Effects of uranium mining on groundwater - Geochemical modeling of aqueous uranium speciation due to changing redox conditions.
As a consequence of rising uranium prices an interest in Sweden’s U deposits has emerged. This raises the important question of the possible environmental impacts of U mining operations. One of the most significant and serious issues is the contamination of groundwater by U following mining activi...
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KTH, Mark- och vattenteknik
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ftkthstockholm:oai:DiVA.org:kth-161064 2024-06-23T07:55:40+00:00 Effects of uranium mining on groundwater - Geochemical modeling of aqueous uranium speciation due to changing redox conditions. Gronowski, Adrian 2013 application/pdf http://urn.kb.se/resolve?urn=urn:nbn:se:kth:diva-161064 eng eng KTH, Mark- och vattenteknik TRITA-LWR Degree Project, 1651-064X 42 http://urn.kb.se/resolve?urn=urn:nbn:se:kth:diva-161064 info:eu-repo/semantics/openAccess Uranium mining Uranium speciation Uraninite Uranium groundwater transport Visual Minteq Civil Engineering Samhällsbyggnadsteknik Student thesis info:eu-repo/semantics/bachelorThesis text 2013 ftkthstockholm 2024-05-27T17:45:25Z As a consequence of rising uranium prices an interest in Sweden’s U deposits has emerged. This raises the important question of the possible environmental impacts of U mining operations. One of the most significant and serious issues is the contamination of groundwater by U following mining activities. The processes of uranium release and subsequent transport in groundwater is closely tied to its aqueous chemistry i.e. aqueous speciation, adsorption to mineral surfaces and dissolved organic carbon (DOM). The chemical parameters exerting the most control over these processes are pH and redox potential. The redox potential plays a decisive role because it controls the solubility of uraninite, a common uranium mineral and ore in Sweden’s bedrock deposits. Thus, by gaining insight into how changing redox conditions affect uraninite solubility, assessments can be made in order to estimate the extent of uranium transport by groundwater. Therefore the effects of the redox po-tential on U mobility will be examined in this work by means of computer modeling in the geochemical software VISUAL MINTEQ 3.0. The composition of the water used for modeling resembled that of a typical bedrock groundwater of Northern Sweden in the areas above the highest coastline. The simulations were carried out under different redox potentials at different pH levels in the presence of ferrihydrite and DOM to include the effects of U adsorption. The results show that the redox potential at which the uraninite mineral dissolves varies depending on the pH of the groundwater. From pH 4.0 to 7.5 the redox potential at which uraninite oxidizes decreases from 240-250 mV to 50-60 mV. This means higher redox conditions are needed for the dissolution of uraninite at low pH. Additionally, it is further concluded that the adsorption of U to ferrihydrite and DOC is important at pH 5-8 and pH < 7 respectively, which therefore play an important role in controlling the mobility of U in the modeled groundwater. Bachelor Thesis Northern Sweden Royal Institute of Technology, Stockholm: KTHs Publication Database DiVA |
institution |
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collection |
Royal Institute of Technology, Stockholm: KTHs Publication Database DiVA |
op_collection_id |
ftkthstockholm |
language |
English |
topic |
Uranium mining Uranium speciation Uraninite Uranium groundwater transport Visual Minteq Civil Engineering Samhällsbyggnadsteknik |
spellingShingle |
Uranium mining Uranium speciation Uraninite Uranium groundwater transport Visual Minteq Civil Engineering Samhällsbyggnadsteknik Gronowski, Adrian Effects of uranium mining on groundwater - Geochemical modeling of aqueous uranium speciation due to changing redox conditions. |
topic_facet |
Uranium mining Uranium speciation Uraninite Uranium groundwater transport Visual Minteq Civil Engineering Samhällsbyggnadsteknik |
description |
As a consequence of rising uranium prices an interest in Sweden’s U deposits has emerged. This raises the important question of the possible environmental impacts of U mining operations. One of the most significant and serious issues is the contamination of groundwater by U following mining activities. The processes of uranium release and subsequent transport in groundwater is closely tied to its aqueous chemistry i.e. aqueous speciation, adsorption to mineral surfaces and dissolved organic carbon (DOM). The chemical parameters exerting the most control over these processes are pH and redox potential. The redox potential plays a decisive role because it controls the solubility of uraninite, a common uranium mineral and ore in Sweden’s bedrock deposits. Thus, by gaining insight into how changing redox conditions affect uraninite solubility, assessments can be made in order to estimate the extent of uranium transport by groundwater. Therefore the effects of the redox po-tential on U mobility will be examined in this work by means of computer modeling in the geochemical software VISUAL MINTEQ 3.0. The composition of the water used for modeling resembled that of a typical bedrock groundwater of Northern Sweden in the areas above the highest coastline. The simulations were carried out under different redox potentials at different pH levels in the presence of ferrihydrite and DOM to include the effects of U adsorption. The results show that the redox potential at which the uraninite mineral dissolves varies depending on the pH of the groundwater. From pH 4.0 to 7.5 the redox potential at which uraninite oxidizes decreases from 240-250 mV to 50-60 mV. This means higher redox conditions are needed for the dissolution of uraninite at low pH. Additionally, it is further concluded that the adsorption of U to ferrihydrite and DOC is important at pH 5-8 and pH < 7 respectively, which therefore play an important role in controlling the mobility of U in the modeled groundwater. |
format |
Bachelor Thesis |
author |
Gronowski, Adrian |
author_facet |
Gronowski, Adrian |
author_sort |
Gronowski, Adrian |
title |
Effects of uranium mining on groundwater - Geochemical modeling of aqueous uranium speciation due to changing redox conditions. |
title_short |
Effects of uranium mining on groundwater - Geochemical modeling of aqueous uranium speciation due to changing redox conditions. |
title_full |
Effects of uranium mining on groundwater - Geochemical modeling of aqueous uranium speciation due to changing redox conditions. |
title_fullStr |
Effects of uranium mining on groundwater - Geochemical modeling of aqueous uranium speciation due to changing redox conditions. |
title_full_unstemmed |
Effects of uranium mining on groundwater - Geochemical modeling of aqueous uranium speciation due to changing redox conditions. |
title_sort |
effects of uranium mining on groundwater - geochemical modeling of aqueous uranium speciation due to changing redox conditions. |
publisher |
KTH, Mark- och vattenteknik |
publishDate |
2013 |
url |
http://urn.kb.se/resolve?urn=urn:nbn:se:kth:diva-161064 |
genre |
Northern Sweden |
genre_facet |
Northern Sweden |
op_relation |
TRITA-LWR Degree Project, 1651-064X 42 http://urn.kb.se/resolve?urn=urn:nbn:se:kth:diva-161064 |
op_rights |
info:eu-repo/semantics/openAccess |
_version_ |
1802648321688338432 |