R B Subramanyam
Articles written in Bulletin of Materials Science
Volume 16 Issue 6 December 1993 pp 433-451
Titanium and its alloys have emerged as cost-effective structural materials in many spheres of chemical and engineering industries including aerospace and power generation. Titanium in its pure form is invariably prepared starting from pure titanium tetrachloride. Titanium tetrachloride obtained by chlorination of the oxide mineral is purified and reduced with either liquid magnesium or sodium or electrolysed to obtain titanium in sponge form. The metal extraction processes are so complex that large scale production technology is limited so far only to a few countries in the world viz. the USA, Japan, CIS, UK and China. India is attempting to enter this arena shortly with a 1000 TPY commercial plant based entirely on home-grown technology.
Among the extraction methods, the magnesium reduction of titanium tetrachloride, patented by W J Kroll in 1940, has received wider attention because of the inherent and relative merits of the process and its viability for economic production on an industrial scale. The original Kroll process, however, has undergone several modifications in the past few decades. The recent technological breakthroughs in the Kroll process as well as in the magnesium recycling technology has resulted in a significant reduction in the production cost of the metal. The paper describes these important innovations and also the efforts that are being put in for the establishment of a commercial plant for metal production in India based on indigenously developed technology.
Volume 17 Issue 6 November 1994 pp 1167-1179
Titanium has emerged as a major structural metal for a wide range of industrial applications due to its attractive engineering properties. India has a large and rich reserve base for this metal in the beach sands of the eastern and southern regions with well established production facilities for their separation into individual minerals. Research and Development activities for establishing the metal production technology have been underway in the country for over two decades. The Defence Metallurgical Research Laboratory, Hyderabad, has already demonstrated the metal production technology by the conventional Kroll process on 2000 kg/batch scale and is now all set for demonstrating the same by the more advanced, energy efficient combined process route on 4000 kg/batch scale. The paper reviews the R & D efforts undertaken so far in the field of metal extraction with emphasis on the current status of this developmental activity at DMRL.
Volume 19 Issue 6 December 1996 pp 921-938 Papers Presented At The Materials Science Section Of The 82nd Indian Science Congress, Calcutta, 1995
Titanium has been finding increasing usage as a structural metal in aerospace and many non-aerospace sectors mainly due to its light weight, high strength and outstanding corrosion resistance properties. India is very fortunate to possess the world’s largest and richest mineral deposit for this metal. Early studies on the metal extraction during mid ’60s at the Bhabha Atomic Research Centre, Bombay and pilot plant studies at the Nuclear Fuel Complex, Hyderabad resulted in the establishment of a ‘Technology Development Centre’ at Defence Metallurgical Research Laboratory (DMRL), Hyderabad. DMRL has already demonstrated titanium sponge production feasibility in 2,000 kg batches by the conventional Krcll process and is presently engaged in the development of the more energy saving ‘combined process technology’ in 4,000 kg batches. Fused salt electrolysis is widely employed to produce magnesium metal in integrated titanium plants so as to regenerate magnesium from the by-product magnesium chloride. DMRL has developed magnesium electrolysis technology in a 30 kA monopolar, modular type cell and is now developing the multipolar cell technology in 7kA, 22·2 V, two-module cell equipped with five bipoles in each module. This paper traces the developmental efforts on titanium metal extraction in India and describes the current efforts underway at DMRL for developing the latest energy efficient and cost effective technologies for the large scale production of both titanium and magnesium metals.
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