Rice husk is residue from processing of rice grains. It is good for making briquettes because rice husk has the optimal moisture content of 8 and 12 % and granulation is also perfect 10x5x2 mm.
Because of those characteristics there is no need for further preparation such as grinding of drying.
Due to low level of lignin, it is not possible to make briquettes in bigger diameter than 75 mm without adding any binder. Although rice husks are perfect for briquetting, they also contain a high silica content, resulting in a high ash content. Briquettes from rice husk are most often used in boilers or furnaces with very high burning temperature to avoid a low silica melting point and sintering (crystallization) of ash.