Vanadium

History, Occurrence, and Uses

Vanadium was discovered in 1801 by Mexican mineralogist Manuel del Rio in a lead ore in Hidalgo, Mexico. He named it erythronium because of the red color its salts when heated with acids. However, del Rio’s discovery was mistakenly thought at that time to be a form of impure chromium. Swedish chemist Sefstrom in 1830 rediscovered this element detecting an unknown metal in the iron ores of Taberg, Sweden. He named it vanadium after the Scandinavian goddess Vanadis. Later in 1830, Wohler determined that del Rio’s erythronium and Sefstrom’s vanadium were the same element. Vanadium metal was prepared for the first time by Roscoe in 1867 in somewhat impure form, as a silvery-white powder, by reduction of vanadium chloride, VCl2, with hydrogen. Hunter and Jones in 1923 prepared the metal at 99.5% purity as a fine gray powder by thermal reduction of vanadium trichloride with sodium in a steel bomb.

Vanadium is added to steel for high resistance to oxidation and to stabilize carbide. Vanadium foil is used for cladding titanium to steel. Vanadium-gallium alloy is used in making superconductive magnets. An important compound of vanadium is pentoxide which has many commercial uses (See Vanadium Pentoxide).

Chemical Properties

Vanadium typically exists in two forms in fresh water depending on the presence of oxidizing or reducing agents in the water. In the presence of reducing agents, vanadium is present as vanadyl compounds (VO²⁺ and VO(OH)⁺) and in the presence of oxidizing substances vanadium is found in the pentavalent form (V⁺⁵) as vanadate compounds such as H2VO4^- and HVO4^2- (Holdway and Sprague, 1979). Vanadiumcompounds also combineswith particulatematter in fresh water with a particular affinity for humic acids (Ünsal, 1982).

Uses

Vanadium is a naturally occurring element, and is the 22nd most abundant element found in geological formations. The initial discovery of vanadium occurred in 1801 by a Spanish chemist and mineralogist working as a teacher in Mexico, Andrés Manuel del Río. He described his analyses of lead ores and further chemical tests concluded that he had discovered a new element. He gave samples of his work to Alexander von Humboldt, who after consulting with a French chemist, was convinced that this new element was chromium.
Vanadium is also commonly used as a catalyst in the production of sulfuric acid and maleic acid anhydride—the latter compound is used in the synthesis of rubber polymers (Cheng et al., 2009). Vanadium pentoxide is used as a catalyst to oxidize sulfur dioxide (SO2) to anhydrous sulfur trioxide (SO3) followed by a reaction with water to generate sulfuric acid (H2SO4). Maleic acid anhydride is prepared by the vanadium pentoxide-catalyzed oxidation of benzene. More recently, vanadium pentoxide has been used as a selective reducing catalyst to reduce NO and NO2 emitted from diesel engines to nitrogen gas (N2) (Matthey, 2010). Other uses of vanadium compounds include the development of new batteries (e.g., vanadium flow and lithium–vanadium batteries), treatment of wastewater for nitrates, and as a colorant in ceramics and enamels.

Reactions

Vanadium forms four oxides: the light grey monoxide, VO or (V2O2); the blue black dioxide, VO2 (or V2O4); the black sesquioxide, V2O3; and the orangered pentoxide, V2O5. The oxides are formed when the metal is heated in air or oxygen. Vanadium combines with chlorine on heating. Three chlorides are known: the green dichloride, VCl2; the pink trichloride, VCl3; and the brownred tetrachloride, VCl4. The more stable tetrachloride is formed when the metal is heated with chlorine at 180°C. The metal also forms three fluorides in valence states +3, +4, and +5. They are the green trifluoride, VF3; a yellowishbrown tetrafluoride, VF4, and the white pentafluoride, VF5. When heated with bromine vapor vanadium forms the green-black tribromide, VBr3. Vanadium forms two iodides, a violet-rose diiodide, VI2, and a deliquescent triiodide, VI3.
Vanadium combines with other nonmetals at elevated temperatures forming binary compounds. Such compounds include nitride, VN; carbide VC, and the sulfides, VS (or V2S2), V2S3, and V2S5.
Vanadium reacts with fused caustic soda and caustic potash to form water soluble vanadates with liberation of hydrogen. The metal, however, is stable in alkaline solutions.

