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
Commodity goods are also treated as commodities, e.g. human labour-power, works of art and natural resources ("earth itself is an instrument of labour"), even though they may not be produced specifically for the market, or be non-reproducible goods. Marx's analysis of the commodity is intended to help solve the problem of what establishes the economic value of goods, using the labor theory of value. This problem was extensively debated by Adam Smith, David Ricardo and Karl Rodbertus-Jagetzow among others. All three of the above-mentioned economists rejected the theory that labour composed 100% of the exchange value of any commodity. In varying