• Optimize process yields by adjusting the existing processes and operating conditions.
• Recover minor metals from historic primary stocks8 such as stockpiled tailings and slag as well as unmined parts of ore bodies.
• Conduct exploration focusing on minor metals to increase reserve base.
During the manufacturing phase, losses occur in the form of production scraps, which are not always recycled. Production scrap can, for example, be runners, grates from casting, spent sputtering targets, scrapings from sputtering chambers, saw dust, and turnings. The amount of production scrap can be significant (Table 10.5). Such low resource efficiencies can also occur for major metals if, for example, high purities or technologies, like sputtering, are involved.
The large impact on primary metal demand can be mitigated by recycling, either within the company itself or by outsourcing to a specialized facility. For special metals, recycling of production scrap is often not common practice, as it requires special technologies.9 The actual recycling success depends on the scrap type, the degree and type of contaminations, and on the technology used. When recycling opportunities are not available, the high value scrap is usually stockpiled or processed without recovering all of the metals in it. A rapidly increasing demand for special metals can lead to a high backlog in production scrap recycling due to capacity limitations. Once appropriate recycling capacities are installed, processing of stockpiles can lead to a significant supply of secondary metals (and falling prices). Examples include indium (2004-2007) and ruthenium (2006-2007).
• Improving efficiency (yield) of manufacturing and recycling processes.
• Developing recycling technology and setting up capacities for as yet un-recycled materials.
Such old tailings, slag deposits, or other mining and smelting residues from activities operated in the past can contain significant (minor) metal resources. With today's mineral processing technologies, e.g., fine-grained minerals could be extracted from tailings that escaped past efforts, improved (metallurgical) processes could recover "unrecoverable" elements, and increased metal prices could focus on certain metals which were not a recovery target in the past and thus were discarded completely.
Recycling technologies exist for super alloys, hard alloys, Ta-capacitor material, (ITO) sputtering targets, casting scrap, and scrap created during Ge- and Si-wafer production, Ge-lenses manufacture, and PV manufacture, among others.