5) were constructed at a municipal landfill in Sweden between 2005 and 2011. The areas were designed using different mixtures of steel slags from the local steel company in the liner. The purpose of this study was to evaluate the hydraulic performance of the cover during the first years after installation.The design of the cover construction was varied like this: a mixture of 50 % electric arc furnace slag (EAFS) and 50 % ladle slag (LS) was tested as liner material in the first test area (A1). A2 and A3 were built using less LS and coarser fractions of EAFS since laboratory tests had given satisfactory results also for these recipes. High infiltration rates in A2 and 3 led to a return to the original weight proportions in A4 and 5, yet another EAF slag was introduced in these areas. The mixing and construction techniques were refined during the first years of the project time: while A1 was built with rather poorly conceived technique, as of A3 the method can be considered as technically mature and approved.The liner performance was evaluated by lysimetry: 10 lysimeters were installed below each test area. The infiltration below the liner corresponded to 44, 74, 71, 19 and 0.4 l/m2*year for A1 to A5. Compared to the legal limit of 50 l/m2*year, the covers of A2 and A3 allowed about 50 % more water to enter the landfill than stipulated.An initial increase of the infiltration was observed, which most likely is related to increasing water saturation of the liner material in the first period after construction. The saturation occurred fastest in A2, where basically no initial increase was observed, probably due to the long time that elapsed between construction and the first sampling event (260 days). In contrast, the saturation in A1 and A4 was quite slow which can be related to the smaller particle size of the slags in these areas and, hence, a less porous liner material. The decrease in A2 and A3 might be explained by mineral transformations within the slag matrix such as carbonation of calcium and magnesium leading to the precipitation of carbonates in the pores of the liner material. Future observations will show if the decreasing trend in A2 and A3 remains such that the infiltration eventually reaches a level falling below the legal limit.The results show that the infiltration criteria can be fulfilled under the condition that at least 50 % of the liner mix consists of ladle slag, a fine-grained slag with cementitious properties. With few adaptations the steel slag can be used with standard construction processes.

Place, publisher, year, edition, pages
Cagliari: CISA, Environmental Sanitary Engineering Centre, 2014
Keywords
Other technology - Environmental engineering, Landfill Technology, Waste Science and Technology, Lysimetry, Steel slag, Övriga teknikvetenskaper - Miljöteknik
National Category
Other Environmental Engineering
Research subject
Waste Science and Technology
Identifiers
urn:nbn:se:ltu:diva-34648 (URN)8e7d5362-de7c-4e50-86a6-e3975c59b977 (Local ID)8e7d5362-de7c-4e50-86a6-e3975c59b977 (Archive number)8e7d5362-de7c-4e50-86a6-e3975c59b977 (OAI)
Conference
International Waste Management and Landfill Symposium : 30/09/2013 - 04/10/2013
Note
Godkänd; 2014; 20140321 (laan)Available from: 2016-09-30 Created: 2016-09-30 Last updated: 2018-05-15Bibliographically approved
Andreas, L., Diener, S. & Lagerkvist, A. (2014). Steel slags in a landfill top cover: Experiences from a full-scale experiment (ed.). Paper presented at . Waste Management, 34(3), 692-701
Open this publication in new window or tab >>Steel slags in a landfill top cover: Experiences from a full-scale experiment
2014 (English)In: Waste Management, ISSN 0956-053X, E-ISSN 1879-2456, Vol. 34, no 3, p. 692-701Article in journal (Refereed) Published
Abstract [en]

A full scale field study has been carried out in order to test and evaluate the use of slags from high-alloy steel production as the construction materials for a final cover of an old municipal landfill. Five test areas were built using different slag mixtures within the barrier layer (liner). The cover consisted of a foundation layer, a liner with a thickness of 0.7 m, a drainage layer of 0.3 m, a protection layer of 1.5 m and a vegetation layer of 0.25 m. The infiltration varied depending on the cover design used, mainly the liner recipe but also over time and was related to seasons and precipitation intensity. The test areas with liners composed of 50% electric arc furnace (EAF) slag and 50% cementitious ladle slag (LS) on a weight basis and with a proper consistence of the protection layer were found to meet the Swedish infiltration criteria of ⩽50 l (m2 a)−1 for final covers for landfills for non-hazardous waste: the cumulative infiltration rates to date were 44, 19 and 0.4 l (m2 a)−1 for A1, A4 and A5, respectively. Compared to the precipitation, the portion of leachate was always lower after the summer despite high precipitation from June to August. The main reason for this is evapotranspiration but also the fact that the time delay in the leachate formation following a precipitation event has a stronger effect during the shorter summer sampling periods than the long winter periods. Conventional techniques and equipment can be used but close cooperation between all involved partners is crucial in order to achieve the required performance of the cover. This includes planning, method and equipment testing and quality assurance.

