USE OF SEDIMENTARY KAOLINS OF GEORGIA IN WHITE-WARES1

Introduction.—From twenty-six different clays tested the eleven best suited to the white ware industries were washed and, after preliminary tests were run, were tried out in the different white ware industries. Laboratory Tests on Crude Clays.—Tables containing data on the physical properties of the green and burned clays are given. Laboratory Tests on Washed Clays.—Test bars and color pats were made from a typical white ware body. The usual physical tests on unburned and burned bodies are reported. Results obtained on the rate of casting and strength of the clays as compared to English and Florida clays are included in the data. Industrial Application.—Plant practice tests carried out at two floor tile and one wall tile plant are reported. Bodies containing eleven Georgia clays were tried out. Better results were obtained in the vitrified bodies than in the porous bodies. The smaller shapes gave better results than the larger. Tests on general ware and electrical porcelain art: in progress. The conclusion is reached that the Georgia sedimentary clays can be used to displace all the china clay in a vitrified tile body but less than half the china clay in plastic bodies. The color of a body is greatly improved by using washed clay: and can be further improved by the addition of cobalt stain.