Rice hulls (or rice husks) are the hard protecting coverings of grains of rice. In addition to protecting rice during the growing season, rice hulls can be put to use as building material, fertilizer, insulation material, &fuel.The hull is formed from hard materials, including opaline silica and lignin.Its uses are… Rice hull ash-- This ash is a potential source of amorphous reactive silica, which has a variety of applications in materials science. Most of the ash is used in the production of Portland cementThe ash also is a very good thermal insulation material. The fineness of the ash also makes it a very good candidate for sealing fine cracks in civil strctures, where it can penetrate deeper than the conventional cement sand mixture. Toothpaste-- In Kerala, India- Rice husks was universally used for over centuries in cleaning teeth - before toothpaste replaced it. Fertilizer-- Sometimes earthworms are used to accelerate the process. Using vermicompostingtechniques, hulls can be converted to fertilizer in about four months. Fireworks-- Rice hulls are coated with fine-grained gunpowder and used as the main bursting charge in aerial fireworks shells. Fuel-- With proper techniques, rice hulls can be burned and used to power steam engines Pet food fiber-- Rice hulls are the outermost covering of the rice and come as organic rice hulls and natural rice hulls. Rice hulls are an inexpensive byproduct of human food processing, serving as a source of fiber that is considered a filler ingredient in cheap pet foods. Insulating material-- Rice hulls themselves are a class A thermal insulating material because they are difficult to burn and less likely to allow moisture to propagate mold or fungi.