Minerals and Metals in Ancient India v2.c44.s6.21

v2.c44.s6.21

Dhātuvāda described a process of coating iron with metallic copper. Plant ash (potassium salt) and sour wine (vinegar or acetic acid) when kept in a copper vessel gives a ‘paint’ (solution containing copper acetate) which when applied on iron gives a deposit of copper (DV, 2-3; Ray, 1956:144 and 452). This is the first Indian reference to the hydrometallurgical route of making copper, using the displacement reaction with iron: