Hassoune H, Lahhit M, Khalid A, Lachehab A
Water, Environment and Energy Laboratory (WEEL), Research & Development Department, OCP Group, P.O. Box 118, El Jadida, Morocco E-mail:
Water Sci Technol. 2017 Oct;76(7-8):1844-1851. doi: 10.2166/wst.2017.368.
The phosphoric acid production obtained by attacking phosphate rock by sulphuric acid cogenerates considerable quantities of phosphogypsum. The world cogeneration is estimated about 100-280 Mt per year. In another context of sustainable development, the phosphate chemical industry develops different ways of phosphogypsum valorization, which makes its storage stack in a suitable way for its potential use as an industrial by-product. Although, this storage can cause an environmental impact largely due to the transfer of trace elements (TEs) to groundwater by leaching. It is therefore important to evaluate the impact linked to the storage in order to limit this transfer. The evaluation is usually performed through leaching tests in columns or reactor. In this work, leaching tests were performed in columns by infiltration-percolation on two filter mediums: phosphogypsum and synthetic sandy soils. The results showed that the phosphogypsum is acting as a filter, which retains and releases the TEs. Most of these TEs (Pb, Se, Ag, Zn and Cu) were highly retained in the synthetic soils surfaces and their contents in waters were considerably lower than the maximum contaminant levels (MCLs). Although As, Cd, Cr and Ni were strongly transferred to groundwater, their respective contents were higher than the MCLs.
通过硫酸分解磷矿生产磷酸会联产大量磷石膏。全球每年的联产产量估计约为100 - 280百万吨。在可持续发展的另一背景下，磷酸盐化学工业开发了多种磷石膏增值利用方式，从而以适合其作为工业副产品潜在用途的方式储存磷石膏堆。然而，这种储存可能会造成较大的环境影响，主要是因为微量元素通过淋溶转移到地下水中。因此，评估与储存相关的影响以限制这种转移很重要。评估通常通过柱体或反应器中的淋溶试验进行。在这项工作中，通过在两种过滤介质（磷石膏和合成砂土）上进行渗滤 - 渗透的柱体淋溶试验。结果表明，磷石膏起到了过滤器的作用，它保留并释放微量元素。这些微量元素中的大多数（铅、硒、银、锌和铜）在合成土壤表面被高度保留，其在水中的含量远低于最大污染物水平（MCLs）。尽管砷、镉、铬和镍大量转移到地下水中，但其各自含量高于最大污染物水平。
