A new approach to sustainable management of industrial phosphogypsum waste: mechanism exploration and industrial application

Yifei Meng; Siyu Gan; Jing Liang; Bin Chen; Rongyue Ma; Yasmeen Alhijjawi; Fan Yang; Shan Ren; Chi He; Jinpeng Shi; Aibin Zhu; Chunbao Xu; Chunli Zheng

doi:10.1016/j.hazadv.2026.101032

A new approach to sustainable management of industrial phosphogypsum waste: mechanism exploration and industrial application

Yifei Meng, Siyu Gan, Jing Liang, Bin Chen, Rongyue Ma, Yasmeen Alhijjawi, Fan Yang^*, Shan Ren, Chi He, Jinpeng Shi, Aibin Zhu, Chunbao Xu^*, Chunli Zheng^*

^*Corresponding author for this work

School of Energy and Environment

Research output: Journal Publications and Reviews › RGC 21 - Publication in refereed journal › peer-review

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Abstract

A novel inexpensive modified calcium oxide (MCA) was prepared using commercial calcium oxide (CCO) and n-butanol and applied to curing phosphogypsum (PG) waste. With the MCA, the soluble phosphorus (SP), soluble fluoride (SF) and pH of PG changed from 230.6 mg/L, 180.7 mg/L and 2.89 drastically to 0.46 mg/L, 8.3 mg/L and 8.58 after 3 days, meeting the GB8978–1996 (SP≤0.5 mg/L, SF≤10 mg/L, pH = 6∼9), remaining stable even after 90 days. Our mechanism study revealed that the MCA reacted with SP to form amorphous CaHPO₄ which further tranformed to Ca₅(PO₄)₃OH. Ca₅(PO₄)₃OH combined with SF to produce Ca₅(PO₄)₃F (K_sp=2.1 × 10^–59). Compared to CaF₂ and CaHPO₄, the K_sp of Ca₅(PO₄)₃F decreased markedly by approximately 10⁴⁸ and 10⁵² times. More importantly, in this work MCA has been industrially applied to cure 790,000-tons PG. Moritoring for >500 days showed that the SP, SF and pH values met the GB8976–1996 standard continuously. This study demonstrated a promising new approach to sustainable management of industrial PG waste by treating PG with the novel inexpensive MCA to solidify SF and SP into precipitates of Ca₅(PO4)₃F with greatly improved long-term stability. © 2026

Original language	English
Article number	101032
Number of pages	9
Journal	Journal of Hazardous Materials Advances
Volume	21
Online published	20 Jan 2026
DOIs	https://doi.org/10.1016/j.hazadv.2026.101032
Publication status	Published - Feb 2026

Funding

This work was financially supported by the Key Research and Development Program of Shaanxi Province, China (No. 2023-ZDLSF-63), the \"Scientists + Engineers\" Team Construction Project of Qin Chuangyuan, Shaanxi Province, China (No. 2023KXJ-169) and the National Natural Science Foundation of China (Grant No. 42261144749), and partially by an CRF grant from the Research Grants Council of the Hong Kong Special Administrative Region, China (Project No. CityU C1017-24G). The authors appreciated Prof. Lingjie Meng, at the Instrumental Analysis Center of Xi'an Jiaotong University for their assistance with characterizations. And we would also like to acknowledge State Key Laboratory of Green and Efficient Development of Phosphorus Resources.

UN SDGs

This output contributes to the following UN Sustainable Development Goals (SDGs)

SDG 9 Industry, Innovation, and Infrastructure

Research Keywords

Fluoride
Industrial application
Long-term stability
Modified calcium oxide
Phosphogypsum waste
Sustainable management

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This full text is made available under CC-BY-NC-ND 4.0. https://creativecommons.org/licenses/by-nc-nd/4.0/

RGC Funding Information

RGC-funded

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title = "A new approach to sustainable management of industrial phosphogypsum waste: mechanism exploration and industrial application",

abstract = "A novel inexpensive modified calcium oxide (MCA) was prepared using commercial calcium oxide (CCO) and n-butanol and applied to curing phosphogypsum (PG) waste. With the MCA, the soluble phosphorus (SP), soluble fluoride (SF) and pH of PG changed from 230.6 mg/L, 180.7 mg/L and 2.89 drastically to 0.46 mg/L, 8.3 mg/L and 8.58 after 3 days, meeting the GB8978–1996 (SP≤0.5 mg/L, SF≤10 mg/L, pH = 6∼9), remaining stable even after 90 days. Our mechanism study revealed that the MCA reacted with SP to form amorphous CaHPO4 which further tranformed to Ca5(PO4)3OH. Ca5(PO4)3OH combined with SF to produce Ca5(PO4)3F (Ksp=2.1 × 10–59). Compared to CaF2 and CaHPO4, the Ksp of Ca5(PO4)3F decreased markedly by approximately 1048 and 1052 times. More importantly, in this work MCA has been industrially applied to cure 790,000-tons PG. Moritoring for >500 days showed that the SP, SF and pH values met the GB8976–1996 standard continuously. This study demonstrated a promising new approach to sustainable management of industrial PG waste by treating PG with the novel inexpensive MCA to solidify SF and SP into precipitates of Ca5(PO4)3F with greatly improved long-term stability. {\textcopyright} 2026",

keywords = "Fluoride, Industrial application, Long-term stability, Modified calcium oxide, Phosphogypsum waste, Sustainable management",

author = "Yifei Meng and Siyu Gan and Jing Liang and Bin Chen and Rongyue Ma and Yasmeen Alhijjawi and Fan Yang and Shan Ren and Chi He and Jinpeng Shi and Aibin Zhu and Chunbao Xu and Chunli Zheng",

