Development of an Efficient Method in the Extraction of Silica from Rice Husk Ash

Rice is one of the major crops grown through the world. Once the paddy is separated from the rice grain, the husk is removed from the grain. This constitute one third of the total mass of grains, commonly known as “Rice Husk”. Rice husk is an agricultural waste abundantly available in producing countries. India alone produces 24 million tons of rice husks every year. Worldwide annual husk output is 80 million tons. Rice husk is considered as a form of waste from rice milling processes and are often left rot in field or burnt in open. But rice husk contains silica in range of 80-90% weight. The silica in rice husk exists in the hydrated amorphous from like silica gel which is easily extractable at a lower temperature range. Energy is also produced in the process which could be recovered in the form of heat or electricity