Effects of wet storage on compression molding of sawdust and mechanism analysis

Abstract

This study investigated the effects of wet storage on characteristics of compression molded sawdust, molding energy consumption and combustion characteristics during 13 days’ storage. Results showed that the hemicellulose content of sawdust decreased following the wet storage time, while the surface porosities increased. After wet storage for 5 days, a large number of orderly small holes were observed on the surface of sawdust. During the wet storage period, the compression ratio energy consumption decreased as a whole, and reached the lowest level when stored for 5 days which was 19.82% lower than that of raw materials. The water resistance of molded sawdust was significantly improved from 3 days of wet storage, and there was no significant change for the bulk density, drop resistance, and radial compressive strength. Comparing with the material, the ignition temperature and burnout temperature of treated sawdust decreased significantly, and the flammability index, comprehensive combustion characteristic index and combustion stability discriminant index all showed an obvious increasing trend. The lowest ignition temperature was found for the sawdust stored for 5 days. The mechanism of wet storage was further analyzed combining with the physicochemical properties.