To understand the behavior of molybdenum and tungsten extracted by tri-alkyl phosphine oxide(TRPO)from peroxide solution,the extraction mechanism was studied by slope method and Raman and FTIR spectroscopy.The empiric...To understand the behavior of molybdenum and tungsten extracted by tri-alkyl phosphine oxide(TRPO)from peroxide solution,the extraction mechanism was studied by slope method and Raman and FTIR spectroscopy.The empirical formulas of molybdenum and tungsten extraction distribution ratio(D_(Mo)and D_(W))as functions of equilibrium pH,TRPO concentration and temperature were obtained by establishing mathematical models.Furthermore,the reliability of the empirical formula was verified in the H^(+)-W-Mo-H_(2)O_(2) solution.The results indicate that the calculated values of D_(Mo)or D_(W)were consistent with the experimental values.The apparent extraction equilibrium constants of molybdenum and tungsten wereK_(Mo)^(app)=8.51×10^(3)(0.74≤pH_(e)≤1.7),K_(Mo)^(app)=99.89×10^(3)(1.7<pH_(e)≤4.62)andK_(W)^(app)=2.65×10^(3)(0.92<pH_(e)<2.16)at 20°C,respectively.The main extraction complex of molybdenum or tungsten was[H_(2)(Mo or W)_(2)O_(3)(O_(2))_(4)(H_(2)O)_(2)]·2TRPO.These empirical formulas can be used to analyze and estimate the extraction and separation of Mo and W from low molybdenum and tungsten concentration solutions.展开更多
The thermodynamic equilibrium diagrams of CaMoO_(4)-CaSO_(4)-H_(2)SO_(4)-H_(2)O,CaMoO_(4)-HCl-H_(2)O and CaSO_(4)-CaCl_(2)-HCl-H_(2)O systems at 298 K were established.The calculation results demonstrated that HCl dis...The thermodynamic equilibrium diagrams of CaMoO_(4)-CaSO_(4)-H_(2)SO_(4)-H_(2)O,CaMoO_(4)-HCl-H_(2)O and CaSO_(4)-CaCl_(2)-HCl-H_(2)O systems at 298 K were established.The calculation results demonstrated that HCl displays a much higher solubility of CaSO_(4)than H_(2)SO_(4).The leaching mechanism of Mo from CaMoO_(4)calcine was systematically investigated from the perspective of the micro particle properties variation.HCl exhibits an excellent leaching performance for Mo from CaMoO_(4)calcine due to the elimination of surface coating and the dissolution of a mass of Mo embedded in CaSO_(4)matrix.Excellent Mo leaching efficiency of 99.7%was achieved under the optimal conditions of decomposing CaMoO_(4)calcine by 2.4 mol/L HCl with a liquid/solid ratio of 10:1 at 50°C for 60 min.Based on the experimental results,a highly efficient and green cycle leaching process of molybdenum from molybdenite was proposed,which eliminated surface coating and physical entraining,and converted most of the calcium from CaMoO_(4)calcine into high purity gypsum by-product.展开更多
基金the financial support from the National Natural Science Foundation of China(No.52104354)the Joint Fund for Nuclear Technology Innovation Sponsored by the National Natural Science Foundation of China and the China National Nuclear Corporation(No.U2067201)。
基金support from the National Natural Science Foundation of China(No.51604304)。
文摘To understand the behavior of molybdenum and tungsten extracted by tri-alkyl phosphine oxide(TRPO)from peroxide solution,the extraction mechanism was studied by slope method and Raman and FTIR spectroscopy.The empirical formulas of molybdenum and tungsten extraction distribution ratio(D_(Mo)and D_(W))as functions of equilibrium pH,TRPO concentration and temperature were obtained by establishing mathematical models.Furthermore,the reliability of the empirical formula was verified in the H^(+)-W-Mo-H_(2)O_(2) solution.The results indicate that the calculated values of D_(Mo)or D_(W)were consistent with the experimental values.The apparent extraction equilibrium constants of molybdenum and tungsten wereK_(Mo)^(app)=8.51×10^(3)(0.74≤pH_(e)≤1.7),K_(Mo)^(app)=99.89×10^(3)(1.7<pH_(e)≤4.62)andK_(W)^(app)=2.65×10^(3)(0.92<pH_(e)<2.16)at 20°C,respectively.The main extraction complex of molybdenum or tungsten was[H_(2)(Mo or W)_(2)O_(3)(O_(2))_(4)(H_(2)O)_(2)]·2TRPO.These empirical formulas can be used to analyze and estimate the extraction and separation of Mo and W from low molybdenum and tungsten concentration solutions.
基金financially supported by the Joint Fund for Nuclear Technology Innovation Sponsored by the National Natural Science Foundation of China and the China National Nuclear Corporation(No.U2067201)。
文摘The thermodynamic equilibrium diagrams of CaMoO_(4)-CaSO_(4)-H_(2)SO_(4)-H_(2)O,CaMoO_(4)-HCl-H_(2)O and CaSO_(4)-CaCl_(2)-HCl-H_(2)O systems at 298 K were established.The calculation results demonstrated that HCl displays a much higher solubility of CaSO_(4)than H_(2)SO_(4).The leaching mechanism of Mo from CaMoO_(4)calcine was systematically investigated from the perspective of the micro particle properties variation.HCl exhibits an excellent leaching performance for Mo from CaMoO_(4)calcine due to the elimination of surface coating and the dissolution of a mass of Mo embedded in CaSO_(4)matrix.Excellent Mo leaching efficiency of 99.7%was achieved under the optimal conditions of decomposing CaMoO_(4)calcine by 2.4 mol/L HCl with a liquid/solid ratio of 10:1 at 50°C for 60 min.Based on the experimental results,a highly efficient and green cycle leaching process of molybdenum from molybdenite was proposed,which eliminated surface coating and physical entraining,and converted most of the calcium from CaMoO_(4)calcine into high purity gypsum by-product.
