Abstract
The demand for low environmental impact of materials in our habitat is one of the current societal challenges. Along with other solutions of waste valorisation, alkali activation as geopolymers can be one possible solution of waste valorisation because they may allow, for instance, an alternative solution for cement-based materials in some applications and it is one contribution for circular economy. This work has focused on the development and processing of geopolymers that incorporates as a fine aggregate a high-sulfidic mining waste (mine tailing), a difficult waste to process. Rheology analysis was applied as an important step to understand not only the geopolymers behaviour but also its transition from the fresh to the hardened state. The effect of precursor binder type (metakaolin or blast furnace slag), of mine tailing content and also the effect of temperature and curing conditions of different formulations were studied in this solution. It was possible to conclude that although this particular mine tailing is not a geopolymer binder precursor, it may be incorporated as an alternative fine aggregate in construction products. Furthermore, rheology could be used to follow up the geopolymer alkali-activation process and even to setup proper curing conditions and components contents in order to optimize the final mechanical strength of this material as a waste management solution. The final properties of these geopolymers compositions were adequate and after 28 days of curing, these geopolymers exhibit significant chemical resistance under severe test conditions.
Highlights
Mining activities produce millions of tons of mine tailing waste after extraction and separation of the ore at world level [1]
This study has evaluated the possibility of a waste management solution using high sulfidic mine tailing as raw material in geopolymer production
Mine tailing was used as a fine aggregate together with metakaolin and blast furnace slag as geopolymer precursors
Summary
Mining activities produce millions of tons of mine tailing waste after extraction and separation of the ore at world level [1]. Mine tailings are usually placed in environmentally controlled landfills, because these materials contain sulphates and some heavy metals This implies the need for large areas of land for the construction of landfills and the need for skilled labor for environmental monitoring. Alkali-activated materials, called geopolymers, have an extensive range of applications as substitutes for ordinary Portland Cement (PC) in certain applications due to their properties, such as chemical durability. These materials can improve mechanical properties and have the ability to withstand high temperatures and chemical attack by acids and salts [3]
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