Gold is a precious metal that has to undergo a number of processes including purification process in order to be used a piece of jewelry or other precious objects. Gold usually exists as flakes, veinters, masses and grains. They are excavated from the earth’s surface and ground for metal extraction. However, at this phase purity of the metal has not been achieved yet because it still has impurities or other substances such as iron, silver and copper. In order to eliminate such impurities, the purification process must be undertaken.
There are a lot of methods to refine or purify gold. The three most common methods are using electricity, using fire and using acid. But, these methods vary when it comes to the complexity of the purification process, the purification level and the cost involved. To understand how gold is purified using each method, please read on.
Purifying Gold Using Fire
The use of fire to purify gold subjects the metal in a heating process. In this process, a clay crucible, burning furnace and filter are required to produce up to 2,000 degrees Fahrenheit heat. The process starts with putting gold in borax that can withstand the level of heat. Heating of gold must be done until the metal is smooth before moving it into another container to cool. After cooling, the metal will be free of other metal substances.
Purifying Gold Using Acid
This is a common and simple approach to eliminate any impurities from gold. Gold refining chemicals like nitric acid and hydrochloric acid are the most common kinds of acids to use for refining gold. These acids are mixed in a beaker in order to make the purifying solution. They will then be filtered before adding gold into the mixture. Once gold comes in contact with the solution, its impurities will be eliminated.
Purifying Gold Using Electricity
This is a recent gold purifying method often referred to as the Wohlwill process. In this method, gold is put in a solution composed of hydrochloric acid and gold chloride. In order to eliminate the metal’s impurities, electricity will pass through this solution. The impurities will then be seen settling into the container’s bottom.
The Wohlwill process is said to be the best gold purification process because it can produce 99.99% of pure gold. Other gold purification process are expected to produce just 99.5% gold. However, the Wohlwill process tends to be costly.