| Abstract Scope |
Nickel is one of the most widely recycled metals and high efficiency recovery procedures for engineering alloys have been practiced for many years. However, more complex alloys including cast, wrought and powder superalloys contain valuable elements that present challenges for recycling. Tight composition restrictions for aircraft turbine alloys may restrict melt charges to same alloy scrap. This poses challenges for secure collection, identification and preprocessing of scrap. Highly reactive elements contained in advanced alloys degrade refractory linings, interact with slags to produce unpredictable recovery, and can generate exogeneous inclusions. The possibility of scrap contamination from tramp elements such as lead, is a constant threat. There is a tension between the introduction of ever more bespoke alloys the melters ability to efficiently recycle them. The path to improvement lies with more effective communication between scrap disposers (users), scrap collectors and processers, and purchasers (melters). Examples of highly successful recycling schemes will be provided. |