How it’s Done: Extracting and Refining Gold
Gold has a long history as a precious metal, a commodity that few of us really understand or appreciate. These days, gold is used as a standard in economics, a point of relation to compare different national currencies. Gold is a physical asset with an intrinsic value, much like property.
Before gold becomes a part of your favorite necklace or makes it to the stock market, it starts out like any other rock. It takes the skilled hands of a gold mining company, like Graystone Company, to turn that rock into that luminous gold we all know and love.
The Extraction Process
Gold starts its life underground, inside rock. It takes a complex extraction process to isolate that gold. The first step in the process is breaking down the large chunks of rock into smaller pieces. Machines reduce the ore into pieces no larger than pebbles and road gravel. The gravel is then ground into a fine powder.
The powder is then thickened with water to form a pulp. This pulp is run through a series of leaching tanks. In the leaching process, gold is dissolved out of the ore using a chemical solvent, most commonly cyanide. Workers then introduce small grains of carbon into the tank. The gold adheres to these grains of carbon, and after filtering the pulp through a screen, the gold-bearing carbon is separated from the pulp.
The carbon then moves to a stripping vessel where a hot caustic solution separates the gold from the carbon. A screen filters out the carbon, which can be reused, and the gold-bearing solution goes through electrowinning. In this process, positive and negative terminals deliver a strong electric current to the solution. Gold collects on the negative terminals.
The gold and negative terminals are melted. Workers add a chemical mixture called flux, and the gold separates from the metal used in the terminal. Workers pour off the flux and then pour the gold into solid bars.
Refining
Although the gold has been extracted, the gold bars are very low-purity. In the refining process, impurities are removed from the gold. Refining companies receive the gold bars and melt them down once again. They then add borax and soda ash, which separate the pure gold from other not-so-precious metals.
Samples of gold are then tested in labs for purity. Most of these samples measure 99.9% purity. The gold is finally cast into bars.
From here, the gold can be combined with other metals and used to create the items you might be using this very second.
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