Iron ore Classification
Iron ore is a combination of minerals from which metallic iron can be extracted for use in manufacturing and construction. Iron ore, a naturally-occurring material, varies in composition range, making it important to study the mineralogy of the ore and the potential levels of impurities. Iron ore is classified according to its mineralogical characteristics, which largely depend on the textural properties of the ore. It is important to classify iron ore for commercial and industrial uses.
Iron ore can be classified into several categories such as Banded Iron Formation (BIF), Hematite-Magnetite, Magmatic deposits and Sedimentary deposits. BIF is a poorly-sorted and finely-grained iron ore containing an abundance of quartz, carbonates, pyrite and iron oxides. Hematite-Magnetite is composed of both hematite and magnetite, the latter having a lower iron content than hematite. This type of ore typically has been formed either by metamorphism or by igneous processes. Magmatic deposits form when molten rock crystallizes and forms rock layers that contain iron-rich minerals such as magnetite and olivine. Sedimentary deposits are sedimentary rocks composed of iron-rich minerals such as silicates, oxides, carbonates and sulfides.
BIF is one of the most common forms of iron ore and is characterized by its layered structure and distinctive texture. This type of ore is typically found in deposits of Silurian and Pre-Cambrian age, though some BIF deposits may also be of younger ages. BIF usually has a high iron content relative to other iron ore types and is relatively easy to process and pelletize.
Hematite-Magnetite ore deposits typically form in metamorphic and eruptive environments, often combined in an oxide or oxide-carbonate assemblage. This type of ore has a high iron content and is typically produced from volcanogenic-sedimentary deposits and is heavily dependent on the characteristics of the host rock for its formation.
Magmatic deposits form when hot molten magma crystallizes and forms rock layers that contain iron-rich minerals such as magnetite and olivine. This type of ore is typically found in massive sulffides, layered complexes or layered mafic-ultramafic intrusions and often occurs in combination with other ore types such as hematite-magnetite ore and BIF.
Sedimentary deposits are sedimentary rocks composed of iron-rich minerals such as silicates, oxides, carbonates and sulfides. These sediments typically form in near-shore and coastal environments, where iron-bearing minerals are commonly transported, concentrated and redeposited. These deposits are typically low in iron content, compared to other ore types, and can have high levels of impurities.
The classification of an iron ore deposit is dependent on several factors, including the mineralogy of the ore and the textural components of the rocks. It is important to classify iron ore for commercial and industrial purposes, as it provides important information about the composition and quality of the ore for efficient and cost-effective processing. Mineralogists and geologists typically rely on the identification of key minerals and textural components, as well as the knowledge of how these components are formed, to classify and evaluate the composition and potential quality of an iron ore deposit.
