Vanadium recovery

Vanadium raw materials are processed to produce vanadium chemicals, eg, the pentoxide and ammonium metavanadate (AMV) primary compounds, by salt roasting or acid leaching. Interlocking circuits, in which unfinished or scavenged material from one process is diverted to the other, are sometimes used. Such interlocking to enhance vanadium recovery and product grade became more feasible in the late 1950s with the advent of solvent extraction. 

Acid Leaching. DHect acid leaching for vanadium recovery is used mainly for vanadium—uranium ores and less extensively for processing spent catalyst, fly ash, and boiler residues. Although 20 in spent catalysts dissolves readily in acid solutions, the dissolution of vanadium from ores and... 

The alkyl phosphoric acids were first recognized as excellent actinide extractants because dibutyl phosphoric acid existed as an impurity in TBP (8). They extract well from unsalted solutions and from systems such as sulfate in which TBP is ineffective. Organo-phosphorus acids are thus suitable for uranium hydr metallurgical applications where ore is leached with sulfuric acid. The Dapex process is an example in which bis(2-ethylhexyl) phosphoric acid (HDEHP) is used alone or in synergistic combination with neutral organophosphorus compounds for uranium and vanadium recovery (9,10). 

The need for new domestic sources of vanadium to meet future demands warrants consideration of recovering vanadium from petroleum products. The need to reduce other pollutants in petroleum products might enhance the technology and economics of vanadium recovery. 

Vanadium. Recovery of vanadium with peroxygens involves both oxidation and complexation. In solution, conversion of lower oxidation states into V(V) allows separation by solvent extraction [398] ... 

Greenberg et al. [86] employed a preirradiation chemical separation involving retention of the vanadium moiety on Chelex-100 resin. Tlie vanadium recovery was 97.6 3%. These authors report a vanadium value of 0.055 0.035 ng/g for bovine semm SRM 1598 and a value of 0.028 0.02 ng/g for random samples of human blood serum. While these values are more in line with those of Versieck et al. in different serum matrices ( l ng), there remains the question of how meaningful are quoted values less than 1 ng for physiological interpretation in clinical chemistry. We conclude, based on serum values from different laboratories, that the vanadium concentration in serum is s 1 ppb. 

Henry and Van Lierde developed a three-compartment cell equipped with an reticulated vitreous carbon cathode mixed with ion-exchange resin and two Ti—Pt anodes separated by a Daramic diaphragm to selectively separate the vanadium from molybdenum (Henry Van Lierde, 1998). In this designed membrane reactor, the pentavalent vanadyl anion was selectively desorbed with respect to molybdenum after its reduction to a tetravalent vanadyl cation. Consequently, 93% vanadium recovery yields were obtained. 

PANsteel Group Research Institute Co., Ltd. Chengdu, Sichuan, 611731, China Vanadium Recovery Steelmaking Plant of PZH Steel Panzhihua, Sichuan, 617062, China... 

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