Potassium Aluminate Geopolymerisation of Acidic Gold Mine Tailings

Felix Ndubisi Okonta, Thabo Falayi, Freeman Ntuli

Research output: Chapter in Book/Report/Conference proceedingConference contribution


Acidic gold mine tailings were alkaline activated using KOH. The effect of potassium aluminate (KA) on the strength and durability of the geopolymers was investigated. A 2.8 KA:KOH geopolymer had a UCS of 18.10 MPa after curing for 5 days at 100 °C. There was an increase in UCS with an increase in loading of KA up to a ratio of 2.8. Beyond the KA:KOH ratio of 2.8, there was a 48% drop in UCS due to excess K+ ions in the system which resulted in the loss of charge balance of the system leading to reduction of UCS. It is worth mentioning that the KA:KOH ratio of 2.8 represented a Si/Al ratio of 1.02. This study showed that KA activation of acidic gold mine tailings is an attractive route to stabilise/solidify hazardous tailing material. Though there is use of elevated temperature to achieve high strength for the KA based geopolymer, this pales in comparison to energy requirements of cement manufacturing and clay brick firing.
Original languageEnglish
Title of host publicationGeoChina 2018: New Prospects in Geotechnical Engineering Aspects of Civil Infrastructures
Subtitle of host publicationSustainable Civil Infrastructures
EditorsH. Khabbaz, H. Youn, M. Bouassida
PublisherSpringer International Publishing
Number of pages6
ISBN (Electronic)978-3-319-95771-5
ISBN (Print)978-3-319-95770-8
Publication statusPublished - 2018


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