Survey of indigenous coals, fly ashes and flue dusts as a potential source of germanium

Abstract

Germanium occurs in the earth's crust in quantities as much as that of lead and zinc, but there are few concentrated deposits and even in these germanium is only present as a secondary element. This rarer metal occurs in certain coals also, and gets concentrated in the fly ash and flue dust deposited in the chimney, when such coals are used in thermal power stations or gas plants. Fly ash and flue dust are the source of germanium in many parts of the world. A number of collieries were approached and representative samples obtained from them were analysed for germanium to spot out the potential raw material of germanium. The fly ashes and flue dusts obtained from the thermal power station, Gujarat State Electricity Board, Porbander, using coals from Newton Chickely, North Chandamatta and Chandmatta collieries, were found to contain about 200 ppm germanium, which is quite rich in comparison to fly ashes utilized in other countries for extraction of germanium. (Shri Narinder Singh, Scientist; and Shri S.B. Mathur, Senior Scientific Assistant; National Metallurgical Laboratory)