Environmental Fate

Natural sources of vanadium in soil come from minerals (over 50 known minerals containing vanadium; Box 37.2) and from the atmospheric deposition of marine aerosols and particulate matter of volcanic origin. Vanadium is not typically mined for directly but is recovered while mining for other minerals. In addition, anthropogenic sources of vanadium also find their way into soil primarily fromthe deposition of particulatematter from fossil fuel combustion sources (e.g., coal- and oil-fueled power plants). Themovement of vanadiumin soil is heavilypH dependent since most vanadium minerals are not soluble in neutral water.
The presence of vanadium in the atmosphere is primarily in the form of compounds bound to particulate matter as gaseous species of vanadium do not exist at ambient temperatures. Examples of vanadium compounds bound to particulate matter include vanadium pentoxide (V2O5), but most measurements of vanadium bound to particles is measured as elemental vanadium and is not speciated to specific compounds or minerals. Vanadium-enriched particles can dry deposit, as do particles in general, as well as be rained out with particles either acting as condensation nuclei or being absorbed directly into water droplets.

Description

Vanadium was discovered in 1830 in Mexico by Andreas Manuel del Rio. It is present at 0.01% in earth’s crust and found in about 65 different minerals. Vanadium is released naturally into the air through the formation of continental dust, marine aerosols, and volcanic emissions. The natural release of vanadium into water and soils occurs primarily as a result of weathering of rocks and soil erosion. Anthropogenic sources include the combustion of fossil fuels, particularly residual fuel oils, which constitute the single largest overall release of vanadium into the atmosphere. Deposition of atmospheric vanadium is also an important source both near and far from industrial plants burning residual fuel oils rich in vanadium. Other anthropogenic sources include leachates from mining tailings, vanadium-enriched slag heaps, municipal sewage sludge, and certain fertilizers. Natural releases to water and soil are far greater overall than anthropogenic releases to the atmosphere.

Chemical Properties

Vanadium is a light-gray or silver-white, ductile solid, lustrous powder, or fused hard lump. Insoluble in water; resistant to corrosion, but soluble in nitric, hydrofluoric, and concentrated sulfuric acids; attacked by alkali, forming water-soluble vanadates. Acts as either a metal or a nonmetal and forms a variety of complex compounds.

Chemical Properties

Vanadium is a soft, ductile, silver-gray metal. It has good resistance to corrosion by alkalis, sulfuric and hydrochloric acid, and salt water. Vanadium metal, sheet, strip, foil, bar, wire, and tubing are used in industries. It is used in high-temperature service, in the production of rust-resistant, high-speed tools, and is an important carbide stabilizer in making steels. In fact, most vanadium is used as an additive to improve steels. Vanadium steel is especially strong and hard, with improved resistance to shock. Vanadium pentoxide (V2O5) is perhaps vanadium’s most useful compound. It is used as a mordant—a material that permanently fi xes dyes to fabrics. Vanadium pentoxide is used as a catalyst in chemical reactions and in the manufacture of ceramics. Vanadium pentoxide can also be mixed with gallium to form superconductive magnets.

Physical properties

Vanadium is a silvery whitish-gray metal that is somewhat heavier than aluminum, butlighter than iron. It is ductile and can be worked into various shapes. It is like other transitionmetals in the way that some electrons from the next-to-outermost shell can bond with otherelements. Vanadium forms many complicated compounds as a result of variable valences. Thisattribute is responsible for the four oxidation states of its ions that enable it to combine withmost nonmetals and to at times even act as a nonmetal. Vanadium’s melting point is 1890°C,its boiling point is 3380°C, and its density is 6.11 g/cm³.

Isotopes

There are 27 isotopes of vanadium. Only vanadium-51 is stable and makes up99.75% of the total vanadium on Earth. The other 0.25% of the vanadium found onEarth is from the radioisotope vanadium-50, which has such a lon+17years that it is considered stable. The other radioactive isotopes have half-lives rangingfrom 150 nanoseconds to one year.

