What is Gold Refining?

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While gold is considered a precious metal by nearly all of the cultures on this planet, it is not always (if ever) found in its pure state. Because gold runs in veins found in ores or are otherwise mixed with other minerals and impurities as it is housed in the depths of the earth, gold has to first be refined in order for any impurities to be burnt off or skimmed off, leaving nothing but nearly 100% pure gold. The process of purifying gold to attain its pure state is known as gold refining, and is the second to the last stage of the whole mining process.

The process and practice of gold refining dates back to ancient times, when people first learned to separate different metals into their own unique constituents with the addition of certain compounds that would help facilitate the separation. One of the earliest practices of gold refining was in Ancient Lydia where the use of salt as an agent to separate impurities form the gold and been employed. While the methods were at best imperfect and rudimentary, it proved to be the precursor of later procedures that were able to refine gold at a much finer and more thorough rate.^[1] Mediaeval gold refining involved the use of certain kinds of acidic compounds to ‘eat off’ the impurities found in the smelted gold, while other cultures employed a vast array of chemical constituents to eat away any impurities that may be found in the metallic slurry.^[2] The refining process allows not only gold ores to be refined to remove any impurities, but to allow for gold alloys to be reverted to its pure state. This makes it possible for refineries to recycle old or broken gold jewelries and accessories back to its original pure state to be reused in the creation of other ornaments.

The gold refining process was heavily employed by mining towns. Refineries were also put to good use by powerful nations and individuals in the dissemination of plundered wealth from other nations. In this respect, refineries worked like modern-day recycling centers that separated the more precious gold from other, less precious metals. The refined gold would then be made into bars or bullion that would add to the fortunes of the kingdom or state that managed to possess them. The fabled Aztec gold of the Mesoamericans was just one of many treasures that fell prey to the fires of the refinery, so that today only very few examples of Mesoamerican gold-crafting remain, with much of the fabled treasure of the Incas, Mayas and Aztec now part of some treasury or other hidden deep within the vaults of some bank. It is said that during the Age of Seafaring, the nations of Portugal and Spain were some of the most crazed refiners of plundered and looted gold, one of the main sources of their then wealth and prestige.^[3]

There is a known practicality to the gold refining process however, as it allows for purer and more aesthetically pleasing examples of gold to be used by artisans in the creation of unique and beautiful works of art. In the absence of gold refining, much of today’s gold jewelry would not possess the grades or ‘karats’ that dictate its level of purity, nor would artisans be able to control the amount of alloying metal to the amount of gold creating a variety of different-hued gold. Because gold is a major type of currency, the purity of gold is often disputed or doubted hence the extreme need for purity in terms of creating bars, ingots, and bullion that are employed for monetary purposes.

Nowadays, in the quest for faster and more efficient methods of refining gold, modern processes with the aid of technology have been employed over the more traditional methods of gold refining, such as the Wohlwill process[4] and the Miller process.^[5] The former method is used to refine gold to its purest state (99.999%), while the latter refines gold to a high state of purity (99.95%) although its results are by no means as fine as the former method. Nowadays, refineries churn out gold that is used for a diverse number of purposes, not limited to currency or jewelry, but also to various industrial applications that require the specialized properties of gold making the process of gold refining one of the most crucial innovations that helped shape the modern world.

What is Gold Refining? - References:

[1] http://geology.com/publications/getting-gold/gold-extraction.shtml
[2] http://books.google.co.uk/books?id=hdaAGF5Y1N0C&pg=PA56
[3] http://books.google.co.uk/books?id=-IIEhFx0OfwC&pg=PA43
[4] http://en.wikipedia.org/wiki/Wohlwill_process
[5] http://en.wikipedia.org/wiki/Miller_process

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