Carbon in Pulp Helps to Purify Gold
Gold is one of the most historically significant, valuable, and precious naturally occurring metals that exists here on Earth. Its history with humans has been both beautiful and tumultuous:a lot of people personally choose to wear gold as rings or other jewelry to symbolize marriage or wealth, while wars have been started over lands that contain vast amounts of gold to mine.
Gold’s most significant part of human history may have been its use as a monetary policy that was called the Gold Standard, which was one of the most widespread forms of monetary policy until the Flat Standard started to be implemented in the early 20th century.
Gold’s value as currency and as a form of jewelry requires gold to be pure and this is where the adsorbent activated carbon plays an important role. Since freshly mined gold ore is rarely ever found in a purified form it must be purified, through a gold extraction process. Although purifying gold had been done for centuries, beginning in the back half of the 20th century activated carbon began to be used to purify gold because of its strong adsorption capabilities.
Activated carbon is used in a gold extraction method called The Gold Cyanidation Process (which is sometimes referred as Gold Leaching). Gold Cyanidation is currently the most commonly used gold extraction method.
Gold Cyanidation works by crushing ore with gold in it into small pieces. Water is then added along with cyanide which breaks the gold down into a pulpy type of liquid. After this is done the gold must be harvested from the cyanide solution. Two processes are commonly used after the Gold Cyanidation Process, they are: The Carbon in Pulp Process (CIP) or The Carbon Column Process.
Both of these processes are very similar in that they use activated carbon to remove the gold from the leaching solution, however the equipment used is different. Carbon in Pulp is used when gold leaching occurs in tank with activated carbon, while the Carbon Column Process removes gold in large stacked columns that are loaded with activated carbon.
Both processes work by utilizing activated carbon which is charged so it can specifically adsorb gold. The gold from the leaching solution is adsorbed by the activated carbon in either the columns or the tanks, leaving behind the water and cyanide.
As activated carbon reaches its adsorption capacity it is removed and sent to a stripping circuit where it is heated to high temperatures and mixed with cyanide and sodium hydroxide. After the gold is removed from the activated carbon the gold is placed in vessel where it is attached to steel cathodes where it is usually removed with a pressure water spray and placed in Dore bars.
Activated carbon can help to purify gold over 99% making its role in modern gold extraction very important.