Origin of Name

Named after the Scandinavian mythological goddess Vanadis because of the many colors exhibited by vanadium’s compounds.

Occurrence

Vanadium is not found in its pure state. Small amounts of vanadium can be found inphosphate rocks and some iron ores. Most of it is recovered from two minerals: vanadinite,which is a compound of lead and chlorine plus some vanadium oxide, and carnotite, a mineral containing uranium, potassium, and an oxide of vanadium. Because of its four oxidationstates and its ability to act as both a metal and a nonmetal, vanadium is known to chemicallycombine with over 55 different elements.Vanadium’s principal ores are roscoelite, patronite, vanadinite, and carnotite, which arefound in the states of Idaho, Montana, Arkansas, and Arizona as well as in Mexico and Peru.It is also a by-product from the production of phosphate ores.

Characteristics

Vanadium is an excellent alloy metal with iron that produces hard, strong, corrosion-resistant steel that resists most acids and alkali. It is even more resistant to seawater corrosion thanis stainless steel. Vanadium is difficult to prepare in a pure form in large amounts. Impureforms seem to work as well as a very pure form of the metal when used as an alloy. Whenworked as a metal, it must be heated in an inert atmosphere because it will readily oxidize.

History

Vanadium was first discovered by del Rio in 1801. Unfortunately, a French chemist incorrectly declared that del Rio’s new element was only impure chromium; del Rio thought himself to be mistaken and accepted the French chemist’s statement. The element was rediscovered in 1830 by Sefstrom, who named the element in honor of the Scandinavian goddess Vanadis because of its beautiful multicolored compounds. It was isolated in nearly pure form by Roscoe, in 1867, who reduced the chloride with hydrogen. Vanadium of 99.3 to 99.8% purity was not produced until 1927. Vanadium is found in about 65 different minerals among which carnotite, roscoelite, vanadinite, and patronite are important sources of the metal. Vanadium is also found in phosphate rock and certain iron ores, and is present in some crude oils in the form of organic complexes. It is also found in small percentages in meteorites. Commercial production from petroleum ash holds promise as an important source of the element. China, South Africa, and Russia supply much of the world’s vanadium ores. High-purity ductile vanadium can be obtained by reduction of vanadium trichloride with magnesium or with magnesium–sodium mixtures. Much of the vanadium metal being produced is now made by calcium reduction of V2O5 in a pressure vessel, an adaptation of a process developed by McKechnie and Seybolt. Natural vanadium is a mixture of two isotopes, ⁵⁰V (0.25%) and ⁵¹V (99.75%). 50V is slightly radioactive, having a long half-life. Twenty other unstable isotopes are recognized. Pure vanadium is a bright white metal, and is soft and ductile. It has good corrosion resistance to alkalis, sulfuric and hydrochloric acid, and salt water, but the metal oxidizes readily above 660°C. The metal has good structural strength and a low-fission neutron cross section, making it useful in nuclear applications. Vanadium is used in producing rust-resistant, spring, and high-speed tool steels. It is an important carbide stabilizer in making steels. About 80% of the vanadium now produced is used as ferrovanadium or as a steel additive. Vanadium foil is used as a bonding agent in cladding titanium to steel. Vanadium pentoxide is used in ceramics and as a catalyst. It is also used in producing a superconductive magnet with a field of 175,000 gauss. Vanadium and its compounds are toxic and should be handled with care. Ductile vanadium is commercially available. Vanadium metal (99.7%) costs about $3/g.

Uses

Vanadium is used as an alloying addition to steel, iron, titanium, copper, and aluminum, with the primary use in the steel industry. Vanadium is also used as a target material for X-rays, as a catalyst for the production of synthetic rubbers, plastics, and chemicals, and in ceramics. Vanadium is an element of pharmacological and nutritional significance; for example, it has increasing therapeutic use in diabetes, and is emerging as a potent anticarcinogenic agent.

