Resins structure in Gold Recovery Process

Ion excha nge resins are offered in the market in form of small spheres or beads and have polymerized molecules with appropriate ionic groups that are selected considering the work that have to do the resins [2]. Ergo, the resins designed for exchanging cations must have radicals –SO₃H or –COOH, and anionic exchangers must have groups –NH₂, NHR, NH₂, or NHR₃ and a specific cation. The group added determines the acidity of the resin (sulfonic groups are more acid than carboxylic groups). The alkalinity depends of the amine group added.

In all ion exchange resin must be considered some characteristic like insolubility of the final product, resistance to chemical attack, and porosity, which must allow the pass of common ions in a hydrated form.

Thermostable resins are polymerized under thermic conditions and don’t change their molecular form. They have all the properties mentioned above. For this reason the most used resin has been formed by polymerization of phenol-formaldehyde and melamine-formaldehyde.