Gold extraction the purity of gold. The parting of gold from silver has been done since ancient times starting in Lydia in the 6th century BC. Various techniques have been practised; salt cementation from ancient times, parting using distilled mineral acids from medieval times, and in modern times using chlorination using the Miller process and electrolysis using the Wohlwill process. Gold extraction Gold extraction refers to the processes required to extract gold from its ores. This may require a combination of comminution, mineral processing, hydrometallurgical, and pyrometallurgical processes to be performed on the ore. Gold mining from alluvium ores was once achieved
Ultra-high-purity steam for oxidation and annealing high temperature combustion. Within its optimal operating range, torches deliver good purity. Pyrolytic systems can support a middle range of flow but have a difficult time with very low flow rates and low steam to hydrogen ratios when adding water vapor to a carrier gas. Also, thermal management of the heat profile of the furnace and incomplete combustion affect furnace performance. In selective oxidation processes, water vapor is needed with hydrogen and without molecular to oxygen. This allows for the oxidation of specific metals. Torches and catalytic system are not 100% efficient so low levels of oxygen may still enter