Uses

The major use of vanadium is as an alloying metal to make a strong and corrosion-resistant form of steel that is well suited for structures such as nuclear reactors. It does not absorbneutrons or become “stretched” by heat and stress, as does normal stainless steel, thus makingvanadium ideal for the construction of nuclear reactors.Some of its compounds, particularly the oxides, are used in chemical industries as catalyststo speed up organic chemical reactions. The yellow-brown vanadium pentoxide (V₂O₅) is usedas a catalyst to facilitate the production of sulfuric acid by the contact process. Vanadium pentoxide is also used as a photographic developer, to dye textiles, and in the production of artificialrubber. When combined with glass, it acts as a filter against ultraviolet rays from sunlight.

Uses

Vanadium foil can be used for a variety of applications such as:

• preparation of vanadium pentoxide for lithium ion batteries
• starting material for synthesis of vanadium oxide
• a substrate for the deposition of aluminium oxide for wear resistant coatings

Definition

A silvery transition element occurring in complex ores in small quantities. It is used in alloy steels. Vanadium forms compounds with oxidation states +5, +4, +3, and +2. It forms colored ions. Symbol: V; m.p. 1890°C; b.p. 3380°C; r.d. 6.1 (20°C); p.n. 23; r.a.m. 50.94.

Production Methods

World resources of vanadium exceed 63 million tons. Vanadium occurs in deposits of phosphate rock, titaniferous magnetite, and uraniferous sandstone and siltstone, in which it constitutes less than 2% of the host rock. Signi?cant amounts are also present in bauxite and carboniferous materials,suchascoal,crudeoil,oilshale,andtarsands(19).
Vanadium is usually recovered as a by-product or a coproduct during the extraction of other compounds, such as iron, titanium, phosphate, or petroleum. It is extracted from carnotite, phosphate rock deposits, titaniferous magnetites, and vanadiferous clays. A process called salt roasting during the initial stage of extraction produces the oxide concentrate. The ores, petroleum residues, iodide thermal decomposition products, and slags formed during ferrovanadate production are crushed, dried, ?nely ground, mixed with a sodium salt, and roasted. The hot ore, containing sodium metavanadate, precipitates as a red cake, is then mixedwithsulfuricacid,andtheresultantprecipitateisdried to form vanadium pentoxide. The vanadium pentoxide can then be processed further to form the required vanadium compound. Pure vanadium is dif?cult to obtain as it tends to be readily contaminated with other elements. Methods to extract pure vanadium include iodide re?ning, electrolytic re?ning in a fused salt, and electrotransport. The highest purity vanadium has been puri?ed by the electrotransport technique. High-purity ductile vanadium can be obtainedbyreductionofvanadiumchloridewithmagnesium or with magnesium-sodium mixtures. Much of thevanadium metal is now produced by calcium reduction of V2O5 in a pressure vessel.

Definition

Symbol V. A silverywhite metallic transition element; a.n. 23; r.a.m. 50.94; r.d. 5.96; m.p. 1890°C; b.p. 3380°C. It occurs in a number of complex ores, including vanadinite (Pb₅Cl(VO₄)₃) and carnotite (K₂(ClO₂)₂(VO₄)₂). The pure metal can be obtained by reducing the oxide with calcium. The element is used in a large number of alloy steels. Chemically, it reacts with nonmetals at high temperatures but is not affected by hydrochloric acid or alkalis. It forms a range of complexes with oxidation states from +2 to +5. Vanadium was discovered in 1801 by Andrés del Rio (1764–1849), who allowed himself to be persuaded that what he had discovered was an impure form of chromium. The element was rediscovered and named by Nils Sefström (1787–1854) in 1880.

Air & Water Reactions

Not oxidized by air and not appreciably affected by moisture at ordinary temperatures. Some hydrogen gas may be created however this would proceed slowly under ambient conditions. Insoluble in water.

Reactivity Profile

VANADIUM is a reducing agent. Finely divided form favors rapid or explosive reactions with oxidizing agents such as air or oxygen. Reacts exothermically with compounds having active hydrogen atoms (such as acids and water) to form flammable hydrogen gas and caustic products. The reactions are much less vigorous than the similar reactions of alkali metals. Can catalyze polymerization reactions in several classes of organic compounds; these polymerizations sometimes proceed rapidly or even explosively. Vanadium is used as a catalyst in the production of synthetic rubber and sulfuric acid.

