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Water and carbon footprints of mining and producing Cu, Mg and Zn : a comparative study of primary and secondary sources

Angel, Hanna LU (2016) In Student thesis series INES NGEK01 20161
Dept of Physical Geography and Ecosystem Science
Abstract
Finding sustainable alternatives to the current degrading activities associated with metal mining and production is essential in order to meet increased resource demand and stricter environmental regulations. One option that recently has gained interest is to recover metals from fly ash, which is produced when incinerating municipal solid waste. As of today, metal resources in fly ash are not utilized in Sweden or in most other parts of the world, but are put on landfills where they are made unavailable for future use. Incentives in terms of economic and environmental gains of recovering metals from fly ashes are needed in order to realize the required installments for such recovery. A few studies have been dedicated to examine the... (More)
Finding sustainable alternatives to the current degrading activities associated with metal mining and production is essential in order to meet increased resource demand and stricter environmental regulations. One option that recently has gained interest is to recover metals from fly ash, which is produced when incinerating municipal solid waste. As of today, metal resources in fly ash are not utilized in Sweden or in most other parts of the world, but are put on landfills where they are made unavailable for future use. Incentives in terms of economic and environmental gains of recovering metals from fly ashes are needed in order to realize the required installments for such recovery. A few studies have been dedicated to examine the economic (and to a smaller extent environmental) benefits of up-scaling successful laboratory attempts of these practices in the past. However, these studies are often compared to the current practices at a certain waste-to-energy plant, or for a specific metal. In general data on environmental parameters, especially water use, for implementing techniques for metal recovery from fly ash is scarce. This study compared the environmental burden in terms of water and carbon footprint of recovering Cu, Mg and Zn from fly ash, compared to conventional mining and production of these metals. To enable such a comparison, a literature study of water use and greenhouse gas emissions for the respective metal recovery methods has been made. Both the current practices in use today, as well as a few potential future alternatives are discussed. The overall findings are that both the carbon- and the water footprint is much larger for mining and producing the studied metals using present practices, i.e. primary metal recovery, compared to recovering them from fly ash. The investigated sources indicate that greenhouse gas emissions for magnesium and zinc recovery could be reduced by a factor of 2 and 15 respectively, if secondary sources are used instead. With currently available techniques, the water footprint can be considered negligible when recovering metals from fly ash. A general lack of data on water use and large inconsistencies in ways of reporting water footprint were affecting the results of this study markedly. Still, it could firmly be concluded that if Cu, Mg and Zn were recovered from fly ash, large savings of CO2e emissions and water could be made compared to only producing these metals from primary sources. (Less)
Popular Abstract (Swedish)
I Sverige förbränns årligen ca 4.5 miljoner ton avfall. Från förbränningen bildas en askrest, som delvis består av så kallad flygaska. I dagsläget används inte denna aska i Sverige, utan läggs på deponi i Norge eller Tyskland, trots att den innehåller värdefulla metaller. Deponering av användbart material kan inte anses som ett hållbart alternativ i en värld med snabbt växande befolkning och ökande belastning på naturens resurser. Då återvinning av material och minskad miljöpåverkan blivit alltmer aktuellt har potentialen av metallutvinning ur flygaska under senare år undersökts allt mer runt om i världen. Att hitta alternativ till dagens tillvägagångssätt att framställa rena metaller är extra intressant då brytning och produktion av... (More)
