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Gold is the most precious metal. It symbolizes wealth, beauty and power. Ever wonder about the process of turning raw material into pure gold? It cannot be used right away after mining. Be it coins, jewellery, bars etc., gold has to go through a long procedure before reaching us. Gold is not a hundred per cent gold, it contains other elements such as minerals, rocks and compounds. It is a fragile metal. Other elements/ metals are mixed with it to strengthen it. A process is followed to make it free from impurities and metals. It is known as the ‘Gold refining process’. Today, we will read briefly about how gold is separated from mixtures.

Extracting Gold Ore from Mines

Gold is present in various forms. It is never purely formed but is present along with many allies. The composition depends on region, climate etc. They are removed before putting gold into practice. The gold refinery process begins when gold ore is obtained from mines. The methods of mining depend on geographical area, accessibility and other factors. Once it is received from the earth’s surface, it is set up for purification.  Here is the list of well-known methods used to refine gold.

• Miller Process

Miller Process got its name from its inventor Francis Bowyer Miller. The process involves the melting of gold. It claims to purify gold to 99.95%. When chlorine gas is passed through melted gold, the impurities turn into solid form. The solid compounds are easily removed. Lastly, to remove platinum and palladium, gold is refined with an electrolytic method.

• Cupellation Process

The gold ore is placed into a bowl, namely a cupel. This flat bowl is placed into a furnace for passing the heat at a specific temperature. The process of Cupellation refines gold by removing impurities by evaporating them. Sometimes, unwanted compounds/ rocks are also absorbed or oxidized. About 99.5% of gold is purified by this procedure.

• Acid for Refining Raw Gold

In this method of refining gold, nitric and hydrochloric acid are used. It claims gold purification up to 99.999%. These acids are very strong and can dissolve all unwanted impurities. When unrefined gold is placed in the solution, the impurities get separated.

• Fire for Gold Refining Process

Fire has been used to purify gold for ages. It is one of the most traditional methods for refining impure gold ore. In this method, the gold is placed into a container. Note that, the container used here has immense strength to withstand higher temperatures. It is heated at 2,000 degrees Fahrenheit. When gold melts, impurities drift at the surface.

• Using Borax and Soda Ash

It is used to treat gold alloy. The impure gold that refining firms receive from producers is called a dore form of gold. In this gold purification method, the alloy (dore form of gold) is melted. Borax and Soda Ash are mixed into it. This separates the other metals from gold.

• Electricity for Purifying Gold

It is an old-school method for gold refining. It was invented in 1874 by Emil Wohlwill. Three main things are required to remove unwanted elements from gold: Anode, Cathode and an Electrolyte solution. Here, the anode will be gold to be refined, cathode is made with 24-karat gold. The process of refining gold with electricity is simple. Anode and Cathode are suspended in the solution. The current is passed through it. It makes gold travel from anode to cathode. And the impurities get dissolved into the solution. In the end, we are left with completely pure gold cathode.

The Conclusion

Understanding the gold refining process gives us insights into the hard work behind pure gold. Purification of gold can be complex if the composition itself is higher. We have mentioned all the popular methods refining agencies might be following. Our motive was to aware you of the backstage process. There is much expertise involved. We must cherish and admire all the people behind the work.