Tungsten has certain valuable properties which give to it its great industrial and strategic defence utility. Among these the most important is the property of ‘self-hardening which it imparts to steel. 95 per cent of the Tungsten is used by the steel industry as it is used for high speed cutting tools that must retain hardness upto a extreme heat even for long periods of times.
Image Source: periodictable.com
Tungsten steel is used in the manufacture of munitions, armour plate’s heavy guns etc. and enables them to stand the heavy charge of modern explosives. Tungsten is easily alloyed with chromium, nickel, molybdencum, titanium, etc. to yield a number of hard facing, heat and corrasion resistant alloys. It is also used for electric bulb filaments, paints, ceramics, textiles etc.
Production and Distribution:
ADVERTISEMENTS:
The total in situ reserves of tungsten ore have been estimated at 43.15 million tonnes or 1, 32,478 tonnes of W03 content. The main reserves are at Degana Rajasthan. It also occurs in Maharashtra, Haryana, West Bengal and Andhra Pradesh.
The chief ore of this valuable strategic metal is Wolfrma (W02-70 to 75 per cent). The mineral occurs very sparingly in Jodhpur and Nagpur districts in thin veins and stringer and in a few alluvial deposits. The Geological Survey of India has discovered rescuers of Tungsten in Sirohi district of Rajasthan.
Vein deposits of wolframite occurring at Degana (Rajasthan) and Chendapathar (West Bengal) are found associated with quartz veins the width of which vary from a few centimeters to three metres or sometimes even more.
In Rajasthan, it is also associated with gravel beds overlain by 2.5m thick sand. The value of tungstate (Wo3) in vein deposit at Degana varies from 0.25 to 0.54%, while gravel deposit averages 0.04%. In Sirohi deposit, it ranges between 0.02 and 2.2%.
ADVERTISEMENTS:
In Chendapathar (Bankura district, West Bengal) deposit, the average tungstate is 0.1%. GSI identified seven mineralized zones in Sakoli basin in Bhandara and Nagpur districts of Maharashtra. The zone is known as Kuhi-Khobana-Agargaon belt. The tungstate (Wo3) contents in Kuhi block varies between 0.01 to 0.19%, in Kobana block 0.13 to 0.38% and in Pardi-Dahegaon-Pipalgaon block 0.48%.
The tailings of the Kolar gold field have been reckoned as a potential source of scheelite. The tailing dumps at the KGF analyse 0.035 to 0.18% tungstate. The concentrates recovered contain 29.8% Wo3 from Balaghat dump and 68% from Walker’s dump. The entire production of tungsten ore/concentration is consumed within the country, part of the domestic requirements are met by imports.