Scholarlink

<p>Phosphogypsum, a massive byproduct of the wet-process phosphoric acid industry, poses severe ecological risks due to the continuous leaching of soluble phosphorus and fluorine during open-air stockpiling. To mitigate these risks, this study developed an in-situ leaching simulation system to replicate stockpile conditions and systematically evaluate the remediation efficiency of Ca-based solidifying agents (Ca(OH)<sub>2</sub> and CaCO<sub>3</sub>). The experiments investigated the impacts of agent dosage and curing time on impurity removal. Results demonstrated that removal efficiencies correlated positively with dosage. Under optimal conditions, removal rates reached 97% for soluble phosphorus and 78% for soluble fluorine. Consequently, mass fractions of soluble phosphorus and fluorine in phosphogypsum decreased to 0.03 and 0.19%, respectively, meeting requirements for gypsum-based building materials. The leaching simulation further indicated that the agents neutralized leachate pH (pH ≥ 6 for surface water and pH ≥ 6.5 for groundwater), effectively suppressing initial contaminant release peaks. Final concentrations in the leachate were significantly reduced to 0.29 and 1.28&#xa0;mg/L for simulated surface water, and 0.05 and 0.03&#xa0;mg/L for groundwater, fully complying with wastewater discharge and groundwater quality standards. Notably, soluble phosphorus and fluorine in the upper phosphogypsum layer dropped to 0.03 and 0.08%, achieving the first-grade standard. This work provides a cost-effective, scalable technical pathway for the simultaneous harmless treatment and resource utilization of phosphogypsum stockpiles.</p> Graphical Abstract <p></p>

错误：搜索内容不能为空，请输入英文关键词
错误：关键词超出字数限制，请精简
高级检索

In-situ remediation of phosphogypsum stockpiles via Ca-based immobilization: leaching behavior and groundwater protection

  • 期刊论文

  • 发表日期：

    2026年4月26日

查看全文
  • Chen Zixiang,
  • Zhang Qutian,
  • Zhang Xia,
  • Zhang Long,
  • Yang Xinyi,
  • Luo Huihua,
  • Kuang Buxiao,
  • Chi Ruan,
  • Zhou Fang,
  • Fang Xiyang

摘要

Phosphogypsum, a massive byproduct of the wet-process phosphoric acid industry, poses severe ecological risks due to the continuous leaching of soluble phosphorus and fluorine during open-air stockpiling. To mitigate these risks, this study developed an in-situ leaching simulation system to replicate stockpile conditions and systematically evaluate the remediation efficiency of Ca-based solidifying agents (Ca(OH)2 and CaCO3). The experiments investigated the impacts of agent dosage and curing time on impurity removal. Results demonstrated that removal efficiencies correlated positively with dosage. Under optimal conditions, removal rates reached 97% for soluble phosphorus and 78% for soluble fluorine. Consequently, mass fractions of soluble phosphorus and fluorine in phosphogypsum decreased to 0.03 and 0.19%, respectively, meeting requirements for gypsum-based building materials. The leaching simulation further indicated that the agents neutralized leachate pH (pH ≥ 6 for surface water and pH ≥ 6.5 for groundwater), effectively suppressing initial contaminant release peaks. Final concentrations in the leachate were significantly reduced to 0.29 and 1.28 mg/L for simulated surface water, and 0.05 and 0.03 mg/L for groundwater, fully complying with wastewater discharge and groundwater quality standards. Notably, soluble phosphorus and fluorine in the upper phosphogypsum layer dropped to 0.03 and 0.08%, achieving the first-grade standard. This work provides a cost-effective, scalable technical pathway for the simultaneous harmless treatment and resource utilization of phosphogypsum stockpiles.

Graphical Abstract