Loading...

Leaching of Uranium from pHospHate Ores of Sheikh Habil Region in the Process of pHospHoric Acid Production (in a Wet Way)

Abdeshahi, Ashkan | 2022

238 Viewed
  1. Type of Document: M.Sc. Thesis
  2. Language: Farsi
  3. Document No: 54958 (46)
  4. University: Sharif University of Technology
  5. Department: Energy Engineering
  6. Advisor(s): Outokesh, Mohammad; Godocynejhad, Davood; Khoshnodi, Khalegh; Ghadiri, Ahmad
  7. Abstract:
  8. In this research, uranium is leached from pHospHate ore of Sheikh Habil region by leaching operation using leaching agent (sulfuric acid) along with production of pHospHoric acid. In the following, the production of yellow cake from the produced liqueur solution (pHospHoric acid) by solvent extraction process is also mentioned. PHospHate ore contains a large amount of calcite and dolomite, which removal of these annoying elements by wet, dry and acid washing methods is the key to success in the production of pHospHoric acid. For this purpose, in the wet method of a flotation system, the dry method of heat furnace and in the acid washing method, various organic and inorganic acids were used to pre-concentrate the ore.The parameters studied in the soil flotation process are ore dimensions, collector concentration, pH, detainer concentration and flotation time. The optimum values of each of them are 75-150μm, 2000g / ton, 6, non-use of detainer and duration of 5 minutes, respectively, which leads to the production of soil with a grade of UO2 of 150 ppm, pHospHate (P2O5) of 36.27% and with The CaO / P₂O₅ ratio was 1.23. On the other hand, the effective parameters in the dry method using a thermal furnace are: ore dimensions, heating time and furnace temperature, each of which has optimal values of 100μm, 2 hours and 800-900 ° C, respectively, which leads to soil production with The UO2 grade was 204 ppm and the pHospHate (P2O5) was 29.42%. Also, the optimal results of the acid washing method were obtained using acetic acid as organic acid in the dimensions of 100μm soil, concentration of 15% by weight of acetic acid, ambient temperature, liquid to solid ratio 15 and duration of 1 hour, which led to the production of liquorice lychee solution with efficiency 58% and on the other hand using sulfuric acid as a mineral acid, its optimal conditions were obtained in 100μm soil dimensions, concentration of 0.1 M sulfuric acid, temperature 40 ° C, liquid to solid ratio 3 and duration of 1 hour, which led to the production of liquorice leach solution with an efficiency of 53.2%.Then the parameters of leaching operation such as liquid to solid ratio (L / S), time, sulfuric acid concentration and temperature were first optimized on calcined soil, that the optimal values of each of them 3, 4 hours, 4 M and 70 ° C, respectively were obtained. After optimizing the leaching parameters, the leaching results were performed on each of the pre-concentrated soils by flotation, calcination and acid leaching methods, and finally the number of optimal steps for the production of pHospHoric acid (H3PO4) with a grade of more than 26%, 3 steps Was obtained.In the final part, uranium was extracted and yellow cake was produced from pHospHoric acid solution produced using D2EHPA + TOPO, D2EHPA + TBP and D2EPA + TOPO + TBP solvents in kerosene (kerosene).Various experimental extraction parameters such as organic to aqueous pHase ratio (O / A), contact time, solvent concentration, redox potential and temperature were investigated by each solvent, and finally the optimal conditions were determined by the ideal solvent, D2EHPA + TOPO with the ratio of 1/2, 10 minutes, concentration of 6% by weight of TOPO, concentration of 20% by weight of D2EHPA, oxidation potential of 800 mV and ambient temperature were obtained as optimal extraction conditions, respectively. The charged solvent was then stripped in contact with pHospHate under various conditions such as organic to aqueous pHase ratio (O / A), contact time, acid concentration, redox potential and 117 temperature. The optimal conditions were 25, 10 minutes, PHospHate concentration of 55%, redox potential of 200 mV and temperature of 40 ° C were obtained respectively. Secondary extraction was performed again with solvent under optimal conditions obtained from primary extraction and then the solvent was washed with 2% sulfuric acid to remove impurities in 4 steps with O / A ratio of 1/4. Finally, by adding 2 M ammonium carbonate with O / A ratio = 2/1 and uranium precipitate was formed at ambient temperature, which after filtration and calcination led to the production of U3O8
  9. Keywords:
  10. Calcination ; Sedimentation ; Solvent Extraction ; Phosphoric Acid ; Oranium ; Yellow Cake ; Acid Washing

 Digital Object List

 Bookmark

No TOC