National Category
Other Environmental Engineering
Research subject
Waste Science and Technology
Identifiers
urn:nbn:se:ltu:diva-7414 (URN)10.1016/j.wasman.2013.12.003 (DOI)000332266100013 ()24393476 (PubMedID)2-s2.0-84893787800 (Scopus ID)5ca6d855-77a6-4d3d-9680-b579df6996a8 (Local ID)5ca6d855-77a6-4d3d-9680-b579df6996a8 (Archive number)5ca6d855-77a6-4d3d-9680-b579df6996a8 (OAI)
Note
Validerad; 2014; 20140107 (andbra)Available from: 2016-09-29 Created: 2016-09-29 Last updated: 2018-07-10Bibliographically approved
Diener, S., Andreas, L., Herrmann, I., Ecke, H. & Lagerkvist, A. (2010). Accelerated carbonation of steel slags in a landfill cover construction (ed.). Paper presented at . Waste Management, 30(1), 132-139
Open this publication in new window or tab >>Accelerated carbonation of steel slags in a landfill cover construction
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2010 (English)In: Waste Management, ISSN 0956-053X, E-ISSN 1879-2456, Vol. 30, no 1, p. 132-139Article in journal (Refereed) Published
Abstract [en]

Steel slags from high-alloyed tool steel production were used in a full scale cover construction of a municipal solid waste (MSW) landfill. In order to study the long-term stability of the steel slags within the final cover, a laboratory experiment was performed. The effect on the ageing process, due to i.e. carbonation, exerted by five different factors resembling both the material characteristics and the environmental conditions is investigated. Leaching behaviour, acid neutralization capacity and mineralogy (evaluated by means of X-ray diffraction, XRD, and thermogravimetry/differential thermal analysis, TG/DTA) are tested after different periods of ageing under different conditions.Samples aged for 3 and 10 months were evaluated in this paper. Multivariate data analysis was used for data evaluation. The results indicate that among the investigated factors, ageing time and carbon dioxide content of the atmosphere were able to exert the most relevant effect. However, further investigations are required in order to clarify the role of the temperature.

