Effect of Desulfurization Gypsum and Quicklime on Performance of Fly Ash Filling Paste

DOI

10.2991/coal-18.2018.48How to use a DOI?

Keywords

filling paste, fly ash, desulfurization gypsum, quicklime, gel activity

Abstract

In order to reduce the filling cost and improve the coefficient of utilization of fly ash in coal mine filling paste, the influence of desulfurization gypsum and quicklime on the setting time and uniaxial compressive strength (UCS) of filling paste with large quantity of fly ash were studied using the control variable method, mechanical analysis, and other means. The hydration products and microstructures of the filling paste on corresponding age were analyzed by X-ray diffraction (XRD) and scanning electron microscopy (SEM), and results indicate the following: desulfurization gypsum can reduce the setting time of fly ash-filling paste and quicklime plays an important role in improving the late strength of fly ash-filling paste. When the cement and fly ash ratio in the gelling agent is 1:6, 8% of desulfurization gypsum can reach filling paste standards. When the quicklime is 4%, the strength improvement has the best effect, but the setting time can’t satisfy the filling paste standard, it can be meet the requirements of the filling paste when 4% quicklime and 4% desulfurization gypsum composite doped. XRD and SEM analysis illustrated that the difference in the types of hydration products and the amount of production at different times lead to different properties of the filling paste. Calcium hydroxide (CH) and a small amount of calcium silicate hydrate (CSH) are the main ingredients in the early stage of hydration products, filling paste activated by desulphurization gypsum generate ettringite (Aft) provides strength in the early age. The main hydration products of filling paste in the later stage are hydrated calcium aluminate (CAH), hydrated calcium aluminosilicate (CASH) and CSH.

Copyright

© 2018, the Authors. Published by Atlantis Press.

Open Access

This is an open access article distributed under the CC BY-NC license (http://creativecommons.org/licenses/by-nc/4.0/).

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TY  - CONF
AU  - Yin Liu
AU  - Boqiang Cui
AU  - Changxiang Wang
AU  - Yao Lu
AU  - Ning Jiang
AU  - Zhanxin Liu
PY  - 2018/10
DA  - 2018/10
TI  - Effect of Desulfurization Gypsum and Quicklime on Performance of Fly Ash Filling Paste
BT  - Proceedings of the 9th China-Russia Symposium "Coal in the 21st Century: Mining, Intelligent Equipment and Environment Protection" (COAL 2018)
PB  - Atlantis Press
SP  - 262
EP  - 269
SN  - 2352-5401
UR  - https://doi.org/10.2991/coal-18.2018.48
DO  - 10.2991/coal-18.2018.48
ID  - Liu2018/10
ER  -