Hazard

Vanadium powder, dust, and most of its oxide compounds are explosive when exposedto heat and air. They are also toxic when inhaled. Vanadium chloride compounds are strongirritants to the skin and poisonous when ingested.
Many of its compounds must be stored in a dry, oxygen-free atmosphere or in containersof inert gas. Protective clothing and goggles should be worn when handling vanadium, as wellas with most of the other transition elements.

Health Hazard

Exposures to high levels of vanadium cause harmful health effects. The major effects from breathing high levels of vanadium are on the lungs, throat, and eyes. Workers who breathe vanadium for short and long periods show lung irritation, coughing, wheezing, chest pain, runny nose, and sore throat. Prolonged period of exposures to respirable dusts and vanadium fume have caused potential symptoms of toxicity among occupational workers. The symptoms of poisoning include, but are not limited to, irritation of the eyes and throat, green tongue, metallic taste, sore throat, cough, drowsiness, wheezing, bronchitis, abdominal cramps, nausea, vomiting, diarrhea, respiratory distress, pulmonary edema, bronchial damage, epistaxis (bloody nose), eczema, conjunctivitis, headache, dry mouth, dizziness, nervousness, insomnia, and tremor. It is not classifi able as a human carcinogen. Vanadium is a natural component of fuel oil, and workers have developed vanadium poisoning during cleaning operations on oil-fi red furnaces.

Flammability and Explosibility

Non flammable

Agricultural Uses

Vanadium (V) is a silvery-white, metallic, transition element of Group 5 of the Periodic Table and exhibits a range of valencies from +2 to +5. The ores containing vanadium include vanadite and carnotite. The pure metal, formed by the reduction of vanadium oxide with calcium, is generally used as an alloying element for steel and iron. Several vanadium compounds are used as oxidation catalysts. They are also used as coloring agents in the ceramic industry.
Vanadium comes under the category of beneficial elements which are non-essential but beneficial to plant growth. It is a very useful nutrient for the green alga Scenedesmus, but the exact amount of vanadium needed for the growth of higher plants is yet to be established.
Vanadium may replace molybdenum to some extent in nitrogen fixation by micro-organisms such as Azotobacter and Rhizobium. An increase in growth due to vanadium is seen in asparagus, rice, lettuce, barley and corn. It has also been speculated that vanadium may function in biological oxidation-reduction reactions.
Vanadium stimulates growth and nitrogenase activity in Anabaena variabilis in the absence of molybdenum. Low concentrations of vanadium are beneficial for the optimal growth of micro-organisms and higher plants. Generally, the concentration of vanadium in plants is about 1 ppm.

Industrial uses

Vanadium is a member of the d-block metals and belongs to group 5 of the periodic table of elements. Vanadium can be found in the earth s crust in numerous minerals and is isolated from ores mostly as a by-product. Its main application is in the steel industry, where it is used as an alloy in combination with iron. Vanadium pentaoxide is also being used as a catalyst for the production of sulfuric acid. The metal vanadium has very similar properties to titanium. Therefore, it is not surprising that its metallocene, vanadium dichloride, was also subjected to research as a potential anticancer agent. Vanadium is an essential trace metal in the human body, but still very little is known about its biological function. Vanadium is mainly found in its ionic state bound to proteins.

Safety Profile

An inhalation hazard. Poison by subcutaneous route. Questionable carcinogen with experimental tumorigenic data. Flammable in dust form from heat, flame, or sparks. Violent reaction with BrF3, Cl2, lithium, nitryl fluoride, oxidants. When heated to decomposition it emits toxic fumes of VOx. See also VANADIUM COMPOUNDS.

Potential Exposure

Vanadium is used as a catalyst in the production of synthetic rubber and sulfuric acid. Most of the vanadium produced is used in ferrovanadium and of this the majority is used in high speed and other alloy steels with only small amounts in tool or structural steels. It is usually combined with chromium, nickel, manganese, boron, and tungsten in steel alloys.

Veterinary Drugs and Treatments

Vanadium supplementation may be useful in the adjunctive treatment of diabetes mellitus, particularly in cats. There is controversy whether or not this treatment is beneficial.

