The Influence of Mechanical Activation of Fly Ash on the Toxic Metals Immobilization by Fly Ash-Based Geopolymers

Abstract

This paper investigates the influence of mechanical activation of fly ash on the toxic metals immobilization by fly ash-based geopolymers. Fly ash was firstly mechanically and then alkali-activated. Mechanical activation of fly ash was conducted in a planetary ball mill. Alkali activation of fly ash was carried out at room temperature by use of sodium silicate solution as an activator. Toxic metals (Pb and Cr) were added in the form of water soluble salts during the synthesis of geopolymers. The immobilization process was assessed via investigation of the mechanical and leaching properties of geopolymers. Structural changes of geopolymers during the toxic metals immobilization were assessed by means of gas adsorption and SEM analyses. Mechanical activation of fly ash led to a significant increase in geopolymer strength and to a reduced leaching of toxic metals from geopolymers.

Williams expansion utilized for assessment of crack behaviour under mixed‐mode loading in alkali‐activated fine‐grained composite

“…As a consequence, a search is underway to identify environmentally friendly alternatives 2 . One possibility that is being tested is the use of geopolymers, 3 resulting from alkali reaction, which activates secondary raw or waste products. Several recent publications are devoted to the presentation of the basic properties of alkali‐activated composites (AAC), 4 as well as to demonstrations/analyses of their practical application 5 .…”