Characterization and solidification of arsenic-rich cyanided tailings
Information on the occurrence of As species and iron sulphide minerals in tailings is essential for predicting therelease of As over extended period of time. Tailings originating from a goldmine in northern Sweden with low content of trace elements except for As were used for this purpose. The domin...
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Luleå tekniska universitet, Geovetenskap och miljöteknik
2014
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ftluleatu:oai:DiVA.org:ltu-17804 2023-12-17T10:47:34+01:00 Characterization and solidification of arsenic-rich cyanided tailings Hamberg, Roger 2014 application/pdf http://urn.kb.se/resolve?urn=urn:nbn:se:ltu:diva-17804 eng eng Luleå tekniska universitet, Geovetenskap och miljöteknik Luleå Licentiate thesis / Luleå University of Technology, 1402-1757 orcid:0000-0002-5010-4815 http://urn.kb.se/resolve?urn=urn:nbn:se:ltu:diva-17804 urn:isbn:978-91-7583-071-1 urn:isbn:978-91-7583-072-8 Local 54cded1a-eaee-4736-a3cb-b42413e37694 info:eu-repo/semantics/openAccess Geochemistry Geokemi Licentiate thesis, comprehensive summary info:eu-repo/semantics/masterThesis text 2014 ftluleatu 2023-11-23T17:10:41Z Information on the occurrence of As species and iron sulphide minerals in tailings is essential for predicting therelease of As over extended period of time. Tailings originating from a goldmine in northern Sweden with low content of trace elements except for As were used for this purpose. The dominating sulphides were pyrrhotite and arsenopyrite. The samples used in the study were post-cyanided, tailings slurries treated with Fe2(SO4)3 and H2O2 to form arsenates and Fe-hydrates for effective As-immobilization. Speciation of the As in ore and tailings samples revealed that mining processes have dissolved the majority of the arsenopyrite in the ore, causing secondary As phases to co-precipitate with newly formed Fe-hydrates. A minor part of the As retained in the tailings was assumed to be As (III)-species. Weathering cell tests (WCT) involving 32 weekly cycles of wetting and air exposure were conducted to assess the effect of weathering on the stability of As in the tailings. As-bearing Fe-hydrates remained intact during the early stages of the WCT; the low release of As during this period was probably due to the dissolution of solubleAs(III)-phases. During the later stages of the WCT, the release of As, Fe and S increased due to pyrrhotite oxidation and the destabilization of As-bearing Fe-hydrates. The majority of the originally present As was still associated with the tailings by the end of the test, but additional pyrrhotite oxidation with the pH falling to >3 could further destabilize these As-bearing Fe-hydrates. In the second part of the study,cyanided tailings were converted into a monolith by using a method called cemented paste backfill (CPB). Two mixtures of CPB were tested; CE with 1 wt. % of cement and CE-FA consisting 2 weight (wt.) % of cement together with 1 wt. % of biofuel fly ash. The stability of As in CPB-masses andun-amended tailings were evaluated using tank leaching tests (TLT) and WCT: s. TheTLT results showed that the CPB mixtures were not suitable for use inunderground backfilling ... Master Thesis Northern Sweden Luleå University of Technology Publications (DiVA) Monolith ENVELOPE(163.283,163.283,-66.950,-66.950) |
institution |
Open Polar |
collection |
Luleå University of Technology Publications (DiVA) |
op_collection_id |
ftluleatu |
language |
English |
topic |
Geochemistry Geokemi |
spellingShingle |
Geochemistry Geokemi Hamberg, Roger Characterization and solidification of arsenic-rich cyanided tailings |
topic_facet |
Geochemistry Geokemi |
description |
Information on the occurrence of As species and iron sulphide minerals in tailings is essential for predicting therelease of As over extended period of time. Tailings originating from a goldmine in northern Sweden with low content of trace elements except for As were used for this purpose. The dominating sulphides were pyrrhotite and arsenopyrite. The samples used in the study were post-cyanided, tailings slurries treated with Fe2(SO4)3 and H2O2 to form arsenates and Fe-hydrates for effective As-immobilization. Speciation of the As in ore and tailings samples revealed that mining processes have dissolved the majority of the arsenopyrite in the ore, causing secondary As phases to co-precipitate with newly formed Fe-hydrates. A minor part of the As retained in the tailings was assumed to be As (III)-species. Weathering cell tests (WCT) involving 32 weekly cycles of wetting and air exposure were conducted to assess the effect of weathering on the stability of As in the tailings. As-bearing Fe-hydrates remained intact during the early stages of the WCT; the low release of As during this period was probably due to the dissolution of solubleAs(III)-phases. During the later stages of the WCT, the release of As, Fe and S increased due to pyrrhotite oxidation and the destabilization of As-bearing Fe-hydrates. The majority of the originally present As was still associated with the tailings by the end of the test, but additional pyrrhotite oxidation with the pH falling to >3 could further destabilize these As-bearing Fe-hydrates. In the second part of the study,cyanided tailings were converted into a monolith by using a method called cemented paste backfill (CPB). Two mixtures of CPB were tested; CE with 1 wt. % of cement and CE-FA consisting 2 weight (wt.) % of cement together with 1 wt. % of biofuel fly ash. The stability of As in CPB-masses andun-amended tailings were evaluated using tank leaching tests (TLT) and WCT: s. TheTLT results showed that the CPB mixtures were not suitable for use inunderground backfilling ... |
format |
Master Thesis |
author |
Hamberg, Roger |
author_facet |
Hamberg, Roger |
author_sort |
Hamberg, Roger |
title |
Characterization and solidification of arsenic-rich cyanided tailings |
title_short |
Characterization and solidification of arsenic-rich cyanided tailings |
title_full |
Characterization and solidification of arsenic-rich cyanided tailings |
title_fullStr |
Characterization and solidification of arsenic-rich cyanided tailings |
title_full_unstemmed |
Characterization and solidification of arsenic-rich cyanided tailings |
title_sort |
characterization and solidification of arsenic-rich cyanided tailings |
publisher |
Luleå tekniska universitet, Geovetenskap och miljöteknik |
publishDate |
2014 |
url |
http://urn.kb.se/resolve?urn=urn:nbn:se:ltu:diva-17804 |
long_lat |
ENVELOPE(163.283,163.283,-66.950,-66.950) |
geographic |
Monolith |
geographic_facet |
Monolith |
genre |
Northern Sweden |
genre_facet |
Northern Sweden |
op_relation |
Licentiate thesis / Luleå University of Technology, 1402-1757 orcid:0000-0002-5010-4815 http://urn.kb.se/resolve?urn=urn:nbn:se:ltu:diva-17804 urn:isbn:978-91-7583-071-1 urn:isbn:978-91-7583-072-8 Local 54cded1a-eaee-4736-a3cb-b42413e37694 |
op_rights |
info:eu-repo/semantics/openAccess |
_version_ |
1785571461421858816 |