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One‐Part Geopolymers Based on Thermally Treated Red Mud/NaOH Blends
Author(s) -
Ke Xinyuan,
Bernal Susan A.,
Ye Nan,
Provis John L.,
Yang Jiakuan
Publication year - 2015
Publication title -
journal of the american ceramic society
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 0.9
H-Index - 196
eISSN - 1551-2916
pISSN - 0002-7820
DOI - 10.1111/jace.13231
Subject(s) - red mud , geopolymer , aluminosilicate , alkali metal , calcination , materials science , chemical engineering , thermal decomposition , hydroxide , sodium hydroxide , compressive strength , calcium hydroxide , curing (chemistry) , mineralogy , composite material , chemistry , organic chemistry , metallurgy , catalysis , engineering
In this study, one‐part “just add water” geopolymer binders are synthesized through the alkali‐thermal activation of the red mud which is relatively rich in both alumina and calcium. Calcination of the red mud with sodium hydroxide pellets at 800°C leads to decomposition of the original silicate and aluminosilicate phases present in the red mud, which promotes the formation of new compounds with hydraulic character, including a partially ordered peralkaline aluminosilicate phase and the calcium‐rich phases C 3 A and α‐C 2 S. The hydration of the “one‐part geopolymer” leads to the formation of zeolites and a disordered binder gel as the main reaction products, and the consequent development of compressive strengths of up to 10 MPa after 7 d of curing. These results demonstrate that red mud is an effective precursor to produce one‐part geopolymer binders, via thermal and alkali‐activation processes.