Iron
Iron has been known since prehistoric times. However, the beginning of its widespread use came much later, because iron rarely occurs in a pure form in nature and its preparation from ores became possible only at a certain level of technology. The importance of iron in modern technology is determined not only by its wide distribution in nature, but rather by a combination of valuable properties. It is plastic, easily forged in cold and hot conditions, amenable to rolling, stamping and drawing processes. Iron has a property to dissolve carbon and other elements – this is the basis for the production of various iron alloys. Physical properties of iron depend on its purity. Industrial iron materials contain impurities of carbon, nitrogen, oxygen, hydrogen, sulfur and phosphorus. Even at very low concentrations of these impurities it strongly modifies the properties of the metal.
Pure iron is obtained in relatively small amounts by electrolysis of aqueous solutions of its salts or by reduction its oxides with hydrogen. Iron is a typical metal, it has a silver-white color. Pure iron material is plastic. Its hardness and brittleness increases with the addition of various impurities (carbon, for example). It has a conductivity property and apparent magnetic properties. There is a group of three metals, which are called "iron triad" - cobalt, iron and nickel (Fe, Co, Ni). They all have similar values of electronegativity, atomic radius and physical properties. Recently, the production of sufficiently pure iron by direct reduction of its ore concentrates, hydrogen, natural gas or coal at relatively low temperatures is gradually increased (Chemwiki.ucdavis.edu).
Iron is an essential metal of modern technologies. The pure iron is hardly used (because of its low strength). Iron is mostly used in the form of alloys, very different by their composition and properties. The share of ferrous alloys accounts for approximately 95% of the total metal production. Carbon-rich alloy (carbon consistency is greater than 2% of the mass) is a cast iron. It is melted in blast furnaces from iron-rich ores. Steel of various grades (carbon content is less than 2% by weight) of the iron is smelted in electric furnaces and converters by oxidation (burning) of excess carbon, removing harmful contaminants and adding alloying elements. High-alloyed steel (with a high content of nickel, chromium, tungsten and other elements) is melted in electric arc furnaces and induction furnaces. For the production of steel and iron alloy, the critical applications are the following processes - vacuum, electro-slag remelting, plasma, electron beam melting and others. Currently, steel smelting methods in continuously operating units are being developed, providing high quality metal and process automation (Topforge.co.uk).
Iron-based materials are able to withstand high and low temperature, vacuum and high pressure, corrosive environments, large AC voltages, nuclear radiation, and so on. The volume of Iron and its alloys production is constantly growing.
Iron is widely used in art and constructing. Iron as an artistic material used since antiquity in Egypt, Mesopotamia, India. Since the Middle Ages, there are numerous highly artistic ironwork in Europe (England, France, Italy, Russia and other) - wrought fences, door hinges, wall brackets, weathervanes, wrought-iron chests and others. In the 20th century, iron used to make gratings, fences, openwork interior walls, candlesticks, monuments.
In modern times, iron accounts for about 95% of steel production in the world. This is one of the most popular and widely used metals. The most important structural materials are steel and cast iron - carbon-containing iron-based alloys. Iron is a component-based alloys of other metals (nickel, for example). Iron is commonly used in electrical engineering. Its unique magnetic properties are used for the production of electric motors and transformers, iron is used as an anode in batteries (Air-iron, iron-nickel batteries). Magnetite is one of the most important materials in the production of non-volatile memory devices (HDDs). Magnetite is nothing that other, but the magnetic iron oxide. Magnetite powder is used as a toner in laser printers. Aqueous solutions of the iron and sulfates are used in industry for cleaning the water in water treatment plants. Iron sulfate (ferrous sulfate heptahydrate) is used for controlling fungi in construction and horticulture.
Also, iron is the material that is recovered from recycled materials (Business Recycling). The smelting of iron from scrap iron is much more profitable economically, this factor is successfully used by all developed countries:
They create enterprises and equipment for collecting and recycling iron waste;
They create favorable economic conditions for scrap procurement and scrap suppliers.
There are following types of scrap iron for its recycling:
scrap steel (all kinds and categories of steel scrap);
scrap iron (for example, machines, beds, baths, shower trays and other iron castings);
stainless steel scrap - scrap and waste of stainless steel with a nickel content.
Works Cited
Business Recycling. "Iron & Steel". N.p., 2016. Web. 23 Feb. 2016.
Chemwiki.ucdavis.edu. "The Iron Triad: Iron, Cobalt, And Nickel - Chemwiki". N.p., 2013. Web. 23 Feb. 2016.
Topforge.co.uk. "The Processes Or Iron And Steel Making". N.p., 2016. Web. 23 Feb. 2016.