Keywords
Landfill Technology, Other technology - Environmental engineering, Upplagsteknik, Övriga teknikvetenskaper - Miljöteknik
National Category
Water Engineering Other Environmental Engineering
Research subject
Urban Water Engineering; Waste Science and Technology
Identifiers
urn:nbn:se:ltu:diva-12037 (URN)10.1016/j.wasman.2009.08.007 (DOI)000273195100017 ()19836224 (PubMedID)2-s2.0-70649111296 (Scopus ID)b172ec40-bf19-11de-b769-000ea68e967b (Local ID)b172ec40-bf19-11de-b769-000ea68e967b (Archive number)b172ec40-bf19-11de-b769-000ea68e967b (OAI)
Note
Validerad; 2010; 20091022 (ysko)Available from: 2016-09-29 Created: 2016-09-29 Last updated: 2018-07-10Bibliographically approved
Diener, S., Andreas, L., Brännvall, E. & Lagerkvist, A. (2010). Evaluation and discussion of steel slag mineralogy after ageing under laboratory and field conditions (ed.). In: (Ed.), (Ed.), The 6th Intercontinental Landfill research Symposium: . Paper presented at Intercontinental Landfill Research Symposium : 09/06/2010 - 12/06/2010 (pp. 107-109).
Open this publication in new window or tab >>Evaluation and discussion of steel slag mineralogy after ageing under laboratory and field conditions
2010 (English)In: The 6th Intercontinental Landfill research Symposium, 2010, p. 107-109Conference paper, Meeting abstract (Other academic)
National Category
Other Environmental Engineering
Research subject
Waste Science and Technology
Identifiers
urn:nbn:se:ltu:diva-40107 (URN)f1827630-bbe8-11df-a707-000ea68e967b (Local ID)f1827630-bbe8-11df-a707-000ea68e967b (Archive number)f1827630-bbe8-11df-a707-000ea68e967b (OAI)
Conference
Intercontinental Landfill Research Symposium : 09/06/2010 - 12/06/2010
Note
Godkänd; 2010; 20100909 (evebra)Available from: 2016-10-03 Created: 2016-10-03 Last updated: 2018-05-15Bibliographically approved
Brännvall, E., Andreas, L., Diener, S., Tham, G., Sjöblom, R. & Lagerkvist, A. (2010). Formation of secondary mineral phases during the ageing of RDF fly ashes (ed.). In: (Ed.), (Ed.), The 6th Intercontinental Landfill Research Symposium: . Paper presented at Intercontinental Landfill Research Symposium : 09/06/2010 - 12/06/2010 (pp. 110-112).
Open this publication in new window or tab >>Formation of secondary mineral phases during the ageing of RDF fly ashes
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2010 (English)In: The 6th Intercontinental Landfill Research Symposium, 2010, p. 110-112Conference paper, Meeting abstract (Other academic)
National Category
Other Environmental Engineering
Research subject
Waste Science and Technology
Identifiers
urn:nbn:se:ltu:diva-38901 (URN)d74cb2f0-bb50-11df-a707-000ea68e967b (Local ID)d74cb2f0-bb50-11df-a707-000ea68e967b (Archive number)d74cb2f0-bb50-11df-a707-000ea68e967b (OAI)
Conference
Intercontinental Landfill Research Symposium : 09/06/2010 - 12/06/2010
Note
Godkänd; 2010; 20100908 (evebra)Available from: 2016-10-03 Created: 2016-10-03 Last updated: 2018-05-15Bibliographically approved
Diener, S., Brännvall, E. & Andreas, L. (2010). Leaching properties of steel slags after ageing under laboratory and field conditions (ed.). In: (Ed.), Ron Zevenhoven. (Ed.), Third International Conference on Accelerated Carbonation for Environmental and Materials Engineering: ACEME10 : November 29 - December 1, 2010, Åbo Akademi University, Åbo/Turku, Finland : proceedings. Paper presented at International Conference on Accelerated Carbonation for Environmental and Materials Engineering : 29/11/2010 - 01/12/2010. Åbo: Åbo Akademi University Press
Open this publication in new window or tab >>Leaching properties of steel slags after ageing under laboratory and field conditions
2010 (English)In: Third International Conference on Accelerated Carbonation for Environmental and Materials Engineering: ACEME10 : November 29 - December 1, 2010, Åbo Akademi University, Åbo/Turku, Finland : proceedings / [ed] Ron Zevenhoven., Åbo: Åbo Akademi University Press, 2010Conference paper, Published paper (Refereed)
Place, publisher, year, edition, pages
Åbo: Åbo Akademi University Press, 2010
National Category
Other Environmental Engineering
Research subject
Waste Science and Technology
Identifiers
urn:nbn:se:ltu:diva-38388 (URN)cc3a96e9-4e4b-4c0f-b122-be873089f9bd (Local ID)978-952-12-2505-5 (ISBN)cc3a96e9-4e4b-4c0f-b122-be873089f9bd (Archive number)cc3a96e9-4e4b-4c0f-b122-be873089f9bd (OAI)
Conference
International Conference on Accelerated Carbonation for Environmental and Materials Engineering : 29/11/2010 - 01/12/2010
Note
Godkänd; 2010; 20120110 (andbra)Available from: 2016-10-03 Created: 2016-10-03 Last updated: 2017-11-25Bibliographically approved
Herrmann, I., Diener, S., Andreas, L. & Lind, L. (2010). Steel slag used in landfill cover liners: laboratory and field tests (ed.). Paper presented at . Waste Management & Research, 28(12), 1114-1121
Open this publication in new window or tab >>Steel slag used in landfill cover liners: laboratory and field tests
2010 (English)In: Waste Management & Research, ISSN 0734-242X, E-ISSN 1096-3669, Vol. 28, no 12, p. 1114-1121Article in journal (Refereed) Published
Abstract [en]

