The possible determination of tungsten in low grade ores from Northern India, Rajasthan State has been explored by energy dispersive X-ray fluorescence analysis /EDXRF/ technique using radioisotope based excitation of W L X-rays and high resolution Si/Li/ detector system. Finely powdered ore has been diluted with optimal quantity of cellulose and converted into pellets to make it suitable for X-ray analysis after homogenization. The experiments have shown the minimum detectable limit of 33 ppm in diluted matrix. The results are compared with the spectrophotometric stannous chloride-thiocyanate method. EDXRF appears to be encouraging for routine and precise analysis of tungsten in low grade ores.
Authors:A. Nigam, R. Tripathi, M. Jangid, M. Chacharkar, and Madan Lal
Tungsten ores from Degana, Rajashthan State, India are studied using Mössbauer spectroscopy. The low grade ore exhibits two types of mineral assemblages as per chemical states of iron. The relation between ferrous/ferric ratio and tungsten concentration also supports the existence of two types of mineral assemblages. The Mössbauer spectroscopy of concentrate ore samples has shown the absence of iron. The energy dispersive X-ray fluorescence spectroscopy on the contrary has evidenced the presence of iron in concentrate ore samples but at lower concentration on comparison with low grade ores. These differences in behaviour in the above spectroscopic studies may be additionally due to higher attenuation of -radiations and higher atomic weight material in the ore concentrates.
Authors:Madan Lal, R. Choudhury, D. Joseph, H. Bajpai, and C. Tyer
Analysis by Energy Dispersive X-ray Fluorescence spectroscopy of monazite ores from Kerala /Chavara and Manavalakurichi/, Orissa /Chattrapur/ and Tamil Nadu /Tirunelveli/ has been carried out for the determination of their elemental composition using109Cd /annular/ and241Am /disc/ radioisotope sources. The elements Y, Zr, Mo, Pb, Th and U were analyzed using a109Cd source, and the elements La, Ce, Pr, Nd, Sm, Gd and Dy were analyzed using the241Am source in side source geometry. Quntitative results on these 13 elements present in these ores were obtained by the EDXRF technique. It was seen that despite the diverse geological settings, there is remarkable similarity in the elemental composition of these ores, although some trace elements do show certain variations from sample to sample. These results are presented and discussed in this paper.