History of Technology in India, Vol. I: From Antiquity to c. 1200 A.D. v1.c17.s4.t2.7

v1.c17.s4.t2.7

It has been proposed that iron could have been made from the iron-bearing shales occurring in the neighbouring Agra-Gwalior range which assays 21.7 p.c. Fe, 41.9 p.c. SiO2, 14 p.c. Al2O3, 6.3 CaO. 2.3 MgO, 1.4 Na2O and 6.8 p.c K2O. This suggestion (Gaur, 1983: 487-500) is plainly unacceptable, since the proportions of SiO2, Al2O3, CaO and MgO are lower in the slags, and iron percentage much higher, than in the iron shale. The raw material must have been rich iron ore (from eastern Uttar Pradesh or Bihar) out of which the iron recovery was incomplete and inefficient on account of solid-state reduction.