Synthesis of electrolytic manganese residue-fly ash based geopolymers with high compressive strength

摘要

A large amount of electrolytic manganese residue (EMR) has been produced in electrolytic manganese industry and caused great damage to the environment. In this study, industrial solid waste of EMR and fly ash (FA) were used as solid aluminosilicate raw materials (ASM) to prepare geopolymers with high mechanical strength and good environmental stability. The influences of EMR/ASM ratio, Liquid/Solid ratio (L/S) and curing conditions were studied to guide the production of geopolymers with excellent properties. The results showed that EMR-FA based geopolymer with acceptable compressive strength (16 MPa), good environmental stability and low leaching toxicity can be obtained under the conditions of EMR/ASM = 0.6, L/S = 0.25 and curing at 80 degrees C for 12 h. The mineral composition of geopolymers was analyzed by X-ray diffraction spectrometer (XRD), which indicated that the geopolymers were mainly amorphous aluminosilicate. By scanning electron microscope and energy dispersive spectrometer analysis, the EMR-FA based geopolymer exhibits a smooth and dense surface of cementitious material with the main elements of silicon, aluminum, calcium and sodium. The geopolymerization was analyzed by Fourier transform infrared spectra and the mechanism was discussed. (C) 2020 Published by Elsevier Ltd.