High-throughput production of metallic nanopowders
The development of nano-structured materials with unique properties has opened the door to virtually limitless potential applications, yet missing industrial processing techniques are impeding market penetration. Scientists initiated the EU-funded project SIMBA to tackle this challenge. Their focus is on developing an industrial-scale inductively coupled plasma (ICP) production setup. Adaptation of conventional ICP batch processing for continuous mode operation will enable higher throughput for larger yields. Online monitoring systems will ensure the safe production of well controlled and high-quality nanoparticles. The system will be used to deliver large quantities of high-quality silicon (Si) and Si-based nanoparticles for the production of novel anode materials in lithium-ion (Li-ion) batteries. Two partners operate plasma processing setups, one at lab scale and one at industrial scale. SIMBA is working to increase yield significantly by optimising processing conditions and reactor design. A combination of empirical measurements and modelling led to the definition of a processing protocol, while production of nanoparticles enabled the assessment of processing parameter effects on particle size. The odels are also supporting the design of new reactor geometries for optimal evaporation efficiency and minimal adhesion of the nanopowders to reaction chamber walls. An important part of SIMBA's efforts is focused on health, safety and the environment (HSE). Emissions of nano- and micro-sized Si into the workspace were low and generally linked to accidents. SIMBA enhanced system safety with development of innovative high-pressure relief valves for the dust-loaded gaseous atmosphere of the closed powder containers. Online monitoring and control is essential. Scientists are now developing a new optical sensor to monitor the precursor powder feed rate as well as testing an optical system to measure particle size directly during particle generation. The latter should be equally applicable to wet-dispersed and gas-borne nanoparticle generation, thus increasing marketability. Scientists are currently optimising the upscaled process to increase Si powder yield while minimising wall losses. The next period is expected to demonstrate major breakthroughs in industrial powder injection with novel online monitoring and functionalisation for the safe production of large quantities of high-quality Si and Si-based nanoparticles.
