Iron Ores

Magnetite Ores :

Magnetite ores can be divided, according to their origin, in to three main categories viz. Sedimentary-metamorphic, contact-metasometic and magmatic.
Raw magnetite
Magnetite ore

● In sedimentary metamorphic ores the ore minerals are usually fine grained and texture may banded. Ores of this type generally contain martite, hematite, iron carbonates and silicates. The gangue is mostly quartz and sulphur and phosphorus contents are generally low. These are most commonly found in USA and Krivoi-Rog ore field in USSR.

● In contact metasomatic ores the magnetite generally occurs in grains of different sizes and amount of sulphide of iron and other metals like copper and zinc. A considerable amount of CaO is present with siliceous gangue.

Hematite Ores :

Hematite ore
Hematite ore

● There are usually of sedimentary metamorphic type iron ores produced. They include the hard homogeneous fine grained hematite taconites from lake superior region of U.S.A. hard quartz banded ores of Sweden and Labrador, coarse grained ore which are easy to crush and grind, high grade ores containing large inclusion of pure hematite. The sulphur and the phosphorus contents of the hematite ores are usually low.

Brown Hematite :
Brown hematite iron ore
Brown hematite

● The brown hematite ores is used to convey a variety of ores mostly sedimentary in origin and the material having moved in solution from initial point of solution. The main ore minerals in the brown hematite are the various iron hydroxides, limonite, hydrogoethites, silicates and siderite.

● The gangue is generally siliceous but occasionally lime along with silica content also be present. In the oolitic ores more 30% of iron may be present as iron silicate of diverse composition.

Siderite :
Siderite ore
Siderite ore

● These are carbonate type of ores and constitute a very small proportion of the total world availability. Siderites are prone to oxidation and the ore often contain considerable amount of hydroxides. Near the surface these ore boides are covered by siderite- limonite- hematite cap.

Titanomagnetites :

● The most important of the complex ores are the Titanomagnetites. The main ore mineral is magnetite with titanium present is line note or as titanomagnetites. Certain of these ores contain vanadium which is recovered from these ores along with iron as a by product. The composition varies considerably and may contain 60 - 70% magnetite and 20 - 27% ilmenite.

Lateritites :

● These are produced due to surface alteration under tropical condition. The formation of iron cap on hard ore extending few meter below the surface. Such ores can contain 50 - 60% iron in the form of hydroxides and a high proportion of alumina which has not been leached out.
● These ore may be contain impurities like chromium, nickel, cobalt etc, in such high proportions that it is worked for recovery.

Share this

Related Posts

Next Post »

Contact Form


Email *

Message *