Global scenario of magnesium metal

Abstract

Magnesium, a metal of high strategic importance finds critical applications in defence, aerospace, nuclear power, electronic and metallurgical industries. The major emerging areas of utilization are transport sector, industrial machinery, packaging, printing, graphic art etc. The largest application of magnesium, however, remains as an alloying element of aluminium. Other end use are as desulphuriser, as graphite noduliser and in electrochemical industry. Magnesium id internationally traded. The U.S.A, Canada and Norway are the biggest producers, while Japan, Germany Yugoslavia and Netherland are the major importing countries. The world consumption of magnesium metal has been recorded as 317000t in 1992. Magnesium occurs in nature as dolomite, magnesite and carnallite ores and as a chloride in sea water, underground natural brines and salt deposits. The prevalent processes for production of primary magnesium metal are mainly through electrolytic route and thermal reduction route. Electrolytic process is based on raw materials like seawater and brine mainly. The various operative processes are Dow process, Norsk Hydro process, National Lead Industry Brine process, American Magnesium Brine process, USSR process and MPLC process. Thermic route basically includes carbothermic reduction and silico thermic reduction processes. Carbothermic process has not been found commercially viable. Under silico thermic route two commercially developed processes are prevalent namely Pidgeon process and Magnetherm process. Energy requirement for the elctrolytic process ranges from 30 to 40 Wh per kilogram of metal, while for silico thermic route it is around 35 kWh/kg of metal. World capacity of primary magnesium production is about 352000t of which about 72% is through electrolytic route and balance through silico-thermic route. Current demand of magnesium in India is estimated to be about 1000t per annum of which 60% account for aluminium alloys, 25% for aerospace and defence sectors and balance for casting and miscellaneous industry. Magnesium technology and its commercial production in India is still in its infancy. India has developed silico thermic reduction process as well as fused salt electrolytic process. The commercial plants, each of capacity 600t/year have become operational since 1990. However, the cost of production is very high compared to the landed cost of imported magnesium. Production is only about 15-20% of the rated capacity. Adequate knowledge and expertise exist in the country for the technological development of magnesium metal. Concerted effort and co-ordinated approach is required by the major player viz., DMRL, MIDHANI, HAL and NML in association with the magnesium metal manufacturers. This is particularly significant in view of the difficult access to the latest available technologies in the field.