Minerals and Ores

Chromite is the ore from which Chromium is extracted. Similarly, Ilmenite is the ore from which Titanium is extracted. The relationship is 'ore : metal extracted'.

Bauxite is the primary ore of aluminium. The Hall-Heroult process is used to extract aluminium from bauxite ore, which is first purified into alumina using the Bayer process.

Minerals like limestone, silica, alumina and gypsum are used in the cement industry.

Correct Answer: Aluminium smelting industries

The iron and steel industry is the basic industry since all the other industries — heavy, medium and light, depend on it for their machinery. Thus, it is the most important metallurgical industry in India.

In the historical context (pre-2000, before Jharkhand and Chhattisgarh were formed), Bihar was the leading coal producer in India, followed by Madhya Pradesh and West Bengal. This sequence reflects the major Gondwana coal fields of that era.

Magnetite (Fe3O4) is a primary ore of iron and is known for its magnetic properties. Other options like galena (lead), cryolite (aluminum), and cinnabar (mercury) are ores for different metals. Magnetite and hematite are the most common sources for industrial iron extraction.

Bauxite is the primary ore from which aluminium is commercially extracted. It consists mainly of aluminium oxide minerals. Silver, copper, and manganese are extracted from different ores such as argentite, chalcopyrite, and pyrolusite, respectively.

The Zawar mines in the Udaipur district of Rajasthan are among the oldest zinc and lead mines in the world. They have been a primary source of these minerals for centuries and are currently operated by Hindustan Zinc Limited.

Scheelite is a calcium tungstate mineral with the chemical formula CaWO₄. Pyrochlorite (CaNaNb₂O₆) is an important ore/mineral of niobium.

Ilmenite (Fe.TiO₃) is an oxide ore of titanium. Hausmannite (Mn₃O₄) is an oxide ore of manganese. Linnaeite (Co₃S₄) is the sulphide ore of cobalt. Hence, only ilmenite (Fe.TiO₃) is the oxide ore of titanium.

The mixture of iron ore, coke and limestone is called ‘charge’. Iron ore is not pure iron oxide. It also contains an assortment of rocky material. This wouldn't melt at the temperature of the furnace, and would eventually clog it up. The limestone is added to convert this into slag which melts and runs to the bottom. The heat of the furnace decomposes the limestone to give calcium oxide.

Soil contains a wide variety of essential minerals and nutrients that plants absorb through their roots. While air provides carbon dioxide and water provides hydrogen and oxygen, the bulk of mineral nutrients like nitrogen, phosphorus, and potassium come from the soil. Chemical fertilizers are used to supplement these natural levels but are not the primary natural source.

The Kolar Gold Fields (KGF), located in the Kolar district of Karnataka, were famous for gold mining for over a century. They were one of the deepest mines in the world before they were closed in 2001 due to high costs and low gold production. The region remains synonymous with India's gold mining history.

Monazite is a reddish-brown phosphate mineral that is a primary ore for thorium, as well as rare earth elements.