Vanadium—-the Essential Material of the Manufacture of Automobile

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As early as 1801, the Mexican mineralogist Andres Delta Ruat found yellow vanadium compounds in iron ore, but he suspected that it was impure lead chromate and didn’t confirm it. In 1831, Swedish chemist Sepstron discovered vanadium. But until 1867, British chemist Rossiter first made and obtained pure vanadium metal.

There is a lot of vanadium in the earth’s crust more than copper, tin, zinc and nickel, with a vanadium atom in an average of every twenty thousand atoms. However, vanadium ore is too dispersed and almost no relatively enriched ore. Almost all of iron ore contain vanadium, but most are less than a ten thousandth. It is strange that marine animals such as sea squirts and sea cucumbers could even take in vanadium from seawater and concentrate it in the blood. It is measured that ash obtained by burning sea squirts and sea cucumbers contains vanadium as much as 15%. Vanadium is silver-gray and shiny metal, which is not only lighter (specific gravity is 6) and refractory (melting point up to 1,735), but also harder than steel so that it can carve glass and quartz. High-purity vanadium is rich in ductility so that it can be pulled into filaments, or pressed into vanadium foil thinner than paper. However, if it contains a small amount of impurities such as nitrogen, hydrogen, oxygen and so on, it will become too brittle to break with a knock.

Vanadium is quite chemically stable. It could not be oxidized at room temperature and even at the high temperature of 300°C, maintaining in a shiny surface. Vanadium is free of the erosion by water, hydrochloric acid, dilute sulfuric acid, dilute nitric acid and alkali solution, and only dissolves in hot concentrated sulfuric acid, concentrated nitric acid, aqua regia and hydrofluoric acid. Besides, it can react with molten sodium hydroxide and sodium carbonate generating vanadates. Pure vanadium is not widely used, just used as X-ray filters and cathode material of electron tube.

To manufacture alloys is the most important use of vanadium metal and vanadium metal powder. Vanadium steel is made by adding less than 1% of vanadium into steel. Although vanadium content is low, the effect is great. A small amount of vanadium can not only significantly increase elasticity of steel, but also make steel hard and strong. Besides, such steel can remain very good impact strength at low temperatures and be free of corrosion in seawater. Thus, vanadium steel in large quantities is used to make cars and cylinders of locomotive as well as engines, shafts and springs of aircraft. Armor-piercing shells made by vanadium steel can penetrate steel plate of 40 centimeters. In the industry, iron ores containing vanadium are directly used to refine vanadium steel rather than adding pure vanadium obtained in advance into steel.

Adding vanadium into pig iron can not only greatly increase tensile properties, compressive resistance, bending resistance and wear resistance, but also double service life. With good corrosion resistance, vanadium-copper alloy is very resistant to seawater corrosion so that it is used to manufacture propellers of ships. And vanadium-aluminium alloy is light with high hardness and elasticity as well as resistance to seawater, so it is used to make seaplanes and hydrogliders.

Red vanadium pentoxide is an important catalyst discovered in recent years. In the sulfuric acid industry, vanadium pentoxide, instead of expensive platinum as a catalyst, can accelerate the reaction of turning sulfur dioxide into sulfur trioxide.

Vanadium salts are of various colors. For example, divalent vanadium salt is usually purple; trivalent vanadium salt is green; tetravalent vanadium salt is light blue; alkaline derivatives of tetravalent vanadium are often brown or black; and vanadium pentoxide is red. These colorful vanadium compounds are used as pigments. These compounds are not only added into the glass for the production of colored glass, but also coated onto ceramic for colored glazes. Most vanadium compounds are toxic, and they will cause pulmonary edema if breathing in too much. However, if adding a trace amount of vanadium salts to the feed of bull and pig, it will increase their food intake, and thicken fat layer.