scorification

Scorification is a metallurgical process used to extract metals, particularly gold and silver, from ores or alloys. It involves heating the material in a crucible with a flux, such as bone ash, litharge, or a mixture of lead and borax. The flux combines with impurities like sulfur, arsenic, and base metals, forming a slag that is less dense than the molten metal. This slag then floats to the surface, allowing the desired precious metals to be separated.

The process relies on the principle that certain elements readily oxidize or form soluble compounds when heated with a suitable flux. These compounds are then absorbed by the porous crucible walls or rise to the surface as a molten slag. Historically, scorification was a common method for assaying precious metals and for their initial purification. It was particularly useful for separating gold and silver from base metals like copper.

Modern metallurgical techniques have largely superseded scorification for large-scale refining due to its labor-intensive nature and the presence of environmental concerns. However, it can still be employed in specialized applications or in artisanal settings where its simplicity and low capital cost are advantageous. The effectiveness of scorification depends on the composition of the ore or alloy and the careful selection of the appropriate flux.