Stricter rules for landfilling within the EU have led to the closure of many landfills and a need for large amounts of cover liner materials. Therefore, the potential utilization of mixtures of electric arc furnace slag (EAFS) and ladle slag (LS), which are currently deposited in landfills, as a material for use as landfill liner was investigated. Laboratory analyses showed the mixtures to have similar compression strength to that of high-strength concrete and low hydraulic conductivity (<10-11 m s-1 in some cases). However, both their hydraulic conductivity and compaction properties were strongly affected by the time between adding water to the mixtures and compacting them (tests showed that a delay of 24 h can lead to an increase in hydraulic conductivity, so it should be compacted as soon as possible after mixing the material with water). In addition, the performance of a cover liner constructed using EAFS and LS was studied in a 2-year field trial on a landfill for municipal solid waste, in which the average amount of leachate collected from ten lysimeters was only 27 L m-2 year-1, easily meeting Swedish criteria for the permeability of covers on non-hazardous waste landfills (≤50 L m-2 year-1). Thus, the material seems to have promising potential for use in barrier constructions.

National Category
Other Environmental Engineering
Research subject
Waste Science and Technology
Identifiers
urn:nbn:se:ltu:diva-8781 (URN)10.1177/0734242X10365095 (DOI)000285411200007 ()20421245 (PubMedID)2-s2.0-78650466526 (Scopus ID)750b0890-078f-11e0-b767-000ea68e967b (Local ID)750b0890-078f-11e0-b767-000ea68e967b (Archive number)750b0890-078f-11e0-b767-000ea68e967b (OAI)
Note
Validerad; 2011; 20101214 (laan)Available from: 2016-09-29 Created: 2016-09-29 Last updated: 2018-07-10Bibliographically approved
Diener, S. (2009). Ageing behaviour of steel slags in landfill liners (ed.). (Licentiate dissertation). Paper presented at . Luleå: Luleå tekniska universitet
Open this publication in new window or tab >>Ageing behaviour of steel slags in landfill liners
2009 (English)Licentiate thesis, comprehensive summary (Other academic)
Abstract [en]

Steel slags are by-products of the steelmaking process. To avoid unnecessary disposal, e.g. into landfill, their chemical and physical properties should be exploited to support alternative uses. Steel slags can be recycled within the steel plant or used as construction material in roads, hydraulic engineering and different types of barriers, including landfill covers. A landfill cover consists of several layers, including a liner with low water and gas permeability in order to reduce methane and leachate emissions. Several studies have demonstrated that steel slags have good potential to fulfil such an application. However, there are questions regarding the stability of the slag minerals over long periods of time. A landfill cover must function well for many decades and centuries. In order to predict the long-term stability of steel slags as a landfill liner, laboratory experiments have been performed to study the effects of accelerated ageing of steel slag under controlled conditions. The factors investigated in the storage atmosphere were carbon dioxide content, relative humidity and temperature. The influence of leachate contact and ageing time were also assessed.This thesis reports the study of electric arc furnace slags and ladle slag from the production of high-alloyed tool steel after accelerated ageing for periods of three months and ten months. Mineralogy and leaching were studied using two different leaching tests, thermal analysis, acid-neutralization capacity assays and X-ray diffraction. For the ageing periods considered, the exposure of the slags to an atmosphere enriched with carbon dioxide had the greatest impact on leaching. In general, calcium, aluminium, sulphur and sodium leached from the slag matrix to the greatest extent while other metals such as chromium, nickel, lead and zinc were found at very low levels in the leachate. The leaching of calcium and aluminium reduced with increasing carbon dioxide level. Thermal analysis revealed the decomposition of carbonates. Weight and enthalpy changes were evaluated between 100 and 1000 °C. The buffer capacity of the steel slags, represented by the acid neutralization capacity (ANC 4.5) was not reduced after 10 months of ageing. However, the division of the titration into two steps revealed a shift of buffering zones for more highly aged samples, probably due to the formation of carbonates. The mineralogy of the investigated steel slags was complex with a large variety of mineral phases, principally calcium silicates, monticellite, periclase and a spinel phase. Other possible phases were gehlenite, merwinite, akermanite and iron. The existence of different solid solution is likely among the slag phases and can cause shifting of peaks in the X-ray diffractogram. Also, calcite was identified. Short-term carbonation has not shown significant impact on mineralogy despite of calcite formation. The results of the study contribute to a better understanding of the chemical and mineral stability of electric arc furnace slag and ladle slag in the environment of a landfill liner. The consequences of slag ageing include reduced leaching rates for certain elements. To predict the long-term behaviour of aged slag, the results of this study should be combined with data from two other sources - an ongoing ageing experiment that includes mechanical tests and a full scale field test at the Hagfors landfill. Additional analytical methods that can better characterise the mineralogy, for example scanning electron microscopy (SEM) and energydispersive X-ray spectroscopy (EDX), should also be applied to better quantify the mineralogical phases and to determine which trace elements are most abundant in specific minerals.

