Carbon in pulp

Carbon in pulp (CIP) is an extraction technique for recovery of gold which has been liberated into a cyanide solution as part of the gold cyanidation process.

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 (i.e., 1%) copper content, froth flotation is more typical.

Activated carbon acts like a sponge to dicyanoaurate, the main soluble gold species in gold extraction technologies. Hard carbon particles (much larger than the ore particle sizes) can be mixed with the solution. The gold cyanide complex adsorb onto the carbon and is proposed to be reduced back to the metal. Because the carbon particles are much larger than the ore particles, the coarse carbon can then be separated from the slurry by screening using a wire mesh.