Minerals and Metals in Ancient India v1.c26.s6.t3.4

v1.c26.s6.t3.4

Zinc is markedly depleted at the closed end or top of each retort (vide Table 18.4), reflecting the movement of zinc vapour during the smelting process. In contrast lead does not appear to have been very mobile during smelting (Tables 18.3 and 18.4). Substantial amount of ZnO (2.18 %) in the retort body or wall (Tables 18.1 and 18.3) is due to the entry of zinc vapour and zinc-rich glass into the pores. The pore volume decreased in the outer and hotter surface of the retort and that is why the zinc content in the outer surface is much less (columns 3 and 4 in Table 18.1).