Rice husk ash is a hard protective covering on rice grains, which are separated from the grains during the milling process. Rice husk ash is an abundantly available waste material in all rice producing countries, and it contains about 30% to 50% of organic carbon. In the course of a typical milling process, the husk is removed from the raw grain to reveal whole brown rice, which upon further milling to remove the bran layer would yield white rice.
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