Solvent Extraction Of Vanadium In Alkaline Medium

Vanadium is an important rare metal element, and it has a wide range of applications. Vanadium is highly dispersedly in nature, so it is mainly obtained in various metallurgical process as a byproduct. Currently, vanadium is mainly abstracted from the slag which contains vanadium, vanadium-titanium magnetite, stone coal, a small amount of waste catalyst and oil residue of containing vanadium. The mainly abstraction methods contain acid leaching, roasting-acid leaching and roasting-alkali leaching with the certain technology. For some low-concentration solution system, some scholars have studied the method of solvent extraction for extracting vanadium. However, the mostly studies were concentrated on acidic or weakly alkaline conditions, while it was relatively less in strongly alkaline condition. This paper mainly explored the use of solvent extraction method in the extraction of vanadium under alkaline conditions.This study explored solvent extraction of vanadium under alkaline conditions. The organic phase was made up of extractant which is n-octyl amine, di-n-octyl amine, Trioctylamine, N235or methyl trioctyl ammonium chloride (MTOAC), DL-2-octanol and sulfonated kerosene. The experimental results showed:the extraction efficiency of MTOAC was better than the others in the same conditions. Extraction system which was composed of15%MTOAC+3.5%DL-2-octanol+81.5%sulfonated kerosene was determined.More than90%of extraction rate could be obtained under the conditions which were temperature30℃, pH value11.5, the phase ratio1.0and the oscillation time5min.The extraction reaction reached equilibrium after extracting three minutes. Extraction rate declined rapidly with the increase of pH value. When the phase ratio was less than1:1, it was prone to emulsion When the phase ratio was more than1:1, it was not conducive to the enrichment of vanadium By the orthogonal experiment, the main factors on the extraction process were determined. The saturation capacity of extractant which reached10.25g·L-1was measured, and counter current extraction cascade experiments were simulated. It result of the extraction of vanadium in the solution could be reduced to a concentration of0.05g-L-1.It also summed up the emulsification in the extraction process and it could be avoided by controlling correlated conditions.The optimum stripping system was determined by the experimental study on stripping from the loaded organic phase, which was0.5mol·L-1NaCl and1.0mol·L-1NaOH, and the stripping rate of vanadium could reach97.72%. After12times of extraction and stripping cycle experiments, the extraction capacity of the organic phase can be reached95%in comparison with the fresh organic phase, which has the good cycle performance.