Abstract [sv]

Stålslagg är en restprodukt som kommer från ståltillverkningen. Den har kemiska och fysikaliska egenskaper som bör utnyttjas och som gör den lämplig för återanvändning, samtidigt som onödig deponering kan undvikas. Stålslagg kan återanvändas inom ståltillverkningen eller så kan den användas som konstruktionsmaterial i väg- och vattenbyggnadskonstruktioner eller i olika typer av barriärkonstruktioner som till exempel deponisluttäckningar. En deponisluttäckning består av flera skikt där tätskiktet ska ha en låg vatten- och gaspermeabilitet för att minska metan- och lakvattenutsläpp. Flera studier visar att stålslagg uppfyller dessa egenskaper och har potential att kunna användas i deponitäckning. Men det finns fortfarande oklarheter angående slaggmineralernas stabilitet över en längre tid. En deponitäcknings funktion förväntas vara stabil i många tiotals eller hundratals år. För att kunna förutsäga det långsiktiga beteendet för stålslagg i ett tätskikt genomfördes ett laboratorieexperiment vars syfte var att studera effekterna av accelererad åldring under kontrollerade förhållanden. De faktorer som studerades var koldioxidhalten, relativa luftfuktigheten, temperaturen, kontakten med lakvatten samt åldringstiden. I denna avhandling presenteras undersökningen av ljusbågsugnsslagg och skänkslagg, från framställning av höglegerat verktygsstål, efter tre respektive tio månaders accelererad åldring. Mineralogin och lakningsegenskaperna studerades genom två typer av laktester, termiska analyser, analys av syraneutraliserande kapacitet samt röntgendiffraktion. För de studerade åldringstiderna var det exponeringen av stålslaggen för en koldioxidrik atmosfär som hade den största inverkan på lakningsegenskaperna. Kalcium, aluminium, svavel och natrium var de ämnen som uppvisade den högsta utlakningen från slaggen medan metaller som krom, nickel, bly och zink endast fanns i väldigt låga koncentrationer i lakvattnet. Utlakningen av kalcium och aluminium minskade med en ökande halt av koldioxid. Termiska analyser visade på en nedbrytning av karbonater. Vikt- och entalpiförändringar mellan 100 och 1000°C utvärderades. Stålslaggens buffertkapacitet, representerad av den syraneutraliserande kapaciteten (ANC pH 4,5), reducerades inte efter tio månaders åldrande. Däremot visade uppdelningen av titreringen i två steg på en förskjutning av buffertområdena för de prover som åldrats tio månader, förmodligen på grund av karbonatbildning. Mineralogin för de undersökta stålslaggerna var komplex med en stor variation av mineralfaser, främst kalciumsilikater, monticellit, periklas och en spinellfas. Andra möjliga mineralfaser var gehlenit, merwinit, åkermanit och järn. Förekomsten av olika fastfaslösningar i stålslaggsmineralerna är sannolik vilket kan orsaka förskjutningar av topparna i diffraktogrammen. Kalcit identifierades också. Karbonatisering under en kort tid visade sig inte ha någon signifikant inverkan på mineralogin, förutom en viss kalcitbildning. Resultaten från studien bidrar till en bättre förståelse av stabiliteten för ljusbågsugns- och skänkslagg i den miljö som finns i ett tätskikt. Åldringen av slaggen resulterade i en reducerad utlakning av vissa element. För att kunna förutsäga det långsiktiga beteendet för åldrad slagg bör resultaten från den här studien kombineras med data från ett pågående åldringsförsök som inkluderar mekaniska tester samt ett fullskaligt fältförsök på Hagfors deponi. Analysmetoder som mer detaljerat kan karaktärisera mineralogin, till exempel svepelektronmikroskopi (SEM) och energidispersiv röntgenspektroskopi (EDX), bör också användas för att bättre kunna kvantifiera mineralfaserna och bestämma vilka spårelement som är vanligast i specifika mineraler.

