ABSTRACT

Phosphogypsum (PG) is a solid waste generated from phosphate fertilisers industries. It represents a serious threat to the aquatic and terrestrial environment because of its acidity and its high content in heavy metals and radionuclides. The aim of this work is to describe the formation of PG during the synthesis of the phosphoric acid, the entrapment of Zinc (Zn) in PG and its lixiviation in presence of a natural organic matter extracted as powder from the cladodes of Opuntia ficus-indica (OFI) using physical and chemical characterisation techniques such as FTIR, XRD, SEM-EDX, laser diffraction, and AAS. The formation of PG mainly occurs in the pH range between 4.6 and 3 and it accompanies the transformation of H₂(PO₄)⁻ into phosphoric acid H₃PO₄. The maximal Zn incorporation within the PG was reached at pH 6 and decreased progressively with pH. Zinc was found to have a great tendency to migrate from PG particles to OFI’s suspensions since a maximum Zn removal percentage of 93% was achieved.

摘要

磷石膏（PG）是磷肥工业产生的固体废物。由于它的酸性以及重金属和放射性核素的高含量，它对水生和陆地环境构成了严重威胁。这项工作的目的是描述在磷酸合成过程中 PG 的形成、锌 (Zn) 在 PG 中的截留及其在从仙人掌叶状体中提取为粉末的天然有机物存在下的浸出(OFI) 使用物理和化学表征技术，例如 FTIR、XRD、SEM-EDX、激光衍射和 AAS。PG 的形成主要发生在 4.6 和 3 之间的 pH 值范围内，它伴随着 H ₂ (PO ₄ )的转化^-转化为磷酸 H ₃ PO ₄。PG 中的最大 Zn 掺入在 pH 6 时达到并随着 pH 值逐渐降低。发现锌具有很大的从 PG 颗粒迁移到 OFI 悬浮液的趋势，因为达到了 93% 的最大锌去除百分比。