Description:
<p class="MsoNormal" style="margin-bottom:0cm;margin-bottom:.0001pt;text-align:justify;line-height:normal"><span lang="EN-US" style="font-size:12.0pt;mso-bidi-font-size:11.0pt;font-family:"Times New Roman",serif;mso-ansi-language:EN-US">Huge amounts of wastes, residues and by-products are generated fromphosphate mining and phosphoric acid production, including flotation tailings, wasteclay, phosphogypsum (PG), and phosphoric acid sludge. In this study, thecharacterization and evaluation of phosphogypsum was conducted on a raw PGsample from an operation in central Florida, USA without any pre-treatment. Thecharacterization results showed that the PG sample contains 230.64 ppm totalrare earth elements (REEs) with 13.23 ppm U and 0.63 ppm Th. The REE content inthis PG sample is lower than that in most other PGs worldwide. PG was selected asan REE resource due to its high volume generation, about 20 million tons peryear from Florida alone. Recovery of REEs from PG must take into account of theenvironmental and economic issues.<o:p></o:p></span></p>