Utilization of phosphogypsum and phosphate tailings for cemented paste backfill

Chen, Qiusong; Zhang, Qinli; Fourie, Andy; Chen, Xin

doi:10.1016/j.jenvman.2017.06.027

Cited by 137 publications

(41 citation statements)

References 25 publications

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“…), and radioactive-elements ( 226 Ra, 238 U) [1,2]. Historically, PG was disposed of on the Earth's surface, which not only wasted a lot of resources, but also caused serious pollution of the atmosphere, soil, and water near the burial locations [3][4][5][6][7].…”

Section: Introductionmentioning

confidence: 99%

Utilisation of Water-Washing Pre-Treated Phosphogypsum for Cemented Paste Backfill

et al. 2019

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Recycling phosphogypsum (PG) for cemented paste backfill (CPB) has been widely used at phosphate mines in China. However, the impurities in PG prolong the setting time and reduce the uniaxial compressive strength (UCS), limiting the engineering application of PG. This paper aims to investigate the feasibility of treated PG (TPG) washed repeatedly using deionised water (DW) for CPB. A water-washing pre-experiment was first conducted to find the proportion with the least DW demand and the effects of water-washing on ordinary PG (OPG). Then, based on the PG:DW ratio obtained from the pre-experiment, the properties of the OPG-based CPB (OCPB) and TPG-based CPB (TCPB) were tested using slump tests, UCS tests, and microstructural analysis. The results show that (1) after 11 water-washings at the PG:DW ratio of 1:1.75, the pH of the supernatant (pH = 6.328) meets the requirements of Chinese standard GB 8978-1996. (2) Water-washing improves the particle gradation quality of PG and removes the soluble impurities adsorbed at the surface of PG crystals. (3) The initial slump values of TCPB are 0.19–1.15 cm higher than that of OCPB, furthermore, the diffusivity values of TCPB are better than the performance of OCPB, with 0.61–1.68 cm of superiority. (4) The UCS values of TCPB are up to 0.838 MPa, 1.953 MPa, and 2.531 MPa, after curing for 7, 14, and 28 days. These are 0.283 MPa, 0.823 MPa, and 0.881 MPa higher than that of OCPB, respectively. It can be concluded that water-washing pre-treatment greatly improves the workability and mechanical property of PG-based CPB. These results are of great value for creating a reliable and environmentally superior alternative for the recycling of PG and for safer mining production.

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Section: Introductionmentioning

confidence: 99%

Utilisation of Water-Washing Pre-Treated Phosphogypsum for Cemented Paste Backfill

et al. 2019

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“…SEM analysis with the HELIOS NamoLab 600i (FEI, Lake Oswego, OR, USA). was used to find the micromorphologic development inside the cemented backfill samples [30]. Owing to the poor conducting performance of backfill, it was necessary to cover a layer of gold coating on samples to enhance the conductive properties of the samples in order to meet the inspection requirements.…”

Section: Microstructural Analysismentioning

confidence: 99%

Slurry Preparation Effects on the Cemented Phosphogypsum Backfill through an Orthogonal Experiment

Zhou

Zhu

et al. 2019

Minerals

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The cemented phosphogypsum (PG) backfill technique provides a new method for massive consumption of PG, and therefore alleviating the environmental pollution of PG. This study considered the effects of slurry preparation on the performance of cemented PG backfill. A L 16 (4 4 ) orthogonal experiment was designed to analyze four factors, namely the solid content, phosphogypsum-to-binder ratio (PG/B ratio), stirring time and stirring speed, with each factor having four levels. According to the range analysis, the solid content played the dominant role in controlling the bleeding rate, while the setting times strongly depended on the PG/B ratio. In terms of strength development of the backfill, the PG/B ratio was shown to be the most significant factor determining the unconfined compressive strength (UCS), followed by the solid content, stirring time and stirring speed. Furthermore, the results showed that the slurry preparation affected the environmental behavior of impurities that originated in PG. By analyzing the concentrations of impurities in the bleeding water of the slurry as well as the leachates of the tank leaching test, the results showed that the release of F − and SO 4 2− was aggravated clearly with the increase in the PG/B ratio, while the release of PO 4 3− always remained at relatively low levels.

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“…Goaf is prone to cause disasters such as overlying rock caving, surface subsidence, and goaf waterlogging, which seriously affect the safety of mine production. The preparation of phosphogypsum into filling materials for mine filling can not only maintain the stability of surrounding rocks, reduce the surface subsidence, and enhance the recovery of resources [25][26][27][28], but it can also completely solve the problem of phosphogypsum stockpiling and ensure the sustainable development of mines [29][30][31][32][33].…”

Section: Introductionmentioning

confidence: 99%

Industrial Experiment of Goaf Filling Using the Filling Materials Based on Hemihydrate Phosphogypsum

Rong

Lan

2020

Minerals

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The surface stockpiling of phosphogypsum not only occupies a large amount of land, but also seriously harms the surrounding ecological environment. The preparation of phosphogypsum into filling materials for mine filling can not only maintain the stability of surrounding rock, reduce surface subsidence, enhance the recovery of resources, but it can also completely solve the problem of phosphogypsum stockpiling. Under certain activation conditions, hemihydrate phosphogypsum has a strong cementing property. It is an important way to reduce the filling cost by using hemihydrate phosphogypsum instead of cement as a cementing material. Through laboratory experiments, the filling materials based on hemihydrate phosphogypsum were developed. In order to further verify its feasibility in practical filling engineering, the industrial experiment of goaf filling was carried out in a phosphorus mine. The results show that the filling system was simple, reliable, and easy to operate and manage. The strength of the filling body basically reached the expected strength target of 2.5 MPa in 3 days. The consolidation speed of the filling materials was faster, which is beneficial to the safe underground construction of the mine. The results of the industrial experiment of goaf filling indicate that the filling materials based on hemihydrate phosphogypsum are suitable for mine filling engineering practice, the work amount is small, and the filling cost is low.

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Utilization of phosphogypsum and phosphate tailings for cemented paste backfill

Cited by 137 publications

References 25 publications

Utilisation of Water-Washing Pre-Treated Phosphogypsum for Cemented Paste Backfill

Utilisation of Water-Washing Pre-Treated Phosphogypsum for Cemented Paste Backfill

Slurry Preparation Effects on the Cemented Phosphogypsum Backfill through an Orthogonal Experiment

Industrial Experiment of Goaf Filling Using the Filling Materials Based on Hemihydrate Phosphogypsum

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