XVm. SOME CHEMICAL PROBLEMS OF THE CERAMIC INDUSTRY IN THE SOUTH A. V. HENRY, GEORGIA SCHOOL OP T~CHNOLOGY, A ~ A N T AGEORGIA ,
Extending through South Carolma, Georgia, and Alabama are large deposits of sedimentary kaolins which are being increasingly used in the manufacture of ceramic whitewares and refractories, and as a filler for paper, rubber, and linoleum. In recent years, these kaolins have found wide application for coating paper. Approximately three-fourths of the domestic production of such clays comes from Georgia and South Carolina. The sedimentary kaolins of the South are of several distinct types and are classifiedas hard, semi-hard, soft, and bauxitic. Due in a large measure to the ease of rehing, the soft kaolins are most generally used in the whiteware and paper trades. The hard kaolins are more commonly distributed and while they are widely utilized in the manufacture of refractories and to a lesser degree in ceramic whitewares, would find a greater market if some economical method of reiining could he developed. Refining by water flotation is the usual and probably the most efficient method. The hard kaolins are relatively dense and are essentially colloidal. These characteristics necessitate increased blunging for complete disintegration into a homogeneous slip and the colloidal nature of the clay makes filter pressing difficult. The use of electrolytes, limited aging, and heating have possibilities. Southern sedimentary kaolins have a color varying from white to ivory. For the manufacture of ivory tableware and sanitary ware and for ivorytinted paper, the kaolins having a color other than white are satisfactory. Much of the kaolin industry, however, depends upon the whiteness of the clay in both the raw and fired condition. Chemistry, in many cases, must be relied upon to bring about this color improvement. The first bauxite discovered in the United States was in northwestern Georgia in 1887. Since that time most of the known deposits of highgrade bauxite have been mined out in this state. Practically the whole of the domestic production now comes from Arkansas with small quantities being produced in Alabama. Mississippi has bauxite reserves but little has been done to develop them. I n these southeastern states are large deposits of low to medium grade bauxite varying in alumina content from 45 to 52 per cent. Deposits of this grade are satisfactory for the manufacture of bauxitic refractories. For the production of aluminum. which offersthe greatest market, a higher grade is necessary. An economical method of enriching the ore would permit the operation of many de2349
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posits which have been abandoned. The same result would be obtained if efficient methods could be devised for the extraction of aluminum from medium grade ores. Recently the Bureau of Mines issued a bulletin describ'mg the results of research in enriching low-grade bauxite by the flotation process. Partial success was obtained. The southeastern states are the country's largest producers of fullers' earth and yet the total quantity produced is relatively small compared to that easily available. Fullers' earth in the South is characterized by a high silica to alumina ratio and low specificgravity. It is peculiarly adapted as a clarifying agent for mineral and vegetable oils for which purpose most of the production is used. It appears probable that further chemical research could enlarge the uses of this earth. Other problems of definite interest to the South are concerned with chemical methods for concentrating cyanite and increased uses of feldspar.
