The consumption of activated carbon is typically in the range of 20 – 60 g/t of gold ore processed and its use for gold recovery is based on their kinetic activity, hardness and price. Basically, the kinetic activity is an important aspect of the selection and in a typical Carbon-in-Pulp (CIP) or Carbon-in-Leach (CIL) plant part of the activated carbon is lost in several ways such as attrition during adsorption, pumping and reactivation. In the current commercial market, most high grade activated carbon cost $ 4-10 per kilogram and gold operations try to reduce costs. Consequently, one of the objectives is to reduce expenditure on activated carbon by buying cheaper grades, using smaller concentrations of more active carbons and employing more resistant activated carbons. It has been noted that the manufacturing process indicates that an improvement in the adsorption kinetics has an impact on the mechanical strength of the carbon and it is important to get a trade-off between adsorption kinetic and strength. This point can be determined by performing close quality control of the coconut-shell-based activated carbon. Obviously, it is important to study the behavior of other materials such as peat or coal.
During the manufacturing process, the finely powdered carbonaceous material is mixed with binders, extruded and activated performing the manufacturer a detailed control of the chemical and physical properties of the final product. Several laboratories employ different tests to evaluate the properties of the activated carbon due to it can be employed for different purposes such as water treatment, gas adsorption, discoloring, and also preparation of some foods. Although the published standard internationally accepted tests for activated carbon are very important guidelines, many manufacturers of activated carbon are used to employ peculiar testing methods and the results are included in the data sheet supplied with the activated carbon. Since, testing procedures are different and could be inexact to compare the information proportioned in the data sheets by different manufacturers of activated carbon. For this reason, the metallurgical laboratory must evaluate the required activated carbon for the adsorption process, otherwise, the operating cost can be affected.