Vanadium partitioning

Orthopyroxene partitions nickel, cobalt, and manganese less than olivine and there are no clear correlations amongst these elements. Although low in abundance, orthopyroxene can be a significant reservoir for the trivalent cations vanadium, scandium plus tetravalent titanium, due to its high modal abundance, especially in depleted xenoliths with little or... 

Canil D. and Fedortchouk Y. (2000) Clinopyroxene-liquid partitioning for vanadium and the oxygen fugacity during formation of cratonic and oceanic mantle lithosphere. J. Geophys. Res. 105, 26003-26016. 

Principal experimental data on spinel-melt partitioning are those of Nielsen et al. (1994) for scandium, nickel, vanadium, zirconium, hafnium, niobium, tantalum, uranium, and thorium and Horn et al. (1994) for scandium, vanadium, gallium, zinc, cobalt, zirconium, hafnium, niobium, and tantalum. These are supplemented by data for hydrous melts by Nielsen and Beard (2000). 

Figure 4 Metal/magnesiowUstite partition coefficients for nickel, cobalt, manganese, chromium, and vanadium at 9 GPa, and the effect of temperature (pressure 9 GPa). Partition coefficients are calculated relative to iron, according to the exchange equihhrium, M - - FeO = Fe + MO. Horizontal lines at right side of the diagram indicate the values of ATd that would he required for an equihhrium explanation for these hve elements in the terrestrial mantle (source Gessmann and Ruhie (1998) these authors favor a high-temperature scenario to attain these concentrations in the mantle).

Gessmann C. K. and Rubie D. C. (1998) The effect of temperature on the partitioning of nickel, cobalt, manganese, chromium and vanadium at 9 GPa and constraints on formation of the Earth s core. Geochim. Cosmochim. Acta 62, 867-882. 

The group Ib elements—copper, silver, and gold—stand in contradistinction to elements such as rubidium and vanadium. These metals are rather electronegative and soft, and prefer two-coordinate directional bonding. These characteristics are not conducive to the incorporation of these elements into rock-forming oxide matrices, and they therefore form their own minerals, occur in the native state, or reside in trace sulfides in the cmst. They also partition readily into fluid phases, promoting their redistribution in the crust, and the formation of ores. 

Compatible element An element with equilibrium solid/melt partition coefficient >1. In garnet (and zircon), heavy REE, scandium, vanadium, and yttrium are compatible. These elements are incompatible in all other rock-forming minerals involved in igneous fractionation processes discussed in this chapter. 

Canil D. (1997) Vanadium partitioning and the oxidation state of Archaean Komatiite magmas. Nature 389, 842—845. 

Canil D. (1999) Vanadium partitioning between orthopyroxene, spinel and sihcate melt and the redox states of mantle source regions for primary magmas. Geochim. Cosmochim. Acta 63, 557-572. 

A laboratory study was undertaken to determine the behaviour of neptunium in the WAK flowsheet, and to devise a procedure for its recovery. Based on static ( ) and counter-current experiments (J5), the conclusion was reached that about half of the Np is co-extracted with the U and Pu in the HA-HS mixer-settlers of WAK while the other half is rejected to the HAW, see Fig.1. It could also be shown that an increase of the aqueous acidity, or the addition of pentavalent vanadium as an oxidant into the lower stages of the HA mixer-settler (6), would increase the Np yield in the organic solvent. In the 1BX-1BS mixer-settlers where the partitioning of U and Pu is carried out by use of uranium (IV)nitrate - hydrazine nitrate, a splitting of the coextracted Np between the two product streams was observed the proportions of the (co-extracted) Np which ended up in the 1CU (uranium product) stream fluctuated from 30 to 93 % while the difference amount (from 7 to 70 %) ended up in the 1 BP (plutonium product) stream. 

The majority of the metallic impurities originally present in the phosphate rock, such as iron, aluminum, magnesium, zinc, lead, cadmium, manganese, nickel, chromium, vanadium, mercury, and arsenic, are acid-soluble, and these become partitioned between the WPA (80%) and the solid waste gypsum (20%) during the acidulation step. Consequently, some portion of these metallic impurities also is found in phosphate fluid... 

Physical and Chemical Properties. The physical and chemical properties of vanadium and its compounds are reasonably well documented (see Tables 3-1 and 3-2). Further information, such as partition coefficients, would be helpful in understanding the transport and transformation of vanadium in the environment. 

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