Minerals and Metals in Ancient India v1.c15.s4.6

v1.c15.s4.6

During the excavation of Period I levels at Ahar, heaps of slag-like material were recovered from more than one trench at three different depths. Evidently the copper-smelting industry at Ahar was extensive. The analysis of the slag is as follows: SiO₂ 35.2-38.2 per cent, Fe₂O₃ + FeO 43.9-48.3, MgO 2.4-3.6, Al₂O₃ 5.3-7.8, MnO₂ 1.2-2.3, CuO 0.7-0.9 and SO₃ 3.6-6.1 per cent Evidently, complete removal of sulphur and recovery of copper were not possible. Copper ore from Khetri indicated 16.7 per cent silica in its composition, which is less than half of the percentage of silica in the slag. So Hegde presumed that the copper ore was fluxed with silica during smelting in the chalcolithic period at Ahar.