Semidirect recycling of cemented carbides

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.