|ALUMINIUM & ASSOCIATED METALS|
Bauxite, the main source of Aluminium, is the third most abundant metal in earth’s crust. Bauxite is a naturally occurring, heterogeneous material composed primarily of one or more aluminium hydroxide minerals, plus various mixtures of silica, iron oxide, titania, aluminosilicate, and other impurities in minor or trace amounts. Guinea and Australia has about one-half of the world’s reserves while other countries with major reserves include Brazil, Jamaica, and India.
Bauxite is the most important aluminium ore. It consists largely of the minerals gibbsite Al(OH)3, boehmite γ – AlO(OH), and diaspore α-AlO(OH), together with the iron oxides goethite and hematite, the clay mineral kaolinite and small amounts of anatase TiO2. It was named after the village Les Baux-de-Provence in southern France, where it was first discovered in 1821 by geologist Pierre Berthier.
Lateritic bauxites (silicate bauxites) are distinguished from karst bauxites (carbonate bauxites). The early discovered carbonate bauxites occur predominantly in Europe and Jamaica above carbonate rocks (limestone and dolomite), where they were formed by lateritic weathering and residual accumulation of intercalated clays or of clayey dissolution residues of the limestone.
The lateritic bauxites occur in many countries of the tropical belt. They were formed by lateritization of various silicate rocks such as granite, gneiss, basalt, syenite and shale. Compared with iron-rich laterites, the formation of bauxites demands even more intense weathering conditions with a very good drainage. This enables dissolution of kaolinite and precipitation of gibbsite. Zones with highest aluminium content are frequently located below a ferruginous surface layer. The aluminium hydroxide in the lateritic bauxite deposits is almost exclusively gibbsite. Bauxite is strip mined (surface mining) because it is found at the surface, with little or no overburden.
Aluminium Resource of India
Bauxite is found in four types of deposit: blanket, pocket, interlayered and detrital. In India, mostly large blanket deposits occur as flat layers lying near the surface and may extend over an area covering many kilometres. Their thickness may vary from a meter or less to 40 meters in exceptional cases although 4-6 meters is average. India has nearly 12% of the global bauxite deposits, which are rich in alumina and have low reactive silica content, making them amenable to digestion at lower temperature and pressure. Moreover, Indian bauxite deposits have low overburden and are available in continuous large blocks, which facilitate mechanised mining, thereby lowering the cost of production.
The overall resource position of bauxite in India is over 3 billion tonnes. India occupies 5th place with a share of 7% of world resources. Out of this 80% of resources are of metallurgical grade. Orissa and Andhra Pradesh account for more than 90% of country’s metallurgical grade resources. The balance is distributed in Jharkhand, Chhattisgarh, Karnataka and Maharashtra. The resources of metallurgical grade bauxite are quite adequate. Out of 1700 million tonnes bauxite available in Eastern Ghat Belt in Orissa and Andhra Pradesh only Panchpatmali deposit in Koraput district in Orissa has been developed into a mine. Many other deposits with good potential are yet to be exploited in Orissa and Andhra Pradesh.
Bauxite resources are dominantly located in the peninsular area. The deposits are associated with both high level and low level laterite. Majority of the Indian deposits are associated with high level laterite occurring in Eastern Ghat, Western Ghat, plateaus in Jharkhand and Madhya Pradesh and among the large areas occupied by ‘low-level’ laterite deposits, bauxite has been recorded in Katni area (Madhya Pradesh); Saurashtra and Kutch (Gujarat); Thane and Kolaba (Maharashtra) and also in parts of Kerala and Tamil Nadu. Vast expanse of laterite profile in central and coastal (both east and west) Peninsular India holds promise for addition to the bauxite resources. With the abundance of resources, Eastern Ghats region of Orissa and Andhra Pradesh would be the area of major bauxite mining activities in future. The large deposits of these areas, with reserves of more than 50 million tones, can be reserved for proposed export oriented alumina plants. Additional bauxite resources are required for the brownfield expansion of the existing alumina producers.
