Solvent Extraction of Molybdenum (VI) from Hydrochloric Acid Leach Solutions using P507. Part II: Stripping and Mechanism

Thermodynamic analysis of the Mo(VI)-H(2)A(2)-NH3-H2O system was conducted for the model establishment of molybdenum stripping from a loaded organic solution consisting of 30% (v/v) P507 in sulfonated kerosene. The results revealed that there were five ranges for the molybdenum stripping using ammonia, and the mole fraction of could be regarded as the saponification of the extractant. The molybdenum can be completely stripped at equilibrium pH higher than 5.0, and the consumption of ammonia for stripping 1mol molybdenum can be expressed as: (mol), where P stands for the saturation of molybdenum in the loaded organic solution. The concentration of molybdenum in strip liquors reached as high as 228g/L using a three-time reflux stripping with a loaded organic solution containing 35.9g/L Mo and a stripping agent consisting of 1.2mol/L NH3H2O and 0.15mol/L NH4NO3 at an A/O ratio of 1/2 and 30 degrees C. The average stripping of molybdenum reached 96.4%, while the average molybdenum concentration in stripped organic solutions was only 1.30g/L. The volume loss of strip liquor can be attributed to the formation of microemulsion during the stripping process.