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doi = "10.1016/j.hazadv.2026.101032",

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TY - JOUR

T1 - A new approach to sustainable management of industrial phosphogypsum waste

T2 - mechanism exploration and industrial application

AU - Meng, Yifei

AU - Gan, Siyu

AU - Liang, Jing

AU - Chen, Bin

AU - Ma, Rongyue

AU - Alhijjawi, Yasmeen

AU - Yang, Fan

AU - Ren, Shan

AU - He, Chi

AU - Shi, Jinpeng

AU - Zhu, Aibin

AU - Xu, Chunbao

AU - Zheng, Chunli

PY - 2026/2

Y1 - 2026/2

N2 - A novel inexpensive modified calcium oxide (MCA) was prepared using commercial calcium oxide (CCO) and n-butanol and applied to curing phosphogypsum (PG) waste. With the MCA, the soluble phosphorus (SP), soluble fluoride (SF) and pH of PG changed from 230.6 mg/L, 180.7 mg/L and 2.89 drastically to 0.46 mg/L, 8.3 mg/L and 8.58 after 3 days, meeting the GB8978–1996 (SP≤0.5 mg/L, SF≤10 mg/L, pH = 6∼9), remaining stable even after 90 days. Our mechanism study revealed that the MCA reacted with SP to form amorphous CaHPO4 which further tranformed to Ca5(PO4)3OH. Ca5(PO4)3OH combined with SF to produce Ca5(PO4)3F (Ksp=2.1 × 10–59). Compared to CaF2 and CaHPO4, the Ksp of Ca5(PO4)3F decreased markedly by approximately 1048 and 1052 times. More importantly, in this work MCA has been industrially applied to cure 790,000-tons PG. Moritoring for >500 days showed that the SP, SF and pH values met the GB8976–1996 standard continuously. This study demonstrated a promising new approach to sustainable management of industrial PG waste by treating PG with the novel inexpensive MCA to solidify SF and SP into precipitates of Ca5(PO4)3F with greatly improved long-term stability. © 2026

AB - A novel inexpensive modified calcium oxide (MCA) was prepared using commercial calcium oxide (CCO) and n-butanol and applied to curing phosphogypsum (PG) waste. With the MCA, the soluble phosphorus (SP), soluble fluoride (SF) and pH of PG changed from 230.6 mg/L, 180.7 mg/L and 2.89 drastically to 0.46 mg/L, 8.3 mg/L and 8.58 after 3 days, meeting the GB8978–1996 (SP≤0.5 mg/L, SF≤10 mg/L, pH = 6∼9), remaining stable even after 90 days. Our mechanism study revealed that the MCA reacted with SP to form amorphous CaHPO4 which further tranformed to Ca5(PO4)3OH. Ca5(PO4)3OH combined with SF to produce Ca5(PO4)3F (Ksp=2.1 × 10–59). Compared to CaF2 and CaHPO4, the Ksp of Ca5(PO4)3F decreased markedly by approximately 1048 and 1052 times. More importantly, in this work MCA has been industrially applied to cure 790,000-tons PG. Moritoring for >500 days showed that the SP, SF and pH values met the GB8976–1996 standard continuously. This study demonstrated a promising new approach to sustainable management of industrial PG waste by treating PG with the novel inexpensive MCA to solidify SF and SP into precipitates of Ca5(PO4)3F with greatly improved long-term stability. © 2026

KW - Fluoride

KW - Industrial application

KW - Long-term stability

KW - Modified calcium oxide

KW - Phosphogypsum waste

KW - Sustainable management

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UR - https://www.scopus.com/record/pubmetrics.uri?eid=2-s2.0-105028251712&origin=recordpage

U2 - 10.1016/j.hazadv.2026.101032

DO - 10.1016/j.hazadv.2026.101032

M3 - RGC 21 - Publication in refereed journal

SN - 2772-4166

VL - 21

JO - Journal of Hazardous Materials Advances

JF - Journal of Hazardous Materials Advances

M1 - 101032

ER -

A new approach to sustainable management of industrial phosphogypsum waste: mechanism exploration and industrial application

Abstract

Funding

UN SDGs

Research Keywords

Publisher's Copyright Statement

RGC Funding Information

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CRF-Sub-pj: A Biorefining Approach to Converting Organic Solid Wastes into Multiple High Value-added Bioproducts

CRF-Sub-pj: A Biorefining Approach to Converting Organic Solid Wastes into Multiple High Value-added Bioproducts

CRF: A Biorefining Approach to Converting Organic Solid Wastes into Multiple High Value-added Bioproducts

Cite this

A new approach to sustainable management of industrial phosphogypsum waste: mechanism exploration and industrial application

Abstract

Funding

UN SDGs

Research Keywords

Publisher's Copyright Statement

RGC Funding Information

Access Output

Other Access Options

Permanent Link

Other Files and Links

Fingerprint

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CRF-Sub-pj: A Biorefining Approach to Converting Organic Solid Wastes into Multiple High Value-added Bioproducts

CRF-Sub-pj: A Biorefining Approach to Converting Organic Solid Wastes into Multiple High Value-added Bioproducts

CRF: A Biorefining Approach to Converting Organic Solid Wastes into Multiple High Value-added Bioproducts

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