Place, publisher, year, edition, pages
Luleå: Luleå tekniska universitet, 2009. p. 31
Series
Licentiate thesis / Luleå University of Technology, ISSN 1402-1757
National Category
Other Environmental Engineering
Research subject
Waste Science and Technology
Identifiers
urn:nbn:se:ltu:diva-26542 (URN)ec7b77f0-155d-11de-ae64-000ea68e967b (Local ID)978-91-86233-25-9 (ISBN)ec7b77f0-155d-11de-ae64-000ea68e967b (Archive number)ec7b77f0-155d-11de-ae64-000ea68e967b (OAI)
Note
Godkänd; 2009; 20090320 (sildie); LICENTIATSEMINARIUM Ämnesområde: Avfallsteknik Examinator: Professor Anders Lagerkvist, Luleå tekniska universitet Tid: Fredag den 24 april 2009 kl 14.15 Plats: F 664f, Luleå tekniska universitetAvailable from: 2016-09-30 Created: 2016-09-30 Last updated: 2017-11-24Bibliographically approved
Brännvall, E., Andreas, L., Diener, S., Tham, G. & Lagerkvist, A. (2009). Influence of accelerated ageing on acid neutralization capacity and mineralogical transformations in refuse derived-fuel fly ashes (ed.). In: (Ed.), Raffaello Cossu (Ed.), SARDINIA 2009: Twelfth International Waste Management and Landfill Symposium ; [5 - 9 October 2009, S. Margherita di Pula, Cagliari, Sardinia, Italy]. Paper presented at International Waste Management and Landfill Symposium : 05/10/2009 - 09/10/2009. Cagliari: CISA, Environmental Sanitary Engineering Centre, 1
Open this publication in new window or tab >>Influence of accelerated ageing on acid neutralization capacity and mineralogical transformations in refuse derived-fuel fly ashes
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2009 (English)In: SARDINIA 2009: Twelfth International Waste Management and Landfill Symposium ; [5 - 9 October 2009, S. Margherita di Pula, Cagliari, Sardinia, Italy] / [ed] Raffaello Cossu, Cagliari: CISA, Environmental Sanitary Engineering Centre , 2009, Vol. 1Conference paper, Published paper (Refereed)
Abstract [en]

