De-oiling of grinding sludge: What is the potential of mechanical de-oiling by a centrifuge?

Grinding sludge is a hazardous waste flow emerging from semi-finished products being machined to their near-net-shape. Annually around 280,000 t of grinding sludge is produced in Germany. Tendency rising. Grinding sludge has a high recycling potential due to the known components and the known alloy type as relevant recyclable material. The GENESIS project focusses on grinding sludge which is produced during machining broaching tools for aircraft applications. The goal is to separate the oil and to recover the metallic fraction for a reuse in near-net-shape sintering processes. For this purpose, a centrifuge is used and the effects of machine parametrisation on the de-oiling efficiency is investigated. In this contribution, the effects of machine parametrisation on the residual oil content and de-oiling efficiency are investigated. It was found that independently from other parameters high rotation speed leads to a low residual oil content.