Aluminium Industry in India
Aluminium Industry in India can be broadly classified into two segments: the Primary Sector which involves the upstream activities of bauxite mining and the Secondary sector which involves the processing moldings of Alumina and processing of Aluminium. Indian market is dominated by integrated players involved in all the stages of the value chain from mining of the bauxite to processing of Aluminium. Bauxite in India is used primarily for preparation of Alumina and Aluminium. Apart from this Bauxite is also used in cement, refractory, chemical and abrasive industries.
Though there are more than 200 mines operating in the country, most of these are small open cast and manually operated. Industry is dominated by five integrated players which are in the manufacture of alumina/ aluminium, viz. the National Aluminium Company Limited (NALCO), a public sector undertaking, Bharat Aluminium Company Limited (BALCO), Hindustan Aluminium Corporation Limited (HINDALCO), Indian Aluminium Comp-any Limited (INDAL), and Madras Aluminium Company Limited (MALCO), all in the private sector.
15 major deposits account for 75% of the country’s production. These are mostly the captive bauxite mines of the major alumina players in the country like Nalco, Hindalco, Balco, Hindalco (Indal), Malco and the mines of GMDC which are either fully mechanized or semi mechanized. Among these, the Panchpatmali bauxite mine of NALCO in Orissa accounts for about 40% of the country’s production.
Major deposits are in East Coast falling in Visakhapatnam and East Godavari districts of Andhra Pradesh and Phulbani, Sundergarh, Bolangir, Sambalpur, Kalahandi, Keonjhar and Koraput districts of Orissa. Other important bauxite occurrences are located in Bilaspur, Surguja and Raigarh districts of Chhattisgarh, Satna, Balaghat, Rewa and Jabalpur districts of Madhya Pradesh, Lohardaga and Gumla districts of Jharkhand, Kolhapur, Raigad, Satara, Sangli, Sindhudurg, Ratnagiri and Thane districts of Maharashtra, Kutch, Jamnagar, Junagarh, Amreli, Bhavnagar, Sabarkantha, Surat, Valsad and Ahmedabad districts of Gujarat State.
NALCO is an integrated aluminium complex, encompassing bauxite mining, alumina refining, aluminium smelting and casting. The mines of NALCO are located at Panchpatmali hills of Koraput district in Orissa, having an area of deposit of 16 sq. km of 4.8 Mn tpa capacity and a resource base of 310 million tones. The quality of ore is Alumina 45% and Silica 2%.
HINDALCO and INDAL
Both is flagship of Aditya Birla Group, are vertically integrated through all stages of the aluminium business. HINDALCO is also into copper sector. Hindalco is the market leader in aluminium production followed by Nalco. Hindalco’s aluminium business comprises primary aluminium, extrusions, rolled products, foils, and alloy wheels. In the value-added segment, Hindalco, along with its subsidiary Indal, has around 50 per cent market share. The company has a smelting capacity of 345,000 tonnes, and alumina refining capacity of 660,000 tonnes and captive power generation of 779 MW. Indal’s operating smelter at Hirakud (Orissa) currently runs at 65,000 tpa, supported by a 67.5 MW Captive Power Plant.
Bharat Aluminium Company Ltd. (BALCO)
The public sector company BALCO was the first company in which the Government of India has disinvested its stakes to M/s Sterlite after liberalization. Earlier extensive exploration by GSI and MECL in 1970s & 1980s in the east and west coast of the country proved huge bauxite reserves in the country. To exploit these reserves giant company NALCO was set up as a public sector company under the Ministry of Mines.
The third largest Aluminium Company in India is held by Sterlite Industries which has 51% share holding and by GOI, which holds the remaining 49%. Balco has capacity of 200,000 tpa of calcined alumina, 100,000 tpa of aluminium metal and 270MW power plant.
