THE POTENTIAL USE OF GEOPOLYMERIC MATERIALS TO IMMOBILIZE TOXIC METALS .1. THEORY AND APPLICATIONS

During the East decade geopolymerisation has emerged as a possible tec hnological 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 y ears that it has been rediscovered and attention has been drawn to its useful chemical and physical properties. This paper will therefore at tempt to briefly discuss the available literature on geopolymerisation in terms of its history reaction kinetics and structure as well as in vestigations into the application of geopolymerisation to various wast e forms. It is evident from the literature that factors governing the formation of geopolymers are still poorly understood although the phys ical and chemical properties suggest that these matrices are well suit ed for the immobilisation of toxic materials and specifically toxic me tals. It is finally concluded that geopolymers offer attractive option s towards simple industrial applications where large volumes of waste materials need to be stabilised. it must also be acknowledged that the se advantages can only be applied optimally once all relevant interact ions regarding the formation of geopolymers from waste materials have 659 been quantified scientifically. Hence, further research. is requir ed regarding the formation of geopolymers and their application in ind ustry. (C) 1997 Elsevier Science Ltd.