Water-Based Spray Drying of WC-Co Powders: A Sustainable Route to Environmentally Safer Granulation Without Compromising Performance

The spray drying of hard metal (WC-Co) powders is a critical step in the production of high-performance cutting and wear-resistant tools. Traditionally, organic solvents such as ethanol or acetone are employed in this process, despite posing substantial health, safety, and environmental risks. This study investigates a sustainable alternative by replacing organic solvents with water in the spray-drying process. We present a comparative analysis of granule morphology, flowability, and final mechanical properties between solvent-based and water-based routes. The water-based approach achieved a d50 of 99 µm, flow time of 27.8 s, and apparent density of 3.18 g/cm3, closely matching the solvent-based values (d50 = 93 µm, flow = 28.4 s, and ρ = 3.14 g/cm3). Hardness (HV30 ≈ 1650) and microstructure were equivalent across both routes, confirming that the substitution does not compromise performance. The water-based process also offers an estimated reduction of over 50% in CO2 emissions compared to traditional methods. These findings support the feasibility of water-based granulation as a viable, scalable, and safer route for WC-Co powder production, in alignment with dematerialization, circular material use, and the broader goals of sustainable development.