Gold Leaching Methods
Gold is one of the most popular precious metals available. The increasing demand for gold has made it necessary to increase its production. Gold is not available from the mines in its pure state that we buy from shops. It must be leached from ore to attain its pure form. Various methods are used to achieve this.
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Cyanide
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The cyanide process is used for leaching on a large scale. Cyanide solution is used for dissolving gold from rocks, which results in precipitation. Gold is dissolved from crushed ore when mixed with the solution. The solution which bears the gold is collected and gold is then precipitated from it.
Bromine
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Bromine is used in different forms. One method is by adding bromide salt and hypochlorine or chlorine, which converts bromine from bromide. Bromine can leach not only gold but platinum as well. The method of using bromine to leach gold is very advantageous due to its easy extraction. However, the high consumption and interference of atomic absorption in assays is a disadvantage.
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Chlorination
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Before using cyanide on a wide scale, chlorination was the most common process. During the process of amalgamation, gold residues are left, which were extracted with the help of chlorine. These days, chlorine is used is Australian and American gold fields for the extraction of gold. However, this is on a small scale if the gold is a small component along with other precious metals.
Iodine
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Iodine is an element that is used for gold dissolution and gives rise to a stable gold complex. The element is very expensive so there is the need for recovery and recycling. For the leaching of gold, the concentration of iodine must be very low and the recycling process is complicated and expensive.
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