After extraction the liquor was cooled to 20℃, filtered to remove any insoluble residues and the extracted liquor from successive cycles was mixed and concentrated by boiling to yield a 10% dye solution based on the initial weight of Chinese gall.
After extraction the liquor was cooled to 20℃, filtered to remove any insoluble residues and the extracted liquor from successive cycles was mixed and concentrated by boiling to yield a 10% dye solution based on the initial weight of Chinese gall.