ترمودینامیک و سازوکار استخراج حلالی توریم از محیط نیتراتی به وسیله‌ی استخراج‌کننده‌ی سیانکس‌ 272 در رقیق‌کننده‌ی کروزن

نوع مقاله: مقاله پژوهشی

نویسندگان

1 پژوهشکده‌ی چرخه‌ی سوخت هسته‌ای، پژوهشگاه علوم و فنون هسته‌ای، سازمان انرژی اتمی ایران، صندوق پستی: 8486-11365، تهران ـ ایران

2 بخش مهندسی معدن، دانشکده‌ی صنعت و معدن زرند، دانشگاه شهید باهنر کرمان، صندوق پستی: 7616914111، کرمان ـ ایران

چکیده

استخراج ناپیوسته‌ی توریم برای تعیین استوکیومتری گونه‌های توریم (IV) استخراج شده به انجام رسید. تأثیر غلظت اسید، استخراج‌کننده و دما بر روی استخراج توریم بررسی شد. یافته‌ها نشان داد که سازوکار استخراج توریم در غلظت‌های پایین و بالای نیتریک اسید (به ترتیب، 1-mol L 001/0 و 1-mol L 8) از نوع حلال‌پوشی و در ناحیه‌ی غلظت‌ متوسط (1-mol L 1) از نوع تبادل کاتیونی است. با استفاده از روش تحلیل شیب، مشخص شد که گونه‌ی استخراج شده‌ی توریم به فاز آلی به صورت A.HA(3NO)2(OH)Th است. بررسی‌های ترمودینامیکی نشان داد که فرایند استخراج توریم (IV) خودبه‌خودی (° >G ) و گرمازا (° >H ) بوده و در آن بی‌نظمی کم می‌شود (° > S). مقدار انرژی فعال‌سازی واکنش استخراج توریم (IV) برابر با 46/17 کیلوژول بر مول محاسبه شد که نشان‌دهنده‌ی آن است که واکنش استخراج به وسیله‌ی فرایند نفوذ کنترل می‌شود.
 

کلیدواژه‌ها


عنوان مقاله [English]

Thermodynamics and mechanism of Th(IV) extraction from nitrate medium with cyanex 272 in kerosene

نویسندگان [English]

  • Saeid Alamdar milani 1
  • Mahmoud Eskandari nasab 2
چکیده [English]

Batch extraction investigation was carried out to elucidate the stochiometry of the extracted Th(IV) species. The effects of nitric acid concentration, extractant concentration and temperature were studied. The results showed that the extraction of thorium follows solvation mechanism in the low
(0.001 mol L-1) and high (8 mol L-1) nitric acid concentration, while the cation exchange mechanism dominates the middle acidic area (1 mol L-1). The extracted species was found to be Th(OH)2(NO3)A.HA on the basis of the slope analysis method. The results of the thermodynamic investigations indicated that the extraction process is spontaneous (G<0), exothermic (H<0), and less random in nature (S<0). The value of activation energy of the extraction reaction was calculated to be 17.46 kJ mol-1 which indicates that the extraction reaction is controlled by the diffusion process.
 

کلیدواژه‌ها [English]

  • Thorium
  • Solvent extraction
  • Cyanex ‌272
  • Mechanism
  • Thermodynamics

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