The key factor for pushing ahead the semidirect recycling route is, that at the moment most of the industrially applied techniques for cemented carbide recycling are based on a modulation of the primary route (indirect recycling) or the zinc-process (direct route). Depending on the scrap quality the latter isn’t appropriate, because of the remaining coating material in the recyclate which reduces its utilizability. Nevertheless a complete processing through the primary route after the mandatory oxidation is neither the ideal method.
Supported by these circumstances our research deals with an alternative as middle course. First a leaching step detaches the coating of the cemented carbide scarp as well as the binder metal. For the remaining hard phase contingent upon its characteristic a suitable treatment for reuse is sought. Secondly adequate hydrometallurgical techniques allow a recuperation of the dissolved cobalt.
As a basis for the process development a kinetic research is performed in dependence of varying parameters. For a profound understanding of the leaching characteristics particularly a systematic and detailed analysis of the respective elements and their interactive interference is performed. Supported by metallographic observation a kinetic model is derived which discloses the limiting factors. Hence an efficient and effective process route will result thereby.