Model Development and Experimental Verification of Liquid Desiccant Drying of Gelcast α-Alumina Ceramic Objects

In this work, the effect of molecular weight of poly(ethylene glycol) (PEG) on the drying rate of gelcast alpha-alumina objects was investigated. Moreover, the effect of the sample shape (cylindrical, spherical, and slab-like shapes) and various effective thicknesses of these shapes were studied. Thermogravimetric analysis and differential scanning calorimetry were used in order to study the diffusion of PEG in the porous network structure. A general model was proposed for drying of green objects in liquid desiccant solutions. The results show that using higher average molecular weight of PEG increases the drying rate. PEG chains diffuse into the network during the drying process and the amount of diffused PEG decreases as the molecular weight of polymer increases and the concentration of solution decreases. The proposed model successfully predicts the drying rate and the dynamic volume change of ceramic objects in various desiccant solutions.