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- Type of Document: M.Sc. Thesis
- Language: Farsi
- Document No: 40304 (07)
- University: Sharif University of Technology
- Department: Materials Science and Engineering
- Advisor(s): Sadrnezhaad, Khatiboleslam; Hakim, Manouchehr
- Abstract:
- In this work, the recovery of rhenium from ferromolybdenum furnace outgoing dust in semi industrial scale was conducted. The ferromolybdenum furnace outgoing dust contains rhenium as major part and large amounts of molybdenum plus Iron and copper as impurities. An overall flow sheet, consist of leaching, solvent extraction and precipitation methods, was design to recovery and purification of rhenium. Firstly, ferromolybdenum furnace outgoing dust was subjected to leaching treatment by 10 g/L sulfuric as solvent at 85 C. Secondly, solvent extraction method was employed, using LIX984N 10 %vol, to separate copper from rhenium containing solution. The results of MacCab thiele diagram for extraction of copper show that the amount of copper in the solution could be easily reduced by using one stage extraction at pH=1. Thirdly, the rhenium containing solution was exposed to ammonium solution to precipitate Iron. For this, experiments were carried out at different pH at ambient temperature. The results show that, at pH=4.7, the whole amounts of iron precipitate while the amount of rhenium was very close to initial analysis. The pH of remaining solution was then adjusted close to zero by adding concentrated sulfuric acid. Finally, using solvent extraction methods, including multi-extraction and stripping steps, rhenium was separated from molybdenum In order to ascertain the separation conditions rhenium from molybdenum, experiments were carried out to extract rhenium and molybdenum by TBP. The results show that extraction percent of rhenium increases by decreasing the value of pH while the extraction of molybdenum decreases. Base on this property, the best condition for separation of rhenium from molybdenum is to extract rhenium at pH close to zero in which 90% of rhenium is extracted in compare to less than 5% molybdenum. The results of MacCabe Thiele diagram for extraction of Rhenium at pH=0 shows that the whole amounts of rhenium is extracted with 2 step of continuous counter current system. Moreover, base on the results of MacCab Thiele diagram for stripping, 2 stages is required for stripping the rhenium from organic phase. The results obtained from McCabe–Thiele plot were compared to those obtained by simulated counter-current experiments. The experimental composition is very close to the theoretical values predicted by the McCabe–Thiele equilibrium isotherm.
- Keywords:
- Rhenium ; Molybdenum ; Copper ; Iron ; Dissolution ; Solvent Extraction ; Precipitation (Chemical)
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