A Mercury Retort That Actually Captures the Vapour: Design, Condensation Budget, and Price for Artisanal Gold Shops

Design, condensation budget, and price of a sealed steel retort with a water-cooled condenser for artisanal gold shops, sized for a 20-gram mercury charge and priced at $42 from local materials. SIMULATED, NOT MEASURED; nothing was built or field-tested. The condenser must reject only 8.53 kJ per burn and 10 litres of cooling water warm by 0.204 C; the thermodynamic capture limit at a 40 C opening is 99.9996 percent, and the practical capture with stated seal, slip, and handling allowances is 98.0 percent, emitting 0.40 g per burn against 20.0 g for open burning. Failure cases are computed at full size: a worn seal gives 89.0 percent capture, a severe seal leak 74.0 percent, opening at 300 C gives 91.02 percent, overloading to 50 g gives 83.3 percent with 8.35 g emitted, and a blocked outlet reaches an assumed 6-atmosphere seal failure at 438.4 C with capture zero for that burn.