STUDIES ON THE BENEFICIATION OF LOW-GRADE COMPLEX TIN ORE FROM TOSHAM, HARYANA

Beneficiation of a low grade granite type tin ore containing 0.3-0.3% Sn from Tosham, Haryana, was studied. The main tin bearing mineral in this ore is cassiterite which occurs in varying grain sizes (from veins of few hundred microns to ultrafine disseminations of a few microns) and exhibits unusual magnetic behaviour. The optimum grind for liberation of the mineral has been found to be about 100-150 mu m. Preconcentration of the tin values was carried out by multistage gravity separation with recirculation of middlings/cleaner tails after careful stage regrinding and further upgradation on magnetic separators. For the concentration of fines, both fine gravity processing and notation techniques were examined. The flowsheet was tested on semi pilot plant scale using low (0.2% Sn) and high (0.86% Sn) grade feed samples. The former yielded a medium grade concentrate analysing 35% Sn with 47% recovery and a low grade product analysing 8% Sn with 16% recovery. In the case of high grade feed, the medium grade concentrate assayed about 43% Sn with 63% recovery and the low grade product assayed 20% Sn with 11% recovery. On the basis of the test results an industrial flowsheet has been suggested.