Primitive Technology

Grate furnace, wood fired smelting experiment (2025x12)

Air date: Dec 04, 2025

A natural-draft brick furnace, 50 cm wide, was built and fueled with wood instead of charcoal to smelt a cylinder of iron ore and charcoal powder. The ore was placed on a small pot meant to catch the melt. The furnace operated for about two hours, successfully melting the ore. However, the catch-pot melted and failed, causing the ore brick to topple, which prevented the proper flow of slag and iron. Small iron prills were visible. The furnace design shows potential because it requires no labor during operation (no bellows) and uses readily available wood fuel to reach high temperatures. The resulting ash was repurposed for mortar production.