I Sverige förbränns årligen ca 4.5 miljoner ton avfall. Från förbränningen bildas en askrest, som delvis består av så kallad flygaska. I dagsläget används inte denna aska i Sverige, utan läggs på deponi i Norge eller Tyskland, trots att den innehåller värdefulla metaller. Deponering av användbart material kan inte anses som ett hållbart alternativ i en värld med snabbt växande befolkning och ökande belastning på naturens resurser. Då återvinning av material och minskad miljöpåverkan blivit alltmer aktuellt har potentialen av metallutvinning ur flygaska under senare år undersökts allt mer runt om i världen. Att hitta alternativ till dagens tillvägagångssätt att framställa rena metaller är extra intressant då brytning och produktion av metaller tyvärr ofta innebär kraftig negativ miljöpåverkan av olika slag. Den här studien jämför miljöpåverkan mellan traditionell brytning och produktion av metallerna koppar, magnesium och zink med framställning av dessa metaller från flygaskor. De parametrar som undersöks är vattenanvändning och växthusgasutsläpp. Baserat på de källor som undersökts kan man dra slutsatsen att det är betydligt mer miljövänligt att återvinna metaller ur flygaska än att bryta dem från jordskorpan och producera dem på traditionellt vis. Då metallutvinning ur flygaska idag främst sker i liten skala, ofta i form av laboratorie-försök, bör potentialen i implementering av fullskaliga anläggningar undersökas mer, då stora besparingar på miljöbelastande aktiviteter kan undvikas vid denna typ av metallproduktion. Förutom miljömässig prestanda bör även tekniska och ekonomiska aspekter vid denna typ av utvinning undersökas för att indikera om metallproduktion från flygaska i framtiden ska kunna agera komplement till nuvarande metoder. (Less)
Please use this url to cite or link to this publication:
author
Angel, Hanna LU
supervisor
organization
course
NGEK01 20161
year
type
M2 - Bachelor Degree
subject
keywords
water footprint, carbon footprint, metal production, fly ash, mining, Physical Geography and Ecosystem Science
publication/series
Student thesis series INES
report number
378
language
English
id
8881212
date added to LUP
2016-06-14 17:01:01
date last changed
2016-06-14 17:01:01
@misc{8881212,
  abstract     = {Finding sustainable alternatives to the current degrading activities associated with metal mining and production is essential in order to meet increased resource demand and stricter environmental regulations. One option that recently has gained interest is to recover metals from fly ash, which is produced when incinerating municipal solid waste. As of today, metal resources in fly ash are not utilized in Sweden or in most other parts of the world, but are put on landfills where they are made unavailable for future use. Incentives in terms of economic and environmental gains of recovering metals from fly ashes are needed in order to realize the required installments for such recovery. A few studies have been dedicated to examine the economic (and to a smaller extent environmental) benefits of up-scaling successful laboratory attempts of these practices in the past. However, these studies are often compared to the current practices at a certain waste-to-energy plant, or for a specific metal. In general data on environmental parameters, especially water use, for implementing techniques for metal recovery from fly ash is scarce. This study compared the environmental burden in terms of water and carbon footprint of recovering Cu, Mg and Zn from fly ash, compared to conventional mining and production of these metals. To enable such a comparison, a literature study of water use and greenhouse gas emissions for the respective metal recovery methods has been made. Both the current practices in use today, as well as a few potential future alternatives are discussed. The overall findings are that both the carbon- and the water footprint is much larger for mining and producing the studied metals using present practices, i.e. primary metal recovery, compared to recovering them from fly ash. The investigated sources indicate that greenhouse gas emissions for magnesium and zinc recovery could be reduced by a factor of 2 and 15 respectively, if secondary sources are used instead. With currently available techniques, the water footprint can be considered negligible when recovering metals from fly ash. A general lack of data on water use and large inconsistencies in ways of reporting water footprint were affecting the results of this study markedly. Still, it could firmly be concluded that if Cu, Mg and Zn were recovered from fly ash, large savings of CO2e emissions and water could be made compared to only producing these metals from primary sources.},
  author       = {Angel, Hanna},
  keyword      = {water footprint,carbon footprint,metal production,fly ash,mining,Physical Geography and Ecosystem Science},
  language     = {eng},
  note         = {Student Paper},
  series       = {Student thesis series INES},
  title        = {Water and carbon footprints of mining and producing Cu, Mg and Zn : a comparative study of primary and secondary sources},
  year         = {2016},
}