نوع مقاله : مقاله پژوهشی
نویسندگان
پژوهشکده چرخه سوخت هسته‌ای، پژوهشگاه علوم و فنون هسته‌ای، سازمان انرژی اتمی ایران، صندوق پستی: 8486-11365، تهران- ایران
چکیده
کانسار فسفات دلیر در 57 کلیومتری جنوب غربی شهر چالوس در استان مازندران و زون البرز مرکزی دارد. میزبان این ذخیره سازند سلطانیه است که یکی از مهم‌ترین سازندهای میزبان فسفات رسوبی در ایران است. نتایج آنالیز پراش اشعه ایکس (XRD) و مطالعات میکروسکوپ نوری و الکترونی بر روی نمونه‌های فسفات کانسار دلیر نشان داد که آپاتیت، کلسیت، کوارتز و دولومیت کانی‌های اصلی و کانی‌های فرعی شامل مونتموریلونیت، پیریت و باریت در مقادیر فرعی به همراه مقادیر جزیی سیدریت، روتیل، ایلیت و گوتیت هستند. میزان 5O2P، U و REE در نمونه‌های موردمطالعه به ترتیب در محدوده 5 تا 1/16 درصد، 9/1 تا 5/5 و 9/45 تا 9/136 پی پی ام متغیر است. نمونه‌های موردمطالعه دارای بیهنجاری منفی Ce است که نشان‌دهنده وجود یک محیط فاقد اکسیژن در زمان نهشت فسفات دلیر می‌باشد. براساس فاکتورهای کنترل‌کننده تمرکز اورانیم در فسفریت‌ها، افق فسفاته سازند سلطانیه به دلیل شرایط آب و هوای گرم تا نیمه‌گرم مرطوب و pH خنثی تا اسیدی آب دریا در زمان تشکیل فسفات، پتانسیل غنی‌شدگی اورانیم را ندارد. در نهایت، با توجه به این‌که نتایج آنالیز شیمیایی نمونه‌های فسفات کانسار دلیر غنی‌شدگی اورانیم نشان نمی‌دهد و هم‌چنین با در نظر گرفتن فاکتورهای کنترل‌کننده تمرکز اورانیم در فسفریت‌ها می‌توان پیش‌بینی کرد احتمالاً سایر ذخایر فسفات سازند سلطانیه فاقد غنی‌شدگی اورانیم هستند.
کلیدواژه‌ها
عنوان مقاله [English]
Geochemistry of uranium and REEs in Dalir phosphate deposit, Central Alborz zone
نویسندگان [English]
- K. Khoshnoodi
- S. Ziapour
Nuclear Fuel Cycle Research School, Nuclear Science and Technology Research Institute, AEOI, P.O.Box:11365-8486, Tehran-Iran
چکیده [English]
The Dalir phosphate deposit is located 57 km southwest of Chalus city in Mazandaran province, the Central Alborz zone. This deposit is hosted by Soltanieh Formation, one of Iran's important hosts of sedimentary phosphates. The results of X-ray diffraction (XRD) analysis and optical and electron microscopy studies on the phosphate samples indicate that the main minerals include apatite, calcite, quartz, and dolomite accompanied by montmorillonite, pyrite, and barite in minor amounts; siderite, rutile, illite, and goethite in trace amounts. The concentration of P2O5, U, and REEs in the studied samples ranged from 5 to 16.1%, 1.9 to 5.5, and 45.9 to 136.9 ppm, respectively. The studied samples have negative Ce anomaly, indicating an anoxic environment during the Dalir phosphate deposition. Based on the factors controlling uranium concentration in phosphorites, the phosphate horizon of Soltanieh Formation does not have uranium enrichment potential due to warm to semi-warm humid paleoclimate with neutral to acidic pH of the seawater during the Dalir phosphate deposition in lower Cambrian. Finally, considering the results of the chemical analysis of phosphate samples of the Dalir deposit (lack of uranium enrichment) and also the factors controlling uranium concentration in phosphorites, it can be predicted that the other phosphate deposits of Soltanieh Formation probably not be uranium enriched.
کلیدواژه‌ها [English]
- Dalir deposit
- Soltanieh formation
- Uranium
- Ce anomaly
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