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Sedira, N., & Castro-Gomes, J. (2020). Microstructure Features of Ternary Alkali-activated Binder Based on Tungsten Mining Waste, Slag and Metakaolin. KnE Engineering, 5(4), 195–206. https://doi.org/10.18502/keg.v5i4.6810

https://doi.org/10.18502/keg.v5i4.6810

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authors

  • Naim Sedira

    Naim Sedira

    Centre of Materials and Building Technologies (C–MADE/UBI), Department of Civil Engineering and Architecture, University of Beira Interior (UBI), 6201–001 Covilhã, Portugal
  • João Castro-Gomes

    João Castro-Gomes

    Centre of Materials and Building Technologies (C–MADE/UBI), Department of Civil Engineering and Architecture, University of Beira Interior (UBI), 6201–001 Covilhã, Portugal

Published Date

  • Apr 13, 2020

Microstructure Features of Ternary Alkali-activated Binder Based on Tungsten Mining Waste, Slag and Metakaolin

KnE Engineering / REMINE International Conference on Valorization of Mining and Industrial Wastes into Construction Materials By Alkali-activation / Pages 195–206

Abstract

This study determines the effect of ground granulated blast furnace slag (GGBFS) and metakaolin (MK) on the microstructural properties of the tungsten mining waste-based alkali-activated binder (TMWM). During this investigation, TMWM was partially replaced with 10 wt.% GGBFS and 10 wt.% MK to improve the microstructure of the binder. In order to understand the effect of the substitutions on the microstructure, two pastes were produced to make a comparative study between the sample contain 100% TMWM and the ternary precursors. Both precursors were activated using a combination of alkaline activator solutions (sodium silicate and sodium hydroxide) with the ratio of 1:3 (66.6 wt.% sodium silicate combined with 33.33 wt.% of NaOH 8M). The alkali-activated mixes were cured in oven at temperature of 60 °C in the first day and at room temperature for the next 27 days. The reaction products N-A-S-H gel and (N,M)-A-S-H gel resulted from the alkaline activation reaction process. In addition, a formation of natrite (Na2CO3) with needles shape occurred as a reaction product of the fluorescence phenomena. However, a dense matrix resulted from the alkline activation of the ternary precursors containg different gels such as N-A-S-H, C-A-S-H and (N,M)-C-A-S-H gel, these results were obtained through SEM-EDS analyses, as well FTIR tests.


Keywords: Mining Waste, Alkali-activated, Microstructure, Slag, Metakaolin

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