Haematite iron oxide

Products and Uses A red powdered haematite, iron oxide. Because it is a mild abrasive it is used in metal cleaners and polishes. 

Oxides Metal ion(s) + oxygen ion Haematite (composed of iron oxide), a red pigment and an iron ore Corundum (composed of aluminum oxide), an abrasive silica (composed of silicon dioxide), common sand... 

Iron Haematite Iron(m) oxide Fe203 Heat oxide with carbon... 

Iron is extracted from its ores haematite and magnetite. Usually it is extracted from haematite (iron(m) oxide). The ore is mixed with limestone and coke and reduced to the metal in a blast furnace. The following is a brief outline of the reactions involved. 

Diffraction patterns can be used to identify the various phases in a catalyst. An example is given in Fig. 10.3b, where XRD is used to follow the reduction of alumina-supported iron oxide at 675 K as a function of time. The initially present oc-Fe2C>3 (haematite) is partially reduced to metallic iron, with Fe3C>4 (magnetite) as the intermediate. The diffraction lines from platinum are due to the sample holder [10]. 

There is a lot of oxygen in the atmosphere, and over the millions of years since the Earth was formed many metals have combined with oxygen to form compounds called oxides. Iron, for example, occurs in the molten core of our Earth, and is often found in the Earth s crust as the ore haematite, which is iron oxide. Iron oxide is a binary compound, which means it contains only two elements. Notice that its name ends with ide . This is true for all binary compounds. Metals tend to combine with non-metals. Where a binary compound is made up of a metal and a non-metal, the first name of the compound is simply the name of the metal it contains and the second is the name of the non-metal, changed to end in ide for example, the compound between copper and chlorine is copper chloride. 

Lamellar-shaped crystalline haematite (a-Fe203) can also be used as a filler. Due to its morphological relationship to micas, it is known as micaceous iron oxide. 

The products are silicic acid (H4Si04 see below) and colloidal hydrated iron oxide (Fe(OH)3), a weak alkali, which dehydrates to yield a variety of iron oxides, for example Fe203 (haematite—dull red colour) and FeOOH (goethite and lepi-docrocite—yellow or orange-brown colour). The common occurrence of these iron oxides reflects their insolubility under oxidizing Earth surface conditions. 

The minerals from which the metals are extracted, existed for millions of years in the earth s crust and are the most stable form of the metal. A considerable amount of energy is required to convert this mineral into the metal. Once this pure metal comes into contact with the natural environment such as sea-water or soils, the metal slowly converts back to its original starting material. Iron, for example, is obtained from the mineral, haematite, an oxide of iron. Once the pure iron comes into contact with water and air (oxygen), it slowly converts back to the oxide. This is called corrosion and the product is familiar to everyone as red rust. Nearly all metals will corrode in natural environments although the rates of corrosion will vary from metal to metal and alloy to alloy. In addition, the rates of corrosion will vary from one natural environment to another. Iron will corrode at approximately 50 pun per year in freshwater but at 120 pm per year in seawater. The reason for this is due to the difference in chemical composition between freshwater and seawater. The latter contains salt (sodium chloride) and this is very deleterious to the corrosion behaviour of the metal. Silver artefacts may be excavated after several hundred years buried in soils with only minimal amounts of corrosion. Those recovered from marine sites after a similar period of burial, have completely corroded and have reverted back to 100% mineral. This is entirely due to the presence of chlorides in seawater. 

Synonyms Burnt sienna Cl 77491 Copperas red Ferrous ferrite Gulf red Indian red Iron mass, spent Iron oxide Iron oxide, spent Iron sponge, spent Pigment red 101 Pigment red 102 Red haematite Red iron oxide Red oxide Turkey red Definition Sienna, siderite, Persian red, Spanish red, and red ochre are natural iron oxide ores used as red pigments Empirical FejOj... 

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