Cold sintering process for manufacturing sustainable materials via reuse and waste valorization: A comprehensive review

The cold sintering process (CSP) has emerged as a low-temperature densification route that couples high uniaxial pressure with a transient liquid phase to promote rapid mass transport and interfacial rearrangement, enabling consolidation at temperatures far below those required in conventional sintering. This review frames CSP through a chemical-engineering lens, linking densification mechanisms to process variables (pressure, temperature, dwell time, liquid chemistry, and powder characteristics) and discussing how these parameters govern dissolution–precipitation, particle sliding/fragmentation, pore closure, and grain-boundary evolution. We then examine CSP as a manufacturing platform for sustainable materials, emphasizing pathways that valorize industrial residues and recycled streams, immobilize contaminants, and reduce thermal energy demand while achieving competitive functional and mechanical properties. Beyond materials outcomes, we analyze scale-up constraints and process integration issues, including liquid distribution and drainage, die-wall friction and thermal/pressure gradients, moisture control, reproducibility windows, and throughput-limiting steps. A structured state-of-the-art comparison is provided to connect composition, processing windows, densification level, and key properties across representative sustainable systems. Finally, we outline research priorities for translation to manufacturing: (i) physics-based process maps and in-situ diagnostics, (ii) metrics-driven sustainability assessment (energy/CO₂-equivalent per kg and performance-normalized indicators), and (iii) scalable equipment concepts and quality control strategies. This perspective positions CSP as a process-intensified route for circular materials manufacturing.