Cost-Effective Treatment of Hemihydrate Phosphogypsum and Phosphorous Slag as Cemented Paste Backfill Material for Underground Mine

The environmental pollution caused by the discharge of phosphogypsum (PG) and phosphorous slag (PS) is a common issue for all countries. In order to fully utilize hemihydrate PG (HPG) and PS and treat goafs in mines, the HPG and PS were used as cementitious materials for cemented paste backfill (CPB...

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Main Authors: Xilong Xue, Yuxian Ke, Qian Kang, Qinli Zhang, Chongchun Xiao, Fengjian He, Qing Yu
Format: Article
Language:English
Published: Wiley 2019-01-01
Series:Advances in Materials Science and Engineering
Online Access:http://dx.doi.org/10.1155/2019/9087538
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author Xilong Xue
Yuxian Ke
Qian Kang
Qinli Zhang
Chongchun Xiao
Fengjian He
Qing Yu
author_facet Xilong Xue
Yuxian Ke
Qian Kang
Qinli Zhang
Chongchun Xiao
Fengjian He
Qing Yu
author_sort Xilong Xue
collection DOAJ
description The environmental pollution caused by the discharge of phosphogypsum (PG) and phosphorous slag (PS) is a common issue for all countries. In order to fully utilize hemihydrate PG (HPG) and PS and treat goafs in mines, the HPG and PS were used as cementitious materials for cemented paste backfill (CPB). The physical and chemical properties of HPG and PS were first analyzed, and then, the characteristics of CPB were evaluated through fluidity tests, gas detection, uniaxial compressive strength (UCS) tests, bleeding tests, and scanning electron microscopy (SEM). After this, the underground environmental impact of CPB-based HPG and PS was investigated through a dynamic leachability experiment. The results show that (1) the UCS of CPB increases with the increase of the HPG content and mass fraction, and the addition of 3% quicklime can eliminate CO2, H2S, and SO2 generated from the slurry of CPB-based HPG-PS; (2) the addition of 3% quicklime and 5% cement to the HPG-PS mixtures can offset the strength loss of CPB in the late curing stage; (3) the UCS of the recommended specimen reaches 1.15–3.32 MPa after curing from 7 to 28 days, with their slump values varying from 15 mm to 26 mm, and the bleeding rates between 0.87% and 1.15%, which can meet the technical requirements of mining methods; (4) the UCS of CPB is the result of the cohydration reaction of hemihydrate gypsum (HG) in HPG and active Al2O3 and SiO2 in PS; and (5) the leaching indexes meet Category IV of the Chinese Groundwater Quality Standard (DZ/T 0290-2015). The results of this investigation provide a cost-efficient way for the efficient mining of phosphate resources and the comprehensive utilization of HPG and PS.
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issn 1687-8434
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language English
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spelling doaj-art-dd0f4939eb884b66bcb61c3a42a4eb892025-02-03T06:07:15ZengWileyAdvances in Materials Science and Engineering1687-84341687-84422019-01-01201910.1155/2019/90875389087538Cost-Effective Treatment of Hemihydrate Phosphogypsum and Phosphorous Slag as Cemented Paste Backfill Material for Underground MineXilong Xue0Yuxian Ke1Qian Kang2Qinli Zhang3Chongchun Xiao4Fengjian He5Qing Yu6School of Resources Environment and Safety Engineering, University of South China, Hengyang 421001, ChinaSchool of Resources and Environmental Engineering, Jiangxi University of Science and Technology, Ganzhou 341000, ChinaSchool of Resources Environment and Safety Engineering, University of South China, Hengyang 421001, ChinaSchool of Resources and Safety Engineering, Central South University, Changsha 410083, ChinaSchool of Resources and Safety Engineering, Central South University, Changsha 410083, ChinaChangsha Design and Research Institute of Nonferrous Metallurgical Co., Ltd, Changsha 410001, ChinaSchool of Resources Environment and Safety Engineering, University of South China, Hengyang 421001, ChinaThe environmental pollution caused by the discharge of phosphogypsum (PG) and phosphorous slag (PS) is a common issue for all countries. In order to fully utilize hemihydrate PG (HPG) and PS and treat goafs in mines, the HPG and PS were used as cementitious materials for cemented paste backfill (CPB). The physical and chemical properties of HPG and PS were first analyzed, and then, the characteristics of CPB were evaluated through fluidity tests, gas detection, uniaxial compressive strength (UCS) tests, bleeding tests, and scanning electron microscopy (SEM). After this, the underground environmental impact of CPB-based HPG and PS was investigated through a dynamic leachability experiment. The results show that (1) the UCS of CPB increases with the increase of the HPG content and mass fraction, and the addition of 3% quicklime can eliminate CO2, H2S, and SO2 generated from the slurry of CPB-based HPG-PS; (2) the addition of 3% quicklime and 5% cement to the HPG-PS mixtures can offset the strength loss of CPB in the late curing stage; (3) the UCS of the recommended specimen reaches 1.15–3.32 MPa after curing from 7 to 28 days, with their slump values varying from 15 mm to 26 mm, and the bleeding rates between 0.87% and 1.15%, which can meet the technical requirements of mining methods; (4) the UCS of CPB is the result of the cohydration reaction of hemihydrate gypsum (HG) in HPG and active Al2O3 and SiO2 in PS; and (5) the leaching indexes meet Category IV of the Chinese Groundwater Quality Standard (DZ/T 0290-2015). The results of this investigation provide a cost-efficient way for the efficient mining of phosphate resources and the comprehensive utilization of HPG and PS.http://dx.doi.org/10.1155/2019/9087538
spellingShingle Xilong Xue
Yuxian Ke
Qian Kang
Qinli Zhang
Chongchun Xiao
Fengjian He
Qing Yu
Cost-Effective Treatment of Hemihydrate Phosphogypsum and Phosphorous Slag as Cemented Paste Backfill Material for Underground Mine
Advances in Materials Science and Engineering
title Cost-Effective Treatment of Hemihydrate Phosphogypsum and Phosphorous Slag as Cemented Paste Backfill Material for Underground Mine
title_full Cost-Effective Treatment of Hemihydrate Phosphogypsum and Phosphorous Slag as Cemented Paste Backfill Material for Underground Mine
title_fullStr Cost-Effective Treatment of Hemihydrate Phosphogypsum and Phosphorous Slag as Cemented Paste Backfill Material for Underground Mine
title_full_unstemmed Cost-Effective Treatment of Hemihydrate Phosphogypsum and Phosphorous Slag as Cemented Paste Backfill Material for Underground Mine
title_short Cost-Effective Treatment of Hemihydrate Phosphogypsum and Phosphorous Slag as Cemented Paste Backfill Material for Underground Mine
title_sort cost effective treatment of hemihydrate phosphogypsum and phosphorous slag as cemented paste backfill material for underground mine
url http://dx.doi.org/10.1155/2019/9087538
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