Investigations on molybdenum concentrates obtained from Rakha Mines

Abstract

Molybdenum concentrates are easily and completely decomposed by nitric and sulphuric acids. A sample was obtained from low grade copper ore of Rakha Mines, which, however, left an insoluble black residue when treated as above. Further, the total of the constituents generally present in the concentrates was only 76.1% and the total sulphur present was much in excess of the amount necessary for its presence in combined state with molybdenum, copper and iron. To ascertain the reasons for the above peculiar behaviour of the molybdenum concentrate, systematic investigations by chemical, spectrographic and X-ray diffraction methods were undertaken. The results of the investigations are presented in this paper. Presence of graphite and free sulphur besides molybdenite and chalcopyrite in the concentrate and graphite in the acid insoluble residue respectively was revealed by X-ray diffraction. Shortage in the total was due to the presence of organic matter and graphite in the concentrate; 11.8% free sulphur accounted for high total sulphur content of the sample. (Dr. H.P. Bhattacharya, Shri A. Ghosh and Dr. J.K. Mukherjee, Scientists, National Metallurgical Laboratory, Jamshedpur)