Geopolymerization mechanism of binder-free mine tailings by sodium silicate

被引：81

作者：

Koohestani, Babak ^{[1
]}

Mokhtari, Pozhhan ^{[2
]}

Yilmaz, Erol ^{[3
]}

Mahdipour, Forough ^{[2
]}

Darban, Ahmad Khodadadi ^{[4
]}

机构：

[1] Tarbiat Modares Univ, Min & Mineral Proc Dept, Tehran, Iran

[2] Sabanci Univ, Mat Sci & Nano Engn, TR-34956 Istanbul, Turkey

[3] Recep Tayyip Erdogan Univ, Geotech Div, Dept Civil Engn, TR-53100 Rize, Turkey

[4] Tarbiat Modares Univ, Fac Engn, Tehran, Iran

来源：

CONSTRUCTION AND BUILDING MATERIALS | 2021年 / 268卷

基金：

美国国家科学基金会;

关键词：

Geopolymer; Portland cement; Tailings; pH; Sodium silicate; Curing; Strength development; SOL-GEL PROCESS; PASTE BACKFILL; ALKALI; PERFORMANCE; CHEMISTRY; ACTIVATOR; MODEL; GLASS; IONS; ACID;

D O I：

10.1016/j.conbuildmat.2020.121217

中图分类号：

TU [建筑科学];

学科分类号：

0813 ;

摘要：

The geopolymerization of solid substances rich in calcium and aluminum including mine tailings by sodium silicate is mainly believed to be under the influence of alkali activation. However, mine tailings' relative neutral condition can decrease sodium silicate's overall alkalinity to an unfavorable condition for alkaline reactivity. The decreased sodium silicate's alkalinity initiates the silica gel's precipitation leading to the overall mine tailings' geopolymerization. This makes sodium silicate as an alternative binder similar to Portland cement in cemented paste backfill. Any changes in mine tailings' chemical state can accelerate or decelerate geopolymerization bringing inadequate knowledge about strength development. Thus, mine tailings' geopolymerization by sodium silicate was investigated at different pH values and compared with cementation by Portland cement. It was found that the elevation in sodium silicate content decreases the acidification influence of mine tailings and postpones the strength development. The setting time of geopolymerised and cemented mine tailings were comparable, but pre-acidification of sodium silicate considerably accelerated the geopolymerization process. This made sodium silicate more advantageous over Portland cement because of manageable curing behavior and strength development. The obtained experimental results were discussed through several mechanical, rheological, microstructural, mineralogical, and chemical tests and analyses. (C) 2020 Elsevier Ltd. All rights reserved.

引用

页数：9

共 66 条

[1] Removal of some heavy metals ions from wastewater by copolymer of iron and aluminum impregnated with active silica derived from rice husk ash [J].