Carbon In Pulp Processing

Cyanide is a lixiviant, or reagent that is used to leach, often in tanks, gold from a solid matrix and form a gold cyanide complex.  The gold cyanide complex is then extracted from the pulp or slurry by adsorption onto activated carbon. CIL stands for carbon-in-leach. This is a gold extraction process called cyanidation where carbon is added to the leach tanks (or reaction vessel) so that leaching and adsorption take place in the same tanks. CIL is slightly different from another gold extraction process called CIP or carbon-in-pulp process. In the latter case leaching takes place in tanks dedicated for leaching followed by adsorption onto carbon in tanks dedicated for adsorption.

Introduced in the early 1980s, Carbon in Pulp is regarded as a simple and cheap process. As such it is used in most industrial applications where the presence of competing silver or copper does not prohibit its use. In the case of high copper content, froth flotation is more typical.