Development and application of screening-level risk analysis for emerging materials

Analysis of a material's impact on society is increasingly recognized as a necessary step in materials development, especially in the area of lead-free piezoelectrics. Evaluations of the environmental, health, and societal impacts that occur throughout the material's life cycle are critical for determining the viability of lead-free alternatives. Risk screening approaches, such as the screening-level Emerging Materials Risk Analysis (EMRA) proposed in this work, may help researchers compare materials or material production routes to determine more sustainable solutions. As a first demonstration of its utility in the development of lead-free piezoelectrics, the approach introduced in this paper is applied to piezoelectric HfO2 (hafnia) to compare mining and processing routes and to elucidate the more sustainable route for HfO2 production. This paper aims to exemplify how the EMRA risk screening approach incorporates perspectives on environmental, health, and societal impacts into the materials research process by providing a relative risk screening evaluation of different material processing routes and/or different materials. Results from applying EMRA to hafnia show that the major known environmental impacts of hafnia mining and processing involve ecosystem destruction and heavy use of fossil fuels and electricity; health impacts related to potentially unsafe working conditions and potential exposure to radioactive elements; and societal impacts including land disputes and supply concerns. Results also demonstrate that the more sustainable production route currently available includes commercial wet mining with land rehabilitation followed by beneficiation via wet processes with consistent personal protective equipment use and water recycling. Almost all of the previously-mentioned impacts are avoided in this life cycle route. Outcomes from this analysis identify hafnia as a potentially sustainable replacement for certain applications of PZT and therefore encourage continued development of the material. Future efforts will test EMRA on a wide variety of other materials and revise the approach accordingly.