The gold furnace played a crucial role in the extraction and refinement process. These furnaces were essential for smelting gold ore to extract the precious metal from the surrounding rock and impurities. The function of a gold furnace was to subject the ore to extremely high temperatures, melting it down to separate the gold from the other elements present in the ore.
Typically, gold furnaces were constructed from heat-resistant materials such as brick, clay, or stone, forming a chamber where the ore could be heated. The furnace was fueled by various combustible materials, including coal, charcoal, or wood, which generated intense heat when burned. The fuel was fed into the furnace through an opening, and airflow was regulated to ensure proper combustion and temperature control.
Once the furnace reached the required temperature, usually exceeding 1,000 degrees Celsius (1,832 degrees Fahrenheit), the gold ore was introduced into the chamber. As the ore heated up, the gold within it began to melt, separating from the rock and other impurities. The molten gold, being denser than the surrounding materials, sank to the bottom of the furnace, forming a layer of liquid gold known as a "button."
To further refine the gold, any remaining impurities or slag were skimmed off the surface of the molten gold. This process, known as fluxing, involved adding a flux material such as borax or silica to the furnace, which helped to bind with and remove the impurities, leaving behind purified gold.
Once the refining process was complete, the molten gold was poured into molds to cool and solidify, forming ingots or bars that could be easily transported and traded. The gold furnace was thus a crucial tool in early mining operations, enabling miners to extract and refine gold ore into a valuable commodity that drove economies and shaped the course of history.