Carcinogenicity

The results of 2-year NTP inhalation study on F344/N rats (at concentrations of 0, 5, 1, or 2mg/m³) and B6C3F1 mice (at concentrations of 1, 2, or 4mg/m³)exposedfor6hperdayfor5daysperweekindicate clear evidence of carcinogenic activity of vanadium pentoxide based on the occurrence of alveolar/bronchiolar neoplasms. Exposure to V2O5 caused a spectrum of nonneoplastic lesions in the respiratory tract (nose, larynx, and lung), including alveolar and bronchiolar epithelium hyperplasia, in?ammation, ?brosis, and alveolar histiocytosis of the lung in male and female rats and mice, and an unusual squamous metaplasia of the lung in male and female rats. Hyperplasiaofthebronchiallymphnodesoccurredinfemale mice. In a 16-day inhalation study in rat, alveolar and bronchiolar epithelial hyperplasia was observed in most rats exposed to 2 or 4mg/m³ V2O5 on days 6 and 13.

Environmental Fate

Vanadium is a gray metal with a body-centered cubic crystal system. Vanadium has oxidation states of +2, +3, +4, and +5. Vanadium is released naturally into the atmosphere by the formation of continental dust, marine aerosols, and volcanic emissions. Vanadium cannot be destroyed in the environment, but it can transform or change its form and attach or separate from airborne particulate, soil, water particulate, and sediment. Vanadium particles in the air settle to the ground or are washed out of the air by rain. Smaller particles, such as those emitted from oil-fueled power plants, may stay in the air for longer times and are more likely to be transported farther away from the site of release. The transport and partitioning of vanadium in water and soil is influenced by many factors, including acidity of the water or soil and the presence of particulates. Vanadium can either be dissolved in water as dissolved ions or may become adsorbed to particulate matter. As an element, vanadium cannot be degraded but can undergo various precipitation or ligand exchange reactions. Bioconcentration is insignificant.

Shipping

UN3285 Vanadium compound, n.o.s., Hazard Class: 6.1; Labels: 6.1-Poisonous materials, Technical Name Required. This number includes vanadium fume or dust.

Purification Methods

Clean the metal by rapid exposure consecutively to HNO3, HCl, HF, de-ionised water and reagent grade acetone, then dry it in a vacuum desiccator. [Brauer in Handbook of Preparative Inorganic Chemistry (Ed. Brauer) Academic Press Vol II pp 1252-1255 1965.]

Toxicity evaluation

In the consolidated form, vanadium metal and its alloys may pose no particular health or safety hazard; however, the toxicity of vanadium alloys may be a function of other components of the alloy. Vanadium compounds have been proved to be associated with the pathogenesis of some human diseases and also in the maintenance of normal body functions. Salts of vanadium interfere with many enzyme systems, for example, ATPases, protein kinases, ribonucleases, and phosphatases. Vanadium may also be an essential trace element, contributing to glucose balance; however, the importance of this element as a micronutrient is yet to be unequivocally accepted. Vanadium deficiency has been associated with disturbances in physiological functions, for instance, thyroid, glucose, and lipid metabolism. Vanadate (VO^-3) mimics the action of insulin in target tissues and is a potential inhibitor of the sodium pump. Vanadium toxicity is enhanced by dietary zinc. Several genes are regulated by this element or by its compounds, including those for tumor necrosis factor-alpha, interleukin-8, activator protein-1, ras, c-raf-1, Mitogen activated protein kinase, p53, and nuclear factor kappa B. When inhaled, vanadium is toxic to alveolar macrophages and therefore may impair pulmonary resistance to infection and clearance of particulate matter. An increase in inflammatory cells of the nasal mucosa has been observed in workers exposed to vanadium.

Incompatibilities

Dust may form explosive mixture with air. Dust, fume, and powders are a strong reducing agent; incompatible with oxidizers (chlorates, nitrates, peroxides, permanganates, perchlorates, chlorine, bromine, fluorine, etc.); contact may cause fires or explosions. Keep away from alkaline materials, strong bases, strong acids, oxoacids, epoxides, bromine trifluoride, lithium, nitryl fluoride, chlorine trifluoride.