The treatment of phosphogypsum with zeolite to use it in binding material

Nizevičienė, Dalia; Vaičiukynienė, Danutė; Michalik, B.; Bonczyk, Michał; Vaitkevičius, Vitoldas; Jusas, Vacius

doi:10.1016/j.conbuildmat.2018.05.208

Cited by 52 publications

(9 citation statements)

References 24 publications

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“…The strength development (compressive, tensile strength as well as Young's modulus) at different curing times of the material will be studied and compared with conventional road base material. Our preliminary results about the potential use of recycled PG as a raw material for concrete were in perfect agreement with the findings of Manal [66], Rashad [67], Nizevičienė [64] and Chen [62]; it showed comparable properties as conventional road base materials. Hence, PG stacks can be engineered as a road base material with competitive properties.…”

Section: Management Approachsupporting

confidence: 89%

“…PG can be used as a road base material, a developed approach to massively recycle PG for industrial application. It is to be mentioned that several attempts to sustainably valorize the high PG residues [15,19,33,40,64]. Moreover, Pérez-López et al [65] provided geochemical data about stack-piles of PG from Huelva, Spain, with an aim to route for restoration plan.…”

Section: Management Approachmentioning

confidence: 99%

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Tunisian phosphogypsum tailings: Assessment of leaching behavior for an integrated management approach

Zmemla

Sdiri

Naifar

et al. 2019

Environmental Engineering Research

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This study has been carried out to evaluate the leaching behavior of Tunisian phosphogypsum (PG) tailings in Skhira city (southern Tunisia). Two PG samples, including old and freshly deposited samples, were characterized in terms of physical, geotechnical, mechanical, chemical and mineralogical properties. Special attention was paid to their leaching behavior when subjected to standard leaching tests. Our results indicated that both samples are mainly composed of more than 31.85% CaO and 31.4% SO3, indicating the predominance of gypsum. This was further confirmed by XRD patterns that revealed the presence of characteristic reflections of gypsum, brushite, quartz and Maladrite. Compressive strength after 90 d exceeded 769 kPa, but still lower than that of natural sand (1,800 kPa). Leaching test was proposed as an appropriate method to determine the released contaminants from PG. The obtained results showed that Fluorine and Phosphorus are the most released elements from PG with 40 and 30%, respectively. The released Se, Cd, and Zn were the only trace elements that exceeded the threshold limits. It seemed that leached element concentrations were independent aging or particle size of the PG. Based on the assessment of leaching behavior, an integrated management approach of the PG deposits was proposed.

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Section: Management Approachsupporting

confidence: 89%

Section: Management Approachmentioning

confidence: 99%

Tunisian phosphogypsum tailings: Assessment of leaching behavior for an integrated management approach

Zmemla

Sdiri

Naifar

et al. 2019

Environmental Engineering Research

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“…The weight loss for hydrated gypsum (BG and PG) was 22.43 and 19.24% for BG and PG respectively, indicating hydration process of the gypsum binder is in compliance with the literature (Nizevičienė, Vaičiukynienė, Vaitkevičius, & Rudžionis, 2016). PG binder weight loss was 6.89% at 950 °C, which indicates that PG hemihydrate was obtained by heat treatment of dihydrate at 180 °C and corresponds to the literature where 6.4% loss is given (Nizevičienė et al, 2018).…”

Section: Methodssupporting

confidence: 85%

The workability kinetics of phosphogypsum binder

Būmanis

Zoriča

Pundienė

et al. 2019

Modern Building Materials, Structures and Techniques (MBMST)

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The dihydrate phosphogypsum (PG) based binder workability kinetics were investigated regarding to waterbinder ratio (W/B) and chemical admixtures added to the composition of PG paste. PG was dried at 60 °C and homogenized to powder like particles with collision milling in disintegrator and calcium sulphate hemihydrate was obtained by heating PG at 180 °C. The obtained binder chemical, mineralogical and technological properties were tested and compared to commercial gypsum plaster. Early age (2 h) and 14 d compression strength was determined. The workability and setting time of both -PG and commercial gypsum was investigated with viscosimeter, ultrasonic pulse velocity and Vicat apparatus and correlation between testing methods was obtained. Results indicate that binder based on PG has slightly lower pH (pH 6.3) than commercial binder (pH 6.8) and finer particle size grading leading to increased W/B ratio and more rapid initial setting time. The set retarder could efficiently increase the setting time of PG binder giving extra workability time which is positive factor for prolonged treatment of binder slurry, i.e. to prepare porous gypsum binder. Such approach would give a safer alternative to PG disposal, closing the materials loop and enhancing the circularity of this material.

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“…Moreover, the impurities in OPG, such as HF and H 3 PO 4 , also prolong the setting time and reduce the uniaxial compressive strength (UCS) of CPB. In this case, researchers have suggested different methods to ensure the backfill quality of PG used as an alternative raw material for application in CPB [16][17][18][19][20][21][22][23][24]. These include, for instance, substantially increasing the proportion of ordinary Portland cement (OPC) in mixtures or adding other tailings, such as fly ash, waste lime and zeolite, as the hydration activators.…”

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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The treatment of phosphogypsum with zeolite to use it in binding material

Cited by 52 publications

References 24 publications

Tunisian phosphogypsum tailings: Assessment of leaching behavior for an integrated management approach

Tunisian phosphogypsum tailings: Assessment of leaching behavior for an integrated management approach

The workability kinetics of phosphogypsum binder

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

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