Uranium and Rare Earth Elements in El-Jalamid Phosphate, Saudi Arabia: concentration and geochemical pattern

Journal Article

El-Taher, Khater EM Ashraf, Mahmoud A. Galmed, Mahmoud M. Nasr, A. . 2016

• المجلة \ الصحيفة: Environmental Earth Sciences
• رقم العدد: 18
• رقم الإصدار السنوي: 75
• الصفحات: 1261-1273

مستخلص المنشور

Uranium (U) and rare earth elements (REEs) play a significant role in the evaluation and follow-up of the ecological impacts of phosphate mining and industrial activities. Fifteen representative phosphate ore samples were collected from the phosphate mines El-Jalamid (8 samples) and Umm Wu’al (4 samples) in Saudi Arabia and El-Sibayia (3 samples) in Egypt and analyzed for U and REEs using inductively coupled plasma mass spectrometry (ICP-MS). Detailed studies of the El-Jalamid phosphatic samples were conducted using scanning electron microscopy (SEM) and energy dispersive X-ray spectroscopy (EDX). The average (range) U concentrations in El Jalamid, Umm Wu’al and El-Sibayia phosphate samples were 20.7 (17.1-27.1), 61.9 (26.8-150.0) and 88.7 (88.5-90.7) mg/kg, respectively. The U contents in the El-Jalamid samples were considerably lower than those of other phosphate ores from different origins and countries. Therefore, the radioecological impacts of mining activities and the application of phosphate fertilizers produced from El-Jalamid ore would be expected to impose relatively limited ecological impacts. The SEM-EDX analyses reveal the presence of uranium-bearing minerals (apatite) and uranyl vanadate minerals (carnotite, K2(UO2)2(VO4)). The highest REE concentration values were recorded for La in all samples, followed by Ce and Nd, with average values of 14.0, 9.3 and 8.0 mg/kg, respectively. The lowest REE concentrations were recorded for Tm in all samples, with an average value of 0.28 mg/kg. El-Jalamid phosphate samples are highly enriched in heavy REEs (HREEs) and depleted in light REEs (LREEs), except for La. The REEs exhibit the same behavior in the phosphate deposits of El-Jalamid, Umm Wu’al, El-Sibayia, Florida and Morocco and the opposite behavior in the phosphate deposits from Jordon and Kola, which are enriched in LREEs (except for La) and depleted in HREEs.