Kaolin Refining

Crude china clay contains several different types of impurities such as undecomposed felspar, granite, quartz, mica, tourmaline, garnet, etc. It is easy to remove the coarser impurities but for finer impurities a proper refining technique has to he used. Three qualities of clay are being produced in India: (1) textile clay (2) paper clay and (3) rubber clay. The standards for china clay are set by the requirements of textile, paper and rubber industries which vary from time to time. There is no standard for pottery quality clay as very little clay was so far used for whiteware manufacture. The importance of proper dilution of clay-water slurry and control over the speed of flowing mixture is explained. The importance of the removal of iron and such other staining materials is also discussed and use of a magnetic separator is suggested. Blending of different varieties of clay is very necessary to have a uniform, quality. Two simple control tests are suggested to get a uniform size refined china clay. © 1955, Taylor & Francis Group, LLC. All rights reserved