Persistent Link:
http://hdl.handle.net/10150/268596
Title:
Geopolymerization of Copper Mine Tailings
Author:
Yang, Fenghua
Issue Date:
2012
Publisher:
The University of Arizona.
Rights:
Copyright © is held by the author. Digital access to this material is made possible by the University Libraries, University of Arizona. Further transmission, reproduction or presentation (such as public display or performance) of protected items is prohibited except with permission of the author.
Embargo:
Release after 12-Dec-2014
Abstract:
Geopolymerization is a chemical reaction process, reacting SiO₂ and Al₂O₃ with alkaline solutions, which can transform aluminosilicate solids or particles to polymer materials. Geopolymers have many engineering applications such as cementation binders for construction and solidification or encapsulation of hazardous heavy metals. Mine tailings mainly consist of SiO₂ and Al₂O₃. Theoretically, mine tailings can be used as source materials for geopolymerization. However, for most researchers, they use fly ash, metakaolin or furnace slag as source minerals, because these minerals are much more reactive with alkaline solutions. Mine tailings are naturally-forming minerals and are considered to be inert in geopolymerization. How are mine tailings to be activated through different reaction conditions? We conducted several tentative or preliminary experiments to study the geopolymerization process step by step. We tried different methods to react mine tailings with alkaline solutions. Mine tailings were submerged into alkaline solutions in a plastic bucket for 6 days in room temperature (20-25 °C). We wanted mine tailings to be activated by soaking. The results were not satisfying. Then we tried to react mine tailings with alkaline solutions at 60 °C and 90 °C. After analyzing, we found that the results were not satisfying either. So, we conducted simplified geopolymerization experiments in order to better understand the chemical reaction mechanism. Pure SiO2 and Al2O3, which were two major reactants, were employed to simplify and simulate the geopolymerization process. We drew some useful conclusions such as that geopolymerization took place at elevated temperatures; Al₂O₃ almost did not react with alkaline solutions at low temperatures, etc. We conducted experiments at elevated temperatures (150 °C, 180 °C, 210 °C). Different levels of pressure (5 MPa, 10 MPa, 20 MPa) were applied to make compact specimens. After many attempts, the results were successful. The highest mechanical strength was about 20 MPa. Most importantly, we obtained polymers produced from geopolymerzation, which could be seen by naked eyes. The experiment techniques such as scanning electron microstructure (SEM) imaging and X-ray diffraction (XRD), inductively-coupled plasma mass spectrometry (ICP-MS), and unconfined compression tests (UCS) were applied to study the geopolymerization reaction mechanism and the feasibility of using mine tailing-based geopolymers as construction materials.
Type:
text; Electronic Thesis
Keywords:
Mining Geological & Geophysical Engineering
Degree Name:
M.S.
Degree Level:
masters
Degree Program:
Graduate College; Mining Geological & Geophysical Engineering
Degree Grantor:
University of Arizona
Advisor:
Zhang, Jinhong

Full metadata record

DC FieldValue Language
dc.language.isoenen_US
dc.titleGeopolymerization of Copper Mine Tailingsen_US
dc.creatorYang, Fenghuaen_US
dc.contributor.authorYang, Fenghuaen_US
dc.date.issued2012-
dc.publisherThe University of Arizona.en_US
dc.rightsCopyright © is held by the author. Digital access to this material is made possible by the University Libraries, University of Arizona. Further transmission, reproduction or presentation (such as public display or performance) of protected items is prohibited except with permission of the author.en_US
dc.description.releaseRelease after 12-Dec-2014en_US
dc.description.abstractGeopolymerization is a chemical reaction process, reacting SiO₂ and Al₂O₃ with alkaline solutions, which can transform aluminosilicate solids or particles to polymer materials. Geopolymers have many engineering applications such as cementation binders for construction and solidification or encapsulation of hazardous heavy metals. Mine tailings mainly consist of SiO₂ and Al₂O₃. Theoretically, mine tailings can be used as source materials for geopolymerization. However, for most researchers, they use fly ash, metakaolin or furnace slag as source minerals, because these minerals are much more reactive with alkaline solutions. Mine tailings are naturally-forming minerals and are considered to be inert in geopolymerization. How are mine tailings to be activated through different reaction conditions? We conducted several tentative or preliminary experiments to study the geopolymerization process step by step. We tried different methods to react mine tailings with alkaline solutions. Mine tailings were submerged into alkaline solutions in a plastic bucket for 6 days in room temperature (20-25 °C). We wanted mine tailings to be activated by soaking. The results were not satisfying. Then we tried to react mine tailings with alkaline solutions at 60 °C and 90 °C. After analyzing, we found that the results were not satisfying either. So, we conducted simplified geopolymerization experiments in order to better understand the chemical reaction mechanism. Pure SiO2 and Al2O3, which were two major reactants, were employed to simplify and simulate the geopolymerization process. We drew some useful conclusions such as that geopolymerization took place at elevated temperatures; Al₂O₃ almost did not react with alkaline solutions at low temperatures, etc. We conducted experiments at elevated temperatures (150 °C, 180 °C, 210 °C). Different levels of pressure (5 MPa, 10 MPa, 20 MPa) were applied to make compact specimens. After many attempts, the results were successful. The highest mechanical strength was about 20 MPa. Most importantly, we obtained polymers produced from geopolymerzation, which could be seen by naked eyes. The experiment techniques such as scanning electron microstructure (SEM) imaging and X-ray diffraction (XRD), inductively-coupled plasma mass spectrometry (ICP-MS), and unconfined compression tests (UCS) were applied to study the geopolymerization reaction mechanism and the feasibility of using mine tailing-based geopolymers as construction materials.en_US
dc.typetexten_US
dc.typeElectronic Thesisen_US
dc.subjectMining Geological & Geophysical Engineeringen_US
thesis.degree.nameM.S.en_US
thesis.degree.levelmastersen_US
thesis.degree.disciplineGraduate Collegeen_US
thesis.degree.disciplineMining Geological & Geophysical Engineeringen_US
thesis.degree.grantorUniversity of Arizonaen_US
dc.contributor.advisorZhang, Jinhongen_US
dc.contributor.committeememberPoulton, Maryen_US
dc.contributor.committeememberKim, KwangMinen_US
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