Title: Optimization of Thermal Treatment Conditions for Enhanced Compressive Strength and Hardness of Jumbo Cashew Nut Shells
Authors: Jimeshio, Joseph Gberindyer, Ekemube Raymond Alex, Nyamkyume Felix Terkula
Volume: 10
Issue: 9
Pages: 286-299
Publication Date: 2026/09/28
Abstract:
Cashew nut shells, which account for 65-70% of the total nut weight, are significant agricultural byproducts with significant potential for briquette production due to their mechanical, chemical, and thermal properties. However, thermal treatment compromises the integrity of cashew nut shells, which lowers briquette quality. The compressive strength and hardness of jumbo cashew nut shells were optimized using Response Surface Methodology with Central Composite Design at temperatures of 200, 250, and 300°C and heating durations of 30, 60, and 90 minutes. Eleven experimental runs were evaluated using Design-Expert(r) software.Both temperature and heating time had a substantial impact on mechanical properties, according to analysis of variance (p<0.05). With R2 values of 0.9876 for compressive strength and 0.9764 for hardness, the quadratic models showed outstanding fit. Optimal conditions of 250°C and 30 minutes were predicted by numerical optimization, resulting in compressive strength of 65.06 N and hardness of 54.01 N with a desirability of 0.642. Model correctness with less than 8% error was proven by validation studies. These ideal circumstances offer a practical trade-off between minimizing energy usage and maintaining the shell mechanical qualities necessary for long-lasting briquette manufacture.