Bharat Aluminium has its own captive open cast, semi-mechanized, Bauxite mines. Overburden, which is in the form of soil & laterite, is first excavated by a combination of shovel / excavator and dumper in order to expose ore-zone. Mainpat is the primary operative mine, which produces approximately 500,000 tpa of Bauxite. Approximately 100,000- 150,000 tpa Bauxite is procured on commission basis from non-captive mines. There are plans to open another deposit named Bodai-Daldali in Kawardha District in the near future. Manipat has about 5.0 million tonnes of reserves while Bodai-Daldali has 7.11 million tonnes of Bauxite reserves. BALCO uses VSS (Vertical Stud Soderberg) technology to produce Aluminium from Alumina.
The method of mining is open cast semi-mechanized. Overburden, which is in the form of soil & laterite, is first excavated by a combination of shovel / excavator and dumper in order to expose ore-zone. Then the ore zone is drilled and blasted. The blasted ore is subject to sorting in order to upgrade the “Run of Grade” to “Plant Feed Grade” i.e. 48% Al2O3. Sorting is carried out at the mine-face and the rejects associated in the ore zone are back-filled concurrently. The area is then leveled and afforested. The sorted ore is then trucked to the Korba complex for further processing.
Mainpat is the primary operative mine, which produces approximately 500,000 tpa of Bauxite. Approximately 100,000- 150,000 tpa Bauxite is procured on commission basis from non-captive mines. There are plans to open another deposit named Bodai-Daldali in Kawardha District in the near future. Mainpat has about 5.0 million tonnes of reserves while Bodai-Daldali has 7.1 million tonnes of Bauxite reserve.
Madras Aluminium Compnay Ltd.
The Madras Aluminium Company Ltd. (MALCO) was established in 1965 at Mettur Dam, near the city of Salem, Tamil Nadu in collaboration with Montecatine of Italy. MALCO is the only integrated primary Aluminium Metal complex in the entire South India with its own captive mining, refining, smelting and power generation operations.
MALCO was taken over by the Sterlite group, a subsidiary of Vedanta resources in 1995.
MALCO has coal-based Captive Power Plant at the same location. Its captive Bauxite Mines are located within the nearby ranges of Yercaud, Kolli and Palani in Tamil Nadu.
MALCO has its own Bauxite mines in the state of Tamil Nadu at Yercaud (Salem district) having reserves of 0.8 million tonnes and Kolli Hills (Namakkal district) having reserves of 0.9 million tones and has a 40,000 tpa smelter and 80,000 tpa refinery at the Mettur Dam complex
Method of mining used is open cast semi-mechanized. Overburden, which is in the form of soil & moorum, is first excavated by a combination of shovel/excavator and dumper in order to expose ore-zone. Then the ore zone is drilled and blasted. The blasted ore is subject to sorting in order to upgrade the “ROM Grade” to “Plant Feed Grade” i.e. 34% Al2O3. Sorting is carried out at the mine-face and the rejects associated in the ore zone are back-filled concurrently. The area is then levelled and afforested. The sorted ore is then trucked to the Mettur Dam Complex for further processing.
|JINDAL Aluminium Ltd. of Jindal group is into downstream processing with a production capacity of 50,000 tons per annum of Aluminium extrusions.|
Salient features of Indian Aluminium Industry
• Highly concentrated industry with only five primary plants in the country
• Controlled by two private groups and one public sector unit
• Bayer-Hall-Heroult technology used by all producers
• Electricity, coal and furnace oil are primary energy inputs
• All plants have their own captive power units for cheaper and un-interrupted power supply
• Energy cost is 40% of manufacturing cost for metal and 30% for rolled products
• Plants have set internal target of 1 – 2% reduction in specific energy consumption in the next 5 – 8 years
• Energy management is a critical focus in all the plants
• Two plants have declared formal energy policy
• Each plant has an Energy Management Cell
• Achievements in energy conservation are highlighted in the Annual Report of the company
• Energy targets are based on best energy figures achieved in their sector / region and by the plant itself in the past
• Generally, government policies were rated as conducive to energy management
• ‘Task Force’ formed by BEE in this sector to work as catalyst in promoting energy efficiency
• High cost of technology is the main barrier in achieving high energy efficiency