Optimization of Re solvent extraction from molybdenite roasting dust leaching solution and the performance evaluation of extraction in a multi-stage mixer-settler

Separation of Re from roasting dust leaching solution of molybdenite using a multi-stage mixer-settler extractor was studied. Systematic solvent extraction tests were performed using TBP as an extractant diluted in kerosene. The optimum extraction conditions were as follows: pH = 0, temperature 25 °C, 500 rpm agitation rate, 6 min contact time and 40% v/v TBP. The results showed that the extraction reaction is exothermic. A flow sheet was developed for the process. Three different extraction ways were studied in a laboratory size mixer-settler: Namely, counter-current, cross-current and co-current. The results showed that counter-current was the best. In addition, it was found that 2 h of continuous operation was necessary to reach a steady state condition for the process. Extraction as high as 95.43% was obtained.