Vanadium powder. Grades, chemical composition.
Vanadium is an element of the V side group of the Mendeleev table, where it is denoted as V. Powder vanadium is gray in color, and in compact form it is a steel-colored, malleable metal. It is chemically active, easily drawn into thin filaments and rolled into foil at normal temperature. An admixture of nitrides or carbides increases its hardness and brittleness.
Physical Properties of Vanadium
|Atomic (molar) mass g/mol||Oxidation state||Density [g/cm3]||Melting point t°C||Boiling point t ° C||Evaporation heat kJ/mol|
|50,94||0, 2, 3, 4, 5||6.11||1887°С||3377°С||460|
At normal temperature, metallic vanadium retains its luster even in wet condensation. Powdered vanadium when heated easily interacts with chlorine, sulfur, O2, and is also capable of dissolving H2 up to 42%. In air, when heated, the powder changes color, becoming covered with oxides of various degrees of oxidation, and when burned, it converts to V2 O5. During heating in an atmosphere of N2, the powder forms nitrides VN2, VN, V3 N, while an excess of chlorine forms tetrachloride VCl4, Compact Vanadium is resistant to the action of chemicals. Only strong acids dissolve it: HF, HN03 or aqua regia. The metal is stable in alkaline solutions, but it is dissolved by molten alkalis. Carbon-containing gases form VC carbide when heated.
Vanadium is first heated in a vacuum to 200° - 250 °C, and then in a medium of H2, which is created by the thermal cleavage of titanium hydride with conversion to an unsaturated state. (The unsaturated titanium hydride is later used to absorb the hydrogen released by the vanadium hydride during powder dehydrogenation.) Compact vanadium is activated at t° 600° - 780 °C, hydrogenation proceeds at t° 50° - 200 °C, When vanadium hydride is ground into a powder, dehydrogenation begins at 650° - 780 °C with a gradual decrease in pressure to 0.05 mm. mercury column and absorption of the released H2, unsaturated titanium hydride. The method makes it possible to obtain a particularly pure vanadium powder. The unit consists of a heat-resistant steel retorts, forevacuum pump, a line for transporting and evacuating H2 with shut-off valves, electric furnaces for heating retorts, as well as instrumentation and control sensors.
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Evek GmbH stocks a wide range of high-quality metal powders at optimal prices. Vanadium powder is supplied in tins with gross weight up to 70 kg. The warranty shelf life is 24 months from the date of production. All products meet the requirements of standards and specifications. We sell our orders in the shortest possible time. Wholesale customers are provided with preferential discounts.