History of Technology in India, Vol. I: From Antiquity to c. 1200 A.D. v1.c13.s2.t5.1

v1.c13.s2.t5.1

As the temperature of the furnace was raised the refractory of the retort got sintered and graphitised and at the same time the following chemical reactions took place inside the retort. At temperature below 1000°C PbO and Ag₂O present in the ore got reduced by carbon producing liquid Pb-Ag alloy and CO gas. At the same time the reed plug got charred and burnt releasing CO gas inside the condenser chamber where it expelled out the air from this chamber and created a reducing atmosphere. At the same time the liquid alloy of Pb-Ag trickled down through the hole and got collected inside the condenser vessel. This must have been followed by the reduction of ZnO to Zn vapour and CO gas at 1200- 1300°C, which were [Figure: APERTURE FOR OUT FLOW OF HOT GASES AND FEEDING FUEL
1. FURNACE CHAMBER 2. PERFORATED PLATE
3. TERRACOTTA PILLAR 4. METAL CONDENSING VESSEL
5. RETORT]