What are the Life Cycle Environmental Impacts of Synthetic Diamond?

Conference poster, 2019

Synthetic diamond is due to its superior properties used in a wide range of applications including cutting and grinding of metals and rocks, but also in analytical equipment lenses and jewelry. The conventional production of synthetic diamond is energy-intensive and typically conducted via high-pressure high-temperature (HPHT) synthesis, while microwave chemical vapor deposition (MW-CVD) is also used but to a lesser extent. The purpose of this study is to assess the environmental impacts of synthetic diamond production via HPHT and MW-CVD synthesis. The method of life cycle assessment (LCA) is applied, where the environmental impacts of a product is studied over its life cycle. In this study, the parts of the life cycle included are the raw material extraction and manufacturing of synthetic diamond. Various types of environmental impacts are assessed, including global warming and acidification. Furthermore, the largest contributors in synthetic diamond production to the environmental impacts, i.e. the hotspots, are identified and potential improvements are discussed. Scenarios were constructed in order to assess the importance of the type of electricity mix that is applied in the production. Preliminary results from the study indicate that the cemented carbide (WC-Co) parts required for the high-pressure apparatus constitute a hotspot in the HPHT synthesis, while the required electricity constitutes a hotspot in the MW-CVD synthesis.The results provided from this study on conventional synthetic diamond production can be applied by synthetic diamond manufacturers in order to identify the largest potentials for improvement in their production. The results can also be used in future full LCA studies, which then include the whole life cycle of synthetic diamond products.