Effect of slurry preparation parameters on the granule characteristics of mould powder during spray drying

Abstract

This study systematically evaluates the effects of slurry formulation, specifically the solid-liquid ratio (SLR) and sodium carboxymethyl cellulose (CMC) binder concentration, on the characteristics of spray-dried mold powder granules. Slurry viscosity increased from 0.14 to 0.38 Pa·s as the solid loading rose from 44.44 to 54.55 wt.%, accompanied by a more negative zeta (180.85 mV). This promoted the formation of larger, hollow granules with reduced packing density (decreasing from 0.57 to 0.48 g·cm⁻³) and lower compressive strength. Conversely, increasing CMC content from 1.00 to 3.00 wt.% increased both slurry viscosity and granule size, resulting in denser particles and raising packing density from 0.45 to 0.59 g·cm⁻³. A synergistic optimum identified at 50.00 wt.% solids loading with 2.00 wt.% CMC, which collectively improved particle sphericity, size uniformity. The optimized particle characteristics of this formulation are expected to ensure efficient utilization, particularly in high-speed continuous casting applications.