Red mud-based geopolymers with tailored alkali diffusion properties and pH buffering ability

JOURNAL OF CLEANER PRODUCTION

卷:148

Article

Ascensao, Guilherme¹  Seabra, Maria Paula¹  Aguiar, Jose Barroso²  Labrincha, Joao Antonio¹ 

[1] Univ Aveiro, Aveiro Inst Mat CICECO, Mat & Ceram Engn Dept, Campus Univ Santiago, P-3810193 Aveiro, Portugal

[2] Univ Minho, Dept Civil Engn, Campus Azurem, P-4800058 Guimaraes, Portugal

关键词: Geopolymer;    Red mud;    Alkali leaching;    pH buffering;   

DOI  :  10.1016/j.jclepro.2017.01.150

来源: Elsevier

【 摘 要 】

This study develop novel porous red mud (RM) based geopolymers and evaluates their potential to ensure prolonged pH control. Several properties of the novel geopolymers were examined including buffering ability, alkalis leaching behaviour, mineralogical composition, microstructure and physical properties. Two experimental plans were defined to evaluate the influence of porosity and RM content on those properties. The pH values of the eluted water and geopolymers OH- ions leaching have been determined over time showing that total OH- ions and the leaching rate can be tailored by controlling the geopolymers porous structure and the availability of free alkaline species. The lower pH gradient over 28th d (1.64 pH units) was achieved by combining a 0.025 wt% pore forming agent (aluminium powder) with 45 wt% MK replacement by red mud. A high and prolonged buffer capacity was accomplished, proving that red mud-based geopolymers have potential to be applied as pH buffering material. (C) 2017 Elsevier Ltd. All rights reserved.

【 授权许可】

Free