Recycling phosphogypsum and construction demolition waste for cemented paste backfill and its environmental impact

Chen, Qiusong; Zhang, Qinli; Qi, Chongchong; Fourie, Andy; Xiao, Chongchun

doi:10.1016/j.jclepro.2018.03.131

Cited by 312 publications

(82 citation statements)

References 40 publications

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“…Over the last years, attempts were made to use PG in a wide range of applications such as road and rail works fills and building constructions, in particular in concrete and supersulfated cement, and high alumina cement [11][12][13][14].…”

Section: Introductionmentioning

confidence: 99%

Phosphogypsum waste as additives to lime stabilization of bentonite

Oumnih

Bekkouch

Gharibi

et al. 2019

Sustain Environ Res

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Waste recycling with increasing the lifecycle of resource is a novel approach for enhancing circular economy. Within this context, this study aims to give a second life cycle to phosphogypsum (PG) waste, which is a byproduct from phosphoric acid manufacture, as useful resources. This study evaluates the sustainability of this harmful waste, which is accumulated in large stockpiles and becomes hazardous during storage, and to stabilize bentonite-based concrete intended for road construction. The effect of raw bentonite (Ca-Na montmorillonite), PG, and lime on the properties of cementitious materials has been investigated through various tests. The properties examined include chemistry (X-ray Fluorescence Spectrometry), mineralogy (X-ray Powder Diffraction and Fourier-Transform Infrared Spectroscopy), calorimetry (Differential Thermal Analysis/Thermogravimetry) and microstructure (Scanning Electron Microscopy) of the mortar based on different mixtures of bentonite, PG and lime. The result show that lime and PG addition involves in the formation of new nanocrystalline phases and the disappearance of certain minerals as portlandite. Calcium silicate hydrate gel appeared in the mixture with 8% of lime, whereas strätlingite was neoformed in the mixture with 8% of lime and 8% of PG. These nanocrystalline phases are responsible for enhancing mechanical strength through the pozzoloanic reaction.

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Section: Introductionmentioning

confidence: 99%

Phosphogypsum waste as additives to lime stabilization of bentonite

Oumnih

Bekkouch

Gharibi

et al. 2019

Sustain Environ Res

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“…Test methods: as the particle size composition of uranium tailings is similar to that of construction sand, the preparation of filling slurry, the filling and curing of test mold, and the test of compressive strength shall refer to "Standard for test method of performance on building mortar" and the corresponding test method of tailing cemented backfill [31][32][33][34]. When the filling slurry preparation was completed, the yield stress and average viscosity of the slurry were obtained by testing the rheological parameters with MCR52 Modular Intelligent Advanced Rheometer.…”

Section: Test Schemementioning

confidence: 99%

Preparation and Mechanical Properties of Cemented Uranium Tailing Backfill Based on Alkali‐Activated Slag

Wang

Chen

et al. 2020

Advances in Materials Science and Engineering

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Backfilling disposal based on cement solidification is one of the ways to solve the environmental and safe problems of uranium tailing surface stacking. Alkali-activated slag, especially sodium silicate activated geopolymer, has become the preferred cementing material for the uranium tailing backfilling system because of its advantages of corrosion resistance and high strength. In this paper, uranium tailings and slag are taken as research objects, and the unconfined compressive strength (UCS) is taken as the main quality index. The preparation method of the cemented uranium tailing backfill based on alkali-activated slag was studied, hereinafter referred to as CUTB. The effects of additive amount, activator amount and activator modulus on the strength of CUTB were investigated. The results show that alkali-activated slag is an effective cementing material for the backfilling system of uranium tailing aggregate. The maximum UCS of 28 d age in the test groups is 16.45 MPa. Quicklime is an important additive for preparing CUTB. When the amount of quicklime is 0%, the early and late strengths of the filling body cannot be measured or at a very low level. At the age of 7 d, the order of each factor is additive amount > activator modulus > activator amount, but at the age of 28 d, the order of each factor is additive amount > activator amount > activator modulus. The test results can provide a basis for choosing cementitious materials for backfilling disposal of uranium tailings.

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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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Recycling phosphogypsum and construction demolition waste for cemented paste backfill and its environmental impact

Cited by 312 publications

References 40 publications

Phosphogypsum waste as additives to lime stabilization of bentonite

Phosphogypsum waste as additives to lime stabilization of bentonite

Preparation and Mechanical Properties of Cemented Uranium Tailing Backfill Based on Alkali‐Activated Slag

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

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