Toxic metals immobilisation
PART I. Theory and Applications
J.G.S. van Jaarsveld, J.S.J.van Deventer and L. Lorenzen
published in : Minerals Engineering, Vol. 10, no. 7, pp. 659-669 (1996)
During the last decade geopolymerisation has emerged as a possible technological solution for the effective stabilisation and immobilisation of toxic materials. Despite the fact that this technology is based on a very old principle, surprisingly little is known about the nature of these reactions or their products. It is only in the last fifteen years that it has been rediscovered and attention has been drawn to its useful chemical and physical properties. This paper will therefore attempt to briefly discuss the available literature on geopolymerisation in terms of its history, reaction kinetics and structure as well as investigations into the application of geopolymerisation to various waste forms. It is evident from the literature that factors governing the formation of geopolymers are still not completely understood, although the physical and chemical properties suggest that these matrices are well suited for the immobilisation of toxic materials and specifically toxic metals. It is finally concluded that geopolymers offer attractive options towards simple industrial applications where large volumes of waste materials need to be stabilised. It must also be acknowledged that these advantages can only be applied optimally once all relevant interactions regarding the formation of geopolymers from waste materials have been quantified scientifically. Hence, further research is required regarding the formation of geopolymers and their application in industry.
Keywords geopolymer, waste processing, zeolites, immobilisation, landfill, fly ash
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