This study is a part of a long-term collaboration between Telge Återvinning AB at Södertälje in South Sweden and Lulea University of Technology (LTU) in the Northern part of Sweden. Ashes and other industrial wastes used for landfill cover construction have been studied for several years. However, there is a need for further investigations with regard to the long-term mechanical and chemical stability of ash liners in landfill cover constructions. Long-term changes of ashes are investigated by laboratory studies on accelerated weathering (ageing) using experimental design. With regard to weathering, several stages can be identified: hydration and carbonation are well known processes while the processes surrounding the conversion of ash to clay minerals are less well known. There are a number of studies showing that the process of mineral transformation during the ageing of coal or MSWI ashes is quite similar to that of volcanic ashes in nature. Yet, the time frames are quite different: while volcanic ashes need several thousands of years for clay mineral development, there are evidences as well that e.g. clay illite is formed from glass phases in MSWI bottom ash after only 12 y or that clay like amorphous material can be formed in micro-scale throughout the surfaces of coal ash particles after 8 y of natural weathering (Zevenbergen et al., 1999; Zevenbergen et al., 1998). There are a lot of studies performed on rapid fly ash conversion into zeolites by hydrothermal alkaline treatment, the success of which strongly depends on alkaline conditions and the silica-alumina composition of the fly ash source (Inada et al., 2005). These results provide further support to the hypothesis that the observed rapid clay like mineral formation arose as a result of the initially high pH of ash, which promotes rapid dissolution of certain components of aluminosilicate glasses. Furthermore, in a long term perspective these aluminosilicates can transform into zeolites, smectites or halloysites dependent on the solution pH and leaching rate. Based on these studies on volcanic, coal or MSWI ashes we presume that refuse derived fuel (RDF) ashes, like those that are used in the Tveta landfill cover, will be subject to analogical weathering and mineral transformation processes.In order to investigate the mineral transformation in RDF fly ashes, a designed laboratory experiment was performed. A reduced factorial experimental design for accelerated ageing has been applied to evaluate the influence of five factors: carbon dioxide (CO2), temperature, relative air humidity, time and, quality of added water (Table 1). Table 1 Factors and levels tested in the reduced multivariate factorial design for the study of accelerated ageing of RFD fly ashesFactorLowMiddleHighCarbon dioxide, CO2 (%)Atmosphere (0.038)20*100Temperature, ºC5 3060Relative air humidity, Rh (%)3065100Time, months31022Water qualityDistilled -LeachateThe influence of these factors on mineralogical composition, leaching behaviour and acid neutralization capacity (ANC) is analysed and evaluated with the aid of multivariate data analysis. The MVDA modelling was performed with SIMCA-P+ 11.5 version program developed by Umetrics AB (Eriksson and Umetrics Academy, 2006). Principle component analysis (PCA) technique was used and presented in this paper. PCA is an interdependence model where all variables are analysed simultaneously as a single set in a data matrix X. Triplicates were tested for each factor combination. Sampling was performed after 3, 10 and 22 months of accelerated ageing. Mineral composition was analysed by X-Ray Diffraction (XRD). Acid neutralisation capacity was performed at 8.3 and 4.5 pH with 0.1 M HCl solution. The experimental set-up of accelerated ageing of RDF fly ashes is showed in Fig. 1. Preliminary evaluation of the mineral transformations in aged RDF fly ashes revealed that the carbonation process was not yet completed in the some of the specimens (Fig.2). This still caused high pH (pH=12.7) in the solution even though a calcite phase was found in all aged fly ashes. Multivariate data analysis confirmed that carbon dioxide affects the pH and ANC of fly ashes during ageing of RDF fly ashes. The specimens prepared with leachate water had higher ANC than the specimens with distilled water. The ANC8.3 was most influenced by 30 ºC temperature and 65 % relative humidity (ANC8.3 = 0.05 mmol/g) and this well corresponds to the results found in the literature. The ageing time factor has the highest influence on ANC4.5. A more detailed analysis of other mineral phases including clay-like minerals in aged fly ashes will be performed later.The results of this study will contribute to the better understanding of ash formation processes and improved possibilities to make beneficial use of ashes as an alternative to landfilling.Figure 1. Experimental set-up for investigations of the long-term behaviour of the ashes under different environmental conditions. Figure 2. XRD patterns of RDF fly ashes at different ageing conditions. a) N33, b) N71, c) N15, d) N85, and e) N51. The peaks are labelled A (anhydrite), C (calcite), E (ettringite), F (Friedel's Salt), Ge (gehlenite), H (halite), He (hematite), P (portlandite), Q (quartz), S (sylvite), V (vaterite).

Place, publisher, year, edition, pages
Cagliari: CISA, Environmental Sanitary Engineering Centre, 2009
National Category
Other Environmental Engineering
Research subject
Waste Science and Technology
Identifiers
urn:nbn:se:ltu:diva-32066 (URN)66e21550-b8a9-11de-b769-000ea68e967b (Local ID)978-88-626-5007-6 (ISBN)66e21550-b8a9-11de-b769-000ea68e967b (Archive number)66e21550-b8a9-11de-b769-000ea68e967b (OAI)
Conference
International Waste Management and Landfill Symposium : 05/10/2009 - 09/10/2009
Note
Godkänd; 2009; 20091014 (evebra)Available from: 2016-09-30 Created: 2016-09-30 Last updated: 2018-05-15Bibliographically approved
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